JP2024020269A - Surface emitting device, display device, method for manufacturing surface emitting device, and sealing member sheet for surface emitting device - Google Patents

Abstract

To provide a surface emitting device with an improved yield by preventing warpage during manufacturing.SOLUTION: In a surface light emitting device 1 comprising a light emitting diode substrate 4 having a light emitting diode element 3 disposed on one side of a support substrate 2, a sealing member 5 encapsulating the light emitting diode element 3 of the light emitting diode substrate 4, an anti-warping layer 7 disposed on an opposite side of the sealing member 5 to the light emitting diode substrate 4, and a diffusion member 6 disposed on an opposite side of the anti-warping layer 7 to the light emitting diode substrate, the encapsulating member 5 has a haze value of 4% or more, a thickness of 50 μm or greater and 800 μm or less, and is composed of a polyolefin resin, and a linear expansion coefficient of a material configuring the anti-warping layer 7 is -15×10-6/°C to 10×10-6/°C, and the linear expansion coefficient of the support substrate 2 is 5×10-6/°C and 100×10-6/°C, and the anti-warping layer 7 and sealing member 5 are in close contact.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a surface emitting device, a display device using the same, a method for manufacturing the surface emitting device, and a sealing member sheet for a surface emitting device.

In recent years, in the field of display devices, there has been a demand for higher quality displays. 2. Description of the Related Art Display devices using light-emitting diode elements have the advantage of high brightness and high contrast, so they have attracted attention and are being developed. Note that in the following description, a "light emitting diode" may be referred to as "LED". For example, backlights using LED elements are being developed as backlights for use in liquid crystal display devices. The above-mentioned backlight is also referred to as a mini-LED backlight.

Here, LED backlights are broadly classified into direct type and edge light type. In small to medium-sized display devices such as mobile terminals such as smartphones, edge-light type LED backlights are often used, but from the viewpoint of brightness, it is preferable to use direct-type LED backlights. It is being considered. On the other hand, in large display devices such as large-screen liquid crystal televisions, direct-type LED backlights are often used.

A direct type LED backlight has a configuration in which a plurality of LED elements are arranged on a substrate. In such direct-type LED backlights, by controlling multiple LED elements independently, so-called local dimming is realized, which adjusts the brightness of each area of the LED backlight according to the brightness and darkness of the displayed image. be able to. This makes it possible to significantly improve contrast and reduce power consumption of the display device.

International Publication No. 2013/018902

In a surface emitting device such as a direct type LED backlight, a diffusion plate or a transmissive reflection plate (hereinafter referred to as a diffusion member) is arranged above the LED element from the viewpoint of suppressing uneven brightness. In order to suppress uneven brightness, it is necessary to place the LED element and the diffusion member apart from each other. Therefore, conventionally, pins or spacers are arranged to maintain a predetermined distance between the LED element and the diffusion member (for example, Patent Document 1). FIG. 12A shows a conventional LED backlight 60 in which pins 65 are arranged to ensure the distance d between the LED elements 63 on the support substrate 62 and the diffusion member 66. FIG. 12(b1) shows a conventional LED backlight 61 in which a spacer 67 is arranged between a support substrate 62 and a diffusion member 66, and FIG. 12(b2) is a schematic plan view of the spacer 67.

When the pins and spacers are arranged in this manner, the light emitted from the LED element may be blocked or reflected by the pins or spacers, resulting in uneven brightness. Therefore, for example, in Patent Document 1, it was necessary to further dispose a diffusion plate or the like above the transmissive reflection plate, making it difficult to make the module thin. As described above, the conventional surface emitting device has a problem in that it is difficult to achieve uniformity of brightness within the surface and a reduction in thickness at the same time.

In order to solve such problems, it is also possible to arrange a sealing member having light diffusing properties between the LED support substrate that supports the LEDs and the diffusion member. This makes it possible to reduce the thickness while improving the in-plane uniformity of brightness, and it is possible that the above-mentioned problems can be solved. However, in the surface emitting device including the LED support substrate and the sealing member, there is a possibility that warping may occur during manufacturing.

The present disclosure has been made in view of the above-mentioned problems, and its main purpose is to provide a surface emitting device that can prevent warpage during manufacturing and improve the yield during manufacturing of the surface emitting device. purpose.

In order to achieve the above object, the present disclosure includes a sealing member that seals a light emitting diode element, a sealing member disposed on the sealing member, and a linear expansion coefficient of −15×10 ⁻⁶ /°C or more of 10×10 Provided is a sealing member sheet for a surface emitting device, which has a warpage prevention layer having a temperature of ^-6 /°C or less.

The present disclosure also provides a surface light emitting device, which is formed by laminating a sealing member for sealing a light emitting diode element and an anti-foaming layer disposed on one side of the sealing member, and is used in a surface light emitting device. Provided is a sealing member sheet for a surface light emitting device, which is a sealing member sheet for a surface light emitting device, in which the elastic modulus of a material constituting the anti-foaming layer is 500 MPa or more.

The present disclosure provides a surface light emitting device used in a surface light emitting device, in which a sealing member for sealing a light emitting diode element and a foaming prevention layer disposed on one side of the sealing member are laminated. Provided is a sealing member sheet for a surface emitting device, in which a material constituting the anti-foaming layer has a melting point of 140° C. or higher.

The present disclosure also provides a light-emitting diode substrate having a support substrate and a light-emitting diode element disposed on one surface side of the support substrate, and a light-emitting diode substrate disposed on a surface of the light-emitting diode substrate facing the light-emitting diode element, the light-emitting diode a sealing member for sealing the element; a warpage prevention layer disposed on a surface of the sealing member opposite to the light emitting diode substrate; and a warpage prevention layer disposed on a surface of the warpage prevention layer opposite to the light emitting diode substrate. A surface emitting device having a diffusion member disposed, wherein the sealing member has a haze value of 4% or more, is thicker than the thickness of the light emitting diode element, and is made of a material constituting the anti-warpage layer. Provided is a surface emitting device having a linear expansion coefficient of -15×10 ⁻⁶ /°C or more and 10×10 ⁻⁶ /°C or less.

The present disclosure further includes a support substrate, and a light emitting diode substrate having a light emitting diode element disposed on one surface side of the support substrate; a sealing member for sealing the element; a diffusion member disposed on a surface of the sealing member opposite to the light emitting diode substrate; and a diffusion member disposed on a surface of the light emitting diode substrate opposite to the light emitting diode element. A surface emitting device having a warpage prevention layer, wherein the sealing member has a haze value of 4% or more, is thicker than the thickness of the light emitting diode element, and is made of a material constituting the warpage prevention layer. Provided is a surface emitting device whose linear expansion coefficient is equal to or greater than that of a material constituting the sealing member.

The present disclosure provides a display device including a display panel and the above-described surface emitting device disposed on the back surface of the display panel.

The present disclosure provides a method for manufacturing the above-mentioned surface emitting device, wherein the anti-warpage layer, the sealing member, and the light-emitting diode substrate arranged such that the light-emitting diode element is on the sealing member side are arranged in this order. Provided is a method for manufacturing a surface emitting device, which includes the steps of preparing an arranged laminate and thermocompression bonding the laminate.

The present disclosure is a method for manufacturing the above-mentioned surface emitting device, which includes a step of thermocompression bonding a first laminate in which the warpage prevention layer and the sealing member are laminated, and a step of thermocompression bonding the thermocompression bonded first laminate. thermocompression-bonding a second laminate on which the light emitting diode substrate, in which the light emitting diode element is arranged so as to face the sealing member, is bonded to the surface on the sealing member side of the surface emitting device. A manufacturing method is provided.

The present disclosure has the advantage that it is possible to provide a surface emitting device that can prevent warping during manufacturing and improve the yield during manufacturing of the surface emitting device.

FIG. 1 is a schematic cross-sectional view illustrating a surface emitting device according to the present disclosure. FIG. 3 is a process diagram showing an example of a method for forming a sealing member in the present disclosure. It is a schematic sectional view illustrating the structure of the sealing member of the surface emitting device in this indication. It is a schematic sectional view showing an example of a second diffusion member. It is a schematic sectional view showing an example of a surface emitting device provided with the second diffusion member in this indication. 3 is a graph illustrating a transmitted light intensity distribution. FIG. 7 is a schematic plan view and a cross-sectional view showing an example of the first aspect of the reflective structure of the second diffusion member. It is a schematic plan view and sectional view showing an example of the 2nd aspect of the reflection structure of the 2nd diffusion member. It is a schematic sectional view showing another example of the 2nd aspect of the reflective structure of the 2nd diffusion member. It is a schematic sectional view showing other examples of the surface emitting device in this indication. FIG. 1 is a schematic diagram showing an example of a display device of the present disclosure. FIG. 2 is a schematic cross-sectional view of a conventional LED backlight.

Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be implemented in many different embodiments, and should not be construed as being limited to the description of the embodiments exemplified below. In addition, in order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each member compared to the embodiment, but this is only an example, and the interpretation of this disclosure is It is not limited to. In addition, in this specification and each figure, the same elements as those described above with respect to the previously shown figures are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

In this specification, when expressing the manner in which another member is placed on top of a certain member, when it is simply expressed as "on the surface side", unless otherwise specified, it means that it is in contact with a certain member, directly above or directly below it. This includes both a case where another member is placed above or below a certain member, and a case where another member is placed above or below a certain member via another member.

Further, in this specification, terms such as "sheet", "film", "plate", etc. are not distinguished from each other based only on the difference in designation. For example, the term "sheet" is used to include members such as films and plates.

As described above, the newly proposed surface emitting device including the LED support substrate and the sealing member has a problem that warpage may occur during manufacturing.

In order to solve the above-mentioned new problem, the present inventors have conducted extensive studies and found that the reason why warpage occurs is that the linear expansion coefficients of the LED support substrate and the sealing member are different after they are bonded by thermocompression during manufacturing. I found out that this was the cause. Thereby, the above-mentioned problem is solved by arranging the warpage prevention layer whose coefficient of linear expansion has a predetermined relationship with respect to the sealing member at an appropriate position with respect to the sealing member.

A. Surface Emitting Device The surface emitting device according to the present disclosure can be divided into three aspects. Each embodiment will be explained separately below.

I. First Embodiment Hereinafter, a surface emitting device of this embodiment will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of a surface emitting device according to this embodiment. As illustrated in FIG. 1, the surface emitting device 1 includes a support substrate 2, an LED substrate 4 having an LED element 3 disposed on one side of the support substrate 2, and A sealing member 5 disposed on the surface side and sealing the LED element 3, a diffusion member 6 disposed on the surface side of the sealing member 5 opposite to the LED substrate 4 side, and the above-mentioned sealing member 5 and the above-mentioned and a warpage prevention layer 7 disposed between the diffusion member 6 and the diffusion member 6. The sealing member 5 in this embodiment has a haze value of 4% or more, a thickness d greater than the thickness of the LED element 3, and a linear expansion coefficient of the material constituting the warpage prevention layer 7: - It is characterized by being within the range of 15×10 ⁻⁶ /°C or more and 10×10 ⁻⁶ /°C or less.

Generally, in a surface emitting device, when a means such as thermocompression bonding is used to bond the sealing member and the LED substrate, the line between the LED substrate and the sealing member is removed during subsequent cooling. Warpage may occur due to differences in expansion coefficients.
Further, when the surface emitting device is used at extremely high or low temperatures, warpage may occur due to the difference in linear expansion coefficient between the LED substrate and the sealing member.

The present embodiment has been made to solve such problems, and the warpage prevention layer is disposed between the sealing member and the diffusion member, and the wires of the material constituting the warpage prevention layer are arranged between the sealing member and the diffusion member. By having an expansion coefficient in the range of -15×10 ⁻⁶ /°C or more and 10×10 ⁻⁶ /°C or less, the above-mentioned problem of warping can be solved.

Further, in the conventional surface emitting device, there was a problem in that, for example, when the surface emitting device was used at an extremely high temperature for a long time, air bubbles were generated between the LED substrate and the sealing member. This may be caused by gas generated from the LED board due to heating, or when a reflective layer, etc. is provided on the LED board, air may be present between the LED board and the reflective layer due to air entrapment at the interface. This occurs due to reasons such as oozing along the surface.

The LED element sealed in the sealing member has a light extraction efficiency compared to an unsealed LED element because the light emitting surface of the sealing member and the LED element are directly joined, and the difference in refractive index at the interface is small. will improve. However, if such bubbles exist, the above-mentioned improvement in light extraction efficiency cannot be achieved, resulting in a problem that the luminous efficiency of the surface emitting device is reduced.
In this embodiment, the above-mentioned problem is also solved by providing the above-mentioned warpage prevention layer.
Hereinafter, the surface emitting device of this embodiment will be explained for each configuration.

1. Sealing Member The sealing member in this embodiment has a haze value of 4% or more and is thicker than the LED element. The sealing member has optical transparency and is arranged on the light emitting surface side of the LED board.

(1) Haze value The haze value of the sealing member in this embodiment is 4% or more, preferably 8% or more, and more preferably 10% or more. If the value is smaller than the above value, uneven brightness cannot be suppressed. On the other hand, the upper limit is not particularly limited, but is, for example, 85% or less, preferably 60% or less, and more preferably 30% or less. In this specification, the haze value is the value of the entire sealing member, and the sealing member is cut out from the surface emitting device and measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory) according to JIS K7136:2000. It can be measured by a method based on .

Methods for adjusting the haze value to obtain the above-mentioned haze value include, but are not particularly limited to, a method that utilizes the degree of crystallinity of the resin, a method that changes the content of fine particles in the resin, and the like. Among these, a method of adjusting the crystallinity of the resin is preferred. This is because when the haze value is increased by increasing the crystallinity of the resin, the effect of reducing straight transmitted light can be obtained.

(2) Thickness The thickness of the sealing member in this embodiment may be thicker than the above-mentioned LED element, and specifically, it is preferably 50 μm or more, more preferably 80 μm or more, and particularly preferably It is 200 μm or more.
On the other hand, the thickness of the LED element is preferably 800 μm or less, more preferably 750 μm or less, particularly preferably 700 μm or less.

Note that "thickness" in this specification is measured using a contact type film thickness measuring device (Thickness Gauge 547-301 manufactured by Mitutoyo). The same applies to measurements of sizes such as "size".

If the thickness is smaller than the above, the thickness is insufficient and the light emitted from the LED element cannot be diffused over the entire light emitting surface, making it impossible to uniformly improve the brightness within the surface. Moreover, if the thickness is larger than the above-mentioned thickness, it is impossible to achieve a thinner structure.

(3) Material of the sealing member The material included in the sealing member in this embodiment is not particularly limited as long as it has the haze value described above, but thermoplastic resins and the like are preferable. By using a thermoplastic resin, for example, the haze value can be adjusted higher than when using a thermosetting resin, and furthermore, the sealing member can be formed at a low temperature.

Further, when the sealing member contains a thermoplastic resin, the sealing member is in the form of a sheet (hereinafter sometimes referred to as a sealing member sheet) made of a sealing material composition containing a thermoplastic resin. ) can be used. FIG. 2 is a process diagram showing an example of a method for forming a sealing member in this embodiment. For example, as shown in FIG. 2(a), an LED board 4 and a sealing member sheet 5a having a warpage prevention layer 7 disposed on one surface are prepared, and on the surface of the LED board 4 on the LED element 3 side, The surface of the sealing member sheet 5a opposite to the warpage prevention member 7 is laminated. Next, by press-bonding them using, for example, a vacuum lamination method, the sealing member 5 with the anti-warp layer 7 disposed on one side and the LED substrate 4 are laminated, as shown in FIG. 2(b). Can form things.

On the other hand, when the sealing member contains a curable resin such as a thermosetting resin or a photocurable resin, a liquid sealing material is usually used. When a liquid sealant is used, a phenomenon may occur in which the end portions are thicker or thinner than the center portion due to surface tension or the like. In addition, in the case of a curable resin, volume shrinkage is likely to occur during curing, and as a result, the thickness of the sealing member after curing may become uneven between the center and end portions. If the thickness of the sealing member is uneven in this way, uneven brightness may occur.

On the other hand, when using a sheet-shaped encapsulant, the thickness distribution of the coating film due to surface tension, which occurs when a liquid encapsulant is used, and the thickness distribution due to heat shrinkage or light shrinkage occur. It is possible to avoid occurrence of surface irregularities of the sealing member, such as occurrence of surface irregularities. Therefore, a sealing member with good flatness can be obtained, and a higher quality display device can be provided.

(a) Thermoplastic resin In this embodiment, as the thermoplastic resin, olefin resin, ethylene-vinyl acetate copolymer (EVA), polyvinyl butyral resin, etc. can be used.

Among these, the thermoplastic resin is preferably an olefin resin. This is because the olefin resin does not particularly easily produce components that degrade the LED substrate, and has a low melt viscosity, so that the above-mentioned LED element can be sealed well. Also, among the olefin resins, polyethylene resins, polypropylene resins, and ionomer resins are preferred.

Here, the polyethylene resin in this specification includes not only ordinary polyethylene obtained by polymerizing ethylene, but also polyethylene obtained by polymerizing a compound having an ethylenically unsaturated bond such as α-olefin. These include resins, resins obtained by copolymerizing a plurality of different compounds having ethylenically unsaturated bonds, and modified resins obtained by grafting other chemical species onto these resins.

In particular, the sealing member in this embodiment preferably uses a polyethylene resin having a density of 0.870 g/cm ³ or more and 0.930 g/cm ^{3 or} less as the base resin from the viewpoint of obtaining the above-mentioned haze value. In particular, it is preferable to use a polyethylene resin having a density of 0.890 g/cm ³ or more and 0.930 g/cm ³ or less as the base resin. When the sealing member is a multilayer member as described below, it is preferable to use a polyethylene resin having the above density as the base resin of the core layer. Note that the density is measured according to JIS Z 8807:2012.
Here, in the present disclosure, the term "base resin" refers to a resin having the largest content mass ratio among the resin components of the resin composition in a resin composition containing the base resin. .

A silane copolymer (hereinafter also referred to as "silane copolymer") obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as a comonomer can be preferably used. By using such a resin, higher adhesion between the LED board and the sealing member can be obtained. As the silane copolymer, those described in JP-A-2018-50027 can be used.

(b) Melting Point The melting point of the thermoplastic resin used in this embodiment is not particularly limited as long as it can seal the LED element, but is preferably, for example, 90° C. or higher and 135° C. or lower. Among these, it is preferable to use a thermoplastic resin that does not soften due to heat generated during LED light emission, and has a temperature of 90° C. or more and 120° C. or less.

The melting point of the thermoplastic resin can be measured, for example, by differential scanning calorimetry (DSC) in accordance with the plastic transition temperature measuring method (JISK7121:2012).
When multiple thermoplastic resins are included, this is the value with the highest melting point. When the sealing member is a multilayer member as described below, it is preferable to use a thermoplastic resin as the base resin of the core layer having the above-mentioned melting point.

(c) Melt mass flow rate (MFR)
In addition, the thermoplastic resin in this embodiment has a melt viscosity that allows it to follow the irregularities of the LED elements and other members arranged on one side of the LED board and enter the gaps by heating. Those having the following are preferably used.

Specifically, the melt mass flow rate (MFR) of the thermoplastic resin used is preferably 0.5 g/10 minutes or more and 40 g/10 minutes or less, and 2.0 g/10 minutes or more and 40 g/10 minutes or less. More preferably, the amount is 2.0 g/10 minutes or more and 20 g/10 minutes or less. By having an MFR within the above range, it is possible to enter the gap between LED elements, etc., and exhibit sufficient sealing performance, and furthermore, the sealing member has excellent adhesion to the LED board. This is because it is possible.

Note that MFR in this specification refers to a value measured according to JIS K7210-1:2014 A method at 190° C. and a load of 2.16 kg. However, the MFR of polypropylene resin refers to the MFR value at 230° C. and a load of 2.16 kg, also according to JIS K7210-1:2014 A method.

Regarding the MFR when the sealing member is a multilayer member as described later, the measurement is performed using the above measurement method while all the layers are in a multilayer state, and the obtained measurement value is used as the multilayer member. The MFR value shall be .

d) Tensile Modulus Furthermore, the thermoplastic resin in this embodiment preferably has a tensile modulus of 20 MPa or more and 300 MPa or less, particularly preferably 20 MPa or more and 200 MPa or less at room temperature (25°C). . The sealing member can exhibit sufficient adhesion to the LED substrate and has excellent impact resistance, for example, when an external impact is applied to the surface emitting device. When the sealing member is a multilayer member as described later, it is preferable to use a thermoplastic resin as the base resin of the core layer having the above elastic modulus. For the above tensile modulus, a value measured according to JIS K7127:1999 is used.

The elastic modulus is measured by tensile measurement as described below.
・Measuring device: Instron universal material testing machine 5565
・Load cell: 1kN
・Sample width: 10mm
・Distance between chucks: 50mm
・Speed: 300mm/min

In addition to the thermoplastic resin, additives such as an antioxidant and a light stabilizer may be added to the sealing member.

e) Coefficient of Linear Expansion In this embodiment, the sealing member has a higher coefficient of linear expansion than the LED substrate described below. Therefore, as described above, after the sealing member and the LED board are thermocompressed in the manufacturing process, the shrinkage rate of the sealing member becomes greater than the shrinkage rate of the LED board, and as a result, the sealing member side is dented. A problem arises in that warping occurs.
The lower limit of the linear expansion coefficient of the material constituting the sealing member used in this embodiment is preferably 20 x 10 ^-6 /°C or more, particularly 150 x 10 ^-6 /°C or more. is preferred. On the other hand, the upper limit is preferably 1500×10 ⁻⁶ /°C or less, particularly preferably 1000×10 ⁻⁶ /°C or less. Specifically, it is preferably within the range of 20 × 10 ^-6 / °C or more and 1500 × 10 ^-6 / °C or less, particularly preferably 20 × 10 ^-6 / °C or more and 1000 × 10 ^-6 / °C or less, Among these, it is preferably within the range of 150×10 ⁻⁶ /°C or more and 1000×10 ⁻⁶ /°C or less. For the linear expansion coefficient, a value measured according to JIS K7197:2012 is used.

(4) Structure of the sealing member The sealing member in the surface emitting device in this embodiment may be a single-layer member in which the sealing member 5 is composed of a single resin layer, as shown in FIG. 1, for example. Often, as shown in FIG. 3, the sealing member 5 includes a plurality of resin layers (FIG. 3(a)) including a core layer 51 and a skin layer 52 disposed on at least one surface of the core layer 51. ) may be a multilayer member in which two layers (in FIG. 3(b), three layers) are laminated. In particular, a two-layer structure including a core layer and the like and a skin layer disposed on the LED substrate side of the core layer is preferable. Note that FIG. 3 shows an example in which a reflective layer R is arranged around the LED element 3.

When the sealing member in this embodiment is a multilayer member with a two-layer structure having a core layer and a skin layer disposed on the LED substrate side of the core layer, the film thickness ratio of the skin layer and the core layer (skin When the ratio of skin layer to core layer is 1:X, the lower limit of X is preferably 0.1 or more, particularly preferably 0.5 or more. On the other hand, the lower limit is preferably 10 or less, particularly preferably 6 or less. That is, the ratio is preferably 1:0.1 to 1:10, particularly preferably 1:0.5 to 1:6.

In addition, when the sealing member in this embodiment is a multilayer member with a three-layer structure, the film thickness ratio between the skin layer and the core layer (skin layer: core layer: skin layer) is set to 1:Y:1. , Y is preferably 1 or more, particularly preferably 2 or more. On the other hand, Y is preferably 10 or less, particularly preferably 8 or less. That is, the film thickness ratio between the skin layer and the core layer (skin layer: core layer: skin layer) is preferably 1:1:1 to 1:10:1, particularly preferably 1:2:1 to 1:8. :1.

When the sealing member in this embodiment is a multilayer member, it is preferable that the core layer and the skin layer have the above-mentioned thermoplastic resins having different density ranges, melting points, etc. as base resins. This is because it becomes easy to ensure the above-mentioned haze value with the core layer and ensure adhesion to the LED board and molding characteristics with the skin layer.

In the case of the above-described multilayer member, it is possible to use a normally expensive material with good adhesion and molding properties that allow it to fit into gaps between LED elements, etc., for the skin layer located on the LED substrate side of the multilayer member. In the above multilayer member, the material constituting the skin layer disposed on the LED board side is not particularly limited as long as it has high adhesion and molding properties, but in the case of the above thermoplastic resin , the above-mentioned silane copolymers, etc. are preferably used. Further, in the case of the thermoplastic resin, the material preferably contains the olefin resin and a silane coupling agent. Note that additives such as antioxidants and light stabilizers may be added to this layer.

(5) Preferred sealing member The sealing member in this embodiment is preferably a multilayer member composed of a plurality of layers including a core layer and a skin layer disposed on at least one outermost surface, The core layer preferably has a base resin of polyethylene resin having a density of 0.900 g/cm ³ or more and 0.930 g/cm ³ or less, and the skin layer has a density of 0.875 g/cm ³ or more and 0.910 g/cm 3 or less. It is preferable that the base resin be a polyethylene resin having a density of ³ or less and a density lower than that of the base resin for the core layer.

As the base resin for the core layer, low density polyethylene resin (LDPE), linear low density polyethylene resin (LLDPE), or metallocene linear low density polyethylene resin (M-LLDPE) can be preferably used. . Among these, from the viewpoint of long-term reliability, low-density polyethylene resin (LDPE) can be particularly preferably used as the base resin for the core layer.

The density of the polyethylene resin used as the base resin for the core layer is 0.900 g/cm ³ or more and 0.930 ^g /cm ³ or less, more preferably 0.920 g/cm ³ or less. This is because by setting the density of the base resin for the core layer within the above range, the haze value of the sealing member in this embodiment can be made equal to or higher than the above specific value. Moreover, the sealing member can be provided with necessary and sufficient heat resistance without undergoing crosslinking treatment.

The melting point of the polyethylene resin used as the base resin for the core layer is preferably 90°C or more and 135°C or less, more preferably 90°C or more and 115°C or less. By setting the melting point within the above range, the heat resistance and molding properties of the sealing member can be maintained within preferable ranges. Note that by adding a high melting point resin such as polypropylene to the core layer sealing material composition, it is possible to raise the melting point of the sealing member to about 165°C. In this case, the content of polypropylene is preferably 5% by mass or more and 40% by mass or less based on the total resin components of the core layer.

The polypropylene contained in the core layer is preferably a homopolypropylene (homoPP) resin. Homo-PP is a polymer consisting only of polypropylene and has high crystallinity, so it has higher rigidity than block PP or random PP. By using this as an additive resin to the sealing material composition for the core layer, the dimensional stability of the sealing member can be improved. In addition, the homo PP used as the additive resin to the encapsulant composition for the core layer has an MFR of 5 g/10 minutes or more and 125 g/ Preferably it is 10 minutes or less. If the MFR is too small, the molecular weight will become too large and the rigidity will become too high, making it difficult to ensure the preferable and sufficient flexibility of the encapsulant composition. Furthermore, if the MFR is too large, fluidity during heating will not be sufficiently suppressed, and the sealing member sheet will not be able to have sufficient heat resistance and dimensional stability.

The melt mass flow rate (MFR) of the polyethylene resin used as the base resin for the core layer is preferably 1.0 g/10 minutes or more and 7.5 g/10 minutes or less at 190° C. and a load of 2.16 kg. More preferably, it is 1.5 g/10 minutes or more and 6.0 g/10 minutes or less. By setting the MFR of the base resin for the core layer within the above range, the heat resistance and molding properties of the sealing member can be maintained within preferable ranges. In addition, it is possible to sufficiently improve processing suitability during film formation and contribute to improvement in productivity of the sealing member.

The content of the base resin based on the total resin components of the core layer is 70% by mass or more and 99% by mass or less, preferably 90% by mass or more and 99% by mass or less. Other resins may be included as long as the base resin is included within the above range.

The base resin for the skin layer of the sealing member may be low density polyethylene resin (LDPE), linear low density polyethylene resin (LLDPE), or metallocene resin, similar to the sealant composition for the core layer. Linear low density polyethylene resin (M-LLDPE) can be preferably used. Among them, from the viewpoint of molding properties, metallocene-based linear low-density polyethylene resin (M-LLDPE) can be particularly preferably used as the sealant composition for the skin layer.

The density of the polyethylene resin used as the base resin for the skin layer is 0.875 g/cm ³ or more and 0.910 g/cm ³ or less, more preferably 0.899 g/cm ³ or less. By setting the density of the base resin for the skin layer within the above range, the adhesion of the sealing member can be maintained within a preferable range.

The melting point of the polyethylene resin used as the base resin for the skin layer is preferably 50°C or more and 100°C or less, more preferably 55°C or more and 95°C or less. By setting it within the above range, the adhesion of the sealing member can be further reliably improved.

The melt mass flow rate (MFR) of the polyethylene resin used as the base resin for the skin layer is preferably 1.0 g/10 minutes or more and 7.0 g/10 minutes or less at 190° C. and a load of 2.16 kg, More preferably, it is 1.5 g/10 minutes or more and 6.0 g/10 minutes or less. By setting the MFR of the base resin for the skin layer within the above range, the adhesion of the sealing member can be maintained within a more preferable range. Further, it is possible to sufficiently improve processing suitability during film formation and contribute to improvement in productivity of the sealing member.

The content of the base resin based on the total resin components for the skin layer is 60% by mass or more and 99% by mass or less, preferably 90% by mass or more and 99% by mass or less. Other resins may be included as long as the base resin is included within the above range.

In all of the encapsulant compositions explained above, a silane copolymer obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as a comonomer is added to each encapsulant composition as necessary. It is more preferable to contain a certain amount. In such a graft copolymer, the degree of freedom of the silanol groups that contribute to adhesive strength is increased, so that the adhesiveness of the sealing member to other members can be improved.

Examples of the silane copolymer include the silane copolymers described in JP-A No. 2003-46105. By using the above-mentioned silane copolymer as a component of the sealant composition, it has excellent strength, durability, etc., as well as weather resistance, heat resistance, water resistance, light resistance, and other various properties, and furthermore, It has extremely excellent heat fusion properties without being affected by manufacturing conditions such as heat-pressure bonding when arranging the sealing member, and the sealing member can be stably obtained at low cost.

As the silane copolymer, any of random copolymers, alternating copolymers, block copolymers, and graft copolymers can be preferably used, but graft copolymers are preferable. More preferred is a graft copolymer in which polymerizable polyethylene is used as the main chain and an ethylenically unsaturated silane compound is polymerized as the side chain. In such a graft copolymer, the degree of freedom of the silanol groups that contribute to adhesive strength is increased, so that the adhesiveness of the sealing member can be improved.

The content of the ethylenically unsaturated silane compound when constituting the copolymer of α-olefin and the ethylenically unsaturated silane compound is, for example, 0.001% by mass or more 15% by mass based on the total mass of the copolymer. It is desirable that the amount is not more than 0.01% by mass and not more than 10% by mass, particularly preferably not less than 0.05% by mass and not more than 5% by mass. If the content of the ethylenically unsaturated silane compound constituting the copolymer of α-olefin and ethylenically unsaturated silane compound is high, it will have excellent mechanical strength and heat resistance, but if the content becomes excessive, , tensile strain, thermal adhesion, etc. tend to be inferior.

The content of the silane copolymer based on the total resin components of the encapsulant composition for the core layer is 0% by mass or more and 20% by mass or less for the encapsulant composition for the skin layer. In the composition, it is preferably 5% by mass or more and 40% by mass or less. In particular, it is more preferable that the sealant composition for the skin layer contains 5% by mass or more of the silane copolymer. Note that the amount of silane modification in the above-mentioned silane copolymer is preferably about 0.1% by mass or more and 2.0% by mass or less. The preferable content range of the silane copolymer in the above-mentioned sealant composition is based on the assumption that the above-mentioned amount of silane modification is within this range, and may be finely adjusted as appropriate according to fluctuations in the amount of modification. desirable.

Additives such as antioxidants and light stabilizers may be added to all the layers of the sealing member.
Moreover, an adhesion improver can be added as appropriate. By adding an adhesion improver, the durability of adhesion to other members can be made higher. As the adhesion improver, a known silane coupling agent can be used, including vinyl trimethoxysilane, vinyltriethoxysilane, an epoxy group-containing silane coupling agent, or a mercapto group-containing silane. Coupling agents can be used particularly preferably.

(6) Total light transmittance The sealing member in this embodiment is not particularly limited as long as it can function as a surface emitting device, but it is preferably 70% or more, especially 80% or more. preferable. Note that the total light transmittance of the sealing member can be measured, for example, by a method based on JIS K7361-1:1997.

(7) Method for forming a sealing member As described above, the sealing member in this embodiment is formed using a sealing member sheet made of a sealing material composition containing the above-mentioned thermoplastic resin and other components. can do.
The above-mentioned sealing member sheet is formed into a sheet by molding a sealing material composition by a conventionally known method.

When the sealing member is a multilayer member, a core layer and a skin layer disposed on one surface of the core layer are formed to have a predetermined thickness using respective sealant compositions for the core layer and the skin layer. By molding a multilayer film having a layered structure, it is possible to manufacture a sealing member 5 having a two-layered structure of a core layer 51 and a skin layer 52, as shown in FIG. 3(a), for example. Alternatively, it is also possible to form a multilayer film with a three-layer structure in which skin layers are arranged on both surfaces of the core layer. Thereby, for example, as shown in FIG. 3(b), a sealing member 5 having a three-layer structure of a skin layer 52, a core layer 51, and a skin layer 52 can be manufactured. Note that the configurations other than the sealing member 5 and the reflective layer R in FIG. 3 are the same as those in FIG. 1, so a description thereof will be omitted here.

2. Warpage Prevention Layer The warpage prevention layer in this embodiment is a layer disposed between the sealing member and the diffusion member described below.

In this embodiment, warping can be prevented by setting the coefficient of linear expansion of the material constituting the warp prevention layer in a predetermined range in a high temperature region. The reason why warping can be prevented by setting the linear expansion coefficient of the material constituting the warpage prevention layer within a predetermined range is as follows.

That is, when manufacturing a surface emitting device, it may include a step of thermocompression bonding the sealing member and the LED board, but the sealing member shrinks more than the LED substrate when cooled after the thermocompression bonding. At this time, since a warpage prevention layer with a small coefficient of linear expansion is arranged on the side of the sealing member opposite to the LED substrate, it is possible to reduce the degree of shrinkage on the side of the sealing member, and as a result, , it becomes possible to suppress the occurrence of warpage.

Furthermore, in this embodiment, by arranging the warpage prevention layer, it is possible to suppress the deformation of the sealing member that occurs when bubbles are generated in the region where bubbles are generated, and thereby, as described above, Furthermore, it is possible to prevent the generation of air bubbles between the sealing member and the LED board. In particular, the above effects can be effectively obtained by using a warpage prevention layer having a predetermined elastic modulus and a predetermined melting point.

a) Coefficient of Linear Expansion The coefficient of linear expansion of the material constituting the warpage prevention layer in the present disclosure is within the range of -15×10 ⁻⁶ /°C or more and 10×10 ⁻⁶ /°C or less.
In the present disclosure, it is particularly preferable that the lower limit of the linear expansion coefficient is −10×10 ⁻⁶ /° C. or more. On the other hand, the upper limit is preferably 5×10 ⁻⁶ /°C or less, particularly preferably 0 or less. That is, it is preferably -10x10 ^-6 /°C or more and 5x10 ^-6 /°C or less, particularly preferably -10x10 ^-6 /°C or more and 0x10 ^-6 /°C or less. On the other hand, considering the materials used, etc., the temperature is usually -10×10 ^-6 /°C or more and 5×10 ^-6 /°C or less. If it is smaller than this, it will cause reverse warping. On the other hand, if it is larger than this, the warpage prevention effect will be insufficient.

The linear expansion coefficient in this embodiment is measured by the following method.
For sheets cut to 5 mm x 20 mm, dimensional changes were measured when the temperature was raised and cooled to room temperature in accordance with JIS K 7197:2012, and the linear expansion coefficient from 100 ° C to 25 ° C was averaged and calculated. . The linear expansion coefficient here takes a positive value during contraction and a negative value during expansion. The measurement was performed using the following measuring device and measurement conditions.
・Measuring device: Seiko Instruments thermomechanical device (TMA/SS-6000)
・Constant load tension mode: 0.1mN
・Measurement temperature range: -50℃ or higher and 160℃ or lower ・Linear expansion coefficient calculation temperature range: 25℃ or higher and 100℃ or lower

b) Elastic modulus The elastic modulus of the warpage prevention layer used in this embodiment is preferably 500 MPa or more, particularly preferably 1000 MPa or more, and especially preferably 4000 MPa or more.
This is because if the elastic modulus is lower than the above range, the effect of suppressing bubble generation and the effect of preventing warping will be reduced. Note that the pressure is 5,500 MPa or less when commonly used materials are taken into consideration.

In this embodiment, the elastic modulus is measured by the tensile measurement described below.
(Measuring method)
・Measuring device: Instron universal material testing machine 5565
・Load cell: 1kN
・Sample width: 10mm
・Distance between chucks: 50mm
・Speed: 300mm/min

c) Thickness The thickness of the anti-warpage layer in this embodiment is preferably in the range of 35 μm or more and 188 μm or less, particularly preferably in the range of 50 μm or more and 150 μm or less, particularly preferably in the range of 100 μm or more and 125 μm or less. Within the above range, it is possible to obtain the effect of preventing warpage and the effect of suppressing the generation of bubbles, and it does not prevent the device from being made more compact.

d) Transmittance and Haze Value The haze value of the warpage prevention layer in this embodiment is preferably 40% or less, particularly preferably 20% or less, and particularly preferably 10% or less.
Within the above range, it is possible to improve the in-plane uniformity of brightness. Note that when the haze value exceeds the above range, the light is absorbed while being scattered inside the sealing member, resulting in a decrease in brightness.
The same method as the method for measuring the haze value of the sealing member described above can be used to measure the haze value.

On the other hand, the total light transmittance of the warpage prevention layer in this embodiment is preferably 80% or more, particularly preferably 90% or more. By having such a high total light transmittance, it is possible to prevent a decrease in brightness of the surface emitting device.

Here, the total light transmittance of the warpage prevention layer can be measured in accordance with JIS K7361-1, and can be measured using a haze meter HM150 manufactured by Murakami Color Research Institute.

e) Melting point The melting point of the warpage prevention layer in this embodiment is preferably 140°C or higher, particularly preferably 260°C or higher. Note that the upper limit is 350° C. or less, taking into consideration the materials normally used.
The melting point in this embodiment can be measured, for example, by differential scanning calorimetry (DSC) in accordance with the plastic transition temperature measuring method (JISK7121).

In this embodiment, since the warpage prevention layer has the above-mentioned melting point, it is possible to effectively prevent the generation of bubbles even when the surface emitting device is used for a long time in a high temperature environment.

f) Materials The materials constituting the warpage prevention layer used in this embodiment are not particularly limited as long as they have the above characteristics, but include polyolefins, polyesters, celluloses, acrylic resins, and polyimide resins. I can do it. Examples of polyolefins include polypropylene (PP). Examples of polyester include polytetraethylene terephthalate (PET) and polyethylene naphthalate (PEN). Examples of celluloses include triacetylcellulose (TAC).
In this embodiment, PP and PET are particularly preferred from the viewpoint of versatility.

g) Others In this embodiment, it is preferable that the warpage prevention layer and the sealing member are in close contact with each other. This is because the warpage prevention effect can be exhibited more efficiently. In this embodiment, "the anti-warp layer and the sealing member are in close contact with each other" refers to a state in which they do not peel off under their own weight when both are taken out.
Specifically, it is preferable that the adhesion strength is 1N or more. As a method for measuring adhesive strength, the following method can be used in accordance with JIS K 6854-2: 1999.

(Measuring method)
The sealing member that is in close contact with the PCB substrate is cut out to a width of 25 mm, and a vertical peel test (300 mm/min) is performed using a peel tester (Tensilon Universal Tester RTF-1150-H) to measure the adhesion strength.

In order to bring the warpage prevention layer and the sealing member into close contact with each other, examples include a method of arranging them via an adhesive layer, and a method of melting and bringing them into close contact by thermocompression bonding.

3. LED Board The LED board in this embodiment is a member in which a plurality of LED elements are arranged on one side of a support substrate.

(1) LED element The LED element is a member disposed on one side of the support substrate, and functions as a light source.
The LED element is not particularly limited as long as it can emit white light when used as a surface emitting device, and examples include LED elements that can emit white, blue, ultraviolet, or infrared light.

The LED element can be a chip-shaped LED element. The form of the LED element may be, for example, a light emitting part (also referred to as an LED chip) itself, or a package LED (also referred to as a chip LED) such as a surface-mounted type or a chip-on-board type. A packaged LED can have, for example, a light emitting part and a protective part that covers the light emitting part and contains resin. Specifically, when the LED element is the light emitting part itself, for example, a blue LED element, an ultraviolet LED element, or an infrared LED element can be used as the LED element. Moreover, when the LED element is a package LED, a white LED element can be used as the LED element, for example.

When the surface emitting device of this embodiment is one that irradiates white light by combining an LED element and the wavelength conversion member, the LED element is a blue LED element, an ultraviolet LED element, or an infrared LED element. is preferred. A blue LED element can generate white light, for example, in combination with a yellow phosphor, or in combination with a red phosphor and a green phosphor. Additionally, ultraviolet LED elements can generate white light when combined with, for example, red, green, and blue phosphors. Among these, it is preferable that the LED element is a blue LED element. This is because the surface emitting device of this embodiment can emit white light with high brightness.

Further, when the LED element is a white LED element, the white LED element is appropriately selected depending on the light emitting method of the white LED element, etc. Examples of the light emitting method of a white LED element include a combination of a red LED, a green LED, and a blue LED, a combination of a blue LED, a red phosphor, and a green phosphor, a combination of a blue LED and a yellow phosphor, and a combination of an ultraviolet LED and a blue LED. Examples include a combination of a red phosphor, a green phosphor, and a blue phosphor.

Therefore, the white LED element may have, for example, a red LED light emitting part, a green LED light emitting part, and a blue LED light emitting part, and the blue LED light emitting part and a protective part containing a red phosphor and a green phosphor. It may have a blue LED light emitting part and a protective part containing a yellow phosphor, and it may have an ultraviolet LED light emitting part and a red phosphor, a green phosphor and a blue phosphor. It may also have a protective part.

Among these, the white LED element has a blue LED light emitting part and a protective part containing a red phosphor and a green phosphor, a blue LED light emitting part and a protective part containing a yellow phosphor, or an ultraviolet LED light emitting part. It is preferable to have a protection part containing a red phosphor, a green phosphor, and a blue phosphor.

Among these, a white LED element may have a blue LED light emitting part and a protective part containing a red phosphor and a green phosphor, or a blue LED light emitting part and a protective part containing a yellow phosphor. preferable. This is because the surface emitting device of this embodiment can emit white light with high brightness.
The structure of the LED element can be similar to that of a general LED element.

The LED elements are usually arranged at equal intervals on one side of the support substrate. The arrangement of the LED elements is appropriately selected depending on the purpose and size of the surface emitting device of this embodiment, the size of the LED elements, and the like. Further, the arrangement density of the LED elements is also appropriately selected depending on the use and size of the surface emitting device of this embodiment, the size of the LED elements, and the like.

The size (chip size) of the LED element can be a general chip size, but a chip size called a mini LED is particularly preferable. The size of the LED element may be, for example, several hundred micrometers square or several tens of micrometers square. Specifically, the size of the LED element can be 100 μm square or more and 2000 μm square or less. Due to the small size of the LED elements, it is possible to arrange the LED elements with high density, that is, to reduce the spacing (pitch) between the LED elements, and to shorten the distance between the LED substrate and the diffusion member, that is, to reduce the distance between the LED elements and the sealing member. This is because the thickness can be reduced. Thereby, the surface emitting device can be made thinner and lighter.

(2) Support substrate The support substrate in this embodiment is a member that supports the above-mentioned LED element, sealing member, diffusion member, etc.

The supporting substrate may be transparent or opaque. Furthermore, the support substrate may be flexible or rigid. The material of the support substrate may be an organic material, an inorganic material, or a composite material made of both an organic material and an inorganic material.

When the material of the support substrate is an organic material, a resin substrate can be used as the support substrate. On the other hand, when the material of the support substrate is an inorganic material, a ceramic substrate or a glass substrate can be used as the support substrate. Moreover, when the material of the support substrate is a composite material, a glass epoxy substrate can be used as the support substrate. Further, as the support substrate, for example, a metal core substrate can also be used. As the support substrate, a printed circuit board on which a circuit is formed by printing can also be used.

The thickness of the support substrate is not particularly limited, and is appropriately selected depending on the presence or absence of flexibility or rigidity, the use and size of the surface emitting device of this embodiment, and the like.
In this embodiment, the support substrate has a linear expansion coefficient lower than that of the sealing member described above. Therefore, as described above, a problem arises in that warpage occurs after the sealing member is thermocompression bonded in the manufacturing process.

The linear expansion coefficient of the support substrate used in this embodiment is usually in the range of 5×10 ⁻⁶ /°C or more and 100×10 ⁻⁶ /°C or less.

(3) Others The LED board in this embodiment is not particularly limited as long as it has the above-mentioned support board and LED element, and can have any necessary configuration as appropriate. Examples of such a structure include a wiring section, a terminal section, an insulating layer, a reflective layer, a heat dissipating member, and the like. Each structure can be similar to that used in a known LED board.

The wiring part is electrically connected to the LED element. The wiring portions are usually arranged in a pattern. Moreover, the wiring part can be arranged on the support base material via an adhesive layer. As a material for the wiring portion, a metal material, a conductive polymer material, or the like can be used.

The wiring portion is electrically connected to the LED element through a bonding portion. As the material for the joint, a bonding agent or solder containing a conductive material such as a metal or a conductive polymer can be used.

A reflective layer can be arranged on the surface of the support substrate where the LED elements are arranged, and in a region other than the LED element mounting area. For example, the light reflected by the second layer of the diffusion member can be reflected by the reflection layer of the support substrate and made to enter the first layer of the diffusion member again, thereby increasing the light utilization efficiency. .

The reflective layer can be similar to reflective layers commonly used in LED substrates. Specifically, examples of the reflective layer include a white resin film containing metal particles, inorganic particles, or pigments and a resin, a metal film, and a porous film. The thickness of the reflective layer is not particularly limited as long as it provides a desired reflectance, and is appropriately set.
The method of forming the LED board can be the same as a known forming method.

4. Diffusion Member The diffusion member is arranged on the side of the sealing member opposite to the LED substrate side. The diffusion member is not particularly limited as long as it has the function of diffusing the light emitted from the LED element and emitting it uniformly in the surface direction, but the following first diffusion member, second diffusion member, and A third diffusion member is mentioned.

4.1 First Diffusion Member The first diffusion member usually has a resin layer in which at least a diffusing agent is dispersed. The above-mentioned diffusion member may be, for example, a resin sheet in which a diffusing agent is dispersed, or a laminate having a resin layer in which a diffusing agent is dispersed on a transparent substrate, but the former is more preferable. The resin contained in the resin layer is not particularly limited as long as it can disperse the diffusing agent, but it is preferably a thermoplastic resin. This is because the diffusing member can be formed using a resin sheet in which a diffusing agent is dispersed, so that the flatness can be improved.

The thermoplastic resin used for the above-mentioned diffusion member is not particularly limited as long as it has high light transmittance, and those commonly used in the field of display devices can be used.

The material of the above-mentioned diffusing agent is not particularly limited as long as it can diffuse the light from the LED element, and for example, it may be an organic material or an inorganic material. When the material of the diffusing agent is an organic material, for example, polymethyl methacrylate (PMMA) can be used. On the other hand, when the material of the diffusing agent is an inorganic material, examples thereof include TiO ₂ , SiO ₂ , Al ₂ O ₃ , silicon, and the like.

The refractive index of the diffusing agent is not particularly limited as long as it can diffuse the light from the LED element, but is, for example, 1.4 or more and 2 or less. Such a refractive index can be measured by an Abbe refractometer, Becke method, minimum argument method, argument analysis, mode line method, ellipsometry method, etc. The shape of the diffusing agent can be, for example, particulate. The average particle size of the diffusing agent is, for example, 1 μm or more and 100 μm or less.

The proportion of the diffusion agent in the diffusion member is not particularly limited as long as it can diffuse the light from the LED element, and is, for example, 40% by weight or more and 60% by weight or less.

4.2 Second Diffusion Member The second diffusion member is a member having a first layer and a second layer in this order from the LED board side, and the first layer has a light transmitting property. The second layer has a reflectance that increases as the absolute value of the incident angle of light with respect to the surface of the second layer on the first layer side becomes smaller; This is a member whose transmittance increases as the absolute value of the incident angle of light with respect to the first layer side surface increases. In this embodiment, by including the above-mentioned diffusion member, it is possible to further improve the in-plane uniformity of brightness and to achieve a reduction in thickness. It is also possible to reduce costs and power consumption.

Hereinafter, the second diffusion member will be explained with reference to the drawings. FIG. 4 is a schematic cross-sectional view showing an example of the second diffusion member. As illustrated in FIG. 4, the diffusion member 11 has a first layer 12 and a second layer 13 in this order. The first layer 12 has light transmittance and light diffusivity, and transmits and diffuses the lights L1 and L2 incident from the surface 12A of the first layer 12 opposite to the surface on the second layer 13 side. Further, the reflectance of the second layer 13 increases as the absolute value of the incident angle of light with respect to the surface 13A of the second layer 13 on the first layer 12 side becomes smaller, and the reflectance of the second layer 13 on the first layer 12 side increases. The transmittance increases as the absolute value of the incident angle of light with respect to the surface 13A increases. Therefore, the second layer 13 reflects the light L1 incident at a low incident angle θ1 to the surface 13A of the second layer 13 on the first layer 12 side, and It is possible to transmit the light L2 that is incident at a high incident angle θ2 relative to the light L2. Note that a low incident angle refers to an incident angle whose absolute value is small, and a high incident angle refers to an incident angle whose absolute value is large.

FIG. 5 is a schematic cross-sectional view showing an example of a surface emitting device of this embodiment including the second diffusion member shown in FIG. 4. As illustrated in FIG. 5, the surface emitting device 10 includes an LED board 4 on which an LED element 3 is arranged on one surface of a support substrate 2, an LED board 4 arranged on the surface side of the LED element 3 side of the LED board 4, and an LED It has a sealing member 5 that seals the element 3 and a diffusion member 11 disposed on the side of the sealing member 5 opposite to the LED substrate 4 side. The diffusion member 11 is arranged so that the surface 11A on the first layer 12 side faces the sealing member 5.

As shown in FIG. 4, the light incident from the surface 11A of the diffusion member 11 on the first layer 12 side is diffused by the first layer 12, and among the light transmitted through the first layer 12 and diffused, the second As shown in FIG. 5, the light L1 incident on the surface 13A of the layer 13 on the first layer 12 side at a low incident angle θ1 is reflected on the surface 13A of the second layer 13 on the first layer 12 side, The light can be made to enter the first layer 12 again and be diffused. Of the light transmitted through the first layer 12 and diffused, the light L2 and L2' incident on the surface 13A of the second layer 13 on the first layer 12 side at a high incident angle θ2 is transmitted to the second layer 12. 13 can be transmitted therethrough and can be emitted from the surface 11B of the diffusion member 11 on the second layer 13 side.

Furthermore, by combining the first layer and the second layer, it is possible to increase Since the light can also be transmitted through the first layer and diffused, the light can be emitted from the second layer side surface of the diffusion member at a high output angle. Therefore, a surface emitting device (especially a direct type LED backlight) having such a diffusion member can diffuse the light emitted from the LED element over the entire light emitting surface, further improving the in-plane uniformity of brightness. can be improved.

In addition, by combining the first layer and the second layer, light that enters at a low incident angle from the first layer side of the diffusion member can be transmitted through the first layer many times, so the light is diffused. It is possible to increase the length of the optical path from the time when the light enters the member from the surface on the first layer side to the time when it exits from the surface on the second layer side of the diffusion member. As a result, a part of the light emitted from the LED element and then emitted from the second layer side surface of the diffusion member can be emitted from a position away from the LED element in the in-plane direction, instead of directly above the LED element. become able to.

(1) First layer The first layer in this embodiment is a member that is disposed on one side of the second layer, which will be described later, and has light transmittance and light diffusivity. Regarding the light transmittance of the first layer, for example, the total light transmittance of the first layer is preferably 50% or more, particularly preferably 70% or more, and particularly preferably 90% or more. . When the total light transmittance of the first layer is within the above range, the brightness of the surface emitting device of this embodiment can be increased.

Note that the total light transmittance of the first layer can be measured, for example, by a method based on JIS K7361-1:1997.

The light diffusing property of the first layer may be, for example, a light diffusing property that randomly diffuses light, or a light diffusing property that mainly diffuses light in a specific direction. Light diffusivity, which mainly diffuses light in a specific direction, is a property of deflecting light, that is, a property of changing the traveling direction of light. As for the light diffusing property of the first layer, when the light diffusing property is such that light is diffused randomly, for example, the diffusion angle of the light incident on the first layer can be 10° or more, and 15° or more. The angle may be 20° or more. Further, the diffusion angle of the light incident on the first layer can be, for example, 85° or less, may be 60° or less, or may be 50° or less. By setting the diffusion angle within the above range, the in-plane uniformity of brightness of the surface emitting device of this embodiment can be further improved.

Here, the diffusion angle will be explained. FIG. 6 is a graph illustrating the transmitted light intensity distribution and is a diagram illustrating the diffusion angle. In this specification, light is perpendicularly incident on one surface of the first layer constituting the diffusion member, and half of the maximum transmitted light intensity Imax of the light emitted from the other surface of the first layer is used. The full width at half maximum (FWHM), which is the difference between the two angles , is defined as the diffusion angle α.

Note that the diffusion angle can be measured using a variable angle photometer or a variable angle spectrophotometer. To measure the diffusion angle, a goniophotometer GP-200 manufactured by Murakami Color Research Institute may be used.

The first layer is not particularly limited as long as it has the above-mentioned light transmittance and light diffusivity, such as a transmission diffraction grating, a microlens array, a diffusing agent-containing resin film containing a diffusing agent and a resin. etc. Specifically, when the first layer has a light diffusing property that mainly diffuses light in a specific direction, examples thereof include a transmission type diffraction grating and a microlens array. On the other hand, when the first layer has a light diffusing property that randomly diffuses light, a resin film containing a diffusing agent can be used. Among these, a transmission type diffraction grating and a microlens array are preferable from the viewpoint of light diffusivity. Note that the transmission type diffraction grating is also referred to as a transmission type diffractive optical element (DOE).

When the first layer is a transmission type diffraction grating, the transmission type diffraction grating is not particularly limited as long as it has the above-mentioned light transmittance and light diffusivity. The pitch etc. of the transmission type diffraction grating may be adjusted as appropriate as long as the above-mentioned light transmittance and light diffusivity can be obtained. Specifically, if the wavelength output by the LED element is a single color such as red, green, or blue, it is possible to effectively bend the light from the LED element by setting the pitch according to each wavelength. It is.

The material constituting the transmission type diffraction grating may be any material that can provide a transmission type diffraction grating having the above-mentioned light transmittance and light diffusivity, and materials commonly used for transmission type diffraction gratings may be used. I can do it. Further, the method for forming the transmission type diffraction grating can be the same as the method for forming a general transmission type diffraction grating.

When the first layer is a microlens array, the microlens array is not particularly limited as long as it has the above-mentioned light transmittance and light diffusivity. The shape, pitch, size, etc. of the microlenses may be adjusted as appropriate as long as the above-mentioned light transmittance and light diffusivity can be obtained. The material constituting the microlens may be any material that can provide a microlens having the above-mentioned light transmittance and light diffusivity, and materials commonly used for microlenses can be used. Further, the method for forming the microlens can be the same as the method for forming a general microlens.

When the first layer is a diffusing agent-containing resin film, the diffusing agent-containing resin film is not particularly limited as long as it has the above-mentioned light transmittance and light diffusivity.

The first layer may have a structure capable of exhibiting light diffusing properties. For example, the first layer may exhibit light diffusing properties in the entire layer, or may exhibit light diffusing properties in the surface. It may be something. Examples of devices that exhibit light diffusivity on the surface include relief-type diffraction gratings and microlens arrays. On the other hand, examples of materials that exhibit light diffusivity in the entire layer include a volumetric diffraction grating and a resin film containing a diffusing agent. Examples of the method of laminating the first layer and the second layer include a method of laminating the first layer and the second layer through an adhesive layer or an adhesive layer, or a method of laminating the first layer directly on one side of the second layer. Examples include a method of forming. Examples of methods for directly forming the first layer on one surface of the second layer include printing methods, resin shaping using a mold, and the like.

(2) Second layer The second layer in this embodiment is arranged on one surface side of the first layer, and the absolute value of the incident angle of light with respect to the surface of the second layer on the first layer side is small. The dependence of the reflectance on the angle of incidence such that the reflectance increases as the surface of the second layer faces the first layer, and the transmittance increases as the absolute value of the angle of incidence of light with respect to the surface of the second layer on the first layer side increases. This is a member having a dependence of the incident angle on the incident angle.

The second layer has an incident angle dependence of reflectance such that the reflectance increases as the absolute value of the incident angle of light with respect to the surface of the second layer on the first layer side becomes smaller. In other words, the reflectance of light incident on the surface of the second layer on the first layer side at a low incidence angle is the same as the reflectance of light incident on the surface of the second layer on the first layer side at a high incidence angle. becomes larger than Among these, it is preferable that the reflectance of light that is incident on the first layer side surface of the second layer at a low incident angle be large.

Specifically, the regular reflectance of visible light incident on the surface of the second layer on the first layer side at an incident angle of ±60° is preferably 50% or more and less than 100%, particularly 80%. It is preferably at least 90% and less than 100%, particularly preferably at least 90% and less than 100%. Note that it is preferable that the regular reflectance of visible light satisfies the above range at all incident angles within ±60°. When the regular reflectance is within the above range, the in-plane uniformity of brightness of the surface emitting device of this embodiment can be further improved.

Further, the average value of the regular reflectance of visible light incident on the surface of the second layer on the first layer side at an incident angle of ±60° is preferably, for example, 80% or more and 99% or less, and among them, It is preferably 90% or more and 97% or less. Note that the above-mentioned average value of regular reflectance refers to the average value of regular reflectance of visible light at each incident angle. When the average value of the specular reflectance is within the above range, the in-plane uniformity of brightness of the surface emitting device in this embodiment can be further improved.

Further, the regular reflectance of visible light incident at an incident angle of 0° (perpendicularly incident) to the surface of the second layer on the first layer side is preferably, for example, 80% or more and less than 100%, Among these, it is preferably 90% or more and less than 100%, particularly preferably 95% or more and less than 100%. When the regular reflectance is within the above range, the in-plane uniformity of brightness of the surface emitting device of this embodiment can be further improved.

Note that "visible light" in this specification means light with a wavelength of 380 nm or more and 780 nm or less. Further, the regular reflectance can be measured using a variable angle photometer or a variable angle spectrophotometer. For measuring the regular reflectance, a goniophotometer GP-200 manufactured by Murakami Color Research Institute can be used.

The second layer has an incident angle dependence of transmittance such that the transmittance increases as the absolute value of the incident angle of light with respect to the surface of the second layer on the first layer side increases. In other words, the transmittance of light incident on the surface of the second layer on the first layer side at a high incidence angle is the same as the transmittance of light incident on the surface of the second layer on the first layer side at a low incidence angle. becomes larger than Among these, it is preferable that the transmittance of light that is incident on the surface of the second layer on the first layer side at a high incident angle be high. Specifically, the total light transmittance of light incident on the surface of the second layer on the first layer side at an incident angle of 70° or more and less than 90° is preferably 30% or more, particularly 40% or more. It is preferably 50% or more, particularly preferably 50% or more. Note that the total light transmittance preferably satisfies the above range at all incident angles of 70° or more and less than 90°. Further, when the absolute value of the incident angle is 70° or more and less than 90°, it is preferable that the total light transmittance satisfies the above range. When the total light transmittance is within the above range, the in-plane uniformity of brightness of the surface emitting device of this embodiment can be further improved.

Note that the total light transmittance of the second layer can be measured by a method based on JIS K7361-1:1997 using, for example, a variable angle photometer or a variable angle spectrophotometer. For measuring the total light transmittance, an ultraviolet-visible near-infrared spectrophotometer V-7200 manufactured by JASCO Corporation can be used.

The second layer is not particularly limited as long as it has the above-mentioned dependence of reflectance and transmittance on the angle of incidence, and various structures having the above-mentioned dependence of reflectance and transmittance on the angle of incidence can be used. Can be adopted. The second layer may include, for example, a dielectric multilayer film or a patterned first reflective film and a patterned second reflective film in order from the first layer side, and the openings of the first reflective film and the patterned second reflective film. Examples include a reflective structure, a reflective diffraction grating, and the like, in which the openings of the two reflective films are located so as not to overlap in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction.

Hereinafter, a case where the second layer is a dielectric multilayer film, a reflective structure, or a reflective diffraction grating will be described.

a) Dielectric multilayer film When the second layer is a dielectric multilayer film, the dielectric multilayer film may be, for example, a multilayer film of an inorganic compound in which inorganic layers with different refractive indexes are laminated alternately, or a multilayer film of an inorganic compound with different refractive indexes. Examples include multilayer resin films in which resin layers are alternately laminated.

(Multilayer film of inorganic compounds)
When the dielectric multilayer film is an inorganic compound multilayer film in which inorganic layers with different refractive indexes are alternately laminated, the inorganic compound multilayer film has the above-mentioned dependence of reflectance and transmittance on the angle of incidence. If so, there are no particular limitations.

Among the inorganic layers having different refractive indexes, the inorganic compound contained in the high refractive index inorganic layer having a high refractive index may have a refractive index of 1.7 or more, and a refractive index of 1.7 or more and 2.5 or less, for example. There may be. Such inorganic compounds include titanium oxide, zirconium oxide, tantalum pentoxide, niobium pentoxide, lanthanum oxide, yttrium oxide, zinc oxide, zinc sulfide, and indium oxide as main components, and titanium oxide, tin oxide, and cerium oxide. Examples include those containing a small amount.

Further, among the inorganic layers having different refractive indexes, the inorganic compound contained in the low refractive index inorganic layer having a low refractive index may have a refractive index of 1.6 or less, and 1.2 or more and 1.6 It may be the following. Examples of such inorganic compounds include silica, alumina, lanthanum fluoride, magnesium fluoride, and sodium aluminum hexafluoride.

The number of laminated high refractive index inorganic layers and low refractive index inorganic layers may be adjusted as appropriate as long as the above-mentioned dependence of reflectance and transmittance on the incident angle can be obtained. Specifically, the total number of laminated high refractive index inorganic layers and low refractive index inorganic layers can be 4 or more. Further, the upper limit of the total number of laminated layers is not particularly limited, but as the number of laminated layers increases, the number of steps increases, so it can be set to 24 layers or less, for example.

The thickness of the multilayer film of an inorganic compound may be 0.5 μm or more and 10 μm or less as long as the above-mentioned dependence of reflectance and transmittance on the incident angle can be obtained. Examples of a method for forming a multilayer film of an inorganic compound include a method in which high refractive index inorganic layers and low refractive index inorganic layers are alternately laminated by a CVD method, a sputtering method, a vacuum evaporation method, a wet coating method, or the like.

(Multilayer film of resin)
When the dielectric multilayer film is a resin multilayer film in which resin layers with different refractive indexes are alternately laminated, the resin multilayer film may be one having the above-mentioned dependence of reflectance and transmittance on the angle of incidence. There are no particular limitations.

Examples of the resin constituting the resin layer include thermoplastic resins and thermosetting resins. Among these, thermoplastic resins are preferred because of their good moldability.

The resin layer contains various additives, such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, thinners, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and refractive index adjusters. A dopant for this purpose may be added.

As thermoplastic resins, polyolefin resins, alicyclic polyolefin resins, polyamide resins, aramid resins, polyester resins, polycarbonate resins, polyarylate resins, polyacetal resins, polyphenylene sulfide resins, tetrafluoroethylene resins, trifluoroethylene resins, Fluororesins such as trifluorochloroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride resin, acrylic resin, methacrylic resin, polyacetal resin, polyglycolic acid resin, and polylactic acid resin can be used. can. Examples of the polyolefin resin include polyethylene, polypropylene, polystyrene, and polymethylpentene. Furthermore, examples of the polyamide resin include nylon 6 and nylon 66. Further, examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polybutyl succinate, and polyethylene-2,6-naphthalate. In the present disclosure, polyester is particularly preferred from the viewpoints of strength, heat resistance, and transparency.

In this specification, polyester refers to homopolyester or copolyester that is a polycondensate of a dicarboxylic acid component skeleton and a diol component skeleton. Here, examples of the homopolyester include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene diphenyllate, and the like. Among these, polyethylene terephthalate is preferred because it is inexpensive and can be used for a wide variety of applications.

Moreover, in this specification, the copolymerized polyester is defined as a polycondensate consisting of at least three or more components selected from the following components having a dicarboxylic acid skeleton and components having a diol skeleton. Components having a dicarboxylic acid skeleton include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 4,4-diphenyldicarboxylic acid, Examples include 4,4-diphenylsulfonedicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid and their ester derivatives. Components having a glycol skeleton include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, diethylene glycol, polyalkylene glycol, 2,2-bis Examples include (4-β-hydroxyethoxyphenyl)propane, isosorbate, 1,4-cyclohexanedimethanol, and spiroglycol.

Among the resin layers having different refractive indexes, the difference in in-plane average refractive index between the high refractive index resin layer having a high refractive index and the low refractive index resin layer having a low refractive index is preferably 0.03 or more, and more preferably It is preferably 0.05 or more, more preferably 0.1 or more. If the difference in the average in-plane refractive index is too small, sufficient reflectance may not be obtained.

Further, it is preferable that the difference between the in-plane average refractive index and the thickness direction refractive index of the high refractive index resin layer is 0.03 or more, and the difference between the in-plane average refractive index and the thickness direction refractive index of the low refractive index resin layer It is preferable that the difference is 0.03 or less. In this case, even if the incident angle becomes large, the reflectance at the reflection peak is unlikely to decrease.

As a preferred combination of the high refractive index resin used for the high refractive index resin layer and the low refractive index resin used for the low refractive index resin layer, firstly, the difference in SP value between the high refractive index resin and the low refractive index resin is It is preferable that the absolute value of is 1.0 or less. When the absolute value of the difference in SP value is within the above range, delamination is less likely to occur. In this case, it is more preferable that the high refractive index resin and the low refractive index resin contain the same basic skeleton. Here, the basic skeleton refers to repeating units that constitute the resin. For example, when one resin is polyethylene terephthalate, ethylene terephthalate is the basic skeleton. For example, when one of the resins is polyethylene, ethylene is the basic skeleton. When the high refractive index resin and the low refractive index resin are resins containing the same basic skeleton, peeling between the layers becomes even more difficult to occur.

Second, the preferred combination of the high refractive index resin used for the high refractive index resin layer and the low refractive index resin used for the low refractive index layer is the difference in glass transition temperature of the high refractive index resin and the low refractive index resin. However, it is preferable that the temperature is 20°C or less. If the difference in glass transition temperature is too large, the thickness uniformity may be poor when forming a laminated film of a high refractive index resin layer and a low refractive index resin layer. Moreover, overstretching may occur also when forming the above-mentioned laminated film.

Further, it is preferable that the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is a polyester containing spiroglycol. Here, the polyester containing spiroglycol refers to a copolyester copolymerized with spiroglycol, a homopolyester, or a polyester blended thereof. Polyester containing spiroglycol is preferable because it has a small difference in glass transition temperature from polyethylene terephthalate or polyethylene naphthalate, is less likely to be overstretched during molding, and is less likely to cause delamination.

More preferably, the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is preferably a polyester containing spiroglycol and cyclohexanedicarboxylic acid. When the low refractive index resin is a polyester containing spiroglycol and cyclohexanedicarboxylic acid, the difference in in-plane refractive index from polyethylene terephthalate or polyethylene naphthalate becomes large, making it easier to obtain a high reflectance. Furthermore, since the difference in glass transition temperature between polyethylene terephthalate and polyethylene naphthalate is small and the adhesive properties are excellent, overstretching is less likely to occur during molding, and delamination is less likely to occur.

It is also preferable that the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is a polyester containing cyclohexanedimethanol. Here, the polyester containing cyclohexanedimethanol refers to a copolyester copolymerized with cyclohexanedimethanol, a homopolyester, or a polyester blended thereof. Polyester containing cyclohexanedimethanol is preferable because it has a small difference in glass transition temperature from polyethylene terephthalate or polyethylene naphthalate, so it is less prone to overstretching during molding and less likely to cause delamination. In this case, the low refractive index resin is more preferably an ethylene terephthalate polycondensate having a copolymerized amount of cyclohexanedimethanol of 15 mol% or more and 60 mol% or less.

By doing so, while having high reflective performance, changes in optical properties are small, particularly due to heating or aging, and peeling between layers is also less likely to occur. An ethylene terephthalate polycondensate having a copolymerized amount of cyclohexanedimethanol within the above range adheres very strongly to polyethylene terephthalate. In addition, the cyclohexanedimethanol group has geometric isomers such as cis or trans, and conformational isomers such as chair or boat, so even when co-stretched with polyethylene terephthalate, it is difficult to crystallize in an oriented manner, resulting in high reflectivity. The change in optical properties due to thermal history is also smaller, and tearing during film formation is less likely to occur.

In the multilayer film of the resin described above, it is sufficient that there is a portion having a structure in which high refractive index resin layers and low refractive index resin layers are alternately laminated in the thickness direction. That is, it is preferable that the order of arrangement in the thickness direction of the high refractive index resin layer and the low refractive index resin layer is not random, and the order of arrangement of resin layers other than the high refractive index resin layer and the low refractive index resin layer is is not particularly limited. In addition, when the multilayer film of the above-mentioned resin has a high refractive index resin layer, a low refractive index resin layer, and another resin layer, as for the permutation of their arrangement, the high refractive index resin layer is A, the low refractive index resin layer is A, the low refractive index resin layer is A, the low refractive index resin layer is When the resin layer is B and the other resin layers are C, it is more preferable that each layer is laminated in a regular permutation such as A(BCA) _n , A(BCBA) _n , A(BABCBA) _n , etc. Here, n is the number of repeating units, and for example, when n=3 in A(BCA) _n , it represents stacking in the permutation ABCABCABCA in the thickness direction.

Further, the number of laminated high refractive index resin layers and low refractive index resin layers may be adjusted as appropriate as long as the above-mentioned dependence of the reflectance and transmittance on the incident angle can be obtained. Specifically, 30 or more high refractive index resin layers and low refractive index resin layers can be alternately laminated, and 200 or more layers each can be laminated. Further, the total number of laminated high refractive index resin layers and low refractive index resin layers can be, for example, 600 or more. If the number of laminated layers is too small, sufficient reflectance may not be obtained. Further, by setting the number of laminated layers within the above range, a desired reflectance can be easily obtained. Further, the upper limit of the total number of laminated layers is not particularly limited, but it can be set to 1500 layers or less, for example, in consideration of deterioration in lamination accuracy due to an increase in the size of the device or an excessively large number of layers.

Further, it is preferable that the multilayer film of the resin described above has a surface layer containing polyethylene terephthalate or polyethylene naphthalate having a thickness of 3 μm or more on at least one side, and it is particularly preferable to have the above-mentioned surface layer on both sides. Moreover, it is more preferable that the thickness of the surface layer is 5 μm or more. By having the above-mentioned surface layer, the surface of the multilayer film of the above-mentioned resin can be protected.

Examples of the method for producing the multilayer film of the above-mentioned resins include a coextrusion method and the like. Specifically, reference can be made to the method for producing a laminated film described in JP-A No. 2008-200861.

Moreover, as the multilayer film of the above-mentioned resin, a commercially available laminated film can be used, and specific examples include Picasus (registered trademark) manufactured by Toray Industries, Inc. and ESR manufactured by 3M Company.

b) Reflective structure The reflective structure has a patterned first reflective film and a patterned second reflective film in order from the first layer side, and has an opening in the first reflective film and a patterned second reflective film in order from the first layer side. The openings are located so as not to overlap in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction.

The reflective structure has two aspects. A first aspect of the reflective structure includes a transparent base material, a patterned first reflective film disposed on one surface of the transparent base material, and a patterned second reflective film disposed on the other surface of the transparent base material. a reflective film, the opening of the first reflective film and the opening of the second reflective film are located so as not to overlap in plan view, and the first reflective film and the second reflective film are arranged apart in the thickness direction. It is something that Further, a second aspect of the reflective structure includes a transparent base material, a patterned convex part that is arranged on one surface of the transparent base material and has light transmittance, and a surface of the convex part on the transparent base material side. The first reflective film has a patterned first reflective film disposed on the opposite surface side and a patterned second reflective film disposed in the opening of the convex portion on one surface of the transparent base material. The opening of the reflective film and the opening of the second reflective film are located so as not to overlap in a plan view, and the first reflective film and the second reflective film are arranged apart from each other in the thickness direction. Each aspect will be explained separately below.

(First aspect of reflective structure)
A first aspect of the reflective structure in this embodiment includes a transparent base material, a patterned first reflective film disposed on one surface of the transparent base material, and a patterned first reflective film disposed on the other surface of the transparent base material. a second reflective film having a shape, the openings of the first reflective film and the openings of the second reflective film are located so as not to overlap in plan view, and the first reflective film and the second reflective film are arranged in the thickness direction. They are located far apart.
In the case of the reflective structure of this embodiment, the first layer is arranged on the surface side of the reflective structure on the first reflective film side in the second diffusion member.

FIGS. 7(a) and 7(b) are a schematic plan view and a cross-sectional view showing an example of the reflective structure of this embodiment, and FIG. 7(a) is a view of the reflective structure as seen from the first reflective film side. FIG. 7(b) is a plan view, and FIG. 7(b) is a cross-sectional view taken along the line AA in FIG. 7(a). As shown in FIGS. 7(a) and 7(b), the reflective structure 20 includes a transparent base material 21, a patterned first reflective film 22 disposed on one surface of the transparent base material 21, and a transparent base material 21. It has a second reflective film 24 disposed on the other surface of the material 21. The opening 23 of the first reflective film 22 and the opening 25 of the second reflective film 24 are located so as not to overlap in plan view. Further, the first reflective film 22 and the second reflective film 24 are respectively arranged on both sides of the transparent base material 21, and are arranged apart from each other in the thickness direction. Note that in FIG. 7(a), the opening of the second reflective film is indicated by a broken line. Moreover, FIG.7(c) is a schematic sectional drawing which shows an example of the surface emitting device provided with the diffusion member which has the reflective structure of this aspect.

In such a reflective structure, a patterned first reflective film and a second reflective film are laminated, and the openings of the first reflective film and the second reflective film are arranged so that they do not overlap in plan view. Therefore, when the diffusion member having the reflective structure of this embodiment is used in a surface emitting device, the first reflective film 22 and At least one of the second reflective films 24 is necessarily present. Therefore, as shown in FIG. 7B, for example, the surface of the reflective structure 20 on the first reflective film 22 side, that is, the side where the first layer (not shown) of the reflective structure 20 (second layer) is arranged. The light L11 that is incident on the surface 13A at a low incident angle can be reflected by the first reflective film 22 and the second reflective film 24.

Further, since the openings of the first reflective film and the openings of the second reflective film are located so as not to overlap in plan view, and the first reflective film and the second reflective film are arranged apart in the thickness direction, Light incident at a high incident angle on the surface of the reflective structure 20 on the first reflective film 22 side, that is, the surface 13A on the side where the first layer (not shown) of the reflective structure 20 (second layer) is arranged. L12 and L13 can be emitted from the opening 23 of the first reflective film 22 and the opening 25 of the second reflective film 24. As a result, a part of the light emitted from the LED element and then emitted from the second layer side surface of the diffusion member can be emitted from a position away from the LED element in the in-plane direction, instead of directly above the LED element. become able to. Therefore, the in-plane uniformity of brightness can be improved.

As the first reflective film and the second reflective film, a general reflective film can be used, and a metal film, a dielectric multilayer film, etc. can be used. As the material for the metal film, metal materials commonly used for reflective films can be used, including aluminum, gold, silver, and alloys thereof. Furthermore, as the dielectric multilayer film, those used for general reflective films can be adopted, and examples include multilayer films of inorganic compounds such as a multilayer film in which zirconium oxide and silicon oxide are alternately laminated. . The materials contained in the first reflective film and the second reflective film may be the same or different.

The pitch of the openings of the first reflective film and the second reflective film may be such that the above-mentioned dependence of the reflectance and transmittance on the incident angle can be obtained, and the pitch of the openings of the first reflective film and the second reflective film may be such that the above-mentioned dependence of the reflectance and transmittance on the incident angle can be obtained. It is appropriately set according to the light distribution characteristics, size, pitch, shape, distance between the LED board and the diffusion member, and the like. The pitches of the openings of the first reflective film and the second reflective film may be the same or different.

The pitch of the openings of the first reflective film may be larger than the size of the LED element, for example. Specifically, the pitch of the openings of the first reflective film can be 0.1 mm or more and 20 mm or less.

Further, the pitch of the openings of the second reflective film is not particularly limited as long as unevenness in brightness can be suppressed, but it is preferably equal to or less than the pitch of the openings of the first reflective film, and It is preferable that the pitch is smaller than the pitch of the openings. Specifically, the pitch of the openings of the second reflective film can be 0.1 mm or more and 2 mm or less. By making the pitch of the openings of the second reflective film fine as described above, it is possible to make the pattern between the second reflective film part and the opening part of the second reflective film difficult to see, thereby reducing unevenness. This makes it possible to emit light from a surface area.

Note that the pitch of the openings of the first reflective films refers to the distance P1 between the centers of the openings 23 of adjacent first reflective films 22, as shown in FIG. 7(a), for example. Further, the pitch of the openings of the second reflective film refers to the distance P2 between the centers of the openings 25 of adjacent second reflective films 24, as shown in FIG. 7A, for example.

The size of the openings of the first reflective film and the second reflective film may be such that the above-mentioned dependence of the reflectance and transmittance on the incident angle can be obtained, and the size, size, pitch, and shape of the LED element, It is set appropriately depending on the distance between the LED board and the diffusion member. The sizes of the openings in the first reflective film and the second reflective film may be the same or different.

As for the size of the opening of the first reflective film, specifically, when the shape of the opening of the first reflective film is rectangular, the length of the opening of the first reflective film is 0.1 mm or more. It can be 5 mm or less.

Further, the size of the opening of the second reflective film is not particularly limited as long as unevenness in brightness can be suppressed, but it is preferably smaller than or equal to the size of the opening of the first reflective film. It is preferable that the size is smaller than the size of the opening of the reflective film. Specifically, when the opening of the second reflective film has a rectangular shape, the length of the opening of the second reflective film can be 0.05 mm or more and 2 mm or less. By making the size of the opening in the second reflective film fine as described above, it is possible to make the pattern between the second reflective film and the opening in the second reflective film difficult to see, thereby making it possible to reduce unevenness. It is possible to emit surface light without any glaring.

Note that the size of the opening of the first reflective film is, for example, when the opening of the first reflective film has a rectangular shape, the size of the opening 23 of the first reflective film 22 as shown in FIG. is the length x1. Further, the size of the opening of the second reflective film refers to the length x2 of the opening 25 of the second reflective film 24, as shown in FIG. 7(a), for example.

The openings of the first reflective film and the second reflective film may have any shape, such as a rectangular shape or a circular shape. The thicknesses of the first reflective film and the second reflective film may be adjusted as appropriate as long as the above-mentioned dependence of the reflectance and transmittance on the incident angle can be obtained. Specifically, the thickness of the first reflective film and the second reflective film can be 0.05 μm or more and 100 μm or less.

The first reflective film and the second reflective film may be formed on the surface of a transparent base material, or may be sheet-shaped reflective films. The method for forming the first reflective film and the second reflective film is not particularly limited as long as it can form a reflective film in a pattern on the surface of the transparent substrate, and examples thereof include sputtering, vacuum evaporation, and the like. Further, when the first reflective film and the second reflective film are sheet-like reflective films, examples of the method for forming the openings include a method of forming a plurality of through holes by punching or the like. In this case, as a method for laminating the transparent base material and the sheet-like reflective film, for example, a method of laminating the sheet-like reflective film to the transparent base material via an adhesive layer or an adhesive layer can be used.

The transparent base material in the reflective structure of this aspect is a member that supports the above-mentioned first reflective film, second reflective film, etc., and also allows the first reflective film and the second reflective film to be arranged apart in the thickness direction. It is a member for

The transparent base material has light transmittance. Regarding the light transmittance of the transparent base material, it is preferable that the total light transmittance of the transparent base material is, for example, 80% or more, and particularly preferably 90% or more. Note that the total light transmittance of the transparent substrate can be measured by a method based on JIS K7361-1:1997.

The material constituting the transparent base material may be any material that has the above-mentioned total light transmittance, such as resins such as polyethylene terephthalate, polycarbonate, acrylic, cycloolefin, polyester, polystyrene, acrylic styrene, quartz glass, Pyrex ( (registered trademark), synthetic quartz, and other glasses.

The thickness of the transparent base material is, for example, as shown in FIG. 7(b). ) has a thickness that allows the light L12 that is incident at a high incident angle to the surface 13A on which the side is arranged to be emitted from the opening 23 of the first reflective film 22 and the opening 25 of the second reflective film 24. This is preferably set as appropriate depending on the pitch and size of the openings of the first reflective film and the second reflective film, the thicknesses of the first reflective film and the second reflective film, and the like. Specifically, the thickness of the transparent base material can be 0.05 mm or more and 2 mm or less, and preferably 0.1 mm or more and 0.5 mm or less.

(Second aspect of reflective structure)
A second aspect of the reflective structure includes a transparent base material, a patterned convex part that is arranged on one surface of the transparent base material and has light transmittance, and a surface opposite to the transparent base material side of the convex part. It has a patterned first reflective film arranged on the surface side, and a patterned second reflective film arranged in the opening of the convex part on one side of the transparent base material, and the patterned second reflective film is arranged in the opening of the first reflective film. The openings of the first reflective film and the second reflective film are located so as not to overlap in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction. In the case of the reflective structure of this embodiment, the first layer is arranged on the surface side of the reflective structure on the first reflective film side in the second diffusion member.

FIGS. 8(a) and 8(b) are a schematic plan view and a cross-sectional view showing an example of the second aspect of the reflective structure in this embodiment, and FIG. 8(a) is a first reflective film side of the reflective structure. FIG. 8(b) is a sectional view taken along line AA in FIG. 8(a). As shown in FIGS. 8(a) and 8(b), the reflective structure 20 includes a transparent base material 21, a patterned convex portion 26 arranged on one surface of the transparent base material 21, and having light transmittance. , a patterned first reflective film 22 disposed on the surface of the convex portion 26 opposite to the surface on the transparent base material 21 side, and a patterned first reflective film 22 disposed at the opening of the convex portion 26 on one surface of the transparent base material 21. It has a patterned second reflective film 24. The opening 23 of the first reflective film 22 and the opening 25 of the second reflective film 24 are located so as not to overlap in plan view. Further, the first reflective film 22 and the second reflective film 24 are separated by a convex portion 26 and are arranged apart in the thickness direction.

In such a reflective structure, a patterned first reflective film and a second reflective film are laminated, and the openings of the first reflective film and the second reflective film are arranged so that they do not overlap in plan view. Therefore, a surface emitting device (especially an LED backlight) using a diffusion member having a reflective structure according to the present embodiment has at least one of the first reflective film and the second reflective film directly above the LED element. One or the other will always exist. Therefore, similarly to the first aspect of the reflective structure, for example, as shown in FIG. 8(b), the surface of the reflective structure 20 on the first reflective film 22 side, that is, the reflective structure 20 (second layer) The light L11 that has entered the surface 13A on the side where the first layer (not shown) is arranged at a low incident angle can be reflected by the first reflective film 22 and the second reflective film 24.

Further, since the openings of the first reflective film and the openings of the second reflective film are located so as not to overlap in plan view, and the first reflective film and the second reflective film are arranged apart in the thickness direction, Light incident at a high incident angle on the surface of the reflective structure 20 on the first reflective film 22 side, that is, the surface 13A on the side where the first layer (not shown) of the reflective structure 20 (second layer) is arranged. L12 can be emitted from the side surface of the convex portion 26 and the opening 25 of the second reflective film 24. As a result, a part of the light emitted from the LED element and then emitted from the second layer side surface of the diffusion member can be emitted from a position away from the LED element in the in-plane direction, instead of directly above the LED element. become able to. Therefore, the in-plane uniformity of brightness can be improved. Further, in this aspect, since the projections are provided, self-alignment of the openings of the first reflective film and the second reflective film is possible, and manufacturing costs can be reduced.

In addition, the materials of the first reflective film and the second reflective film, the pitch of the openings of the first reflective film and the second reflective film, the sizes of the openings of the first reflective film and the second reflective film, the first reflective film and The shape of the opening of the second reflective film, the thickness of the first reflective film and the second reflective film, the method of forming the first reflective film and the second reflective film, etc. can be the same as in the first embodiment. .
Further, the transparent base material can be the same as in the first embodiment.

The convex portion in the reflective structure of this embodiment is a member for arranging the first reflective film and the second reflective film so as to be apart from each other in the thickness direction. The convex portion has light transmittance. Regarding the light transmittance of the convex portion, the total light transmittance of the convex portion is preferably 80% or more, and particularly preferably 90% or more. Note that the total light transmittance of the convex portion can be measured by a method based on JIS K7361-1:1997.

The material constituting the convex portion may be any material that can form a patterned convex portion and has the above-mentioned total light transmittance, such as a thermosetting resin, an electron beam curing resin, and the like.

The height of the convex portion is, for example, as shown in FIG. ) is at such a height that the light L12 that is incident at a high incident angle on the surface 13A on which the convex portion 26 is disposed can be emitted from the side surface of the convex portion 26 and the opening 25 of the second reflective film 24. is preferably set as appropriate depending on the pitch and size of the openings of the first reflective film and the second reflective film, the thicknesses of the first reflective film and the second reflective film, and the like. Specifically, the height of the convex portion can be 0.05 mm or more and 2 mm or less, and preferably 0.1 mm or more and 0.5 mm or less.

The pitch, size, and shape in plan view of the convex portions can be the same as the pitch, size, and shape of the openings of the second reflective film. The surface of the convex portion may be, for example, a smooth surface as shown in FIG. 8(b), or a rough surface as shown in FIG. 9(a). When the surface of the convex part is a rough surface, light diffusing properties can be imparted to the convex part.

Further, the shape of the surface of the convex portion may be, for example, a flat surface as shown in FIG. 8(b), or a curved surface as shown in FIG. 9(b). When the surface of the convex portion is a curved surface, light diffusing properties can be imparted to the convex portion.

The method for forming the convex portions is not particularly limited as long as it is capable of forming patterned convex portions, and examples thereof include printing methods, resin molding using molds, and the like.

c) Reflection type diffraction grating When the second layer is a reflection type diffraction grating, the reflection type diffraction grating is not particularly limited as long as it has the above-mentioned dependence of reflectance and transmittance on the angle of incidence.

The pitch and the like of the reflection type diffraction grating may be adjusted as appropriate as long as the above-mentioned dependence of the reflectance and transmittance on the incident angle can be obtained. Specifically, if the wavelength output by the LED element is a single color such as red, green, or blue, it is possible to effectively reflect the light from the LED element by setting the pitch according to each wavelength. It is.

The material constituting the reflection type diffraction grating may be any material that can provide a reflection type diffraction grating having the incident angle dependence of reflectance and transmittance as described above, and materials commonly used for reflection type diffraction gratings may be used. Can be adopted. Further, the method for forming the reflection type diffraction grating can be the same as the method for forming a general reflection type diffraction grating.

4.3 Third Diffusion Member The third diffusion member is a resin plate containing a light-transmitting resin such as polystyrene (PS) or polycarbonate, and has many voids inside or has an uneven surface. Examples include those having the following, and those commonly used in the field of display devices can be used.

5. Wavelength Conversion Member In the surface emitting device of this embodiment, for example, the wavelength conversion member may be disposed on the side of the diffusion member opposite to the LED substrate side, and the wavelength conversion member may be placed on the LED substrate side of the diffusion member. may be placed.

The wavelength conversion member is a member containing a phosphor that absorbs light emitted from the LED element and emits excitation light. The wavelength conversion member has a function of generating white light when combined with the LED board.

The wavelength conversion member usually has at least a wavelength conversion layer containing a phosphor and a resin. The wavelength conversion member may be, for example, a single wavelength conversion layer, or may be a laminate having a wavelength conversion layer on one side of a transparent base material. Among these, a single wavelength conversion layer is preferable from the viewpoint of thinning. More preferably, a sheet-like wavelength conversion member is used.

The phosphor can be appropriately selected depending on the color of light emitted from the LED element, and includes blue phosphor, green phosphor, red phosphor, yellow phosphor, and the like. For example, when the LED element is a blue LED element, a green phosphor and a red phosphor may be used as the phosphor, or a yellow phosphor may be used. Further, for example, when the LED element is an ultraviolet LED element, a red phosphor, a green phosphor, and a blue phosphor can be used as the phosphor.

As the phosphor, for example, a phosphor used in a wavelength conversion member of an LED backlight can be used. Furthermore, quantum dots can also be used as phosphors. The content of the phosphor in the wavelength conversion member layer is not particularly limited as long as it can generate the desired white light, and is similar to the content of the phosphor in the wavelength conversion member of a general LED backlight. It can be done.

Moreover, the resin contained in the wavelength conversion member is not particularly limited as long as it can disperse the phosphor. The above-mentioned resin can be the same as the resin used for wavelength conversion members of general LED backlights, and can include thermosetting resins such as silicone resins and epoxy resins.

The thickness of the wavelength conversion member is not particularly limited as long as it can generate desired white light when used in a surface emitting device, and may be, for example, 10 μm or more and 1000 μm or less.

6. Other Optical Members In the surface emitting device of this embodiment, for example, an optical member may be further disposed on the surface of the diffusion member opposite to the surface on the LED substrate side. Examples of the optical member include a prism sheet, a reflective polarizing sheet, and the like.

(1) Prism sheet The prism sheet in this embodiment has a function of condensing incident light and intensively improving brightness in the front direction. The prism sheet is, for example, one in which a prism pattern containing acrylic resin is arranged on one side of a transparent resin base material. As the prism sheet, for example, a brightness enhancement film BEF series manufactured by 3M Company can be used.

(2) Reflective polarizing sheet The reflective polarizing sheet in this embodiment transmits only a first linearly polarized light component (for example, P-polarized light), and a second linearly polarized light component that is orthogonal to the first linearly polarized light component. It has a function of reflecting (for example, S-polarized light) without absorbing it. The second linearly polarized light component reflected by the reflective polarizing sheet is reflected again, and in a depolarized state (a state that includes both the first linearly polarized light component and the second linearly polarized light component), The light is incident on a reflective polarizing sheet. Therefore, the reflective polarizing sheet transmits the first linearly polarized light component of the light that enters again, and the second linearly polarized light component that is perpendicular to the first linearly polarized light component is reflected again.

Thereafter, by repeating the same process as above, approximately 70% or more and 80% or less of the light emitted from the second layer is emitted as the first linearly polarized component. Therefore, when the surface emitting device of this embodiment is used in a display device, the polarization direction of the first linearly polarized light component (transmission axis component) of the reflective polarizing sheet is made to match the transmission axis direction of the polarizing plate of the display panel. As a result, all the light emitted from the surface emitting device can be used for image formation on the display panel. Therefore, even if the light energy input from the LED element is the same, it is possible to form an image with higher brightness than when no reflective polarizing sheet is provided.

Examples of reflective polarizing sheets include the DBEF series of brightness enhancement films manufactured by 3M. Further, as the reflective polarizing sheet, for example, a high brightness polarizing sheet WRPS manufactured by Shinwha Intertek and a wire grid polarizer can also be used.

7. Application The application of the surface emitting device in this embodiment is not particularly limited, but it can be suitably used for a display device. It can also be used for lighting devices and the like.

II. Second Embodiment Next, a second embodiment of the surface emitting device of this embodiment will be described.
FIG. 10 is a schematic cross-sectional view showing an example of the surface emitting device of this embodiment. As illustrated in FIG. 10, the surface emitting device 1 of this embodiment includes a support substrate 2, an LED board 4 having an LED element 3 disposed on one side of the support substrate 2, and an LED on the LED board 4. A sealing member 5 disposed on the side of the element 3 side and sealing the LED element 3; a diffusion member 6 disposed on the side of the sealing member 5 opposite to the LED substrate 4 side; and the LED substrate. 4, and an anti-warpage layer 7 disposed on the opposite surface of the sealing member 5. The sealing member 5 in this embodiment has a haze value of 4% or more, is thicker than the LED element 3, and has a linear expansion coefficient of the material constituting the warp prevention layer 7. It is characterized by having a coefficient of linear expansion equal to or larger than that of the material constituting No. 5.

In the surface emitting device of this embodiment, when a means such as thermocompression bonding is used to bond the sealing member and the LED substrate, the line between the LED substrate and the sealing member is removed during subsequent cooling. Warpage may occur due to differences in expansion coefficients.
Further, when the surface emitting device is used at extremely high or low temperatures, warpage may occur due to the difference in linear expansion coefficient between the LED substrate and the sealing member.

This embodiment, like the first embodiment, has been made to solve this problem, and the warpage prevention layer is arranged on the surface of the LED board opposite to the sealing member. However, the problem of warping described above is solved by making the coefficient of linear expansion of the material constituting the warpage prevention layer equal to or larger than the coefficient of linear expansion of the material constituting the sealing member. .

The surface emitting device of this embodiment will be described below. Note that this embodiment is the same as the first embodiment above, except that the arrangement position of the warpage prevention layer and the material constituting the warpage prevention layer are different. Descriptions of components other than the prevention layer will be omitted.

1. Warpage prevention layer The warpage prevention layer in this embodiment is a layer disposed on the surface of the LED board opposite to the sealing member.
In this embodiment, the coefficient of linear expansion of the material constituting the warpage prevention layer is equal to or greater than the coefficient of linear expansion of the material constituting the sealing member. The reason why warping can be prevented by making the coefficient of linear expansion of the material constituting the warpage prevention layer equal to or larger than the coefficient of linear expansion of the material constituting the sealing member is as follows.

That is, when manufacturing a surface emitting device, there is a step of thermocompression bonding the sealing member and the LED substrate, but the sealing member shrinks more than the LED substrate when cooled after the thermocompression bonding. At this time, since a warpage prevention layer having a coefficient of linear expansion equal to or larger than the sealing member is disposed on the surface of the LED board opposite to the sealing member, the warpage is prevented due to contraction of the sealing member. Since the prevention layer also contracts, it becomes possible to reduce the degree of warpage of the LED board, and as a result, it becomes possible to suppress the occurrence of warpage.

a) Coefficient of Linear Expansion In this embodiment, the larger the difference in the coefficient of linear expansion between the material constituting the warpage prevention layer and the material constituting the sealing member, the better; Considering the material used for the stop member, there are certain limitations. Therefore, the difference in linear expansion coefficients is usually 400×10 ⁻⁶ /°C or less, and may be equivalent.

In addition, equivalent in this embodiment means within the range of 0.8 or more and 1.2 or less, especially 0.95 or more and 1.0 or less, when the linear expansion coefficient of the material constituting the sealing member is 1. This refers to cases within the range.

The coefficient of linear expansion of the material constituting such a warpage prevention layer is usually within the range of 300 x 10 ^-6 /°C or more and 500 x 10 ^-6 /°C, particularly 350 x 10 ^-6 /°C or more and 450 x 10 A temperature within the range of ^-6 /℃ or less is used.
The linear expansion coefficient in this embodiment is measured by the same method as described in the first embodiment.

b) Thickness The thickness of the anti-warp layer in this embodiment is preferably 25% or more of the thickness of the sealing member, particularly 35% or more, particularly preferably 45% or more. Note that the upper limit is set to 50% or less from the concept of making the device more compact. Within the above range, it is possible to obtain a warping prevention effect, and it does not prevent the device from being made more compact.

c) Elastic modulus The elastic modulus of the warpage prevention layer used in this embodiment is preferably equal to or higher than the elastic modulus of the sealing member.
Specifically, when the elastic modulus of the sealing member is 1, it is preferably 0.8 or more, particularly preferably 0.9 or more. Note that it is usually 2.5 or less.

Further, as an actual value, it is preferably 35 MPa or more, particularly preferably 40 MPa or more, and especially preferably 85 MPa or more. This is because if the elastic modulus is lower than the above range, the warpage prevention effect will be reduced. In addition, when considering the materials normally used, the pressure is 300 MPa or less.

The elastic modulus is measured by tensile measurement as described below.
・Measuring device: Instron universal material testing machine 5565
・Load cell: 1kN
・Sample width: 10mm
・Distance between chucks: 50mm
・Speed: 300mm/min

d) Material The material constituting the warpage prevention layer used in this embodiment is not particularly limited as long as it has the above characteristics, but among them, materials similar to those used as the sealing member can be used. .
A preferred material is an olefin resin. Also, among the olefin resins, polyethylene resins, polypropylene resins, and ionomer resins are preferred.

(2) Others It is preferable that the anti-warpage layer in this embodiment is in close contact with the LED substrate. This is because the warpage prevention effect can be further improved.
The specific degree of adhesion and the like are the same as in the first embodiment, so a description thereof will be omitted here.
Examples of methods for bringing the warpage prevention layer and the LED board into close contact include a method of disposing an adhesive layer between the two and adhering them, and a method of melting and adhering the warpage prevention layer by thermocompression bonding. .

III. Third Embodiment The surface emitting device of this embodiment uses an anti-foaming layer instead of the anti-warpage layer in the first embodiment, and the elastic modulus of the anti-foaming layer is 500 MPa or more. There are two embodiments: a certain embodiment and an embodiment in which the foaming prevention layer has a melting point of 140° C. or higher.

In conventional surface emitting devices, for example, when the surface emitting device is used at extremely high temperatures for a long period of time, there is a problem in that air bubbles are generated between the LED substrate and the sealing member. This may be caused by gas generated from the LED board due to heating, or when a reflective layer, etc. is provided on the LED board, air may be present between the LED board and the reflective layer due to air entrapment at the interface. This occurs due to reasons such as oozing along the surface.

The LED element sealed in the sealing member has the light emitting surface of the sealing member and the LED element directly joined, and the difference in refractive index at the interface is smaller, so light is extracted compared to an unsealed LED element. Increased efficiency. However, if such bubbles exist, the above-mentioned improvement in light extraction efficiency cannot be obtained, and as a result, a problem arises in that the luminous efficiency of the surface emitting device is reduced.

In this embodiment, by providing the anti-foaming layer having the above-mentioned characteristics, it is possible to suppress deformation in which the surface shape of the sealing member becomes convex, which is assumed to occur during foaming.
As a result, even if gas is generated from the LED board, for example, the presence of the anti-foaming layer applies pressure to the sealing member, making it possible to prevent the generated gas from becoming bubbles. .

The elastic modulus of the anti-foaming layer used in this embodiment may be at least 500 MPa, preferably at least 1,000 MPa, particularly preferably at least 4,000 MPa.

This is because if the elastic modulus is lower than the above range, the effect of suppressing bubble generation will be reduced.
Note that the pressure is 5,500 MPa or less when commonly used materials are taken into consideration.

The melting point of the anti-foaming layer in this embodiment may be 140°C or higher, but preferably 260°C or higher. Note that the upper limit is 350° C. or less, taking into consideration the materials normally used.

In this embodiment, it is more preferable to use an antifoaming layer having the above-mentioned elastic modulus and the above-mentioned melting point.
The method for measuring the elastic modulus and melting point is the same as that described in the first embodiment.

Unlike the anti-warpage layer described above, the anti-foaming layer used in this embodiment does not necessarily have a coefficient of linear expansion within a predetermined range. However, since the foam prevention layer has a linear expansion coefficient similar to that of the warpage prevention layer in the first embodiment, it is possible to obtain the same warpage prevention effect as in the first embodiment. can do.

The other points of the surface emitting device of this embodiment are the same as those of the surface emitting device of the first embodiment except that the anti-warpage layer is replaced with the anti-foaming layer, so the explanation here will be omitted.

B. Display Device The present disclosure provides a display device including a display panel and the above-described surface emitting device disposed on the back surface of the display panel.

FIG. 11 is a schematic diagram showing an example of a display device of the present disclosure. As illustrated in FIG. 11, the display device 100 includes a display panel 31 and a surface emitting device 1 according to the present disclosure, which is disposed on the back surface of the display panel 31.

According to the present disclosure, by having the above-described surface emitting device, it is possible to achieve a reduction in thickness while improving in-plane uniformity of brightness. Therefore, a high quality display device can be obtained.

1. Surface Emitting Device The surface emitting device according to the present disclosure is the same as that described in the section “A. Surface emitting device” above.

2. Display Panel The display panel in the present disclosure is not particularly limited, and includes, for example, a liquid crystal panel.

C. Method for manufacturing surface emitting device The present disclosure provides a method for manufacturing the surface emitting device according to the first embodiment. The present disclosure can be divided into two embodiments.

I. First Embodiment The method for manufacturing a surface emitting device of this embodiment is the manufacturing method described in the first embodiment of the surface emitting device, in which the warpage prevention layer, the sealing member, and the LED element are The present invention is characterized by the step of preparing a laminate in which the LED substrates are arranged in this order so as to be on the side of the sealing member, and bonding the laminate by thermocompression.
In this embodiment, first, a laminate in which the LED substrate, the sealing member, and the anti-warpage layer are arranged in this order is prepared.

Here, the LED substrate, the sealing member, and the anti-warpage layer are the same as those described in the first embodiment of the surface emitting device, so their descriptions will be omitted here.
Next, a step of thermocompression bonding the laminate is performed.

The thermocompression bonding method in this embodiment is not particularly limited as long as it can thermocompression bond them, but vacuum lamination, vacuum packing, heat lamination, etc. can be used.

In this embodiment, a surface emitting device can be manufactured by arranging a diffusion member on the warpage prevention layer side of the press-bonded laminate and bonding it using an adhesive or the like.

II. Second Embodiment The method for manufacturing a surface emitting device according to the present embodiment is the manufacturing method described in the first embodiment of the surface emitting device, in which the warp prevention layer and the sealing member are laminated. a step of thermocompression-bonding a first laminate, and a step of arranging the LED substrate on the surface of the thermocompression-bonded first laminate on the sealing member side, with the LED element disposed on the sealing member side; The method is characterized by comprising a step of thermocompression bonding the two laminates.

In this embodiment, first, a first laminate in which the warpage prevention layer and the sealing member are stacked is prepared. Next, the first laminate is thermocompression bonded by the same method as in the first embodiment.

Next, a second laminate in which the LED board is disposed on the sealing member side surface of the first laminate that has been thermocompression bonded is thermocompression bonded by the same method as in the first embodiment.
In this embodiment, a surface emitting device can be manufactured by arranging a diffusion member on the warpage prevention layer side of the press-bonded second laminate and bonding it using an adhesive or the like.

D. Sealing member sheet for surface light emitting device The sealing member sheet for surface light emitting device of the present disclosure has the following two aspects.

1. First Aspect The sealing member sheet for a surface emitting device of the present embodiment includes a sealing member for sealing an LED element and a warpage prevention layer disposed on one side of the sealing member. This is a sealing member sheet for a surface emitting device used in a surface emitting device, in which the linear expansion coefficient of the material constituting the warpage prevention layer is -15×10 ⁻⁶ /°C or more 10×10 ⁻⁶ /°C. It is characterized by being within a range of ℃ or less.

The surface emitting device includes a support substrate, an LED substrate having the LED element disposed on one side of the support substrate, the sealing member disposed on the LED element side of the LED substrate, and the warpage. The prevention layer and the diffusion prevention member are laminated in this order.

The warpage prevention layer used in this embodiment is the same as that described in the first embodiment of the surface emitting device. Further, the LED substrate, the sealing member, and the anti-reflection member are the same as those described in the surface emitting device, so their descriptions will be omitted here.

2. Second Aspect The encapsulant sheet for a surface emitting device of this embodiment includes a laminate of a encapsulating member for encapsulating an LED element and an anti-foaming layer disposed on one surface of the encapsulating member. A sealing member sheet for a surface emitting device used in a surface emitting device, wherein the elastic modulus of the material constituting the foam prevention layer is 500 MPa or more, and the melting point of the material constituting the foam prevention layer. It has two forms, one in which the temperature is 140°C or higher.

The surface emitting device includes a support substrate, an LED substrate having the LED element disposed on one side of the support substrate, the sealing member disposed on the LED element side of the LED substrate, and the foamed The prevention layer and the diffusion prevention member are laminated in this order.

The anti-foaming layer used in this embodiment is the same as that described in the third embodiment of the surface emitting device. Further, the LED substrate, the sealing member, and the anti-reflection member are the same as those described in the surface emitting device, so their descriptions will be omitted here.

Note that the present disclosure is not limited to the above embodiments. The above-mentioned embodiments are illustrative, and any embodiment that has substantially the same configuration as the technical idea stated in the claims of the present disclosure and provides similar effects is the present invention. within the technical scope of the disclosure.

Below, experimental examples related to the sealing member will be shown, and then examples and comparative examples of the present disclosure will be shown to explain the present disclosure in further detail.

A. Experimental example (Experimental example 1)
As shown in FIG. 11, a surface emitting device 1 is manufactured which includes a support substrate 2, a light emitting diode substrate 4 having a light emitting diode element 3, a sealing member A (thickness: 450 μm) 5, a diffusion member A6, and a wavelength conversion member 9. did. Table 1 shows the haze value, layer structure, density, and transmittance at a wavelength of 450 nm of the sealing member A. Table 2 shows the evaluation results of brightness unevenness evaluated by the following method.

The members used are as follows.
- Light emitting diode substrate LED chips B0815ACQ0 (chip size 0.2 mm x 0.4 mm, manufactured by Generites) were squarely arranged on a support substrate (reflectance 95%) at a pitch of 6 mm.
・Diffusion member A (diffusion plate)
55K3 (manufactured by Entire)
・Wavelength conversion member (QD)
QF-6000 (manufactured by Showa Denko Materials)

The thickness of the sealing member and the optical properties shown in Table 1 were determined by measuring the sealing member sample after the sealing member sheet was sandwiched between ETFE films (thickness 100 μm) and heat treated by vacuum lamination. This is the value. The optical properties were measured by peeling off the ETFE film and measuring only the sealing member sample. The vacuum lamination conditions were as follows.

(Vacuum lamination conditions)
(a) Vacuuming: 5.0 minutes (b) Pressure: changed from 0 kPa to 100 kPa in 5 seconds (c) Pressure maintenance: (100 kPa): 7 minutes (d) Temperature: 150°C

(Experiment example 2)
The occurrence of brightness unevenness was evaluated in the same manner as in Experimental Example 1, except that the following diffusion member B was used instead of the diffusion member A. The results are shown in Table 2.
・Diffusion member B
A second diffusion member having a prism structure in which a prism surface is formed on the light emitting diode element side as a first layer, and a dielectric multilayer film as a second layer.

(Experiment examples 3 and 4)
The occurrence of brightness unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that instead of sealing member A, sealing member B (thickness: 450 μm) shown in Table 1 was used.

(Experiment Examples 5 and 6)
The occurrence of brightness unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that instead of the sealing member A, the sealing member D (thickness: 450 μm) shown in Table 1 was used.

(Comparison experiment examples 1 and 2)
The occurrence of brightness unevenness was evaluated in the same manner as Experimental Examples 1 and 2, except that instead of the sealing member A, a pin was provided between the diffusion member and the light emitting diode substrate. The results are shown in Table 2. At this time, the distance between the light emitting diode element and the diffusion member was 500 μm.

(Comparison experiment examples 3 and 4)
The occurrence of brightness unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that instead of the sealing member A, a cured Si product (thickness: 450 μm) using a highly transparent potting type liquid silicone composition was provided. The results are shown in Table 2.

(Comparison experiment examples 5 and 6)
The occurrence of brightness unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that instead of the sealing member A, the sealing member C (thickness: 450 μm) shown in Table 1 was used. The results are shown in Table 2.

[Brightness unevenness evaluation method]
Regarding the obtained surface emitting device, the luminance during LED emission was measured using a two-dimensional color luminance meter CA2000, and luminance unevenness was evaluated. The index of brightness unevenness was determined as follows based on the uniformity value.

[Evaluation criteria]
Uniformity = minimum value of front brightness / maximum value of front brightness A: Uniformity greater than 0.9 B: Uniformity 0.8 or more and 0.9 or less C: Uniformity less than 0.8

The surface emitting devices (Experimental Examples 1 to 6) according to the present disclosure were able to suppress the occurrence of uneven brightness, while comparative Experimental Examples 1 and 2 in which pins were provided in place of the sealing member A, and liquid Si In Comparative Experimental Examples 3 and 4 using the cured product and Comparative Experimental Examples 5 and 6 using the sealing member C having a low haze value, it was not possible to suppress the occurrence of brightness unevenness.

B. Examples of the first embodiment and the second embodiment Examples of surface emitting devices of the first embodiment and the second embodiment will be shown below.

[Example B-1]
(Formation of laminate of sealing member and warpage prevention layer)
To 100 parts by mass of the following base resin 1, 5 parts by mass of Additive Resin 1 (weathering agent masterbatch) and 20 parts by mass of Additive Resin 2 (silane-modified polyethylene resin) were mixed to form a PET film integrated seal. A composition for a sealing member for molding a sealing member material was obtained.

・Base resin 1
A metallocene-based linear low-density polyethylene resin (M-LLDPE) having a density of 0.901 g/cm ³ , a melting point of 93°C, and an MFR at 190°C of 2.0 g/10 minutes.

・Additional resin 1 (weathering agent masterbatch)
KEMISTAB62 (HALS): 0.6 parts by mass for 100 parts by mass of a low-density polyethylene resin having a density of 0.919 g/cm ³ and an MFR of 3.5 g/10 min at 190°C.
KEMISORB12 (UV absorber): 3.5 parts by mass. KEMISORB79 (UV absorber): Masterbatch containing 0.6 parts by mass

・Additional resin 2 (silane modified polyethylene resin)
5 ^parts by mass of vinyltrimethoxysilane and a radical generator (reaction catalyst ) and 0.15 parts by mass of dicumyl peroxide as a silane-modified polyethylene resin obtained by melting and kneading at 200°C. This additive resin 2 has a density of 0.901 g/cm ³ and an MFR of 1.0 g/10 minutes.

Next, a biaxially stretched polyethylene terephthalate film (optical grade) with a film thickness of 50 μm was used as a warpage prevention layer, and this was integrated by pressure bonding with the film into which the above-described composition for a sealing member was melt-extruded. A warp prevention layer laminate was formed in which a warp prevention layer and a sealing member having a film thickness of 300 μm were laminated.

Next, the PCB substrate and the warpage prevention layer laminate were laminated using a vacuum laminator. The PCB board is a layered layer of white paint, copper, and glass epoxy in this order.

From the hot plate side of the vacuum laminator, place the hot plate, Teflon (registered trademark) coated glass sheet 0.3 mm, glass (thickness 3 mm), release PET (release surface: top), and glass epoxy side on the above release PET side. The above PCB substrate, the warpage prevention layer laminate with the sealing member on the PCB substrate side, release PET (release surface: bottom), glass (thickness 3 mm), and Teflon (registered trademark) coated glass sheet. In a state in which 0.3 mm thick layers were laminated, lamination processing was performed using a vacuum heating laminator under the conditions of the vacuum laminator: 130° C. for 8 minutes. After lamination was completed, the glass sheet was moved to a cooling rack and cooled for about 10 to 15 minutes to obtain a sealing member laminate of the first embodiment. Various evaluations were performed regarding the sealing member laminate as a surface emitting device.

[Example B-2]
A sealing member laminate of the first embodiment was obtained in the same manner as in Example B-1 except that the thickness of the warpage prevention layer was 100 μm.

[Example B-3]
The same composition for a sealing member as in Example B-1 and the same PCB substrate as in Example B-1 were used.
First, a film in which the composition for a sealing member is melt-extruded is bonded to the glass epoxy surface of the PCB member to a thickness of 160 μm as a warpage prevention layer, and then to the white painted surface of the PCB member. A film in which the composition for a sealing member was melt-extruded was bonded to a film thickness of 240 μm to obtain a sealing member laminate of the second embodiment.

[Example B-4]
A sealing member laminate of the second embodiment was obtained in the same manner as in Example B-3 except that the thickness of the sealing member was 320 μm and the thickness of the anti-warpage layer was 80 μm.

[Example B-5]
A sealing member laminate of the first embodiment was obtained in the same manner as in Example B-2, except that a biaxially stretched polyethylene terephthalate film (general-purpose grade) different from that in Example 2 was used as the warpage prevention layer. .
[Example B-6]
A sealing member laminate was obtained in the same manner as in Example B-1, except that the sealing member laminate was produced by bonding the sealing member and the anti-warpage layer with a dry lamination adhesive.
The main ingredient of the adhesive for dry lamination was polycarbonate urethane, and the curing agent was an isocyanate curing agent. Further, the blending ratio of the base resin and the curing agent was 10:1, and the base resin and the curing agent were dissolved in a solvent to each have a concentration of 50% by mass (ethyl acetate solution).

Sealing member lamination for backlights, in which PET and sheet-shaped sealing members are bonded and laminated using a laminator capable of dry lamination using a two-component adhesive consisting of the above-mentioned main ingredient and curing agent. manufactured the body. A biaxially oriented polyethylene terephthalate film (optical grade) was used as the PET film. This PET film was fed out from the first paper feed side of the laminator, and the adhesive was dissolved in the solvent ethyl acetate on the PET surface to determine the solid content coating amount. Gravure coating was performed to give a thickness of 2 to 15 g/m2 (film thickness after curing: 2 to 15 μm), and the solvent was evaporated and dried in a drying hood at about 70 to 90° C. to prepare an adhesive surface. Thereafter, the sealing member was fed out from the second paper feed and bonded using nip rolls to form a PET/adhesive/sealing member, and then rolled up using a winding unit to produce a sealing member laminate. Further, after producing the laminated roll, it was cured by aging treatment at 30 to 50°C for about 70 to 200 hours.

[Comparative example B-1]
A sealing member laminate was obtained in the same manner as in Example B-1, except that the warpage prevention layer laminate was used as a sealing member with a film thickness of 400 μm.

[Comparative example B-2]
A sealing member laminate of the first embodiment was obtained in the same manner as in Example B-1, except that a polycarbonate film (standard grade) with a film thickness of 100 μm was used as the warpage prevention layer.

[Evaluation method]
(linear expansion coefficient)
For a sheet cut to 5 mm x 20 mm, the dimensional change was measured when the temperature was raised and then lowered to room temperature in accordance with JIS K7197, and the linear expansion coefficient from 100°C to 25°C was averaged and calculated. The linear expansion coefficient here takes a positive value during contraction and a negative value during expansion. The measurement was performed using the following measuring device and measurement conditions.
・Measuring device: Seiko Instruments thermomechanical device (TMA/SS-6000)
・Constant load tension mode: 0.1mN
・Measurement temperature range: -50℃ to 160℃
・Linear expansion coefficient calculation temperature range: 25℃~100℃

(Modulus of elasticity)
The tensile measurements were carried out as shown below.
(Measuring method)
・Measuring device: Instron universal material testing machine 5565
・Load cell: 1kN
・Sample width: 10mm
・Distance between chucks: 50mm
・Speed: 300mm/min

(melting point)
Measurement was performed using a differential scanning calorimeter (DSC-60 Plus, manufactured by Shimadzu Corporation) in accordance with JIS K 7121.

(Total light transmittance)
Measured by a method based on JIS K7361-1:1997.

(Haze value)
It was measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory) in accordance with JIS K7136.

(Amount of warpage)
Immediately after vacuum lamination, each sealing member laminate is allowed to stand on a horizontal surface in an environment at room temperature for 24 hours or more. Thereafter, the height from the horizontal plane of the corner to the bottom of the substrate was measured using a steel straightedge in accordance with JIS B 7514.

(Foaming test)
Immediately after vacuum lamination, each sealing member laminate was placed in a constant temperature bath at 100° C. for 1000 hours in accordance with JIS C 60068-2-2, and the presence or absence of foaming was observed.

(brightness unevenness)
A diffusion member was placed on the sealing member side surface of the sealing member laminate obtained in Examples B-1 to B-6 and Comparative Examples B-1 to B-2, and each A surface emitting device corresponding to the above was obtained. The measurement method and evaluation criteria for brightness unevenness are the same as those shown in the above experimental example. Further, as the diffusion member, the same one as the diffusion member B used in Experimental Example 2 was used.

The results are shown in Table 3.

C. Example of Third Embodiment Next, an example of the surface emitting device of the third embodiment will be described.

[Example C-1]
A sealing member laminate of the third embodiment was obtained in the same manner as in Example B-1 above, except that a biaxially stretched polyethylene terephthalate film (optical grade) having a thickness of 35 μm was used as the foaming prevention layer. Various evaluations were performed regarding the sealing member laminate as a surface emitting device.

[Example C-2]
A sealing member laminate was obtained in the same manner as in Example B-1 above, except that the anti-warping layer was used as the anti-foaming layer.

[Example C-3]
A sealing member laminate was obtained in the same manner as in Example B-2 above, except that the anti-warping layer was used as the anti-foaming layer.

[Example C-4]
A sealing member laminate was obtained in the same manner as in Example B-1 above, except that random polypropylene with a film thickness of 100 μm was used as the foaming prevention layer.

[Example C-5]
A sealing member laminate was obtained in the same manner as in Comparative Example B-2 above, except that the anti-warping layer was used as the anti-foaming layer.

[Comparative example C-1]
A sealing member laminate was obtained in the same manner as Comparative Example B-1.

[Evaluation method]
The elastic modulus, melting point, and foaming test were conducted in the same manner as in "B. Examples of the first embodiment and the second embodiment" above.
The results are shown in Table 4.

That is, the present disclosure can provide the following inventions.
[1] A surface-emitting device for use in a surface-emitting device, in which a sealing member for sealing a light-emitting diode element and a warpage prevention layer arranged on one side of the sealing member are laminated. A sealing member sheet for a surface emitting device, wherein the linear expansion coefficient of the material constituting the warpage prevention layer is within the range of -15×10 ^-6 /°C or more and 10×10 ^-6 /°C or less. Stopper sheet.
[2] The sealing member sheet for a surface emitting device according to [1], wherein the thickness of the sealing member is 50 μm or more and 800 μm or less.
[3] The sealing member sheet for a surface emitting device according to [1] or [2], wherein the sealing member includes a thermoplastic resin.
[4] The surface emitting device according to any one of [1] to [3], wherein the sealing member has a polyethylene resin having a density of 0.870 g/cm ³ or more and 0.930 g/cm ³ or less as a base resin. Sealing material sheet for equipment.
[5] The surface emitting device according to any one of [1] to [4], wherein the sealing member has a core layer and a skin layer disposed on at least one surface side of the core layer. Sealing material sheet.
[6] The sealing member sheet for a surface emitting device according to [5], wherein the core layer and the skin layer have different melting points of thermoplastic resins contained as base resins.
[7] The sealing member sheet for a surface emitting device according to [6] or [7], wherein the sealing member has a thermoplastic resin having a melting point of 90° C. or higher and 120° C. or lower as the base resin of the core layer. .
[8] The core layer in the sealing member uses a polyethylene resin as a base resin having a density of 0.900 g/cm ³ or more and 0.930 g/cm ³ or less, and the skin layer has a density of 0.875 g/cm ³ or more. For a surface emitting device according to any one of [5] to [7], wherein the base resin is a polyethylene resin having a density of 0.910 g/cm ³ or less and lower density than the base resin for the core layer. Sealing material sheet.
[9] A surface light emitting device for use in a surface light emitting device, which is formed by laminating a sealing member for sealing a light emitting diode element and an anti-foaming layer disposed on one side of the sealing member. A sealing member sheet for a surface emitting device, wherein the material constituting the anti-foaming layer has an elastic modulus of 500 MPa or more.
[10] A surface-emitting device for use in a surface-emitting device, which is formed by laminating a sealing member for sealing a light-emitting diode element and an anti-foaming layer disposed on one side of the sealing member. A sealing member sheet for a surface emitting device, wherein a material constituting the anti-foaming layer has a melting point of 140°C or higher.
[11] A support substrate, a light emitting diode substrate having a light emitting diode element disposed on one side of the support substrate, and a light emitting diode substrate disposed on the surface of the light emitting diode element side of the light emitting diode substrate, the light emitting diode element being disposed on the side of the light emitting diode element, a sealing member to be sealed; a warpage prevention layer disposed on a surface of the sealing member opposite to the light emitting diode substrate; and a warpage prevention layer disposed on a surface of the warpage prevention layer opposite to the light emitting diode substrate. a diffusion member, the sealing member has a haze value of 4% or more, is thicker than the thickness of the light emitting diode element, and has a linear expansion of the material constituting the warpage prevention layer. A surface emitting device having a coefficient within a range of -15×10 ⁻⁶ /°C or more and 10×10 ⁻⁶ /°C or less.
[12] a support substrate; a light emitting diode substrate having a light emitting diode element disposed on one surface side of the support substrate; and a light emitting diode substrate disposed on a surface of the light emitting diode substrate on the light emitting diode element side, a sealing member to be sealed; a diffusion member disposed on a surface of the sealing member opposite to the light emitting diode substrate; and a warp disposed on a surface of the light emitting diode substrate opposite to the light emitting diode element. A surface emitting device having a prevention layer, wherein the sealing member has a haze value of 4% or more, is thicker than the thickness of the light emitting diode element, and has a linear expansion of a material constituting the warpage prevention layer. A surface emitting device having a coefficient equal to or larger than a linear expansion coefficient of a material constituting the sealing member.
[13] The surface emitting device according to [11] or [12], wherein the thickness of the sealing member is 50 μm or more and 800 μm or less.
[14] The surface emitting device according to any one of [11] to [13], wherein the sealing member includes a thermoplastic resin.
[15] The surface emitting device according to any one of [11] to [14], wherein the sealing member has a polyethylene resin having a density of 0.870 g/cm ³ or more and 0.930 g/cm ³ or less as a base resin. Device.
[16] The surface emitting device according to any one of [11] to [15], wherein the sealing member includes a core layer and a skin layer disposed on at least one surface side of the core layer.
[17] The surface emitting device according to [16], wherein the core layer and the skin layer have different melting points of thermoplastic resins contained as base resins.
[18] The surface emitting device according to [16] or [17], wherein the sealing member has a thermoplastic resin having a melting point of 90° C. or higher and 120° C. or lower as the base resin of the core layer.
[19] The core layer in the sealing member uses a polyethylene resin as a base resin having a density of 0.900 g/cm ³ or more and 0.930 g/cm ³ or less, and the skin layer has a density of 0.875 g/cm ³ or more. The surface emitting device according to any one of [16] to [18], wherein the base resin is a polyethylene resin having a density of 0.910 g/cm ³ or less and lower than the base resin for the core layer.
[20] A display device comprising a display panel and the surface emitting device according to any one of [11] to [19], which is disposed on the back surface of the display panel.
[21] The method for manufacturing a surface emitting device according to [11], wherein the light emitting diode is arranged such that the anti-warpage layer, the sealing member, and the light emitting diode element are on the side of the sealing member. A method for manufacturing a surface emitting device, comprising the steps of preparing a laminate in which the substrates are arranged in this order, and bonding the laminate by thermocompression.
[22] The method for manufacturing the surface emitting device described in [11], which includes the step of thermocompression bonding the first laminate in which the warpage prevention layer and the sealing member are laminated, and thermocompression-bonding a second laminate in which the light emitting diode substrate, in which the light emitting diode element is placed on the sealing member side, is arranged on the surface of the first laminate facing the sealing member; A method for manufacturing a surface emitting device.

DESCRIPTION OF SYMBOLS 1, 10... Surface emitting device 2... Support substrate 3... LED element 4... LED board 5... Sealing member 6... Diffusion member 7... Warpage prevention layer 100... Display device

Claims (10)

a light emitting diode substrate having a support substrate and a light emitting diode element disposed on one side of the support substrate;
a sealing member disposed on a surface of the light emitting diode element side of the light emitting diode substrate and sealing the light emitting diode element;
a warpage prevention layer disposed on a surface of the sealing member opposite to the light emitting diode substrate;
A surface emitting device comprising: a diffusion member disposed on a surface of the anti-warpage layer opposite to the light emitting diode substrate;
The sealing member has a haze value of 4% or more,
The thickness of the sealing member is 50 μm or more and 800 μm or less,
The sealing member is made of polyolefin resin,
The linear expansion coefficient of the material constituting the warpage prevention layer is within the range of -15 x 10 ^-6 /°C or more and 10 x 10 ^-6 /°C or less,
The linear expansion coefficient of the supporting substrate is within the range of 5×10 ⁻⁶ /°C or more and 100×10 ⁻⁶ /°C or less,
A surface emitting device in which the warpage prevention layer and the sealing member are in close contact with each other. The surface emitting device according to claim 1, wherein the sealing member has a polyethylene resin having a density of 0.870 g/cm ³ or more and 0.930 g/cm ³ or less as a base resin. The surface emitting device according to claim 1, wherein the sealing member includes a core layer and a skin layer disposed on at least one side of the core layer. having the skin layer on the anti-warpage layer side,
The skin layer has a density of 0.875 g/cm ³ or more and 0.910 g/cm ³ or less, a melting point of 50° or more and 100° C. or less, and a silane copolymer content of 5% by mass or more and 40% by mass. The surface emitting device according to claim 3, which is the following. The surface emitting device according to claim 3, wherein the core layer and the skin layer have different melting points of thermoplastic resins contained as base resins. The surface emitting device according to claim 3, wherein the sealing member has a thermoplastic resin having a melting point of 90° C. or higher and 120° C. or lower as the base resin of the core layer. The core layer in the sealing member has a base resin made of polyethylene resin having a density of 0.900 g/cm ³ or more and 0.930 g/cm ³ or less, and the skin layer has a density of 0.875 g/cm ³ or more and 0.910 g or less. 4. The surface emitting device according to claim ³ , wherein the base resin is a polyethylene resin having a density of less than /cm3 and lower density than the base resin for the core layer. a display panel;
A display device comprising the surface emitting device according to any one of claims 1 to 7, disposed on the back surface of the display panel. A method for manufacturing a surface emitting device according to claim 1, comprising:
A laminate is prepared in which the warpage prevention layer, the sealing member, and the light emitting diode substrate with the light emitting diode element facing the sealing member are arranged in this order, and the laminate is bonded by thermocompression. A method for manufacturing a surface emitting device, comprising steps. A method for manufacturing a surface emitting device according to claim 1, comprising:
a step of thermocompression bonding a first laminate in which the warpage prevention layer and the sealing member are laminated;
Thermocompression bonding a second laminate in which the light emitting diode substrate, in which the light emitting diode element is placed on the sealing member side, is arranged on the sealing member side surface of the thermocompression bonded first laminate; and,
A method for manufacturing a surface emitting device, comprising:

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