WO2012081410A1 - Light diffusing member, method for manufacturing same, and display device - Google Patents

Abstract

Disclosed is a light diffusing member, which is provided with: a base material having light transmitting characteristics; a plurality of light diffusing sections formed on one surface of the base material; and light blocking layers, which are formed in regions on the one surface of the base material, said regions being different from the regions where the light diffusing sections are formed. Each of the light diffusing sections has a light outputting end surface on the base material side, and a light inputting end surface, which is positioned on the side opposite to the base material side, and which has an area larger than that of the light outputting end surface. The value of the distance from the light inputting end surface to the light outputting end surface of the light diffusing section is larger than the value of the thickness of the light blocking layer. The light diffusing section is configured of two or more layers laminated on the base material.

Description

Light diffusing member, manufacturing method thereof, and display device

The present invention relates to a light diffusing member, a manufacturing method thereof, and a display device.
This application claims priority based on Japanese Patent Application No. 2010-278573 filed in Japan on December 14, 2010, the contents of which are incorporated herein by reference.

2. Description of the Related Art Liquid crystal display devices are widely used as portable electronic devices such as cellular phones or displays for televisions, personal computers, and the like. However, in general, liquid crystal display devices are known to have excellent visibility from the front, but have a narrow viewing angle. Various devices have been devised for widening the viewing angle. As one of them, a configuration in which a member for diffusing light emitted from a display body such as a liquid crystal panel (hereinafter referred to as a light diffusing member) is provided on the viewing side of the display body can be considered.

For example, Patent Document 1 below discloses a light diffusion sheet that includes a sheet main body and a plurality of substantially wedge-shaped portions that are embedded on the emission surface side in the sheet main body and expand toward the emission surface side. . In this light diffusing sheet, the side surface of the substantially wedge-shaped portion is formed by a folded surface, and the angle formed by each folded surface of the side surface and the perpendicular of the incident surface becomes larger as it approaches the exit surface side. In this light diffusing sheet, the side surface of the substantially wedge-shaped portion is configured as described above, so that the light incident perpendicularly to the incident surface is totally reflected on the side surface a plurality of times to increase the diffusion angle.

JP 2005-157216 A

When manufacturing the light diffusion sheet described in Patent Document 1, it is extremely difficult to form a substantially wedge-shaped portion having a side surface composed of a plurality of bent surfaces on the sheet body. In addition, it is complicated to embed a UV curable resin or the like in the substantially wedge-shaped portion without a gap after forming the substantially wedge-shaped portion in the sheet body, and the manufacturing process becomes complicated. If, for example, the inclination angle of the bent surface cannot be formed with high accuracy or the resin is not sufficiently embedded in the substantially wedge-shaped portion, the desired light diffusion performance cannot be obtained.

An aspect of the present invention has been made to solve the above-described problems, and provides a light diffusing member capable of obtaining a desired light diffusing performance without complicating the manufacturing process, and a method for manufacturing the same. One of the purposes. Another object is to provide a display device including the light diffusing member and having excellent display quality.

In order to achieve the above object, a light diffusing member according to an aspect of the present invention includes a light-transmitting base material, a plurality of light diffusing portions formed on one surface of the base material, and one surface of the base material. A light-shielding layer formed in a region different from the formation region of the light diffusing portion, wherein the light diffusing portion is located on the base material side on the light emitting end surface, on the side opposite to the base material side, It has a light incident end face with an area larger than the area of the light exit end face, the dimension from the light entrance end face to the light exit end face of the light diffusing part is larger than the thickness of the light shielding layer, the light diffusing part, It consists of two or more layers laminated on the substrate.

In the light diffusing member according to an aspect of the present invention, the two or more layers constituting the light diffusing portion are made of at least two kinds of different materials, and the side surfaces of the two or more layers have different inclination angles. Good.

In the light diffusing member according to one aspect of the present invention, a light scatterer may be included in at least one of the two or more layers constituting the light diffusing portion.

The light diffusing member according to an aspect of the present invention may be configured such that the plurality of light diffusing portions have air in a gap between the plurality of light diffusing portions.

In the light diffusing member according to an aspect of the present invention, the plurality of light diffusing portions are arranged between the light diffusing portions so that the light diffusing portions are spaced apart from each other when viewed from the normal direction of the one surface of the base material. The light shielding layer may be arranged in a stripe shape when viewed from the normal direction of one surface of the substrate.

In the light diffusing member according to an aspect of the present invention, at least one of the dimension in the short direction of the plurality of light diffusing portions and the dimension in the short direction of the plurality of light shielding layers may be random.

In the light diffusing member according to an aspect of the present invention, the plurality of light diffusing portions are arranged in a scattered manner when viewed from the normal direction of one surface of the base material, and the light shielding layer is a region where the light diffusing portion is formed. It may be formed continuously in different regions.

In the light diffusing member according to one aspect of the present invention, the plurality of light diffusing portions may be randomly arranged as viewed from the normal direction of one surface of the base material.

In the light diffusing member according to one aspect of the present invention, the planar shape of the light diffusing portion viewed from the normal direction of one surface of the base material may be a circle or a polygon.

In the light diffusing member according to an aspect of the present invention, the light shielding layer may include any of black resin, black ink, a single metal, or a multilayer film of a single metal and a metal oxide.

According to another aspect of the present invention, there is provided a method for producing a light diffusing member, wherein a light-shielding layer having an opening is formed on one surface of a light-transmitting substrate, and at least two or more different materials are formed on one surface of the substrate. A plurality of negative photosensitive resin layers formed so as to cover the light shielding layer, from the surface opposite to the one surface of the substrate on which the light shielding layer and the plurality of negative photosensitive resin layers are formed, Exposing the plurality of negative photosensitive resin layers through the openings of the light shielding layer, developing the plurality of negative photosensitive resin layers after the exposure, and having a light emission end face on the substrate side, and Forming a plurality of light diffusing portions having a light incident end face having an area larger than the area of the light emitting end face on the opposite side of the base material side on one surface of the base material.

The light diffusing member manufacturing method according to another aspect of the present invention may use any one of black resin, black ink, a single metal, or a multilayer film of a single metal and a metal oxide as the material of the light shielding layer. Good.

A display device according to still another aspect of the present invention is provided on the viewing side of the display body and the viewing side of the display body, and emits light in a state in which the angular distribution of light incident from the display body is wider than before incidence. A viewing angle enlarging member that is made of the light diffusing member of the present invention.

In the display device according to still another aspect of the present invention, the display body includes a plurality of pixels that form a display image, and among the plurality of light diffusion portions of the light diffusion member, between adjacent light diffusion portions. The maximum pitch may be smaller than the pitch between the pixels of the display body.

In a display device according to still another aspect of the present invention, the display body includes a light source and a light modulation element that modulates light from the light source, and the light source emits directional light. Good.

In the display device according to still another aspect of the present invention, the display body may be a liquid crystal display element.

According to the aspect of the present invention, it is possible to provide a light diffusing member capable of obtaining a desired light diffusing performance and a manufacturing method thereof without complicating the manufacturing process. According to the aspect of the present invention, it is possible to provide a display device that includes the light diffusing member and is excellent in display quality.

It is a perspective view which shows the liquid crystal display device of 1st Embodiment. It is sectional drawing of a liquid crystal display device. It is sectional drawing which shows the liquid crystal panel in a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a schematic diagram for demonstrating an effect | action of a viewing angle expansion film. It is a schematic diagram for demonstrating an effect | action of a viewing angle expansion film. It is a perspective view which shows the liquid crystal display device of 2nd Embodiment. It is sectional drawing of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the other example of a viewing angle expansion film. It is sectional drawing which shows the other example of a viewing angle expansion film. It is a perspective view which shows the liquid crystal display device of 3rd Embodiment. It is sectional drawing of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a schematic diagram for demonstrating an effect | action of a viewing angle expansion film. It is a schematic diagram for demonstrating an effect | action of a viewing angle expansion film. It is a top view which shows the other example of the light-diffusion part in a viewing angle expansion film. It is a top view which shows the other example of the light-diffusion part in a viewing angle expansion film. It is a top view which shows the other example of the light-diffusion part in a viewing angle expansion film. It is a top view which shows the other example of the light-diffusion part in a viewing angle expansion film. It is a top view which shows the other example of the light-diffusion part in a viewing angle expansion film. It is a top view which shows the other example of the light-diffusion part in a viewing angle expansion film. It is a schematic diagram for demonstrating the effect | action of the viewing angle expansion film of another example. It is a schematic diagram for demonstrating the effect | action of the viewing angle expansion film of another example. It is a perspective view which shows the liquid crystal display device of 4th Embodiment. It is sectional drawing of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the manufacturing process of the viewing angle expansion film of a liquid crystal display device. It is a perspective view which shows the other example of a viewing angle expansion film. It is sectional drawing which shows the other example of a viewing angle expansion film.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5B.
In the present embodiment, an example of a liquid crystal display device including a transmissive liquid crystal panel as a display body will be described.
In all of the following drawings, in order to make each component easy to see, the scale of the size may be changed depending on the component.

FIG. 1 is a perspective view of the liquid crystal display device of the present embodiment as viewed obliquely from below (back side). FIG. 2 is a cross-sectional view of the liquid crystal display device of this embodiment.
As shown in FIGS. 1 and 2, the liquid crystal display device 1 (display device) of the present embodiment includes a backlight 2 (light source), a first polarizing plate 3, a liquid crystal panel 4 (light modulation element), and a second polarizing plate. The liquid crystal display body 6 (display body) which has 5 and the viewing angle expansion film 7 (viewing angle expansion member, a light-diffusion member) are comprised. In FIG. 2, the liquid crystal panel 4 is schematically illustrated as a single plate, but the detailed structure thereof will be described later. The observer sees the display from the upper side of the liquid crystal display device 1 in FIG. 2 where the viewing angle widening film 7 is arranged. Therefore, in the following description, the side on which the viewing angle widening film 7 is disposed is referred to as a viewing side, and the side on which the backlight 2 is disposed is referred to as a back side.

In the liquid crystal display device 1 of the present embodiment, the light emitted from the backlight 2 is modulated by the liquid crystal panel 4, and a predetermined image, character, or the like is displayed by the modulated light. Further, when the light emitted from the liquid crystal panel 4 passes through the viewing angle widening film 7, the angle distribution of the emitted light becomes wider than before entering the viewing angle widening film 7, and the light is widened. Is injected from. Thereby, the observer can visually recognize the display with a wide viewing angle.

Hereinafter, a specific configuration of the liquid crystal panel 4 will be described.
Here, an active matrix transmissive liquid crystal panel will be described as an example, but a liquid crystal panel applicable to the present embodiment is not limited to an active matrix transmissive liquid crystal panel. The liquid crystal panel applicable to the present embodiment may be, for example, a transflective (transmission / reflection type) liquid crystal panel or a reflection type liquid crystal panel. Further, each pixel has a switching thin film transistor (Thin Film Transistor, hereinafter). Or a simple matrix type liquid crystal panel that is not provided with TFT).

FIG. 3 is a longitudinal sectional view of the liquid crystal panel 4.
As shown in FIG. 3, the liquid crystal panel 4 includes a TFT substrate 9, a color filter substrate 10, and a liquid crystal layer 11. The TFT substrate 9 is provided as a switching element substrate. The color filter substrate 10 is disposed to face the TFT substrate 9. The liquid crystal layer 11 is sandwiched between the TFT substrate 9 and the color filter substrate 10. The liquid crystal layer 11 is surrounded by a TFT substrate 9, a color filter substrate 10, and a frame-shaped seal member (not shown) that bonds the TFT substrate 9 and the color filter substrate 10 at a predetermined interval. It is enclosed in the space. The liquid crystal panel 4 of the present embodiment performs display in, for example, a VA (Vertical Alignment, vertical alignment) mode, and a vertical alignment liquid crystal having a negative dielectric anisotropy is used for the liquid crystal layer 11. A spherical spacer 12 is disposed between the TFT substrate 9 and the color filter substrate 10 to keep the distance between these substrates constant. The display mode is not limited to the VA mode described above, and a TN (Twisted Nematic) mode, an STN (Super Twisted Nematic) mode, an IPS (In-Plane Switching) mode, or the like can be used.

The TFT substrate 9 has a plurality of pixels (not shown) as a minimum unit area for display arranged in a matrix. A plurality of source bus lines (not shown) and a plurality of gate bus lines (not shown) are formed on the TFT substrate 9. The plurality of source bus lines are formed to extend in parallel to each other. The plurality of gate bus lines (not shown) extend in parallel to each other and are formed to be orthogonal to the plurality of source bus lines. Therefore, on the TFT substrate 9, a plurality of source bus lines and a plurality of gate bus lines are formed in a lattice pattern, and a rectangular region partitioned by adjacent source bus lines and adjacent gate bus lines is one. One pixel. The source bus line is connected to the source electrode of the TFT described later, and the gate bus line is connected to the gate electrode of the TFT.

A TFT 19 having a semiconductor layer 15, a gate electrode 16, a source electrode 17, a drain electrode 18, and the like is formed on the surface of the transparent substrate 14 constituting the TFT substrate 9 on the liquid crystal layer 11 side. As the transparent substrate 14, for example, a glass substrate can be used. On the transparent substrate 14, for example, from a semiconductor material such as CGS (Continuous Grain Silicon), LPS (Low-temperature Poly-Silicon), α-Si (Amorphous Silicon). A semiconductor layer 15 is formed. A gate insulating film 20 is formed on the transparent substrate 14 so as to cover the semiconductor layer 15. As a material of the gate insulating film 20, for example, a silicon oxide film, a silicon nitride film, or a laminated film thereof is used.
A gate electrode 16 is formed on the gate insulating film 20 so as to face the semiconductor layer 15. As the material of the gate electrode 16, for example, a laminated film of W (tungsten) / TaN (tantalum nitride), Mo (molybdenum), Ti (titanium), Al (aluminum), or the like is used.

A first interlayer insulating film 21 is formed on the gate insulating film 20 so as to cover the gate electrode 16. As a material of the first interlayer insulating film 21, for example, a silicon oxide film, a silicon nitride film, or a laminated film thereof is used. A source electrode 17 and a drain electrode 18 are formed on the first interlayer insulating film 21. The source electrode 17 is connected to the source region of the semiconductor layer 15 through a contact hole 22 that penetrates the first interlayer insulating film 21 and the gate insulating film 20. Similarly, the drain electrode 18 is connected to the drain region of the semiconductor layer 15 through a contact hole 23 that penetrates the first interlayer insulating film 21 and the gate insulating film 20. As a material for the source electrode 17 and the drain electrode 18, the same conductive material as that for the gate electrode 16 is used. A second interlayer insulating film 24 is formed on the first interlayer insulating film 21 so as to cover the source electrode 17 and the drain electrode 18. As the material of the second interlayer insulating film 24, the same material as the first interlayer insulating film 21 described above or an organic insulating material is used.

A pixel electrode 25 is formed on the second interlayer insulating film 24. The pixel electrode 25 is connected to the drain electrode 18 through a contact hole 26 that penetrates the second interlayer insulating film 24. Therefore, the pixel electrode 25 is connected to the drain region of the semiconductor layer 15 using the drain electrode 18 as a relay electrode. As the material of the pixel electrode 25, for example, a transparent conductive material such as ITO (Indium Tin Oxide, Indium Tin Oxide) or IZO (Indium Zinc Oxide, Indium Zinc Oxide) is used. With this configuration, when the scanning signal is supplied through the gate bus line and the TFT 19 is turned on, the image signal supplied to the source electrode 17 through the source bus line passes through the semiconductor layer 15 and the drain electrode 18 to form a pixel electrode. 25. An alignment film 27 is formed on the entire surface of the second interlayer insulating film 24 so as to cover the pixel electrode 25. This alignment film 27 has an alignment regulating force for vertically aligning liquid crystal molecules constituting the liquid crystal layer 11. Note that the form of the TFT may be the bottom gate TFT shown in FIG. 3 or the top gate TFT.

On the other hand, a black matrix 30, a color filter 31, a planarizing layer 32, a counter electrode 33, and an alignment film 34 are sequentially formed on the surface of the transparent substrate 29 constituting the color filter substrate 10 on the liquid crystal layer 11 side. The black matrix 30 has a function of blocking light transmission in the inter-pixel region, and is a photo in which metal such as a multilayer film of Cr (chromium) or Cr / Cr oxide, or carbon particles is dispersed in a photosensitive resin. It is made of resist. The color filter 31 includes dyes of red (R), green (G), and blue (B), and one pixel electrode 25 on the TFT substrate 9 is any one of R, G, and B. Two color filters 31 are arranged to face each other. The flattening layer 32 is made of an insulating film that covers the black matrix 30 and the color filter 31, and has a function of smoothing and flattening a step formed by the black matrix 30 and the color filter 31. A counter electrode 33 is formed on the planarization layer 32. As the material of the counter electrode 33, a transparent conductive material similar to that of the pixel electrode 25 is used. Further, an alignment film 34 having a vertical alignment regulating force is formed on the entire surface of the counter electrode 33. The color filter 31 may have a multicolor configuration of three or more colors of R, G, and B.

As shown in FIG. 2, the backlight 2 includes a light source 36 such as a light emitting diode and a cold cathode tube, and a light guide plate 37 that emits light toward the liquid crystal panel 4 using internal reflection of light emitted from the light source 36. ,have. The backlight 2 may be an edge light type in which the light source is disposed on the end face of the light guide, or may be a direct type in which the light source is disposed directly under the light guide. As the backlight 2 used in the present embodiment, it is desirable to use a backlight having a directivity by controlling the light emission direction, that is, a so-called directional backlight. By using a directional backlight that allows collimated or substantially collimated light to enter the light diffusion portion of the viewing angle widening film 7 to be described later, blurring can be reduced and light utilization efficiency can be increased. The directional backlight described above can be realized by optimizing the shape and arrangement of the reflection pattern formed in the light guide plate 37. A first polarizing plate 3 that functions as a polarizer is provided between the backlight 2 and the liquid crystal panel 4. A second polarizing plate 5 that functions as a polarizer is provided between the liquid crystal panel 4 and the viewing angle widening film 7.

Hereinafter, the viewing angle widening film 7 will be described in detail.
FIG. 5A is a cross-sectional view of the viewing angle widening film 7.
As shown in FIGS. 1, 2, and 5 </ b> A, the viewing angle widening film 7 includes a base material 39 and a plurality of light diffusion portions 40 formed on one surface of the base material 39 (a surface opposite to the viewing side). And a light shielding layer 41 formed on one surface of the base material 39. As shown in FIG. 2, the viewing angle widening film 7 is formed on the second polarizing plate 5 with the side where the light diffusing portion 40 is provided facing the second polarizing plate 5 and the base 39 side facing the viewing side. Is arranged.

In the following description, the horizontal direction of the screen of the liquid crystal panel 4 is defined as the x axis, the vertical direction of the screen of the liquid crystal panel 4 is defined as the y axis, and the thickness direction of the liquid crystal display device 1 is defined as the z axis.
The light diffusion portion 40 is formed so as to extend in the vertical direction (y-axis direction) of the screen of the liquid crystal panel 4. The light diffusing portion 40 has a rectangular shape with a horizontal cross section (xy cross section), a surface 40a on the base material 39 side serving as a light emission end surface is small, and a surface opposite to the base material 39 serving as a light incident end surface. The area of 40b is formed large. The plurality of light diffusing portions 40 are arranged in stripes at regular intervals as viewed from the normal direction (z-axis direction) of the base material 39. The light shielding layer 41 is arranged in a stripe shape between the adjacent light diffusion portions 40 arranged in a stripe shape when viewed from the normal direction (z-axis direction) of the base material 39.

Examples of the base material 39 include transparent resin base materials such as triacetyl cellulose (TAC) film, polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN), and polyethersulfone (PES) film. Preferably used. The base material 39 becomes a base when a material for the light shielding layer 41 or the light diffusion portion 40 is applied later in a manufacturing process described later. Therefore, the base material 39 needs to have heat resistance and mechanical strength in a heat treatment step during the manufacturing process. Therefore, as the base material 39, a glass base material or the like may be used in addition to the resin base material. However, it is preferable that the thickness of the base material 39 is as thin as possible without impairing heat resistance and mechanical strength. The reason is that as the thickness of the base material 39 is increased, there is a possibility that display blur may occur. Further, the total light transmittance of the substrate 39 is preferably 90% or more in accordance with JIS K7361-1. When the total light transmittance is 90% or more, sufficient transparency can be obtained. In this embodiment, a TAC film having a thickness of 100 μm is used as an example.

The light diffusing unit 40 is made of an organic material having optical transparency and photosensitivity such as acrylic resin and epoxy resin. The total light transmittance of the light diffusing section 40 is preferably 90% or more as defined in JIS K7361-1. When the total light transmittance is 90% or more, sufficient transparency can be obtained. As shown in FIGS. 1, 2, and 5 </ b> A, the light diffusing unit 40 includes two layers of a first layer 42 and a second layer 43 that are stacked in this order from the base material 39 side. In the case of this embodiment, the first layer 42 and the second layer 43 are formed of different materials. The first layer 42 is formed of an acrylic resin-based transparent negative resist, and the second layer 43 is formed of an epoxy resin-based transparent negative resist.

As shown in FIG. 5A, the light diffusing portion 40 has a small area of the surface 40 a on the base material 39 side that is a light emission end face, and gradually increases the area of the horizontal section as it is away from the base material 39. ing. That is, when viewed from the base material 39 side, the light diffusing portion 40 has a so-called reverse-tapered truncated pyramid shape. The inversely tapered side surface 40 c of the light diffusing portion 40 is composed of a side surface 42 c of the first layer 42 and a side surface 43 c of the second layer 43. The interface 40d between the first layer 42 and the second layer 43 is formed in parallel with the light emitting end surface 40a and the light incident end surface 40b of the light diffusion portion 40. The width W1 (dimension in the short direction) of the light emission end face 40a of the light diffusion portion 40 is, for example, 10 μm, and the pitch P1 between the adjacent light diffusion portions 40 is 20 μm.

The angle θ2 formed between the side surface 43c of the second layer 43 and the light incident end surface 40b is larger than the angle θ1 formed between the side surface 42c of the first layer 42 and the interface 40d. In the following description, an angle θ2 formed between the side surface 43c of the second layer 43 and the light incident end surface 40b is referred to as an inclination angle of the side surface 43c of the second layer 43, and an angle formed between the side surface 42c of the first layer 42 and the interface 40d. θ1 is referred to as an inclination angle of the side surface 42c of the first layer 42. The inclination angle θ1 of the side surface 42c of the first layer 42 and the inclination angle θ2 of the side surface 43c of the second layer 43 are preferably about 60 to 90 degrees. Therefore, for example, the inclination angle θ1 of the side surface 42c of the first layer 42 is desirably 75 degrees, and the inclination angle θ2 of the side surface 43c of the second layer 43 is desirably 80 degrees. However, the inclination angle θ1 of the side surface 42c of the first layer 42 and the inclination angle θ2 of the side surface 43c of the second layer 43 are angles that can sufficiently diffuse the incident light without causing a large loss of incident light. If there is, it will not be specifically limited.

The light diffusion part 40 is a part that contributes to the transmission of light in the viewing angle widening film 7. That is, as shown in FIG. 5A, the light incident on the light diffusing unit 40 is totally reflected by the tapered side surface 40c of the light diffusing unit 40 and guided in a state of being substantially confined in the light diffusing unit 40. And is injected.

As shown in FIGS. 1, 2, and 5 </ b> A, the light shielding layer 41 is formed in a region other than the regions where the light diffusion units 40 are formed, on the surface of the base 39 on which the light diffusion unit 40 is formed. Is formed. For example, the light shielding layer 41 is made of an organic material having light absorption and photosensitivity such as a black resist. In addition, metal films such as Cr (chromium) and Cr / Cr oxide multilayer films, and pigments and dyes used for black ink may be used. The width (dimension in the short direction) of the light shielding layer 41 is, for example, 10 μm.

The layer thickness of the light shielding layer 41 is set to be smaller than the height from the light incident end surface 40b of the light diffusion portion 40 to the light emitting end surface 40a. In the present embodiment, the thickness of the light shielding layer 41 is about 150 nm as an example, and the height from the light incident end face 40b to the light emitting end face 40a of the light diffusing portion 40 is about 50 μm as an example. In the gap between the plurality of light diffusing portions 40, the light shielding layer 41 exists in a portion in contact with one surface of the base material 39, and air exists in other portions.

Note that the refractive index of the first layer 42 and the refractive index of the second layer 43 are preferably substantially equal. The reason is that, for example, if the refractive index of the first layer 42 and the refractive index of the second layer 43 are significantly different, the interface 40d is transmitted when light passes through the interface 40d between the first layer 42 and the second layer 43. This is because unnecessary refraction or reflection of light may occur, and a desired light diffusion angle may not be obtained, or the amount of emitted light may be reduced. For the same reason, it is desirable that the refractive index of the base material 39 and the refractive index of the first layer 42 be substantially equal.

Basically, the inclination angle of the side surface 40c of the light diffusing unit 40 is such that the light incident on the light incident end surface 40b of the light diffusing unit 40 is totally or substantially perpendicularly reflected so that the side surface 40c of the light diffusing unit 40 is totally reflected. It is set to an angle exceeding the critical angle with respect to the normal line.
Incidentally, as shown in FIG. 5B, in the case of the viewing angle widening film 107 in which the inclination angle θ3 of the side surface 140c of the light diffusing unit 140 is constant, the light L1 incident perpendicularly to the light incident end surface 140b of the light diffusing unit 140 Is totally reflected by the side surface 140 c of the light diffusing unit 140. However, the light L2 incident at an angle other than 90 degrees with respect to the light incident end face 140b of the light diffusing unit 140 has an incident angle smaller than the critical angle, and is transmitted through the side surface 140c of the light diffusing unit 140 to emit light. There is a possibility that it cannot be taken out from the end face 140a. Further, when the inclination angle of the side surface 140c of the light diffusing unit 140 is constant, the light L1 incident perpendicularly to the light incident end surface 140b of the light diffusing unit 140 is emitted in a concentrated manner at a specific diffusion angle. As a result, light cannot be uniformly diffused over a wide angle range, and a bright display can be obtained only with a specific viewing angle.

On the other hand, in the viewing angle widening film 7 of the present embodiment, as shown in FIG. 5A, the side surface 40c of the light diffusing portion 40 has two different inclination angles θ1 and θ2, and the second layer The inclination angle θ2 of the side surface 43c of 43 is larger than the inclination angle θ1 of the side surface 42c of the first layer 42. Thereby, the light L0 incident perpendicularly to the light incident end surface 40b in the central portion of the light diffusing portion 40 is transmitted through the light diffusing portion 40 without being incident on the side surface 40c. On the other hand, the light L1 incident perpendicularly to the light incident end face 40b at the peripheral edge of the light diffusing portion 40 is totally reflected by the side surface 43c of the second layer 43, for example, and then the angle is changed to change the first layer 42 and the base material. 39 is sequentially transmitted and injected to the outside. The light L2 incident at an angle other than 90 degrees with respect to the light incident end surface 40b of the light diffusing unit 40 is totally reflected at, for example, the side surface 42c of the first layer 42, and then the angle is changed to change the first layer 42 and the base material 39. Are sequentially transmitted and injected to the outside. Thus, in the case of this embodiment, since the side surface 40c of the light-diffusion part 40 has two different inclination angles, it is possible to prevent the light diffusion angles from being concentrated on one. As a result, the light diffusion characteristics of the viewing angle widening film 7 can be made smoother, and a bright display can be obtained with a wide viewing angle.

In the case of the present embodiment, since air is interposed between the adjacent light diffusion portions 40, if the light diffusion portion 40 is formed of, for example, acrylic resin, the side surface 40c of the light diffusion portion 40 is made of acrylic resin and air. It becomes the interface. Even if the periphery of the light diffusing unit 40 is filled with another low refractive index material, the difference in the refractive index between the inside and the outside of the light diffusing unit 40 is larger than when any low refractive index material exists outside. The maximum is when air is present. Therefore, from Snell's law, in the configuration of the present embodiment, the critical angle is the smallest, and the incident angle range in which light is totally reflected by the side surface 40c of the light diffusing unit 40 is the widest. As a result, light loss is further suppressed, and high luminance can be obtained.

However, as shown in FIG. 5A, the light L3 incident at an angle greatly deviated from 90 degrees with respect to the light incident end face 40b of the light diffusing portion 40 is an angle less than the critical angle with respect to the side surface 40c of the light diffusing portion 40. And is transmitted through the side surface 40c of the light diffusion portion 40 without being totally reflected. Still, since the light shielding layer 41 is provided in a region other than the region where the light diffusion portion 40 is formed, the light transmitted through the side surface 40 c of the light diffusion portion 40 is absorbed by the light shielding layer 41. Therefore, it is difficult for display blurring and contrast to be lowered. However, when the amount of light transmitted through the side surface 40c of the light diffusing unit 40 increases, a light amount loss occurs, and an image with high luminance cannot be obtained. Therefore, in the liquid crystal display device 1 of the present embodiment, it is preferable to use a backlight that emits light at an angle that does not enter the side surface 40c of the light diffusing portion 40 at a critical angle or less, that is, a so-called directional backlight. .

Next, a manufacturing method of the liquid crystal display device 1 having the above configuration will be described with reference to FIGS. 4A to 4E.
Below, it demonstrates centering on the manufacturing process of the viewing angle expansion film 7. FIG.
The outline of the manufacturing process of the liquid crystal display 6 will be described first. First, the TFT substrate 9 and the color filter substrate 10 are respectively produced. Thereafter, the surface of the TFT substrate 9 on which the TFT 19 is formed and the surface of the color filter substrate 10 on which the color filter 31 is formed are arranged to face each other, and the TFT substrate 9 and the color filter substrate 10 are sealed. Paste through. Thereafter, liquid crystal is injected into a space surrounded by the TFT substrate 9, the color filter substrate 10, and the seal member. And the 1st polarizing plate 3 and the 2nd polarizing plate 5 are each bonded together on both surfaces of the liquid crystal panel 4 produced in this way using an optical adhesive agent. Through the above steps, the liquid crystal display body 6 is completed.
In addition, since a conventionally well-known method is used for the manufacturing method of the TFT substrate 9 and the color filter substrate 10, description is abbreviate | omitted.

First, as shown in FIG. 4A, a triacetylcellulose base material 39 having a 10 cm square and a thickness of 100 μm is prepared, and carbon is contained on one surface of the base material 39 as a light shielding layer material by using a spin coating method. The black negative resist is applied to form a coating film 44 having a thickness of 150 nm.
Next, the base material 39 on which the coating film 44 is formed is placed on a hot plate, and the coating film is pre-baked at a temperature of 90 ° C. Thereby, the solvent in the black negative resist is volatilized.

Next, using an exposure apparatus, as shown in FIG. 4B, the coating film 44 is irradiated with light E through a photomask 45 provided with a plurality of light-shielding patterns 47 to perform exposure. At this time, an exposure apparatus using a mixed line of i-line having a wavelength of 365 nm, h-line having a wavelength of 404 nm, and g-line having a wavelength of 436 nm is used. The exposure dose is 100 mJ / cm ² . In the case of this embodiment, in the next step, the transparent negative resist is exposed using the light shielding layer 41 as a mask to form the light diffusing portion 40, so that the position of the opening 46 of the photomask 45 is the position where the light diffusing portion 40 is formed. Correspond. The plurality of light shielding patterns 47 are band-like patterns having a width of 10 μm, and are arranged at a pitch of 20 μm.

It is desirable that the pitch of the light shielding patterns 47 is smaller than the interval (pitch) of the pixels of the liquid crystal panel 4. As a result, at least one light diffusing portion 40 is formed in the pixel, so that a wide viewing angle can be achieved when combined with a liquid crystal panel having a small pixel pitch used for mobile devices, for example.

After the exposure using the photomask 45 described above, the coating film 44 made of a black negative resist is developed using a dedicated developer, dried at 100 ° C., and as shown in FIG. The light shielding layer 41 is formed on one surface of the base material 39. The opening between the adjacent light shielding layers 41 corresponds to the formation region of the light diffusion portion 40 in the next process. In the present embodiment, the light shielding layer 41 is formed by a photolithography method using a black negative resist, but instead of this configuration, if a photomask in which the light shielding pattern 47 and the opening 46 of the present embodiment are reversed is used, A positive resist can also be used. Or you may form directly the light shielding layer 41 patterned using the vapor deposition method, the printing method, etc. FIG.

Next, as shown in FIG. 4D, a transparent negative resist made of an acrylic resin is applied as a material of the first layer 42 of the light diffusing portion 40 to the upper surface of the light shielding layer 41 by using a spin coat method, and a 25 μm thick first resist is formed. A coating film 48 (a negative photosensitive resin layer) for one layer is formed.
Next, the base material 39 on which the coating film 48 is formed is placed on a hot plate, and the coating film 48 is pre-baked at a temperature of 95 ° C. Thereby, the solvent in the transparent negative resist is volatilized.

Further, a transparent negative resist made of an epoxy resin is applied as a material for the second layer 43 of the light diffusion portion 40 to the upper surface of the coating film 48 by using a spin coating method, and a coating film 49 for the second layer having a film thickness of 25 μm. (Negative photosensitive resin layer) is formed.
Next, the base material 39 on which the coating film 49 is formed is placed on a hot plate, and the coating film 49 is pre-baked at a temperature of 95 ° C. Thereby, the solvent in the transparent negative resist is volatilized.
In this way, the two-layered coating films 48 and 49 made of different types of transparent negative resists are formed.

Next, the coating films 48 and 49 are irradiated with diffused light F from the base material 39 side using the light shielding layer 41 as a mask to perform exposure. At this time, an exposure apparatus using a mixed line of i-line having a wavelength of 365 nm, h-line having a wavelength of 404 nm, and g-line having a wavelength of 436 nm is used. The exposure amount is 500 mJ / cm ² . In the exposure process, parallel light or diffused light is used. Further, as means for irradiating the base material 39 with the parallel light emitted from the exposure apparatus as diffused light F, a diffusion plate having a haze of about 50 is disposed on the optical path of the light emitted from the exposure apparatus. By performing exposure with the diffused light F, the coating films 48 and 49 having a two-layer structure are exposed radially from the opening between the light shielding layers 41, and the reverse tapered side surface of the light diffusing unit 40 is formed.
Thereafter, the base material 39 after the above exposure process is placed on a hot plate, and post-exposure baking (PEB) of the coating films 48 and 49 is performed at a temperature of 95 ° C.

Next, the coating films 48 and 49 made of a transparent negative resist are developed using a dedicated developer, and post-baked, for example, at 100 ° C. to 150 ° C., and as shown in FIG. 4E, the first layer 42 and the second layer A plurality of light diffusion portions 40 made of 43 are formed on one surface of the base material 39.
Through the above steps, the viewing angle widening film 7 of the present embodiment is completed. The total light transmittance of the viewing angle widening film 7 is preferably 90% or more. When the total light transmittance is 90% or more, sufficient transparency can be obtained, and the optical performance required for the viewing angle widening film can be sufficiently exhibited. The total light transmittance is as defined in JIS K7361-1.

In the above example, the liquid resist is applied at the time of forming the light shielding layer 41 and the light diffusing portion 40, but instead of this configuration, a film resist is applied to one surface of the base material 39. Also good.

Finally, with the completed viewing angle widening film 7 as shown in FIG. 2, with the base material 39 facing the viewing side and the light diffusion part 40 facing the second polarizing plate 5, an optical adhesive or the like is used. Used to attach to the liquid crystal display body 6.
Through the above steps, the liquid crystal display device 1 of the present embodiment is completed.

If the exposure is performed using one type of transparent negative resist as the material of the light diffusion portion, the side surface of the light diffusion portion has a single inclination angle. On the other hand, in the present embodiment, when forming the light diffusion portion 40, the two-layer coating films 48 and 49 made of different types of transparent negative resists are formed and exposed. In this case, the photosensitive part of the transparent negative resist after the exposure process has a single inclination angle over the two layers. However, since the photocuring characteristics of the respective transparent negative resists are different, the photosensitive portions of the coating films 48 and 49 are cured in different shapes. As a result, in the state where the light diffusion portion 40 is completed after development, the inclination angle of the side surface 42c of the first layer 42 and the inclination angle of the side surface 43c of the second layer 43 are different.

According to the present embodiment, as shown in FIG. 5A, the light L0, L1, L2 incident on the viewing angle widening film 7 has a viewing angle in a state where the angle distribution is wider than before entering the viewing angle widening film 7. Injected from the magnifying film 7. Therefore, even if the observer inclines the line of sight from the front direction (normal direction) of the liquid crystal display body 6, a good display can be visually recognized. In particular, in the case of the present embodiment, since the light diffusion portion 40 extends in a stripe shape in the vertical direction of the screen, the angular distribution spreads in the horizontal direction (left-right direction) of the screen of the liquid crystal display body 6. Therefore, the observer can visually recognize a good display in a wide range in the left-right direction of the screen.

On the other hand, the light L3 obliquely incident on the viewing angle widening film 7 is light that is obliquely transmitted through the liquid crystal panel 4, and is light that is different from a desired retardation, that is, light that causes a decrease in so-called display contrast. . The viewing angle widening film 7 of this embodiment can increase the display contrast because such light is cut by the light shielding layer 41. Furthermore, since the external light incident on the viewing angle expansion film 7 from the viewing side is also cut by the light shielding layer 41, the scattering of the external light is suppressed, and the visibility of display in a bright place can be improved.

In the present embodiment, the light diffusing portion 40 is formed using the two-layered coating films 48 and 49 made of different types of transparent negative resists. Therefore, the plurality of light diffusion portions 40 whose side surface 40c has two types of inclination angles θ1 and θ2 can be easily formed by a single photolithography process. Therefore, the viewing angle widening film 7 that can exhibit the desired light diffusion performance can be produced without complicating the manufacturing process.

Further, in the step of forming the light diffusion portion 40, assuming that exposure is performed using a photomask from the side of the coating films 48 and 49 made of a transparent negative resist, the substrate 39 on which the light-shielding layer 41 having a minute size is formed and the photo Alignment with the mask is very difficult, and it is inevitable that a deviation occurs. On the other hand, in the case of the present embodiment, since light is irradiated from the back side of the base material 39 using the light shielding layer 41 as a mask, the light diffusion portion 40 is self-aligned with the position of the opening of the light shielding layer 41 (self It is formed in an aligned state. As a result, the light diffusion portion 40 and the light shielding layer 41 are in close contact with each other, so that no gap is formed between them, and the contrast can be reliably maintained.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 6 to 8E.
The basic configuration of the liquid crystal display device of this embodiment is the same as that of the first embodiment, and the shape of the light diffusion portion of the viewing angle widening film is different from that of the first embodiment. Therefore, in this embodiment, description of the basic composition of a liquid crystal display device is abbreviate | omitted, and only a viewing angle expansion film is demonstrated.
FIG. 6 is a longitudinal sectional view showing the liquid crystal display device of the present embodiment. FIG. 7 is a longitudinal sectional view showing the viewing angle widening film of this embodiment, and FIGS. 8A to 8E are sectional views showing the viewing angle widening film in order of the manufacturing process.
6, 7, and 8 </ b> A to 8 </ b> E, the same reference numerals are given to the same components as those used in the first embodiment, and detailed description thereof will be omitted.

In the first embodiment, the width (dimension in the short direction) of the plurality of light diffusion portions 40 is constant. On the other hand, in the viewing angle widening film 52 of the present embodiment, as shown in FIGS. 6 and 7, the width (dimension in the short direction) of the light shielding layer 41 is constant, and the first layer 54, the second layer The widths (dimensions in the short direction) of the plurality of light diffusion portions 53 formed of the layer 55 are randomly different. That is, the width of the plurality of light diffusion portions 53 is not constant, and the average width obtained by averaging the widths of the plurality of light diffusion portions 53 is 10 μm. Further, the two inclination angles of the side surface 53c of the light diffusion portion 53 are uniform over the plurality of light diffusion portions 53, and are the same as those in the first embodiment. Other configurations are the same as those in the first embodiment.

In the manufacturing process of the viewing angle widening film 52 of the present embodiment, as shown in FIG. 8B, the photomask 56 used when forming the light shielding layer 41 has a light shielding property in which the width is randomly different from the opening 57 having a constant width. Pattern 58. In designing the photomask 56, the following method may be used. First, openings 57 having a constant width are arranged at a constant pitch. Next, using a random function, for example, the reference position data of each opening 57 such as the center point of the opening 57 is fluctuated to vary the position of the opening 57. Thereby, the some light shielding pattern 58 from which a width | variety differs at random can be obtained. The manufacturing process itself of the viewing angle widening film 52 is the same as that of the first embodiment.

In the liquid crystal display device 51 of the present embodiment as well, a first embodiment in which a viewing angle widening film capable of exhibiting desired light diffusion performance in the horizontal direction (left and right direction) of the screen can be produced without complicating the manufacturing process. The same effect as the form can be obtained.

Generally, it is known that when regular patterns such as stripes and lattices are overlapped with each other, an interference fringe pattern (moire) is visually recognized when the period of each pattern is slightly shifted. When the viewing angle widening film in which a plurality of light diffusion portions are arranged at a constant pitch and a liquid crystal panel in which a plurality of pixels are arranged at a constant pitch are overlapped as in the first embodiment, There is a possibility that moire occurs between the periodic pattern formed by the light diffusing unit and the periodic pattern formed by the pixels of the liquid crystal panel, thereby degrading the display quality. On the other hand, according to the liquid crystal display device 51 of the present embodiment, since the widths of the plurality of light diffusion portions 53 are random, moire due to interference occurs with the regular arrangement of the pixels of the liquid crystal panel 4. The display quality can be maintained.

[Modification of Second Embodiment]
FIG. 9A is a perspective view showing a modification of the viewing angle widening film of the embodiment. FIG. 9B is a cross-sectional view showing a modification of the viewing angle widening film.
Although the width of the light shielding layer 41 is constant in the above embodiment, in addition to making the width of the light diffusion portion 63 random as in the viewing angle widening film 62 shown in FIGS. 9A and 9B, the width of the light shielding layer 64. May be random.

Even in this configuration, an effect that moire is suppressed and display quality can be maintained is obtained.
However, when the inclination angles of the side surfaces of the plurality of light diffusion portions 63 are uniform and the width of the light shielding layer 41 is random, the ratio of the light incident on the viewing angle widening film 62 absorbed by the light shielding layer 64 As a result, the light utilization efficiency may be slightly reduced. From this viewpoint, it is preferable that the width of the light shielding layer is constant.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS. 10 to 13B.
The basic configuration of the liquid crystal display device of this embodiment is the same as that of the first and second embodiments, and the shape of the light diffusion portion of the viewing angle widening film is different from that of the first and second embodiments. Therefore, in this embodiment, description of the basic composition of a liquid crystal display device is abbreviate | omitted, and only a viewing angle expansion film is demonstrated.
FIG. 10 is a perspective view showing the liquid crystal display device of the present embodiment. FIG. 11 is a cross-sectional view of the liquid crystal display device. 12A to 12E are cross-sectional views sequentially showing the manufacturing process of the viewing angle widening film of this embodiment. 13A and 13B are diagrams for explaining the operation of the viewing angle widening film.
In FIG. 10, FIG. 11, FIG. 12A to 12E, and FIGS. 13A and 13B, the same components as those used in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. To do.

In the first and second embodiments, the plurality of light diffusion portions are formed in a strip shape so as to extend in the y-axis direction. On the other hand, in the viewing angle widening film 67 of the present embodiment, as shown in FIGS. 10 and 11, the light diffusion portion 68 composed of the first layer 69 and the second layer 70 is parallel to one surface of the base material 39. The horizontal cross section when cut by the plane (xy plane) is circular, the area of the horizontal cross section on the side of the base material 39 that becomes the light emission end face 68a is small, and as the distance from the base material 39 increases, that is, as it approaches the light incident end face 68b. The area of the horizontal section is gradually increasing. That is, the shape of each light diffusion portion 68 is substantially a truncated cone shape.

The plurality of light diffusion portions 68 are regularly arranged in a scattered manner on the base material 39. Among the plurality of light diffusing portions 68, for example, the light diffusing portions 68 in each row arranged in the y-axis direction are arranged at a constant pitch. The light diffusion portions 68 in each row aligned in the x-axis direction are arranged at a constant pitch. In addition, the light diffusing portions 68 in a predetermined row arranged in the y-axis direction and the light diffusing portions 68 in the row adjacent to the row in the x-axis direction are arranged at positions shifted by ½ pitch in the y-axis direction. Has been. The diameter of the light emission end face 68a of the light diffusing portion 68 is, for example, 20 μm, and the pitch between adjacent light diffusing portions 68 is 25 μm. Since the plurality of light diffusion portions 68 are scattered on the base material 39, the light shielding layer 71 of this embodiment is continuously formed on the base material 39.

In addition, each light diffusion portion 68 has a two-layer structure of a first layer 69 and a second layer 70 made of different types of transparent negative resists, and the inclination angle of the side surface 69 c of the first layer 69 and the second layer 70. The inclination angle of the side surface 70c is preferably about 60 to 90 degrees, and the relationship between these two inclination angles is the same as in the first embodiment. The configuration other than the light diffusing unit 68 is the same as that of the first embodiment.

In the manufacturing process of the viewing angle widening film 67 of the present embodiment, as shown in FIG. 12B, the photomask 72 used when forming the light shielding layer 71 has a plurality of circular light shielding patterns 73. The manufacturing process itself of the viewing angle widening film 67 is the same as that of the first embodiment.

Also in the liquid crystal display device 66 of the present embodiment, the same effects as those of the first and second embodiments can be obtained such that a viewing angle widening film capable of exhibiting desired light diffusion performance can be produced without complicating the manufacturing process. It is done.

In the case of the present embodiment, as shown in FIG. 13A, the cross-sectional shape of the light diffusing portion 68 in the xz plane is the same as that of the light diffusing portion 40 (see FIG. 5A) of the first embodiment. Therefore, the effect that the viewing angle widening film 67 expands the angle distribution of light in the xz plane is the same as that of the first embodiment. However, when viewed from the front direction (z-axis direction) of the screen of the liquid crystal display device 66, the shape of the light diffusing portion 40 of the first embodiment is a line shape, whereas the present embodiment is shown in FIG. 13B. The shape of the light diffusing portion 68 is circular. Therefore, the light L totally reflected by the side surface 68c of the light diffusing unit 68 is diffused in all directions of 360 degrees. Therefore, according to the viewing angle widening film 67 of the present embodiment, the viewer visually recognizes a good display from all directions with respect to the screen as well as the horizontal direction of the screen as in the first and second embodiments. be able to.

[Modification of Third Embodiment]
In the above embodiment, as shown in FIG. 14A, an example of the light diffusing portion 68 having a circular planar shape is shown. However, for example, as shown in FIG. 14B, a light diffusing portion 68B having a hexagonal planar shape may be used. good. Alternatively, as shown in FIG. 14C, a light diffusion portion 68C having a rectangular planar shape may be used. Alternatively, as shown in FIG. 14D, a light diffusion portion 68D having a square planar shape may be used. Alternatively, as shown in FIG. 14E, a light diffusion portion 68E having an octagonal planar shape may be used. Alternatively, as shown in FIG. 14F, a light diffusing portion 68F having a shape in which two opposite sides of a rectangle are curved outward may be used.

For example, in the case of the rectangular light diffusion portion 68C shown in FIG. 15A, the diffusion of the light L4 in the direction perpendicular to the long side is stronger than the diffusion of the light L5 in the direction perpendicular to the short side. Therefore, it is possible to realize a viewing angle widening film in which the intensity of light diffusion differs in the vertical direction (up and down direction) and the horizontal direction (left and right direction) depending on the length of the side. With the octagonal light diffusing unit 68E shown in FIG. 15B, the light L is diffused in a concentrated manner in the vertical direction, the horizontal direction, and the oblique 45 degree direction, in which viewing angle characteristics are particularly important in liquid crystal display devices. Can do. Thus, when anisotropy of the viewing angle is required, different light diffusion characteristics can be obtained by appropriately changing the shape of the light diffusion portion.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS. 16 to 18E.
The basic configuration of the liquid crystal display device of this embodiment is the same as that of the third embodiment, and the arrangement of the light diffusion portions of the viewing angle widening film is different from that of the third embodiment. Therefore, in this embodiment, description of the basic composition of a liquid crystal display device is abbreviate | omitted, and only a viewing angle expansion film is demonstrated.
FIG. 16 is a perspective view showing the liquid crystal display device of the present embodiment. FIG. 17 is a cross-sectional view of the liquid crystal display device. 18A to 18E are cross-sectional views sequentially showing the manufacturing process of the viewing angle widening film of this embodiment.
In FIG. 16, FIG. 17, and FIGS. 18A to 18E, the same reference numerals are given to the same components as those used in the first to third embodiments, and detailed description thereof will be omitted.

In the third embodiment, the plurality of light diffusion portions 68 are regularly arranged. On the other hand, in the viewing angle widening film 77 of this embodiment, as shown in FIGS. 16 and 17, a plurality of light diffusion portions 68 are randomly arranged. Therefore, although the pitch between the adjacent light diffusion portions 68 is not constant, the average pitch obtained by averaging the pitches between the adjacent light diffusion portions 68 is set to 25 μm. Other configurations are the same as those of the third embodiment.

In the manufacturing process of the viewing angle widening film 77 of the present embodiment, as shown in FIG. 18B, the photomask 78 used when forming the light shielding layer 71 has a plurality of circular light shielding patterns 73 arranged at random. Yes. The photomask 78 may be designed by the following method. First, the light shielding patterns 73 are regularly arranged at a constant pitch. Next, using a random function, for example, the reference position data of each light shielding pattern 73 such as the center point of the light shielding pattern 73 is fluctuated to vary the position of the light shielding pattern 73. Thereby, a photomask 78 having a plurality of light-shielding patterns 73 arranged at random can be manufactured. The manufacturing process of the viewing angle widening film 77 is the same as in the first to third embodiments.

Also in the liquid crystal display device 76 of the present embodiment, the first to third embodiments in which the viewing angle widening film 77 that can exhibit the desired light diffusion performance in all directions of the screen can be manufactured without complicating the manufacturing process. The same effect can be obtained. In addition, since the light diffusing portions 68 are randomly arranged, moire due to interference does not occur with the regular arrangement of the pixels of the liquid crystal panel 4, and the display quality can be maintained.

In the third and fourth embodiments, the dimensions of the plurality of light diffusion portions are all the same. However, the dimensions may be different among the plurality of light diffusion portions. The dimensions of the plurality of light diffusion portions may be a plurality of types or may be randomly changed. By doing so, for example, the arrangement density of the light diffusion portions can be increased by filling the space between the circular light diffusion portions having a large diameter with a circular light diffusion portion having a small diameter. As a result, the ratio of light shielded by the light shielding layer can be reduced and the light utilization efficiency can be increased.

The technical scope of the aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the aspect of the present invention. For example, in the above-described embodiment, an example of a light diffusion portion having a two-layer structure has been described. However, for example, a first layer 82 made of a material having different photocuring characteristics, such as a viewing angle widening film 81 shown in FIG. A light diffusing portion 85 composed of the second layer 83 and the third layer 84 may be provided. In this case, if the inclination angles of the side surfaces 82c, 83c, 84c of the layers 82, 83, 84 are made different from each other, the diffusion angle of the light reflected by the side surfaces 82c, 83c, 84c of the layers 82, 83, 84 is changed. It is possible to change in more stages, and the light diffusion characteristics can be made smoother.

In addition, the plurality of layers constituting the light diffusing portion are not necessarily formed of different materials. For example, even if the same resin material, for example, acrylic resin, is used for the first layer 89 and the second layer 90 constituting the light diffusion portion 88 as in the viewing angle widening film 87 shown in FIG. It is also possible to mix light scatterers 19 such as glass beads having a refractive index different from that of acrylic resin into the first layer 89 and the second layer 90 as optically different layers. According to this configuration, since the light L is scattered by the light scatterer 91 when passing through the first layer 89, a wide viewing angle can be achieved.

In the above embodiment, an example of a liquid crystal display device is given as an example of a display body. However, the present invention is not limited to this, and the aspect of the present invention may be applied to an organic electroluminescence display device, a plasma display, or the like.

Moreover, although the example which adhere | attaches a viewing angle expansion film on the 2nd polarizing plate of a liquid crystal display body was shown in the said embodiment, the viewing angle expansion film and the liquid crystal display body do not necessarily need to contact.
For example, another optical film or an optical component may be inserted between the viewing angle widening film and the liquid crystal display. Or a viewing angle expansion film and a liquid crystal display body may exist in the position which left | separated. In addition, in the case of an organic electroluminescence display device, a plasma display, or the like, a polarizing plate is unnecessary, so that the viewing angle widening film and the polarizing plate do not come into contact with each other.

Moreover, as a configuration in which at least one of an antireflection layer, a polarizing filter layer, an antistatic layer, an antiglare treatment layer, and an antifouling treatment layer is provided on the viewing side of the base material of the viewing angle widening film in the above embodiment. Also good. According to this configuration, it is possible to add a function to reduce external light reflection, a function to prevent the adhesion of dust and dirt, a function to prevent scratches, and the like according to the type of layer provided on the viewing side of the substrate. Further, it is possible to prevent deterioration of viewing angle characteristics with time.

In the above embodiment, the light diffusing portion has a symmetrical shape with respect to the central axis, but it does not necessarily have a symmetrical shape. For example, when an intentionally asymmetric angular distribution is required according to the application and usage of the display device, for example, when there is a request to widen the viewing angle only on the upper side or only on the right side of the screen, light diffusion is performed. The inclination angle of the side surface of the part may be asymmetric.

In addition, the specific configuration relating to the arrangement and shape of the light diffusing part and the light shielding layer, the dimensions and materials of each part of the viewing angle widening film, the manufacturing conditions in the manufacturing process, etc. is not limited to the above embodiment, and can be changed as appropriate. .

The aspect of the present invention can be used for various display devices such as a liquid crystal display device, an organic electroluminescence display device, and a plasma display.

DESCRIPTION OF SYMBOLS 1,51,66,76 ... Liquid crystal display device (display device), 2 ... Backlight (light source), 4 ... Liquid crystal panel (light modulation element), 6 ... Liquid crystal display body (display body), 7, 52, 62, 67, 77, 81, 87 ... viewing angle widening film (light diffusion member, viewing angle widening member), 39 ... base material, 40, 53, 63, 68, 68b, 68c, 68d, 68e, 68f, 88 ... light diffusion Part, 41, 64, 71 ... light shielding layer, 42, 54, 69, 82, 89 ... first layer, 43, 55, 70, 83, 90 ... second layer, 84 ... third layer, 48, 49 ... coating Film (negative photosensitive resin layer), 91... Light scatterer.

Claims (16)

A substrate having optical transparency;
A plurality of light diffusion portions formed on one surface of the substrate;
A light-shielding layer formed in a region different from the formation region of the light diffusion portion on one surface of the base material,
The light diffusing portion has a light emission end face on the base material side and a light incident end face having an area larger than the area of the light emission end face, located on the opposite side of the base material side,
The dimension from the light incident end face of the light diffusion portion to the light exit end face is larger than the thickness of the light shielding layer,
The light diffusing member, wherein the light diffusing portion is composed of two or more layers laminated on the base material. The two or more layers constituting the light diffusion portion are made of at least two kinds of different materials,
The light diffusing member according to claim 1, wherein inclination angles of side surfaces of the two or more layers are different from each other. The light diffusing member according to claim 1, wherein a light scatterer is included in at least one of the two or more layers constituting the light diffusing portion. The light diffusing member according to claim 1, wherein the plurality of light diffusing portions are configured such that air exists in a gap between the plurality of diffusing portions. The plurality of light diffusion portions are arranged in stripes at intervals from each other when viewed from the normal direction of one surface of the base material,
The light diffusing member according to claim 1, wherein the light shielding layer is disposed between the plurality of diffusing portions, and is disposed in a stripe shape when viewed from the normal direction of one surface of the base material. 6. The light diffusing member according to claim 5, wherein at least one of a short dimension of the plurality of light diffusion portions and a short dimension of the plurality of light shielding layers is random. The plurality of light diffusion portions are arranged in a scattered manner when viewed from the normal direction of one surface of the base material,
The light diffusion member according to claim 1, wherein the light shielding layer is continuously formed in a region different from a region where the light diffusion portion is formed. The light diffusing member according to claim 7, wherein the plurality of light diffusing portions are randomly arranged when viewed from a normal direction of one surface of the base material. The light diffusing member according to claim 7, wherein the planar shape of the light diffusing portion viewed from the normal direction of one surface of the base material is a circle or a polygon. 2. The light diffusing member according to claim 1, wherein the light shielding layer includes any one of black resin, black ink, a single metal, or a multilayer film of a single metal and a metal oxide. Forming a light-shielding layer having an opening on one surface of a light-transmitting substrate,
On one surface of the base material, a plurality of negative photosensitive resin layers made of at least two different materials are formed so as to cover the light shielding layer,
From the surface opposite to the one surface of the substrate on which the light shielding layer and the plurality of negative photosensitive resin layers are formed, the plurality of negative photosensitive resin layers are exposed through an opening of the light shielding layer,
Developing the plurality of the negative photosensitive resin layers after the exposure, and having a light emission end face on the substrate side and having a light incident area larger than the area of the light emission end face on the side opposite to the substrate side The manufacturing method of the light-diffusion member including forming the several light-diffusion part which has an end surface in one surface of the said base material. 12. The method of manufacturing a light diffusing member according to claim 11, wherein any one of black resin, black ink, metal simple substance, or a multilayer film of metal simple substance and metal oxide is used as the material of the light shielding layer. A display body, provided on the viewing side of the display body, and a viewing angle widening member that emits light in a state where the angular distribution of light incident from the display body is wider than before incidence, and
The display device in which the viewing angle widening member includes the light diffusing member according to claim 1. The display body has a plurality of pixels forming a display image,
The display device according to claim 13, wherein a maximum pitch between adjacent light diffusion portions among the plurality of light diffusion portions of the light diffusion member is smaller than a pitch between the pixels of the display body. The display body includes a light source and a light modulation element that modulates light from the light source,
The display device according to claim 13, wherein the light source emits light having directivity. The display device according to claim 13, wherein the display body is a liquid crystal display element.

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