WO2018182340A1 - Quantum dot reflective sheet, manufacturing method therefor, and backlight unit and display device, which include same - Google Patents

Abstract

A quantum dot reflective sheet, a manufacturing method therefor, and a backlight unit and a display device, which include the same, are disclosed. The quantum dot reflective sheet according to one embodiment of the present invention comprises: a reflective barrier layer; a quantum dot layer formed on the reflective barrier layer; and a transparent barrier layer arranged on the quantum dot layer.

Description

Quantum dot reflective sheet, manufacturing method thereof, backlight unit and display device including same

The present invention relates to a quantum dot reflective sheet, a method of manufacturing the same, a backlight unit and a display device including the same.

Display devices are facing market demands for larger and thinner devices, and conventional CRT devices do not fully satisfy these requirements, and are represented by liquid crystal display (LCD) devices and organic light emitting diode (OLED) devices. The demand for flat panel displays (FPD) is exploding.

LCD is one of the most widely used FPDs, and consists of two substrates on which electrodes are formed and a liquid crystal layer interposed therebetween, and is transmitted by applying a voltage to the electrodes to rearrange liquid crystal molecules in the liquid crystal layer. A device that displays an image by adjusting the amount of light.

Unlike OLEDs that can emit light, LCDs, which are passive light emitting devices, cannot be self-illuminated, so a backlight unit is necessary. As a light source used in the backlight assembly, it has been replaced by a light emitting diode (LED) which is a point light source from a cold cathode fluorescent lamp (CCFL).

When using LED as a light source of the backlight assembly, white light is generated by passing blue light (blue LED) through a phosphor (pigment) to realize white light, and the light spectrum is relatively blue and yellow, whereas green and red are relatively strong. Because of this weakness, even though RGB is implemented through a color filter, the wavelengths of light are different, so colors come out at wavelengths that are not the same as natural colors.

In order to improve color reproducibility, QD-LED (Quantum Dot Light Emitting Diode) to QDEF (Quantum Dot Enhancement Film), etc., which have improved color reproducibility using nano-sized semiconductor materials, have been applied.

They have the advantage of having a wide color reproducibility in a manner of controlling the emission wavelength by adjusting the composition, size and shape of the nano-sized semiconductor material. However, the dual QD-LED is manufactured by mixing and curing a semiconductor particle (RED QD) converting blue light into red light and a semiconductor particle (GREEN QD) converting green light into a binder. And deterioration due to blue light, causing a darkening phenomenon.

In order to solve the above problem, a technique of inserting a quantum dot enhancement film (QDEF) into the backlight unit of the LCD has been applied. The backlight unit in which the QDEF is inserted disperses RED QD and GREEN QD in a binder by disposing the QDEF on the light guide plate, and manufactures the film, and in order to suppress degradation due to moisture or oxygen, which is a problem of quantum dot, It is prepared by covering both sides with two passivation films and placing them on the light guide plate.

Existing QDEF uses high viscosity resin, QD is not dispersed well when manufacturing QDEF, so the thickness of film for securing physical properties becomes thick and there is a problem of cost increase as QD usage is increased. There was a problem in that the thickness difference due to the problem of spreadability during QDEF manufacturing could not be obtained the desired optical properties.

In addition, there is a problem in that the thickness of the QDEF is increased because two passivation films covering the QD are necessary to suppress deterioration due to moisture or oxygen due to the problem of the QD itself.

The present invention is to provide a quantum dot reflective sheet and a method of manufacturing the coating layer on the reflective sheet containing a quantum dot.

In addition, the present invention is to provide a backlight unit including the quantum dot reflective sheet.

The present invention also provides a display device including the backlight unit.

The quantum dot reflective sheet according to an embodiment of the present invention for solving the above problems includes a quantum dot layer including a reflective barrier layer, a quantum dot layer formed on the reflective barrier layer and a transparent barrier layer formed on the quantum dot layer. .

Quantum dot reflective sheet according to an embodiment of the present invention for solving the above problems, a reflection sheet including a base layer, a reflective layer formed on the base layer and a cover layer formed on the reflective layer, formed on the reflective sheet It includes a quantum dot layer and a transparent barrier layer formed on the quantum dot layer.

In addition, according to one embodiment of the present invention, the quantum dot layer may include at least one quantum dot of RED QD, GREEN QD, BLUE QD.

In addition, according to an embodiment of the present invention, the quantum dot layer may further include light scattering particles.

Further, according to an embodiment of the present invention, the light scattering layer including light scattering particles may be further included on any one or more of the upper surface or the lower surface of the quantum dot layer.

In addition, according to one embodiment of the present invention, the reflective barrier layer may include a reflective film and a barrier film formed on any one or more of an upper surface or a lower surface of the reflective film.

In addition, according to an embodiment of the present invention, the reflective barrier layer may include a barrier film formed on the reflective film and a lower surface of the reflective film, and the barrier film may include a metal film and a protective film formed on a lower surface of the metal film. have.

In addition, according to an embodiment of the present invention, it may further include a dot print (DP) formed for color correction of the upper edge area of the quantum dot layer.

Method of manufacturing a quantum dot reflective sheet according to an embodiment of the present invention for solving the above problems, providing a reflective sheet comprising a base layer, a reflective layer formed on the base layer and a cover layer formed on the reflective layer And forming a quantum dot layer on the reflective sheet and forming a transparent barrier layer on the quantum dot layer.

In addition, according to an embodiment of the present invention, the forming of the quantum dot layer may include forming a first pattern layer by coating a first composition through a wet coating process to have a first pattern on the reflective sheet. And forming a second pattern layer by coating a second composition to fill the space between the first patterns and planarize the top surface of the quantum dot layer.

According to an aspect of the present invention, a backlight unit includes a light guide plate, a light source that provides light toward the light guide plate, and a light disposed below the light guide plate and traveling to the lower region of the light guide plate to the upper side. In order to improve the brightness of the light, a quantum dot reflective sheet including a reflective barrier layer, a quantum dot layer formed on the reflective barrier layer and a transparent barrier layer disposed on the quantum dot layer.

According to an aspect of the present invention, a backlight unit includes a light guide plate, a light source that provides light toward the light guide plate, and a light disposed below the light guide plate and traveling to the lower region of the light guide plate to the upper side. In order to improve the brightness of the light, a reflective sheet including a base layer, a reflective layer formed on the base layer and a cover layer formed on the reflective layer, a quantum dot layer formed on the reflective sheet and a transparent barrier layer formed on the quantum dot layer It includes a quantum dot reflection sheet including a.

According to an exemplary embodiment of the present invention, a light guide plate, a light source that provides light toward a light guide plate, and a light disposed below the light guide plate and converting or reflecting light traveling to a lower region of the light guide plate to an upper side A backlight unit including a quantum dot reflection sheet including a reflective barrier layer, a quantum dot layer formed on the reflective barrier layer, and a transparent barrier layer disposed on the quantum dot layer, to improve brightness of light; Display panel.

According to an exemplary embodiment of the present invention, a light guide plate, a light source that provides light toward a light guide plate, and a light disposed below the light guide plate and converting or reflecting light traveling to a lower region of the light guide plate to an upper side In order to improve the brightness of the light, a reflective sheet including a base layer, a reflective layer formed on the base layer and a cover layer formed on the reflective layer, a quantum dot layer formed on the reflective sheet and a transparent barrier layer formed on the quantum dot layer The backlight unit may include a quantum dot reflection sheet, and a display panel on the backlight unit.

According to the quantum dot reflective sheet according to an embodiment of the present invention, a manufacturing method thereof, a backlight unit and a display device including the same, a display device is obtained by securing a uniform thickness of the layer including the quantum dot and reducing the thickness by excluding the passivation film. It is possible to achieve a thinner, and can easily obtain the desired optical properties while reducing the manufacturing cost by reducing the QD usage.

In addition, as the quantum dot layer is disposed under the light guide plate, it is possible to solve the problem that defects on the QDEF are easily visualized compared to the case where the conventional quantum dot layer is disposed above the light guide plate.

1 is an exploded perspective view of a display device according to an exemplary embodiment.

2 is a cross-sectional view of the display device of FIG. 1.

3 is a cross-sectional view of a quantum dot reflective sheet according to an embodiment of the present invention.

4 is a cross-sectional view illustrating the quantum dot reflective sheet of FIG. 3 in more detail.

5 is a cross-sectional view of a quantum dot reflective sheet according to an embodiment of the present invention.

6 is a cross-sectional view illustrating the quantum dot reflective sheet of FIG. 5 in more detail.

7 is a cross-sectional view illustrating a relationship between a quantum dot reflection sheet and a light guide plate pattern.

8 is a cross-sectional view illustrating a quantum dot reflective sheet on which a quantum dot layer is formed according to an exemplary embodiment of the present invention.

9 to 11 are cross-sectional views for describing in detail the pattern shapes of the quantum dot layer of FIG. 8.

12 to 14 are cross-sectional views illustrating a quantum dot reflecting sheet on which a quantum dot layer is formed according to other exemplary embodiments.

15 and 16 are cross-sectional views illustrating a quantum dot reflective sheet on which a quantum dot layer is formed, according to another exemplary embodiment.

17 is a cross-sectional view for describing a method of manufacturing a pattern of the quantum dot layer of FIG. 8.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented to fully convey the spirit of the present invention to those skilled in the art. The invention is not limited to the examples presented herein but may be embodied in other forms.

1 is an exploded perspective view of a display device according to an exemplary embodiment. 2 is a cross-sectional view of the display device of FIG. 1. 3 is a cross-sectional view of a quantum dot reflective sheet according to an embodiment of the present invention. 4 is a cross-sectional view illustrating the quantum dot reflective sheet of FIG. 3 in more detail.

1 and 2, a display device 1000 according to an exemplary embodiment of the present invention includes a backlight unit 100 and a display panel 200.

The backlight unit 100 includes a storage container 110, a light guide plate 120, a light source 130, and a quantum dot reflection sheet 140.

The storage container 110 includes not only the lower storage container 110 but also an intermediate storage container 160 that covers and fixes the backlight unit 100 from the top, the backlight unit 100, and the display panel 200. It may include an upper storage container 300 to cover the.

The light guide plate 120 is disposed on the bottom surface of the storage container 110.

For example, in the backlight unit 100 including a side view type light emitting diode (LED), the light guide plate 120 emits light toward the front surface by changing a traveling direction of light incident from the side surface.

A plurality of convex stripes (not shown) may be formed on the upper surface of the light guide plate 120 to change the traveling direction of the light, and a predetermined pattern may be formed on the lower surface of the light guide plate 120.

For example, the lower surface of the light guide plate 120 may further include a scattering pattern 121. The scattering pattern 121 may include light scattering particles 122, and the light scattering particles 122 may include any one or more selected from the group consisting of an oxide, a polymer, and an organic-inorganic composite. It is more advantageous to make mixed white light as some light emitted from the light guide plate 120 toward the storage container 110 passes through the light scattering particles 122 and scattering occurs.

Some of the light incident into the light guide plate 120 is scattered by the light scattering particles 122 of the scattering pattern 121 formed on at least one of the upper surface and the lower surface of the light guide plate 120 so that the front surface of the light guide plate 120 The other portion may be reflected by the reflective sheet 140 provided under the light guide plate 120 to the inside of the light guide plate 120.

In this case, the quantum dot particles of the quantum dot layer 142 coated on the reflective barrier layer 141 to be described later absorb blue light and emit red or green light.

As such, the light guide plate 120 may emit light uniformly to the entire surface of the light guide plate 120 by refraction, reflection, and scattering of light generated therein.

The light guide plate 120 may employ, for example, poly methyl methacrylate (PMMA) or transparent polycarbonate (PC).

For example, the backlight unit 100 may further include at least one optical sheet 150 disposed on the light guide plate 120.

The optical sheet 150 refracts or scatters light in order to widen the viewing angle of the display device 1000 and increase brightness. The optical sheet 150 may include various sheets. The optical sheet 150 may include at least one, and optionally, may include two or more optical sheets. For example, the optical sheet 150 may include a diffusion sheet 151, a prism sheet 152, and a double brightness enhancement file (DBEF) 153.

The light source 130 is disposed on at least one side of the storage container 110 to provide blue light toward the light guide plate 120.

For example, the light source 130 may be a side view type or a top view type light emitting diode (LED).

The quantum dot reflective sheet 140 includes a reflective barrier layer 141 and a quantum dot layer 142 formed on the reflective barrier layer 141.

The display panel 200 is disposed on the backlight unit 100.

The display panel 200 may include a liquid crystal layer (not shown), a transparent electrode layer (not shown), a transparent substrate (not shown), and a color filter array (not shown).

The color filter includes a red filter, a blue filter, and a green filter formed in a region corresponding to each pixel so that colors are displayed for each of the pixels constituting the display panel 200.

As such, the display panel 200 generates an image by blocking or transmitting the light generated from the backlight unit 100. In detail, each pixel constituting the display panel 200 blocks or transmits light of the backlight unit 100 to generate an image of various colors.

Hereinafter, a detailed structure of the quantum dot reflection sheet 140 and a manufacturing method thereof will be described in more detail.

3 and 4, the quantum dot reflective sheet 140A is a reflective barrier layer 141, a quantum dot layer 142 formed on the reflective barrier layer 141, and a transparent formed on the quantum dot layer 142. The barrier layer PF is included.

The reflective barrier layer 141 is disposed between the storage container 110 and the light guide plate 120 to reflect the light emitted from the light guide plate 120.

In more detail, the reflective barrier layer 141 is formed on at least one of the reflective film 141-1 and the upper surface or the lower surface of the reflective film 141-1. It includes. The quantum dot reflective sheet 140A of FIGS. 3 and 4 has a reflective sheet structure formed by integrating a reflective barrier layer and a quantum dot layer.

The reflective film 141-1 includes any one selected from the group consisting of transparent polyethylene terephthalate (PET), white polyethylene terephthalate (PET), polycarbonate (PC), and polyacrylate. Preferably, the reflective layer 141-1 may use transparent or white polystyrene terephthalate (PET).

In the case of the reflective barrier layer 141, when moisture and the like penetrate through the side and bottom surfaces, moisture may penetrate into the quantum dot layer 142 formed on the reflective barrier layer 141 to cause degradation of the quantum dot. have.

Accordingly, the reflective barrier layer 141 may include barrier films 141-2 and 141-3 formed on at least one of an upper surface and a lower surface of the reflective film 141-1.

The barrier layers 141-2 and 141-3 are disposed on the lower surface and / or the upper surface of the reflective layer 141-1 to prevent deterioration of the quantum dot due to moisture or heat, and the barrier layer 141-2. , 141-3 may be formed by depositing or coating on the reflective film 141-1 or laminating a separate barrier film before forming the quantum dot layer 142.

For example, the barrier layers 141-2 and 141-3 may include at least one of an organic material and an inorganic material, and the barrier layers 141-2 and 141-3 may be formed of an organic layer or an inorganic layer. It may include any one or more. That is, the barrier layers 141-2 and 141-3 may have an organic layer including an organic material or an inorganic layer including an inorganic material. In addition, the organic-inorganic composite layer containing both an organic material and an inorganic material or may have a structure in which the organic layer and the inorganic layer are continuously stacked.

The barrier films 141-2 and 141-3 have an oxygen permeability of about 0.01 cm ³ .mm / m ² .day.atm to 0.5 cm ³ .mm / m ² .day.atm and 0.001 g / m ² .day It may have a moisture permeability of ~ 0.01 g / m ² .day. When the oxygen permeability and the moisture permeability are provided, the quantum dot of the quantum dot layer 142 may be stably preserved from the external environment.

For example, the barrier layer 145-2 may form a transparent oxide layer by laminating a metal foil including metals such as Al and Ni or depositing the metal.

For example, the reflective film 141-1 may be white polyethylene terephthalate (PET). White polyethylene terephthalate (PET) is used for products in a relatively large area, and fine bubble particles are dispersed in its internal matrix to scatter and reflect light, so the average reflectance is somewhat lower than that of retroreflective film, but it is inexpensive and has a thickness of 100㎛. In this case, it has a reflectance of 94% or more in the entire visible wavelength range. In this case, it is not necessary to form a separate reflective layer below the reflective film 141-1.

For example, the reflective film 141-1 may be transparent polyethylene terephthalate (PET). In case of transparent polyethylene terephthalate (PET), the inside is transparent and there is almost no scattering of light, and thus light passes through as it is, and in this case it cannot serve as a reflective film. Accordingly, for example, the reflective barrier layer 141 may include a barrier film formed on the bottom surface of the reflective film 141-1 and the reflective film 141-1, and the barrier film is a metal film 141-2. ) And a passivation layer 141-4 formed on the bottom surface of the metal layer 141-2. The metal film 141-2 is formed on the bottom surface of the reflective film 141-1 to reflect light passing through the transparent polyethylene terephthalate (PET), as well as a barrier to prevent penetration of moisture. It can act as a film. In this case, a separate passivation layer 141-4 may be formed to protect the metal layer 141-2 from external impact. The metal layer 141-2 includes a reflective material, but is not limited thereto. For example, the metal layer 141-2 may include Ag or Al. The protective layer 141-4 may use any one selected from the group consisting of transparent polyethylene terephthalate (PET), white polyethylene terephthalate (PET), polycarbonate (PC), and polyacrylate.

Prior to forming the barrier layer or the metal layer on the reflective layer 141-1, a primer layer may be formed on the upper and / or lower surface of the reflective layer 141-1 to form a gap between the reflective layer and the barrier layer or the metal layer. It can improve adhesion.

In addition, a primer layer may be further formed on the barrier layer to improve adhesion to the quantum dot layer 142 formed later. The primer layer is not limited thereto, but may include, for example, a urethane or acrylic primer.

Although not shown, the reflective barrier layer 141 may be porous to the top surface of the reflective barrier layer 141 before coating the quantum dot layer 142 in order to more efficiently disperse the quantum dot. Through the porosity treatment, irregularities are formed on the surface of the reflective barrier layer 141 to efficiently disperse the quantum dot.

The quantum dot layer 142 is formed on the reflective barrier layer 141. The quantum dot layer 142 includes at least one quantum dot of RED QD, GREEN QD, and BLUE QD.

The quantum dot (QD) refers to a small spherical semiconductor particle of nanometer (nm) size, it may be composed of a core (shell) of about 2 to 10nm size.

The quantum dot (QD) is not particularly limited as long as it is commonly used, for example, -VI compound, -V compound, -VI compound, -V compound, -VI compound, -III- compound , -IV-group compounds, and -IV- group compounds may be included.

The core is not limited thereto, but for example, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, SiC, Ca, It may include at least one of Se, In, P, Fe, Pt, Ni, Co, Al, Ag, Au, Cu, FePt, Fe ₂ O ₃ , Fe ₃ O ₄ , Si, and Ge. The shell is not limited thereto, for example, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, GaSe, InN, It may include at least one of InP, InAs, InSb, TlN, TlP, TlAs, TlSb, PbS, PbSe, and PbTe.

For example, it is preferable to use cadmium selenite (CdSe), cadmium telluride (CdTe), or cadmium sulfide (CdS) as a core of the quantum dot (QD), and to use zinc sulfide (ZnS) as the shell.

The quantum dot QD emits light by itself or absorbs light to emit light of a specific wavelength. The electrons in the quantum dot (QD) are located at a low energy level (or band) in a stable state. At this time, when the quantum dot QD absorbs light from the outside, electrons of low energy level move to a high energy level (or band). Since electrons located at high energy levels are unstable, electrons move naturally from the high energy level to the low energy level. As such, while moving from the high energy level to the low energy level, the electrons emit light as much as the energy difference between the high energy level and the low energy level. In this case, the wavelength of the emitted light is determined by the energy difference between the high energy level and the low energy level.

The smaller the quantum dot (QD) can emit light of a shorter wavelength, the larger the size can emit light of a longer wavelength. For example, a quantum dot (QD) of about 5.5 nm in diameter can emit green light, and a quantum dot (QD) of about 10 nm in diameter can emit red light.

The composition for coating the quantum dot layer 142 may include a quantum dot and a binder of at least one of RED QD, GREEN QD, and BLUE QD, and the composition may be prepared by dispersing the quantum dot in a binder. May be formed of a polymer acrylate (acrylate) resin material.

The quantum dot layer 142 may include more than twice the GREEN QD (GQD) than the RED QD (RQD). For example, the content ratio of GREEN QD (GQD) and RED QD (RQD) included in the quantum dot layer 142 may be dispersed in a ratio of 10: 1 to 2: 1.

QDs are dispersed in the binder, so that the QDs may be surrounded by the binder and protected from an external environment such as, for example, moisture.

For example, the composition further includes light scattering particles (P) of 0.1 to 10.0 ㎛ diameter. In this case, the light scattering particles (P) may include any one or more selected from the group consisting of oxides, polymers and organic-inorganic composites.

For example, the light scattering particles P may be spherical particles including silica, borosilicate, polystyrene, and the like.

Some light emitted from the light guide plate 120 toward the storage container 110 passes through the light scattering particles P of the quantum dot layer 142, so that scattering occurs.

The reflective sheet 140 includes a transparent barrier layer PF disposed on the quantum dot layer 142.

The transparent barrier layer PF is formed of polyethylene terephthalate (PET) and coated on a transparent film and a transparent film provided to protect the quantum dot layer 142 from external force so that moisture and oxygen penetrate the quantum dot layer 142. It includes a barrier film that prevents it.

5 is a cross-sectional view of a quantum dot reflective sheet according to an embodiment of the present invention. 6 is a cross-sectional view illustrating the quantum dot reflective sheet of FIG. 5 in more detail.

The quantum dot reflective sheet according to FIGS. 5 and 6 has a structure in which a reflective sheet, a quantum dot layer formed on the reflective sheet, and a transparent barrier layer formed on the quantum dot layer are stacked, except for the structure of the reflective sheet. The repeated content in the same configuration as the quantum dot reflection sheet of FIGS. 3 and 3 will be omitted.

Referring to FIGS. 5 and 6, the quantum dot reflection sheet may include a reflection sheet 140B, a quantum dot layer 142 formed on the reflective sheet 140B, and a transparent barrier layer PF formed on the quantum dot layer 142. It includes.

The reflective sheet 140B includes a base layer 140-1, a reflective layer 140-2 formed on the base layer 140-1, and a cover layer 140-3 formed on the reflective layer 140-2. ) May be included.

The base layer 140-1 and the cover layer 140-3 are selected from the group consisting of transparent polyethylene terephthalate (PET), white polyethylene terephthalate (PET), polycarbonate (PC) and polyacrylate. It may include one. The reflective layer 140-2 includes a reflective material, but is not limited thereto. For example, the reflective layer 140-2 may include Ag or Al.

Referring to FIG. 6, the quantum dot reflection sheet according to the exemplary embodiment of the present invention may further include a dot print (DP) formed for color correction of the upper edge region of the quantum dot layer 142. The dot print DP may be formed as halftones in the upper edge region of the quantum dot layer 142 and more specifically in the upper edge region of the transparent barrier layer PF.

In general, in the case of a backlight device to which QDEF is applied, a difference in the amount of light occurs inside the light guide plate and an edge portion, and the passivation film PF and the barrier layer 143-2 are formed on the top surface of the quantum dot layer 142. And QDs adjacent to both ends of the quantum dot layer 142 may be deteriorated due to oxygen and moisture because they are formed only on the bottom surface and do not cover the side surface. Accordingly, the quantum dot reflecting sheet may not function properly at the edge part, and thus the primary color (blue) of the LED light source may leak out as it is, and may be recognized externally.

The dot print DP prevents blue light from being emitted from the edge portion of the quantum dot reflection sheet 140 to be converted into white light, thereby preventing blue light from being viewed by an observer.

The dot print DP includes one or more of yellow, amber, and mixed phosphors thereof.

The yellow phosphor may include one or more of garnet-based, oxide-based, and nitride-based. The garnet is composed of YAG (yttrium aluminum garnet) and TAG (Terbium Aluminum Garnet) (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ , Tb ₃ Al ₅ O ₁₂ : Ce ³⁺ and oxide type (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu ²⁺ and a nitride of La ₃ Si ₆ N ₁₁ : Ce ^{3+, which} is a nitride, may be used alone or in combination.

7 is a cross-sectional view illustrating a relationship between a quantum dot reflection sheet and a light guide plate pattern.

Referring to FIG. 7, a predetermined pattern may be formed on the bottom surface of the light guide plate 120 to change a traveling direction of light.

For example, the lower surface of the light guide plate 120 may further include a scattering pattern 121. The scattering pattern 121 may include light scattering particles 122, and the light scattering particles 122 may include any one or more selected from the group consisting of an oxide, a polymer, and an organic-inorganic composite. It is more advantageous to make mixed white light as some light emitted from the light guide plate 120 toward the storage container 110 passes through the light scattering particles 122 and scattering occurs.

Some of the light incident into the light guide plate 120 may be scattered by the light scattering particles 122 of the scattering pattern 121 formed on the bottom surface of the light guide plate 120 and may be emitted to the front surface of the light guide plate 120. The other part is reflected into the light guide plate 120 by the reflective sheet 140 provided under the light guide plate 120.

In this case, the quantum dot particles of the quantum dot layer 142 coated on the reflective sheet 140 absorb blue light and then emit red or green light.

8 is a cross-sectional view illustrating a quantum dot reflective sheet on which a quantum dot layer is formed according to an exemplary embodiment of the present invention. 9 to 11 are cross-sectional views for describing in detail the pattern shapes of the quantum dot layer of FIG. 8.

8 to 11, the quantum dot layer 142 according to the exemplary embodiment of the present invention may include a first pattern layer PT1 coated to have a first pattern on the reflective barrier layer 141, and The second pattern layer PT2 fills between the first patterns and planarizes an upper surface of the quantum dot layer.

The first pattern layer PT1 serves as a guide pattern for adjusting the thickness of the quantum dot layer 142. That is, it is difficult to manufacture an optical sheet having a uniform thickness due to the spreadability of the composition when forming the quantum dot layer 142 using a low viscosity composition having a viscosity of 1,000 cps or less in general. In the case of an optical sheet, the transmission and reflection characteristics of light are important. The larger the thickness variation of the sheet, the more the desired optical properties cannot be obtained. In particular, the optical sheet has a problem that the visibility of light due to the thickness variation is deteriorated. There is a need to do it.

For example, the RED QD and the GREEN QD may be included in any one or more selected from the group consisting of the first pattern layer PT1 and the second pattern layer PT2. That is, the QDs may be included only in the first pattern layer PT1 or only in the second pattern layer PT2, and may also be included in the first pattern layer PT1 and the second pattern layer PT2. All may be included. For example, when QDs are included in the first pattern layer PT1 and the second pattern layer PT2, the amounts of QDs included in both layers may be the same ratio, and different ratios may be different. Can be.

Accordingly, when the quantum dot layer 142 is formed, the first pattern layer PT1 may be preferentially formed to serve as a guide, thereby forming a coating layer having a uniform thickness. In addition, since the low-viscosity composition is formed at the time of forming the first pattern layer PT1, the pattern formation thereof may also be somewhat difficult. Accordingly, the first pattern layer may be immediately cured by simultaneously performing pattern formation and UV irradiation using a UV curable resin. PT1) can be formed.

The cross section of the first pattern formed on the first pattern layer PT1 may be manufactured in any shape, but for example, a shape in which a part of a polygon, a side surface or a top surface of a triangle, a quadrangle, a pentagon or more is curved. Or it may be formed to have any shape of a circle.

The thickness of the quantum dot layer 142 may be 200 μm or less. For example, the thickness of the first pattern layer PT1 may be 1 to 150 μm, and the thickness of the second pattern layer PT2 may be greater than or equal to the thickness of the first pattern layer.

Patterns having the same width as the first pattern may be repeatedly formed. The first pattern may be formed to have a width and a spacing of 50 to 500 μm. Accordingly, since the second pattern is formed to fill the gaps between the first patterns, that is, the second pattern may have the same width and spacing as the first pattern.

For example, the composition may use a UV curable resin having a viscosity of 1,000 cps or less, and more preferably the composition may use a UV curable resin having a viscosity of 600 cps or less. When the quantum dot layer is formed using a high viscosity resin of 1,000 cps or more, it is difficult to form a thin coating layer according to high viscosity, and it is difficult to form a coating layer having a uniform thickness as well.

12 to 14 are cross-sectional views illustrating a quantum dot reflecting sheet on which a quantum dot layer is formed according to other exemplary embodiments.

12 to 14, the quantum dot layer 142 according to another embodiment of the present invention is formed on both ends of the reflective barrier layer 141 to provide a space for accommodating the quantum dot layer. It may include a wall (W).

The wall W serves to control the flow of the quantum dot layer 142 on the reflective barrier layer 141 regardless of viscosity. For example, one or more walls W may be formed in the space on the reflective barrier layer 141.

For example, the cross section of the wall may be formed such that a triangle, a quadrangle, a pentagonal polygon or more, a part of a side surface, or an upper surface has a shape including a curve or a circle.

15 and 16 are cross-sectional views illustrating a quantum dot reflective sheet on which a quantum dot layer is formed, according to another exemplary embodiment.

15 and 16, the quantum dot layer 142 according to another exemplary embodiment of the present invention is formed on an upper surface of the reflective barrier layer 141 to receive a recess for accommodating the quantum dot layer 142. It may include a recess (R).

The recess R serves to control the flow of the quantum dot layer 142 on the reflective barrier layer 141 regardless of viscosity. For example, the recess R may include at least one recess formed on an upper surface of the reflective barrier layer 141.

Referring to FIG. 15, the recess R may include a plurality of recesses formed on an upper surface of the reflective barrier layer 141. In contrast, referring to FIG. 16, the reflective barrier layer 141 may be formed. It may be formed at portions except both ends of the upper surface.

For example, a cross section of the recess R may be formed such that a triangle, a quadrangle, a pentagonal polygon or more, a part of a side surface or an upper surface has a shape including a curve or a circle.

17 is a cross-sectional view for describing a method of manufacturing a pattern of the quantum dot layer of FIG. 8.

Referring to FIG. 17, a method of manufacturing the quantum dot reflective sheet 140 according to an embodiment of the present invention may include a reflection sheet including a base layer, a reflection layer formed on the base layer, and a cover layer formed on the reflection layer. And providing a coating layer 142 on the reflective sheet and forming a transparent barrier layer on the quantum dot layer.

Detailed description of the composition is as described above and the repeated description thereof will be omitted below.

In one embodiment of the present invention, the step of forming the quantum dot layer 142, by coating the first composition through a wet coating process to have a first pattern on the reflective sheet, the first pattern layer (PT1) And forming a second pattern layer PT2 by coating a second composition to fill the gap between the first pattern and planarize the top surface of the quantum dot layer 142.

For example, at least one of the first composition or the second composition includes a quantum dot and a binder of at least one of RED QD, GREEN QD, and BLUE QD.

The first pattern may be formed through a wet coating process, for example, a roll using a printing roller having a shape corresponding to the first pattern to form the first pattern on the reflective layer 141. Roll-to-roll gravure printing can be performed.

For example, prior to performing the wet coating process, the method may include forming a shape corresponding to the first pattern on the printing roller, wherein the cross-section of the first pattern is triangular, square or circular. It may be formed to have a shape corresponding to the first pattern.

For example, the binder is a UV curable resin having a viscosity of 1,000 cps or less, preferably 600 cps or less, and curing the first pattern layer by irradiating UV simultaneously with the coating of the composition when the first pattern layer is formed. You can. In this case, a UV lamp may be used as a device for irradiating UV, which may be disposed under the reflective layer 141. Alternatively, although not shown, the UV lamp may be disposed behind the traveling direction of the printing roller to continuously irradiate UV. Can be.

The first pattern layer serves as a guide pattern for forming the quantum dot layer 142. When the quantum dots are adjacent to the expensive material or the reflective layer 141, the light conversion efficiency is lowered, thereby reducing the quantum dot reflection sheet. In order to achieve the desired optical properties, there is a problem in that the amount of use of more quantum dots is required.

Accordingly, in order to maximize the efficiency of the quantum dot in the quantum dot layer 142, that is, the absorption probability of light by the quantum dot, the quantum dots may be disposed on the upper side of the quantum dot layer 142 as much as possible. That is, when the density of the quantum dot increases toward the upper side of the quantum dot layer 142, the light conversion efficiency may be maximized by increasing the probability of absorption and emission by the quantum dot.

Accordingly, in order to guide the quantum dots to the upper side of the quantum dot layer 142 and minimize the amount of quantum dots used, the quantum dots are used to form the second pattern layer PT2 when the first pattern layer PT1 is formed. Less than the content can be used.

For example, the contents of the RED QD and the GREEN QD of the first composition forming the first pattern layer PT1 may be compared with the contents of the RED QD and GREEN QD of the second composition forming the second pattern layer PT2. It may be up to 80%.

Further, according to the method of manufacturing the quantum dot reflective sheet of the present invention, the method may further include forming a barrier layer by coating an organic material or an inorganic material on at least one surface of both surfaces of the reflective sheet.

For example, the reflective sheet may include a film including any one selected from the group consisting of transparent polyethylene terephthalate (PET), white polyethylene terephthalate (PET), polycarbonate (PC) and polyacrylate. have.

For example, the film is white polyethylene terephthalate (PET), and may further include forming a barrier layer under the film.

For example, the film may be transparent polyethylene terephthalate (PET), and may further include forming a lower reflective layer including a reflective material under the film.

In another embodiment of the present invention, the forming of the quantum dot layer 142 may include forming a wall on both ends of the reflective sheet to provide a space for accommodating the quantum dot layer and RED. The method may include filling a space inside the wall by coating a composition including at least one quantum dot of QD, GREEN QD, and BLUE QD.

In another embodiment of the present invention, the forming of the quantum dot layer 142 may include a recess for accommodating the upper surface of the reflective sheet to receive the quantum dot layer before forming the quantum dot layer. and forming a quantum dot layer, wherein the forming the quantum dot layer comprises coating a composition including RED QD, GREEN QD and a binder on the reflective sheet on which the recess is formed to fill the recess. can do.

As described above, the exemplary embodiments of the present invention have been described, but the present invention is not limited thereto, and a person skilled in the art does not depart from the spirit and scope of the following claims. It will be understood that various changes and modifications are possible in the following.

Claims (19)

Reflective barrier layers; A quantum dot layer formed on the reflective barrier layer; And A quantum dot reflection sheet comprising a transparent barrier layer formed on the quantum dot layer. A reflection sheet including a base layer, a reflection layer formed on the base layer, and a cover layer formed on the reflection layer; A quantum dot layer formed on the reflective sheet; And A quantum dot reflection sheet comprising a transparent barrier layer formed on the quantum dot layer. The method according to claim 1 or 2, The quantum dot layer is a quantum dot reflective sheet including at least one quantum dot of RED QD, GREEN QD, BLUE QD. The method according to claim 1 or 2, The quantum dot layer is a quantum dot reflective sheet further comprises light scattering particles. The method according to claim 1 or 2, A quantum dot reflecting sheet further comprising a light scattering layer including light scattering particles on any one or more of the top or bottom surface of the quantum dot layer. The method of claim 1, The reflective barrier layer may include a reflective film and a barrier film formed on at least one of an upper surface and a lower surface of the reflective film. The method of claim 6, The reflective barrier layer may include a barrier film formed on the reflective film and a lower surface of the reflective film, The barrier film includes a metal film and a protective film formed on the lower surface of the metal film. The method according to claim 1 or 2, A quantum dot reflection sheet further comprising a dot print (DP) formed for color correction of the upper edge region of the quantum dot layer. Providing a reflective sheet comprising a base layer, a reflective layer formed on the base layer, and a cover layer formed on the reflective layer; Forming a quantum dot layer on the reflective sheet; And Method of manufacturing a quantum dot reflective sheet comprising the step of forming a transparent barrier layer on the quantum dot layer. The method of claim 9, Forming the quantum dot layer, Forming a first pattern layer by coating the first composition through a wet coating process to have a first pattern on the reflective sheet; And Forming a second pattern layer by coating a second composition to fill the gaps between the first patterns and to planarize the top surface of the quantum dot layer. Light guide plate; A light source providing light toward the light guide plate; And In order to improve the brightness of the light by converting or reflecting the light traveling under the light guide plate to the lower region of the light guide plate upward, a transparent barrier disposed on the quantum dot layer formed on the reflective barrier layer and the quantum dot layer A backlight unit comprising a quantum dot reflective sheet including a barrier layer. Light guide plate; A light source providing light toward the light guide plate; And A reflection layer including a base layer, a reflection layer formed on the base layer, and a cover layer formed on the reflection layer to improve brightness of the light by converting or reflecting the light that is disposed below the light guide plate and proceeds to the lower area of the light guide plate upwards; And a quantum dot reflection sheet including a sheet, a quantum dot layer formed on the reflective sheet, and a transparent barrier layer formed on the quantum dot layer. The method according to claim 11 or 12, wherein The quantum dot layer is a quantum dot reflective sheet further comprises light scattering particles. The method according to claim 11 or 12, wherein A quantum dot reflecting sheet further comprising a light scattering layer including light scattering particles on any one or more of the top or bottom surface of the quantum dot layer. The method of claim 11, The reflective barrier layer may include a reflective film and a barrier film formed on at least one of an upper surface and a lower surface of the reflective film. The method of claim 15, The reflective barrier layer may include a barrier film formed on the reflective film and a lower surface of the reflective film, The barrier film includes a metal film and a protective film formed on the lower surface of the metal film. The method according to claim 11 or 12, wherein A quantum dot reflection sheet further comprising a dot print (DP) formed for color correction of the upper edge region of the quantum dot layer. A light guide plate, a light source for providing light toward the light guide plate, and disposed on the reflection barrier layer and the reflection barrier layer so as to be disposed under the light guide plate to convert or reflect the light traveling to the lower region of the light guide plate to the upper side to improve the brightness of the light. A backlight unit including a quantum dot reflection sheet including a quantum dot layer and a transparent barrier layer disposed on the quantum dot layer; And And a display panel on the backlight unit. A light guide plate, a light source providing light toward the light guide plate, and a base layer, a reflective layer formed on the base layer, to improve brightness of light by converting or reflecting light disposed under the light guide plate to a lower portion of the light guide plate to an upper side; A backlight unit including a reflective sheet including a cover layer formed on the reflective layer, a quantum dot layer formed on the reflective sheet, and a quantum dot reflective sheet including a transparent barrier layer formed on the quantum dot layer; And And a display panel on the backlight unit.

Images