JPWO2020145251A1 - Anisotropic diffuser, backlight unit, liquid crystal display and electronic equipment - Google Patents

Abstract

In the anisotropic diffuser plate 10 of the present invention, when the incident light from the incident surface 41 is emitted as the emitted light diffused from the emitting surface 51, the light diffusing ability in the left-right direction and the light diffusing ability in the front-rear direction are different. , Incident light having a size of 3 mmΦ perpendicular to the incident surface 41 is incident from the light source, and the diffused light distribution in the left-right direction and the diffused light distribution in the front-rear direction of the emitted light are evaluated by a brightness meter, and the half value in the left-right direction is evaluated. When the length is MD [mm] and the half-value length in the anteroposterior direction is TD [mm], the ratio (MD / TD) has a region showing anisotropic diffusion of 1.4 or more and less than 10.0. The total light transmittance of the emitted light with respect to the incident light is 70% or more and 99% or less.

Description

The present invention relates to an anisotropic diffuser, a backlight unit, a liquid crystal display device, and an electronic device.

As a liquid crystal display device, a liquid crystal display device including a liquid crystal panel as an image display unit and a surface emitting light source as a backlight arranged on the back side of the liquid crystal panel is known.

In this liquid crystal display device, the surface light emitting light source includes a lamp box (housing) and light emitting elements as a plurality of point light sources arranged in a grid pattern (matrix shape) in the lamp box, and is a liquid crystal display device. Further includes a light diffusing plate (anisotropic diffuser) arranged on the front side of the surface emitting light source, that is, between the surface emitting light source and the liquid crystal panel (see, for example, Patent Document 1).

In recent years, it has been proposed to use a light emitting diode (LED) as a light emitting element (point light source) in a liquid crystal display device having such a configuration from the viewpoint of energy saving and miniaturization of the light emitting element and the liquid crystal display device.

However, an LED is a light emitting element having an extremely high directivity of emitting light to be emitted in a concentrated manner toward the front as compared with a white light bulb or a fluorescent lamp. Further, from the viewpoint of miniaturization of the liquid crystal display device, the LED is required to be arranged at a position where the distance from the light diffusing plate is small.

Therefore, when an LED is used as the light emitting element included in the surface light emitting light source, the light emitting element (LED) that allows the LED to be seen through is scattered due to insufficient light diffusivity in the light diffusing plate. As a result, there is a problem that display unevenness occurs in the image displayed by the liquid crystal display device. It is also conceivable to reduce the light transmission of the light diffusing plate, that is, to increase the content of the diffusing material used in the light diffusing plate, for the purpose of suppressing the scatteredness of the LEDs. However, in this case, there is a problem that the amount of light from the surface emitting light source via the light diffusing plate cannot be sufficiently obtained, which causes deterioration of the display characteristics of the image in the liquid crystal display device.

Further, in a liquid crystal display device, the liquid crystal panel generally has a rectangular shape. Therefore, when the light emitted from the LED, which is a highly directional point light source, is isotropically diffused by the light diffusing plate, the diffused light is outside the display area of the liquid crystal panel in the lateral direction of the liquid crystal panel. Will be spread to. In that case, since a part of the diffused light is wasted, it is required to anisotropically diffuse the emitted light by the light diffusing plate.

JP-A-2009-63998

An object of the present invention is an anisotropic diffuser plate in which both light diffusivity with excellent anisotropy and excellent light transmittance are achieved, light diffusivity with excellent anisotropy and excellent light. It is an object of the present invention to present a highly reliable liquid crystal display device and electronic device provided with a backlight unit having both transparency and such a backlight unit.

Such an object is achieved by the present invention described in the following (1) to (14).
(1) An anisotropic diffuser plate in which the light diffusing ability in the left-right direction and the light diffusing ability in the front-rear direction are different when the incident light incident from the incident surface is emitted as the emitted light diffused from the emitting surface. ,
The incident light having a size of 3 mmΦ perpendicular to the incident surface is incident from the light source, and the diffused light distribution in the left-right direction and the diffused light distribution in the front-rear direction of the emitted light are evaluated by a luminance meter.
The half-value length is twice the distance from the center at the position showing the half-luminance value, which is half the brightness value at the center through which the optical axis of the incident light passes, and the half-value length in the left-right direction is defined as the half-value length. When MD [mm] and the half-value length in the front-rear direction are TD [mm], the ratio (MD / TD) has a region showing anisotropic diffusion of 1.4 or more and less than 10.0, and An anisotropic diffuser having a total light transmittance of 70% or more and 99% or less with respect to the incident light having a size of 3 mmΦ.

(2) It has a resin base material and a curable resin layer that is laminated on the exit surface side of the resin base material and is cured by irradiation with radiation.
The curable resin layer has an uneven pattern along the front-rear direction on the surface on the exit surface side.
The anisotropic diffusion plate according to (1) above, wherein the breaking elongation of the resin constituting the curable resin layer is 5% or more.

(3) The resin base material exhibits heat shrinkability that can be shrunk by heating.
The anisotropic diffusion plate according to (2) above, which is contracted in the left-right direction and stretched in the range of 2% or more and 40% or less in the front-rear direction.

(4) The aspect ratio of the uneven pattern is D / P when the average pitch, which is the average value of the width, is P [μm] and the average depth, which is the average value of the depths, is D [μm]. The anisotropic diffuser plate according to (2) or (3) above, wherein is 0.2 or more and 5.0 or less.

(5) The anisotropic diffusion plate according to any one of (2) to (4) above, wherein the resin base material is composed of a polycarbonate resin as a main material.

(6) The anisotropic diffusion plate according to any one of (2) to (5) above, wherein the resin base material contains a light diffusing agent.

(7) The anisotropic diffusion plate according to any one of (2) to (6) above, wherein the curable resin layer is a UV curable layer that is cured by irradiation with ultraviolet rays.

(8) The anisotropic diffusion plate according to any one of (2) to (7) above, wherein the curable resin layer contains a light diffusing agent.

(9) The anisotropic diffuser according to any one of (1) to (8) above, wherein a low refractive index layer lower than the refractive index of the anisotropic diffuser is formed on the incident surface.

(10) The anisotropic diffusion plate according to any one of (1) to (9) above, wherein a dielectric multilayer film is formed on the incident surface.

(11) The anisotropic diffuser according to any one of (1) to (10) above, wherein the anisotropic diffuser has an optical phase difference of 200 nm or less.

(12) The anisotropic diffusion plate according to any one of (1) to (11) above and a light emitting substrate arranged to face the anisotropic diffusion plate are provided.
The light emitting substrate is a backlight unit having a base substrate and a plurality of light emitting diodes arranged in a grid pattern on a surface of the base substrate facing the anisotropic diffusion plate.

(13) A liquid crystal display device including the backlight unit according to (12) above and a liquid crystal panel arranged to face the anisotropic diffusion plate side of the backlight unit.
(14) An electronic device including the liquid crystal display device according to (13) above.

According to the present invention, when the incident light incident from the incident surface is emitted as the emitted light diffused from the emitting surface, the anisotropic diffuser has different light diffusing ability in the left-right direction and light diffusing ability in the front-rear direction. Is incident light having a size of 3 mmΦ perpendicular to the incident surface from a light source, and evaluates the diffused light distribution in the left-right direction and the diffused light distribution in the front-rear direction of the emitted light with a brightness meter. The half-value length is twice the distance from the center at the position showing the half-brightness value, which is half the brightness value at the center through which the optical axis of the incident light passes, and the half-value length in the left-right direction. When is MD [mm] and the half-value length in the front-rear direction is TD [mm], the ratio (MD / TD) has a region showing anisotropic diffusion of 1.4 or more and less than 10.0, and The total light transmittance of the emitted light with respect to the incident light having a size of 3 mmΦ is 70% or more and 99% or less. Therefore, it can be said that this anisotropic diffuser has both excellent light diffusivity and excellent light transmission. Therefore, even if an LED is used as an optical element in a liquid crystal display device provided with such an anisotropic diffusion plate, it is possible to accurately suppress or prevent the scatteredness of the LED being seen through the anisotropic diffusion plate. In addition, the diffused light can be accurately suppressed or prevented from being wasted, and the image can be displayed with excellent display characteristics. In addition, when a liquid crystal display device equipped with an anisotropic diffuser is applied to an in-vehicle center information display, the light diffusion angle in the vertical direction can be suppressed as compared with the light diffusion angle in the horizontal direction, so that the image is reflected on the windshield. It is possible to prevent crowding. As a result, the electronic device provided with this liquid crystal display device has excellent reliability.

FIG. 1 is a vertical sectional view showing an embodiment of the liquid crystal display device of the present invention. FIG. 2 is a perspective view showing an embodiment of an anisotropic diffusion plate included in the liquid crystal display device shown in FIG. FIG. 3 is a partially enlarged vertical sectional view showing an enlarged portion A of the anisotropic diffusion plate shown in FIG. FIG. 4 is a side view showing an embodiment of an automobile display panel having the liquid crystal display device of the present invention as a display unit.

Hereinafter, the anisotropic diffuser plate, the backlight unit, the liquid crystal display device, and the electronic device of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

In the anisotropic diffuser plate of the present invention, when the incident light incident from the incident surface is emitted as the emitted light diffused from the emitting surface, the light diffusing ability in the left-right direction and the light diffusing ability in the front-rear direction are different. The incident light having a size of 3 mmΦ is incident on the incident surface perpendicularly to the incident surface, and the diffused light distribution in the left-right direction and the diffused light distribution in the front-rear direction of the emitted light are evaluated by a brightness meter. The half value length is twice the distance from the center at the position showing the half brightness value, which is half the brightness value of the center brightness value at the center through which the optical axis of the incident light passes, and the half value length in the left-right direction is MD. When [mm] and the half-value length in the front-rear direction are TD [mm], the region has a region showing anisotropic diffusion with a ratio (MD / TD) of 1.4 or more and less than 10.0, and the above. The total light transmittance of the emitted light with respect to the incident light having a size of 3 mmΦ is 70% or more and 99% or less.

As described above, according to the present invention, the anisotropic diffusion plate has a ratio (MD / TD) of 1. When incident light having a size of 3 mmΦ is incident from a light source perpendicular to the incident surface. It has a region showing anisotropic diffusion of 4 or more and less than 10.0. Therefore, it can be said that this anisotropic diffuser has excellent light diffusivity with anisotropy. Further, the total light transmittance of the emitted light with respect to the incident light having a size of 3 mmΦ is 70% or more and 99% or less. Therefore, it can be said that this anisotropic diffuser has excellent light transmission. Therefore, even if an LED is used as an optical element in a liquid crystal display device provided with an anisotropic diffuser having such a configuration, it is possible to accurately suppress the scatteredness of the LED being seen through the anisotropic diffuser. Alternatively, the image can be displayed with excellent display characteristics by accurately suppressing or preventing the diffused light from being wasted. As a result, the electronic device provided with this liquid crystal display device has excellent reliability.

Hereinafter, first, a liquid crystal display device including the anisotropic diffuser of the present invention, that is, the liquid crystal display device of the present invention will be described.

<Liquid crystal display device>
FIG. 1 is a vertical sectional view showing an embodiment of the liquid crystal display device of the present invention, FIG. 2 is a perspective view showing an embodiment of an anisotropic diffusion plate included in the liquid crystal display device shown in FIG. 1, and FIG. 2 is a partially enlarged vertical sectional view showing an enlarged portion A of the anisotropic diffusion plate shown in 2. In the following description, the upper side in FIG. 1 is referred to as "upper" and the lower side is referred to as "lower". Further, in FIGS. 2 and 3, the X direction is referred to as "horizontal direction", the Y direction is referred to as "front-back direction", and the Z direction is referred to as "vertical direction". In addition, the drawings to be used (including the drawings shown in FIGS. 1 to 3 and the following) are displayed in an appropriately enlarged or reduced size so that the parts to be described can be recognized.

As shown in FIG. 1, the liquid crystal display device 100 is a surface emitting light source 30 as a backlight, which is arranged on the opposite side (rear side) of the liquid crystal panel 20 constituting the image display unit and the display surface of the liquid crystal panel 20. A direct-type liquid crystal display device (direct-type liquid crystal display) having an anisotropic diffusing plate 10 arranged between the liquid crystal panel 20 and the surface emitting light source 30.

The liquid crystal panel 20 constitutes a transmissive image display unit having a liquid crystal cell 21 and two polarizing plates 22 arranged on the front surface (upper surface) and the back surface (lower surface) of the liquid crystal cell 21, respectively. There is. Here, the liquid crystal cell 21 has, for example, a configuration having a pair of transparent electrodes and an inclusion body containing a liquid crystal compound enclosed between the transparent electrodes, and is further arranged corresponding to the transparent electrodes on the front side. By having the color filter, it is possible to display a color image.

The surface light emitting light source 30 (light emitting substrate) has an opening that opens to the front side (upper surface side) by having a flat plate-shaped base material (base substrate) and a wall portion that stands up from the edge of the base material. The lamp box 31 (housing) on which the portions are formed, and the light emitting element 32 as a plurality of point light sources arranged in the lamp box 31 by being arranged in a grid pattern on the front surface (upper surface) side of the base material. It has.

In the surface emitting light source 30, the light emitting element 32 is composed of a light emitting diode (LED) having an extremely high directivity of emitting light emitted in a concentrated manner toward the front as compared with a white light bulb or a fluorescent lamp.

Further, the anisotropic diffusion plate 10 is fixed to the lamp box 31 so as to close the opening. As a result, the anisotropic diffusion plate 10 is arranged between the lamp box 31 and the liquid crystal panel 20. That is, the anisotropic diffuser 10 is arranged to face the lamp box 31 on the lower surface side, and the light (incident light) emitted by the liquid crystal panel 20 on the upper surface side passes through (transmits) the anisotropic diffuser 10. Then, when the emitted light is emitted as diffused light, the light diffusing ability in the left-right direction and the light diffusing ability in the front-rear direction are diffused with different anisotropy. Then, the light (emitted light) diffused with anisotropy is applied to the liquid crystal panel 20.

At least one isotropic diffuser plate that isotropically diffuses the light emitted by the light emitting element 32 may be arranged between the surface emitting light source 30 and the anisotropic diffuser plate 10. Further, at least one prism sheet that disperses and refracts the diffused light from the anisotropic diffuser 10 toward the liquid crystal panel 20 is arranged between the anisotropic diffuser 10 and the liquid crystal panel 20. May be good.

Further, in such a liquid crystal display device 100, a backlight unit (backlight unit of the present invention) is configured by the anisotropic diffusion plate 10 and the surface emitting light source 30.

In the liquid crystal display device 100 having the above configuration, the anisotropic diffusion plate 10 is composed of the anisotropic diffusion plate of the present invention. Therefore, when the anisotropic diffuser plate 10 emits the incident light incident from the incident surface 41 on the surface emitting light source 30 side as the emitted light diffused from the emitting surface 51 on the liquid crystal panel 20 side, the anisotropic diffuser plate 10 is in the left-right direction. The light diffusing ability and the light diffusing ability in the anteroposterior direction can be diffused with different anisotropy. That is, the incident light having a size of 3 mmΦ perpendicular to the incident surface 41 is incident from the light source, the diffused light distribution in the left-right direction and the diffused light distribution in the front-rear direction of the emitted light are evaluated by a luminance meter, and the incident light The half-value length is twice the distance from the center of the position showing the half-luminance value, which is half the brightness value at the center through which the optical axis passes, and the half-value length in the left-right direction is MD [mm]. When the half-value length in the front-rear direction is TD [mm], it has a region showing anisotropic diffusion with a ratio (MD / TD) of 1.4 or more and less than 10.0. The total light transmittance of the emitted light with respect to the incident light having a size of 3 mmΦ is 70% or more and 99% or less. Therefore, it can be said that the anisotropic diffusing plate 10 is capable of achieving both excellent light diffusivity and excellent light transmission.

Therefore, in the liquid crystal display device 100, an LED is used as the light emitting element 32, and the separation distance between the base material (base substrate) included in the lamp box 31 and the anisotropic diffusion plate 10 is set to, for example, 0.5 mm or more. Due to the miniaturization (thinning) of the liquid crystal display device 100, such as 10.0 mm or less, the light emitting element 32 (LED) can be seen through the anisotropic diffuser plate 10 even if it is set close to the liquid crystal display device 100. It is possible to accurately suppress or prevent interspersedness. Therefore, it is possible to obtain a liquid crystal display device 100 capable of displaying an image with excellent display characteristics.

Further, the aspect ratio A / B when the length in the left-right direction of the display area of the liquid crystal panel 20 is A and the length in the front-rear direction is B is 1.2 or more and 3.0 or less, preferably 1. Even if the display area of the liquid crystal panel 20 has a rectangular shape as shown below, the diffused light (emitted light) is the liquid crystal panel in the front-rear direction, which is the lateral direction of the liquid crystal panel 20. It is possible to accurately suppress or prevent the diffusion to the outside of the display area of 20. That is, it is possible to accurately suppress or prevent waste of the diffused light (emitted light). As a result, the power consumed by the liquid crystal display device 100 can be reduced.

In the present embodiment, such an anisotropic diffuser plate 10 forms a rectangular flat plate in a plan view, like the liquid crystal panel 20 and the surface emitting light source 30, and the incident surface 41 and the liquid crystal panel on the surface emitting light source 30 side. The exit surface 51 on the 20 side is composed of a flat surface and an uneven surface, respectively, and is laminated on the resin base material 40 located on the incident surface 41 side and the resin base material 40 located on the exit surface 51 side. It is composed of a laminate having a curable resin layer 50.

In the anisotropic diffusion plate 10 having such a shape, it is the anisotropic diffusion plate 10, that is, the curable resin layer 50, that exhibits anisotropy in which the ratio (MD / TD) is 1.4 or more and less than 10.0. The resin group constituting the anisotropic diffusion plate 10 can be configured such that the exit surface 51 is composed of an uneven surface (concave and convex pattern) and the total light transmittance is 70% or more and 99% or less. The material 40 and the curable resin layer 50 are both made of a transparent resin material. Hereinafter, the resin base material 40 and the curable resin layer 50 will be described in order.

The resin base material 40 has a function of supporting the curable resin layer 50, and also has a function of contracting in the left-right direction by heating and stretching in the front-rear direction, so that the exit surface 51 of the curable resin layer 50 can be formed. , The concavo-convex surface (concave-convex pattern) having the ratio (MD / TD) of 1.4 or more and less than 10.0 is exhibited.

The resin base material 40 contains a transparent resin (base resin) having thermoplasticity as a main material, thereby imparting the above-mentioned function to the resin base material 40.

The transparent resin is not particularly limited, but for example, a polyester resin such as an acrylic resin, a polystyrene resin, a polyethylene resin, a polypropylene resin, a polyethylene terephthalate (PET), or a polyethylene naphthalate (PEN), or a polycarbonate resin. , Cycloolefin resin, vinyl chloride resin, polyacetal resin and other transparent resins, and one or a combination of two or more of these can be used. Among these, a polycarbonate resin is particularly preferable. Polycarbonate-based resin is rich in mechanical strength such as transparency (translucency) and rigidity, and also has high heat resistance. Therefore, by using polycarbonate-based resin as the transparent resin, the transparency and resin base in the resin base material 40 can be obtained. The impact resistance and heat resistance of the material 40 can be improved. Further, since the polycarbonate-based resin is a transparent resin having excellent elasticity, it is possible to reliably impart the function of shrinking in the left-right direction and stretching in the front-rear direction by heating to the resin base material 40. ..

Various resins can be used as the polycarbonate-based resin, and among them, an aromatic polycarbonate-based resin is preferable. The aromatic polycarbonate-based resin has an aromatic ring in its main chain, whereby a resin base material 40 having higher strength can be obtained.

This aromatic polycarbonate resin is synthesized, for example, by an interfacial polycondensation reaction between bisphenol and phosgene, a transesterification reaction between bisphenol and diphenyl carbonate, and the like.

Examples of the bisphenol include bisphenol A and bisphenol (modified bisphenol) which is the origin of the repeating unit of polycarbonate represented by the following formula (1).

(In the formula (1), X is an alkyl group having 1 to 18 carbon atoms, an aromatic group or a cyclic aliphatic group, and Ra and Rb are independently alkyl groups having 1 to 12 carbon atoms. , M and n are integers from 0 to 4, respectively, and p is the number of repeating units.)

Specific examples of the bisphenol that is the origin of the repeating unit of the polycarbonate represented by the above formula (1) include 4,4'-(pentane-2,2-diyl) diphenol and 4,4'-(. Pentan-3,3-diyl) diphenol, 4,4'-(butane-2,2-diyl) diphenol, 1,1'-(cyclohexylhexanediyl) diphenol, 2-cyclohexyl-1,4-bis ( 4-Hydroxyphenyl) benzene, 2,3-biscyclohexyl-1,4-bis (4-hydroxyphenyl) benzene, 1,1'-bis (4-hydroxy-3-methylphenyl) cyclohexane, 2,2'- Examples thereof include bis (4-hydroxy-3-methylphenyl) propane, and one or a combination of two or more of these can be used.

In particular, as the polycarbonate resin, it is preferable that the main component is a bisphenol type polycarbonate resin having a skeleton derived from bisphenol. By using such a bisphenol type polycarbonate resin, the resin base material 40 exhibits further excellent strength.

Further, the resin base material 40 may further contain a fluorescent whitening agent. By configuring the resin base material 40 to contain a fluorescent whitening agent, when the anisotropic diffuser plate 10 emits the incident light from the surface emitting light source 30 to the liquid crystal panel 20 side as the emitted light, it is white. Light (emission light) can be emitted more reliably.

Specifically, the surface emitting light source provided with the anisotropic diffuser plate 10 by containing the fluorescent whitening agent in the resin base material 40 has 0.28 ≦ x ≦ 0 in the xy chromaticity diagram. It is preferable to emit light that satisfies the relationship of 40 and 0.28 ≦ y ≦ 0.40, and the relationship of 0.30 ≦ x ≦ 0.36 and 0.30 ≦ y ≦ 0.36. It is more preferable to emit a satisfactory light. As a result, the anisotropic diffusion plate 10 can emit white light from the surface emitting light source 30 toward the liquid crystal panel 20.

The fluorescent whitening agent is not particularly limited, and examples thereof include benzophenone type, benzotriazole type, hydroxyphenyltriazine type and benzooxyzazolylthiophene type compounds, and one or more of these. Can be used in combination, but among them, the benzooxyzazolylthiophene type is preferable. As a result, in the xy chromaticity diagram, x and y can be relatively easily satisfied with the above relationship.

The content of the fluorescent whitening agent in the resin base material 40 is preferably set to 0.001 wt% or more and 0.07 wt% or less, more preferably 0.003 wt% or more and 0.01 wt% or less. As a result, in the xy chromaticity diagram, x and y that satisfy the above relationship can be easily obtained.

Further, when the light (incident light) from the light emitting element 32 is transmitted to the resin base material 40 as the emitted light through the anisotropic diffusion plate 10 and is emitted to the liquid crystal panel 20, the emitted light is equalized. A light diffusing agent that diffuses anisotropically may be contained. As a result, it is possible to finely adjust the size of the half-value length MD in the left-right direction and the size of the half-value length TD in the front-rear direction in which the emitted light is emitted.

Such a light diffusing agent may be a compound composed of any constituent material as long as it is in the form of particles and has a difference in refractive index with respect to the transparent resin, but the constituent material is carbonic acid. Inorganic materials such as calcium, barium sulfate, aluminum hydroxide, potassium aluminum silicate, aluminum silicate, magnesium silicate, magnesium oxide, zinc oxide, silicon dioxide, titanium oxide, calcium fluoride, potassium fluoride, silicone-based Examples thereof include organic materials (resin-based materials) such as resins, acrylic resins, acrylic nitrile-based resins, polystyrene-based resins, and olefin-based resins, and one or a combination of two or more of these can be used. However, among them, a silicone-based resin having a polyorganosiloxane skeleton is preferable. By using a silicone-based resin (silicone-based material) as the constituent material, the light diffusing agent having the difference in refractive index can be relatively easily formed.

Silicone resins are monofunctional siloxane units (M units) represented by R ₃ SiO _0.5 (R is a monovalent organic group) and bifunctional siloxane units represented by R ₂ SiO _1.0 (R is a monovalent organic group). At least one of (D unit), a trifunctional siloxane unit (T unit) represented by RSiO _1.5 , and a tetrafunctional siloxane unit (Q unit) represented by SiO _2.0 (where Q). It is a resin having a polyorganosiloxane skeleton whose main component is (excluding the resin composed of a single unit). Then, by appropriately selecting a combination of these M units, D units, T units, and Q units, a light diffusing agent having a refractive index difference with respect to the transparent resin can be easily formed.

The organic group R in each unit includes an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a decyl group and a dodecyl group, and a cyclohexyl group. Examples thereof include a cyclic alkyl group, a phenyl group, an aryl group such as a xsilyl group, and an aralkyl group such as a phenylethyl group.

Further, the average particle size of the light diffusing agent is preferably set to 1.0 μm or more and 5 μm or less, and more preferably 1.5 μm or more and 3 μm or less.

When the light diffusing agent is contained, the content of the light diffusing agent in the resin base material 40 is preferably set to 0.1 wt% or more and 10 wt% or less, more preferably 1.0 wt% or more and 5.0 wt% or less. ..

In addition to the above-mentioned transparent resin, fluorescent whitening agent and light diffusing agent, the resin base material 40 further contains an antioxidant, a filler, a plasticizer, a light stabilizer, an ultraviolet absorber and a heat ray absorbing agent, if necessary. It may contain various additives such as an agent and a flame retardant.

The resin base material 40 having the above structure has a function of contracting in the left-right direction (X direction) and stretching in the front-rear direction (Y direction) by heating, but the elongation rate in the front-rear direction is 2% or more. It is preferably stretched within the range of 40% or less, and more preferably stretched within the range of 10% or more and 25% or less. By setting the elongation rate within the above range, the exit surface 51 of the curable resin layer 50 has an uneven surface (unevenness) exhibiting anisotropy having a ratio (MD / TD) of 1.4 or more and less than 10.0. It can be configured relatively easily with a pattern).

The average thickness of the resin base material 40 is preferably set to about 0.05 mm or more and 1.0 mm or less, preferably about 0.1 mm or more and 0.5 mm or less. By setting the average thickness of the resin base material 40 within such a range, the anisotropic diffusion plate 10 is thinned, and the anisotropic diffusion plate 10 is accurately suppressed or prevented from bending. be able to. Therefore, the anisotropic diffusing plate 10 can be imparted with light diffusing property and light transmitting property having more uniform anisotropy over the entire area.

As shown in FIGS. 2 and 3, the curable resin layer 50 is a layer that is laminated on the side opposite to the incident surface 41 of the resin base material 40 and is cured by irradiation with radiation, and is an exit surface 51 (exit surface 51 side). The surface of the surface) is provided with an uneven pattern in which the ridgeline of the convex portion is along the front-rear direction and the overall shape is wavy.

The curable resin layer 50 is provided with a concavo-convex pattern extending in the front-rear direction on the exit surface 51, having a wavy cross-sectional shape in the left-right direction, and having a plurality of concave portions and convex portions alternately and repeatedly formed. The magnitude of the ratio (MD / TD) of the exit surface 51 is 1.4 or more and less than 10.0.

Such a curable resin layer 50 contains a resin composition that is cured by irradiation with radiation as a main material. As a result, the exit surface 51 having the uneven pattern, which has a fine shape, can be reliably formed, so that the size of the ratio (MD / TD) of the exit surface 51 can be relatively easily set to 1.4. The size can be set to less than 10.0.

The curable resin layer 50 is not particularly limited as long as it is a layer that is cured by irradiation with radiation, but preferably a UV curable layer that is cured by irradiation with ultraviolet rays is used, thereby providing an uneven pattern. The curable resin layer 50 can be formed at a relatively low cost. Therefore, in the following, a UV curable curable resin layer 50 containing a resin composition that is cured by irradiation with ultraviolet rays as a main material will be described as a representative.

((Meta) acrylate monomer)
The resin composition is not particularly limited as long as it is a material that can be cured by irradiation with ultraviolet rays, but it is preferable that the resin composition mainly contains a (meth) acrylate monomer. As a result, the (meth) acryloyl groups of the (meth) acrylate monomer are bonded to each other to form a network of the (meth) acrylate monomer, and as a result, a curable resin layer 50 in which the resin composition is cured is formed. To.

Since the surface hardness of the curable resin layer 50 formed by such a resin composition is high, the size of the ratio (MD / TD) of the exit surface 51 can be relatively easily set to 1.4 or more. It can be set to a size less than 0.0.

The (meth) acrylate monomer is not particularly limited. Trimethylol ethoxylated propantriacrylate, pentaerythritol triacrylate ethoxylated, pentaerythritol tetraacrylate ethoxylated, polyethylene glycol diacrylate, polypropylene glycol acrylate, ethoxylated bisphenol A diacrylate, ethoxylated hydrogenated bisphenol A diacrylate, ethoxylated cyclohexane Examples thereof include dimethanol diacrylate, tricyclodecane dimethanol diacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, urethane acrylate, isobolonyl acrylate and the like. One or a combination of two or more of these can be used.

(Other materials)
Further, the resin composition may contain other materials in addition to the (meth) acrylate monomer described above.

Other materials are not particularly limited, but are, for example, resin materials such as monomers and polymers other than the (meth) acrylate monomer, photopolymerization initiators, ultraviolet absorbers, colorants, sensitizers, stabilizers, and surfactants. Examples thereof include agents, antioxidants, antioxidants, antistatic agents, surface modifiers, hydrophilization additives, light diffusing agents, and the like, and one or a combination of two or more of these can be used.

((UV absorber))
The resin composition further contains an ultraviolet absorber, so that the weather resistance of the curable resin layer 50 obtained from the resin composition is more excellent.

The ultraviolet absorber is not particularly limited, and examples thereof include triazine-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ultraviolet absorbers, and one or two of these can be used in combination.

The content of the ultraviolet absorber in the resin composition is not particularly limited, but is preferably 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the (meth) acrylate monomer. It is more preferably more than 10 parts by mass and less than 10 parts by mass. If the content of the ultraviolet absorber with respect to the (meth) acrylate monomer is less than the above lower limit value, the strength of the curable resin layer 50 may decrease depending on the type of the ultraviolet absorber. Further, even if the content of the ultraviolet absorber with respect to the (meth) acrylate monomer exceeds the above upper limit value, no further improvement in weather resistance is observed, and depending on the type of the ultraviolet absorber, the curable resin layer 50 is transparent. There is a risk of impairing sex.

((Photopolymerization initiator))
Further, since the resin composition further contains a photopolymerization initiator, the degree of curing of the curable resin layer 50 obtained by curing the resin composition by photopolymerization by ultraviolet irradiation is more excellent. Therefore, the curable resin layer 50 having more excellent strength can be obtained.

The photopolymerization initiator is not particularly limited, and is, for example, benzoin or benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether, aromatic ketones such as benzophenone and benzoyl benzoic acid, and benzyl. Alpha-dicarbonyls such as, benzyl dimethyl ketal, benzyl ketals such as benzyl diethyl ketal, acetophenone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenyl Ketone, 2-hydroxy-2-methyl-1-phenyl-1-propane-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methyl-propane-1-one, 2-methyl-1 -[4- (Methylthio) phenyl] -2-morpholinopropanone-1 and other acetophenones, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone and other anthraquinones, 2,4-dimethylthioxanthone, Thioxanthones such as 2-isopropylthioxanthone and 2,4-diisopropylthioxanthone, phoshinoxides such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 1-phenyl-1,2-propanedione- Examples thereof include alpha-acyloximes such as 2- (o-ethoxycarbonyl) oxime, amines such as ethyl p-dimethylaminobenzoate and isoamyl p-dimethylaminobenzoate, and among these, 1- (4) -Dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenyl-1-propane-1-one, 1- (4- (4-) Acetphenones such as isopropylphenyl) -2-hydroxy-2-methyl-propan-1-one and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1 are preferable. As a result, the curing of the resin composition can proceed more rapidly by photopolymerization by ultraviolet irradiation.

The content of the photopolymerization initiator in the resin composition is not particularly limited, but is preferably 0.5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the (meth) acrylate monomer. It is more preferably more than 10 parts by mass and less than 10 parts by mass. If the content of the photopolymerization initiator with respect to the (meth) acrylate monomer is less than the above lower limit value, it may be difficult to sufficiently cure the resin composition depending on the type of the photopolymerization initiator, and (meth) ) Even if the content of the photopolymerization initiator with respect to the acrylate monomer exceeds the above upper limit value, no further improvement is observed.

((Surface conditioner))
Further, the surface conditioner is added for the purpose of improving the wettability and uniformity of the coating film composed of the resin composition to the resin base material 40, the smoothness of the surface, and the surface slip property of the cured coating film. .. For example, a fluorine-based, modified silicone-based, or acrylic-based adjusting agent can be used. Above all, it is preferable to contain at least one of a fluorine-based and a modified silicone-based adjusting agent. As these modifiers, a compound composed of a modified polyether compound, an alkyl modified product, and a modified polyester compound is preferable, and a compound composed of the modified polyether compound is more preferable.

((Light diffuser))
Further, when the light (incident light) from the light emitting element 32 is transmitted to the curing type resin layer 50 through the anisotropic diffusion plate 10 and emitted to the liquid crystal panel 20 as the emitted light, the emitted light is emitted. A light diffusing agent that diffuses isotropically may be contained. As a result, it is possible to finely adjust the size of the half-value length MD in the left-right direction and the size of the half-value length TD in the front-rear direction in which the emitted light is emitted.

As such a light diffusing agent, the same compounds as described in the above-mentioned light diffusing agent contained in the resin base material 40 can be used.

Further, the average particle size of the light diffusing agent is preferably set to 0.5 μm or more and 5 μm or less, and more preferably 1.0 μm or more and 3 μm or less.

When the light diffusing agent is contained, the content of the light diffusing agent in the curable resin layer 50 is preferably set to 1.0 wt% or more and 40 wt% or less, more preferably 5.0 wt% or more and 25 wt% or less.

As described above, in the anisotropic diffusion plate 10, the incident surface 41 on the surface emitting light source 30 side of the resin base material 40 and the emitting surface 51 on the liquid crystal panel 20 side of the curable resin layer 50 are flat surfaces and respectively. It is composed of an uneven surface. Such an anisotropic diffusion plate 10 has a configuration having a region exhibiting anisotropic diffusion in which the ratio (MD / TD) is 1.4 or more and less than 10.0. Of the incident surface 41 and the exit surface 51, the exit surface 51 extends in the front-rear direction, the cross-sectional shape in the left-right direction is wavy, and a plurality of concave portions and convex portions are alternately and repeatedly formed. By providing a pattern (see FIGS. 2 and 3).

On such an exit surface 51, the wavy uneven pattern functions as a light diffusing means for anisotropically diffusing light (emission light), whereby the emission light emitted from the emission surface 51 is divided into the ratio. (MD / TD) is diffused with anisotropic diffusion satisfying 1.4 or more and less than 10.0.

The aspect ratio D / P of this uneven pattern is 0. When the average pitch, which is the average value of the width, is P [μm] and the average depth, which is the average value of the depth, is D [μm]. It is preferably 1 or more and 3.0 or less, more preferably 0.15 or more and 1.0 or less, further preferably 0.2 or more and 0.7 or less, and 0.22 or more and 0.43 or less. Is particularly preferable. By setting the magnitude of the aspect ratio D / P within such a range, the magnitude of the ratio (MD / TD) can be surely set within the range of 1.4 or more and less than 10.0.

At this time, the average pitch P of the uneven pattern is preferably 1.0 μm or more and 40 μm or less, more preferably 2.0 μm or more and 25 μm or less, and further preferably 4.0 μm or more and 15 μm or less. , 8.0 μm or more and 12 μm or less is particularly preferable. The average depth D of the uneven pattern is preferably 0.5 μm or more and 30 μm or less, more preferably 1.0 μm or more and 10 μm or less, and further preferably 2.0 μm or more and 6.0 μm or less. , 3.0 μm or more and 4.5 μm or less is particularly preferable. As a result, in a plan view of the anisotropic diffusion plate 10, the relationship in which the magnitude of the ratio (MD / TD) is 1.4 or more and less than 10.0 is satisfied on the entire surface of the anisotropic diffusion plate 10. , The emitted light can be emitted substantially uniformly from the emitting surface 51.

Here, the exit surface 51 of the curable resin layer 50 causes the incident light having a size of 3 mmΦ to be incident from the light source perpendicularly to the incident surface 41, and the diffused light distribution in the left-right direction and the diffusion in the front-rear direction of the emitted light. The light distribution is evaluated with a brightness meter, and the half value length is twice the distance from the center of the position showing the half brightness value, which is half the brightness value at the center where the optical axis of the incident light passes. A region in which the ratio (MD / TD) is 1.4 or more and less than 10.0 when the half-value length in the left-right direction is MD [mm] and the half-value length in the front-back direction is TD [mm]. However, the ratio (MD / TD) is preferably 1.5 or more and less than 6.0, and more preferably 1.8 or more and 3.0 or less. It is good to be there. As a result, it can be said that the anisotropic diffusion plate 10 exhibits a diffusing ability having more excellent anisotropy. Therefore, in the liquid crystal display device 100, it is possible to more accurately suppress or prevent the interspersedness in which the light emitting element 32 (LED) is seen through through the anisotropic diffuser plate 10.

Further, in the present embodiment, since the wavy uneven pattern is arranged so that the stretching direction is parallel to the Y direction (front-back direction), the light diffusing ability in the X direction (horizontal direction) is in the Y direction (left-right direction). Since it exhibits diffusivity with greater anisotropy than the light diffusivity in the front-back direction, the half-value length MD in the left-right light intensity distribution of the emitted light is larger than the half-value length TD in the front-rear direction light diffusivity distribution. Is also getting bigger. Therefore, by setting the ratio (MD / TD) within the above range, the diffused light (emission light) with respect to the liquid crystal panel 20 in which the aspect ratio A / B in the display area is within the above range. It is possible to more accurately suppress or prevent the diffused light from being diffused outside the display area of the liquid crystal panel 20 when the light is irradiated. Further, even if the light emitting elements 32 included in the surface light emitting light source 30 are arranged in a grid pattern in the lamp box 31 so as to be evenly spaced in both the left-right direction and the front-rear direction, the ratio (MD / TD) is set. Within the above range, the dispersed emission light can be more uniformly applied to the display region included in the liquid crystal panel 20 in which the aspect ratio A / B is within the above-mentioned range.

In the present specification, the "ratio (MD / TD)" is a parameter (characteristic value) indicating the light diffusing ability of the emitted light emitted from the emitting surface 51. Specifically, when the light emitted from the light source is incident on the anisotropic diffuser plate 10 vertically from the incident surface 41 side of the anisotropic diffuser plate 10 as incident light, the incident light is incident on the exit surface 51 side. The light intensity distribution of the emitted light measured by using a brightness meter arranged on the optical axis has a large normal direction of the emitting surface 51, that is, the optical axis direction of the incident light, and a tangential direction of the incident surface 51, that is, the incident light. It becomes smaller as it is closer to the vertical direction perpendicular to the optical axis. In the emitted light showing such a luminous intensity distribution, in the present specification, a position showing a half luminance value in which the emitted light has a half luminance value with respect to the central luminance value of the emitted light at the center through which the optical axis of the incident light passes. Twice the distance from the center is called the half-value length. In the present embodiment, the half-value length in the luminous intensity distribution in the left-right direction (X direction) of the emitted light is larger than the half-value length in the luminous intensity distribution in the front-back direction (Y direction). Therefore, the "ratio (MD / TD)" can be obtained by finding the quotient between the half-value length in the luminosity distribution in the left-right direction of the emitted light and the half-value length in the luminosity distribution in the front-back direction of the emitted light. Further, the larger the "ratio (MD / TD)" is, the more the anisotropic diffuser plate 10 has a light diffusing ability with greater anisotropy.

The curable resin layer 50 as described above preferably has a breaking elongation of 5% or more, preferably 7.5% or more, of the resin constituting the curable resin layer 50, that is, a cured product of the resin composition cured by irradiation with radiation. It is more preferably 200% or less, and further preferably 7.5% or more and 50% or less. By setting the breaking elongation within the above range, the uneven pattern formed on the exit surface 51 of the curable resin layer 50 by the shrinkage in the left-right direction and the stretching in the front-rear direction of the resin base material 40 is formed on the average pitch P. And, as a pattern in which the magnitude of the average depth D is set within the above-mentioned range, it can be relatively easily formed. Further, when the uneven pattern is formed on the exit surface 51, it is possible to accurately suppress or prevent defects such as cracks from occurring in the uneven pattern.

The average thickness of the curable resin layer 50 is not particularly limited, but is preferably 0.2 μm or more and 20 μm or less, and more preferably 1 μm or more and 10 μm or less. If the thickness of the curable resin layer 50 is less than the lower limit, the strength of the curable resin layer 50 may decrease. On the other hand, when the thickness of the curable resin layer 50 exceeds the upper limit value, the ratio () is applied to the exit surface 51 of the curable resin layer 50 due to the shrinkage of the resin base material 40 in the left-right direction and the stretching in the front-rear direction. There is a possibility that it becomes impossible to form an uneven surface (unevenness pattern) in which MD / TD) exhibits anisotropy of 1.4 or more and less than 10.0.

Further, the anisotropic diffuser plate 10 composed of the laminate of the resin base material 40 and the curable resin layer 50 as described above is perpendicular to the incident surface 41 in the region where the uneven pattern is formed. When an incident light having a size of 3 mmΦ is incident from a light source, the total light transmittance of the light emitted as the emitted light may be 70% or more and 99% or less, but 80% or more and 99. % Or less, more preferably 85% or more and 99% or less, and even more preferably 87% or more and 99% or less. Thereby, it can be said that the anisotropic diffuser plate 10 exhibits more excellent light transmission. Therefore, in the liquid crystal display device 100, the amount of light from the surface emitting light source 30 can be sufficiently obtained, and the liquid crystal display device 100 having excellent image display characteristics can be obtained while reducing the power consumption.

Further, the anisotropic diffusion plate 10 preferably has an optical phase difference of 200 nm or less, more preferably 150 nm or less. Here, in the case of a liquid crystal display device for in-vehicle use, the anisotropic diffusion plate 10 may be exposed to a high temperature of 60 to 80 ° C., and when the phase difference is larger than 200 nm, the height constituting the resin base material is high. The anisotropic diffusion plate 10 due to the orientation of the molecular chains is distorted at a high temperature, and the anisotropic diffusion performance may change.

Further, the anisotropic diffusion plate 10 may include a low refractive index layer formed on the incident surface 41. This low refractive index layer has a refractive index lower than the refractive index of the anisotropic diffuser plate 10, and by configuring the anisotropic diffuser plate 10 to be applied, the incident light from the surface emitting light source 30 can be emitted. , The refractive index reflected on the surface emitting light source 30 side can be reduced. Therefore, the amount of light emitted as the emitted light from the emitting surface 51 is increased.

The low refractive index layer may be an inorganic layer, an organic layer, or a layer of a composite of an organic system and an inorganic system.

Examples of the inorganic low refractive index layer include metal fluoride fine particles and the like. Examples of the metal fluoride fine particles include magnesium fluoride, aluminum fluoride, calcium fluoride, lithium fluoride and the like, and one or a combination of two or more of these can be used. In addition, in order to impart adhesion of the metal fluoride fine particles, a resin base layer may be formed on the incident surface 41 by ultraviolet rays, an electron beam curing resin, or the like.

Examples of the organic low refractive index layer include a fluororesin having a low refractive index due to the large amount of fluorine atoms contained in the resin. As the fluororesin, polytetrafluoroethylene and polyvinylidene fluoride are preferable, and for example, it can be formed by laminating a sheet made of a fluororesin on an incident surface 41 via an adhesive.

Further, examples of the low refractive index layer made of an organic-based and inorganic-based composite include a layer containing ultraviolet rays or an electron beam-curable resin and inorganic fine particles having voids, metal fluoride fine particles, and the like. Examples of the inorganic fine particles having voids include fine particles in which gas is filled inside the inorganic fine particles, fine particles having a porous structure containing gas inside, and the like. Specific examples thereof include hollow silica fine particles and silica fine particles having a nanoporous structure. Examples of the metal fluoride fine particles include magnesium fluoride, aluminum fluoride, calcium fluoride, lithium fluoride and the like. The average particle size of the inorganic fine particles and the metal fluoride fine particles is preferably 5 to 100 nm, more preferably 20 to 80 nm, and even more preferably 40 to 70 nm. When the average particle size of the fine particles is in this range, excellent transparency can be imparted to the low refractive index layer.

Further, the anisotropic diffusion plate 10 may include a dielectric multilayer film formed on the incident surface 41. With this dielectric multilayer film, it is possible to reduce the reflectance of the incident light from the surface emitting light source 30 reflected on the surface emitting light source 30 side. Therefore, the amount of light emitted as the emitted light from the emitting surface 51 is increased.

This dielectric multilayer film is composed of repeating a high refractive index layer containing a high refractive index dielectric material and a low refractive index layer containing a low refractive index dielectric material, and these high refractive index dielectric materials and low refractive index materials are formed. Examples of the refractive index dielectric material include ceramic materials, glass materials, resin materials, and the like, and among these, one or two so that the high refractive index layer has a higher refractive index than the low refractive index layer. It is used in combination of seeds and above.

Examples of the ceramic material include alumina, zirconia, magnesia, silica, titanium oxide, niobium pentoxide, aluminum nitride, silicon nitride, silicon carbide, barium titanate, and perovskite-type barium titanate calcium crystal particles (BCTZ-type crystal particles). ), Calcium fluoride, magnesium fluoride and the like. Moreover, as a glass material, for example, quartz glass, borosilicate glass and the like can be mentioned. Further, examples of the resin material include polyethylene, polypropylene, polytetrafluoroethylene, polyethylene terephthalate, polyvinylidene fluoride, polyphenylene sulfide, phenol resin, melamine resin, unsaturated polyester resin, epoxy resin and the like.

Further, in the present embodiment, the wavy uneven pattern is arranged on the exit surface 51 so that the stretching direction is parallel to the Y direction (front-back direction), but the present invention is not limited to this, and for example, a liquid crystal display. When the panel 20 has a long rectangular shape in the Y direction, the concavo-convex pattern can be arranged so that the extending direction of the concavo-convex pattern is parallel to the X direction (left-right direction).

Further, in the present embodiment, the case where the curable resin layer 50 is laminated on the liquid crystal panel 20 side (exit surface 51 side) of the resin base material 40 in the anisotropic diffusion plate 10 has been described, but the present invention is limited to this. However, for example, the curable resin layer 50 may be laminated on both the liquid crystal panel 20 side (exit surface 51 side) and the light emitting element 32 side (incident surface 41 side) of the resin base material 40, or the resin. It may be laminated independently on the light emitting element 32 side (incident surface 41 side) of the base material 40.

Next, the anisotropic diffusion plate 10 having the above-described configuration can be manufactured, for example, as follows.

<Manufacturing method of anisotropic diffusion plate 10>
[1] First, a resin base material 40 stretched in the X direction (left-right direction) is prepared. That is, a resin base material 40 exhibiting heat shrinkability capable of shrinking in the X direction by heating is prepared.

The method for producing the stretched resin base material 40 is not particularly limited, but first, for example, general molding such as a calendar method, an inflation extrusion method, an extrusion molding method such as a T-die extrusion method, or a wet casting method. A method of obtaining a resin base material 40 stretched in the X direction by molding a non-stretched resin base material 40 using the method and then performing a uniaxial stretching treatment on the non-stretched resin base material 40. Can be mentioned.

The draw ratio for stretching the resin base material 40 in the X direction is such that when the resin base material 40 is heat-shrinked by heating in the subsequent step [3], the resin base material 40 is heat-shrinked in the X direction. The rate is preferably set to be 25% or more and 60% or less, and more preferably 30% or more and 50% or less.

[2] Next, a curable resin layer 50 is formed on the upper surface of the resin base material 40, in which the formation of an uneven pattern on the exit surface 51 is omitted. That is, the curable resin layer 50 having a flat upper surface is formed.

The surface (upper surface) of the resin base material 40 is subjected to plasma treatment, corona treatment, chromic acid treatment, ozone exposure treatment, and flame exposure for the purpose of improving the adhesion between the resin base material 40 and the curable resin layer 50. Surface treatments such as treatment, high piezoelectric exposure treatment, ionizing radiation treatment, primer treatment, and anchor coating treatment may be applied.

Further, the curable resin layer 50 in which the formation of the uneven pattern is omitted is a liquid in which the resin composition, which is a constituent material constituting the curable resin layer 50, is dissolved in a solvent on the resin base material 40 to form a varnish. It can be obtained by coating or spraying the material, then volatilizing the solvent and then irradiating with radiation to cure the resin composition.

Examples of the solvent used when preparing the liquid material containing the resin composition include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, methanol, ethanol and propanol. , Alcohols such as butanol, 2-pentanone, isophorone, ketones such as diisobutylketone, esters such as ethyl acetate, butyl acetate, isobutyl acetate, methoxypropyl acetate, cellosolvent solvents such as ethyl cellosolve, methoxypropanol, ethoxypropanol , Glycol-based solvents such as methoxybutanol, and the like. These can be used alone or in combination.

Further, the application or spraying of the liquid material on the resin base material 40 can be carried out by using a method such as die coating, curtain die coating, gravure coating, comma coating, bar coating and lip coating.

[3] Next, the resin base material 40 having the curable resin layer 50 laminated on the upper surface is heated to shrink along the X direction and stretch along the Y direction.

Of the heating and stretching of the resin base material 40, the heating of the resin base material 40 causes the resin base material 40 to shrink along the contraction direction of the resin base material 40, that is, the X direction, and as a result, the curable resin layer 50 is formed. By deforming the exit surface 51 (upper surface) so as to be folded along the Y direction, a wavy uneven pattern along the Y direction is formed on the exit surface 51.

Examples of the method for heating the resin base material 40 include a method of blowing hot air or steam onto the lower surface of the resin base material 40, a method of immersing the lower surface side of the resin base material 40 in hot water, and a method of immersing the lower surface side of the resin base material 40 in hot air. A tenter stretching method capable of controlling shrinkage in the transport direction while clamping the width direction of the resin base material 40 (film) can be mentioned.

Further, by stretching the resin base material 40 along the Y direction, it is possible to suppress a long-period swell that occurs along the Y direction that occurs when the resin base material 40 contracts in the X direction, which causes a poor appearance. This is because the resin base material 40 contracts in the X direction and at the same time expands in the thickness direction and the Y direction corresponding to the Poisson's ratio. Therefore, the expansion in the Y direction can be controlled at the same time as the contraction in the X direction and the Y direction. This is because stretching is effective in suppressing long-period uneven undulations that occur along the Y direction.

As described above, the curable resin layer 50 laminated on the upper surface of the resin base material 40 by the step of stretching the resin base material 40 along the Y direction while shrinking along the X direction due to heating of the resin base material 40. By forming a concavo-convex pattern on the exit surface 51, it is relatively easy to create a concavo-convex surface (concavo-convex pattern) having anisotropy of the ratio (MD / TD) of 1.4 or more and less than 10.0. Can be formed.

Specifically, the elongation rate of the resin base material 40 along the Y direction due to stretching is preferably 2% or more and 40% or less, and more preferably 10% or more and 25% or less. By setting the elongation rate within the above range, the exit surface 51 of the curable resin layer 50 has an uneven surface (unevenness) exhibiting anisotropy having a ratio (MD / TD) of 1.4 or more and less than 10.0. It can be configured relatively easily with a pattern).
By going through the above steps, the anisotropic diffusion plate 10 can be manufactured.

<Electronic equipment>
Next, a case where the electronic device (the electronic device of the present invention) including the liquid crystal display device 100 described above is applied to a display panel of an automobile will be described as an example.

FIG. 4 is a side view showing an embodiment of an automobile display panel having the liquid crystal display device of the present invention as a display unit. In the following description, the upper side in FIG. 1 is referred to as "upper" and the lower side is referred to as "lower".

As shown in FIG. 4, the display panel 150 (electronic device of the present invention) including a display unit for displaying a center information display, a speedometer, a tachometer, a water temperature gauge, a fuel gauge, etc. has a liquid crystal display unit 100. It is configured and used by being mounted on an automobile 200. The display panel 150 is built in the upper part of the dashboard 201 of the automobile 200, whereby information such as the speed of the automobile and the number of revolutions of the engine displayed by the liquid crystal display device 100 is displayed as an image by the driver H. Is recognized by. By configuring the display unit of such a display panel 150 with a liquid crystal display device 100 provided with an anisotropic diffusion plate 10, the light diffusion angle in the vertical direction can be suppressed as compared with the light diffusion angle in the left-right direction. It is possible to prevent the reflection on the front glass of 200.

The electronic device of the present invention includes a personal computer, a smartphone, a television, a video camera, an electronic organizer, and a medical device (for example, a sphygmomanometer, a glucose meter, and a liquid crystal display for an endoscope) in addition to the display panel of the automobile shown in FIG. It can be applied to an electronic device having a display unit such as a device) and a device having a touch panel (for example, an automatic ticket vending machine).

The anisotropic diffuser plate, the backlight unit, the liquid crystal display device, and the electronic device of the present invention have been described above, but the present invention is not limited thereto.

For example, in the above embodiment, the case where the liquid crystal display device provided with the anisotropic diffuser of the present invention is applied to the direct type liquid crystal display device has been described, but the present invention is not limited to this, and for example, the edge light type liquid crystal display device. It can also be applied to.

Further, in the above embodiment, the case where the anisotropic diffuser of the present invention is applied to the diffuser for a liquid crystal display included in the liquid crystal display device has been described, but the anisotropic diffuser of the present invention is a cover for lighting. , Window glass, roof members for daylighting, etc.

Hereinafter, the present invention will be described in more detail based on Examples. The present invention is not limited to these examples.

1. 1. Production of Anisotropic Diffusion Plate (Example 1)
<1> A 0.3 mm thick flat plate that is cooled and solidified after stretching a resin plate extruded with a T-die from a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Company, Ltd., "Iupilon E-2000-N") between heating rolls. A polycarbonate substrate having a shape was prepared as the resin substrate 40.

When the stretching ratio for roll-stretching the resin base material 40 in the X direction is heat-shrinked by heating the resin base material 40 in the subsequent step <3>, the resin base material 40 is heat-shrinked in the X direction. It was set so that it could shrink until the shrinkage rate reached 50%.

<2> Next, in forming the curable resin layer 50, the resin composition shown below was prepared.

That is, urethane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., "UA-122P"): 80 parts by mass, ethoxylated bisphenol A diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., "A-BPE-4"): 20 parts by mass. The mixture was prepared to obtain a mixture (main component).

Further, with respect to 100 parts by mass of the obtained mixture, as additives, a polymerization initiator (manufactured by Lamberti, "KIP100F"): 7 parts by mass and a surface conditioner (manufactured by Big Chemie, "BYK-378"). : 0.01 part by mass was added, methoxypropanol as a solvent was added so that the non-volatile content was 50%, and the mixture was stirred to dissolve all the components to obtain a resin composition.

Next, the obtained resin composition was applied to the resin base material 40 with a bar coater so that the thickness after drying (thickness of the coat layer) was 3 μm to obtain a coating layer.

Then, the resin base material 40 coated with the coating layer is dried in a hot air oven at 100 ° C. for 10 minutes to form a coating layer, and then using an electrodeless UV lamp manufactured by FUSION Systems, an irradiation distance of 95 mm and a conveyor speed of 3 mm / The coat layer was photocured by irradiating with ultraviolet rays under the conditions of min, irradiation intensity 450 mW / cm ² , and integrated light amount 1000 mJ / cm ² . As a result, a curable resin layer 50 coat layer was formed on the resin base material 40.

The resin composition prepared to form the curable resin layer 50 was placed in an aluminum cup, dried in a hot air oven at 100 ° C. for 3 hours, and then used with an electrodeless UV lamp manufactured by FUSION Systems to have an irradiation distance of 95 mm. A resin plate having a 1 mm thick curable resin layer 50 was prepared by irradiating ultraviolet rays under the conditions of a conveyor speed of 3 mm / min, an irradiation intensity of 450 mW / cm ² , and an integrated light amount of 1000 mJ / cm ² . Then, the elongation at break of the produced curable resin layer 50 was measured using an autograph device (manufactured by Shimadzu Corporation, AG-5kNG) according to ASTM-D638, and found to be 8.2%. ..

<3> Next, the resin base material 40 on which the curable resin layer 50 of 220 mm in the X direction × 100 mm in the Y direction is formed is heated to a heating temperature of 180 using a biaxial stretching test device (EX10-B, manufactured by Toyo Seiki Seisakusho Co., Ltd.). At ° C., the mixture was contracted at a shrinkage rate of 44% in the X direction at a rate of 178 mm / min, and at the same time stretched at a stretch rate of 25% at a rate of 40 mm / min in the Y direction to obtain an anisotropic diffusion plate 10. It was.

Further, when the average pitch P and the average depth D of the uneven pattern formed on the exit surface 51 were measured using a laser microscope (“VK-9700” manufactured by KEYENCE), 10.2 μm and 16. It was 0 μm.

(Example 2)
An anisotropic diffusion plate 10 of Example 2 was obtained in the same manner as in Example 1 except that the thickness of the coat layer was set to 2 μm to form the curable resin layer 50.

(Example 3)
Example 1 above, except that the thickness of the coat layer was set to 2 μm to form the curable resin layer 50, the shrinkage rate in the X direction using the biaxial stretching device was set to 33%, and the stretching rate in the Y direction was set to 18%. In the same manner as above, the anisotropic diffusion plate 10 of Example 3 was obtained.

(Example 4)
As a mixture (main component) of the resin composition for forming the curable resin layer 50, urethane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., "U-200PA"): 80 parts by mass, ethoxylated bisphenol A diacrylate ( "A-BPE-4" manufactured by Shin-Nakamura Chemical Co., Ltd.): Different from Example 4 in the same manner as in Example 1 except that 20 parts by mass was prepared to obtain a mixture (main component). A directional diffuser 10 was obtained. The elongation at break of the resin layer composition forming the curable resin layer was 49.9%.

(Example 5)
As a mixture (main component) of the resin composition for forming the curable resin layer 50, urethane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., "U-200PA"): 40 parts by mass, polypropylene glycol diacrylate (Shin-Nakamura) Chemical Industry Co., Ltd., "APG-700"): 40 parts by mass, ethoxylated bisphenol A diacrylate (Shin-Nakamura Chemical Industry Co., Ltd., "A-BPE-4"): 20 parts by mass, and the mixture ( The anisotropic diffusion plate 10 of Example 5 was obtained in the same manner as in Example 1 except that the main component) was obtained and the thickness of the coat layer was set to 2 μm in order to form the curable resin layer 50. It was. The elongation at break of the resin layer composition forming the curable resin layer was 11.0%.

(Example 6)
A spherical silica diffuser having an average particle size of 2.5 μm (manufactured by Nippon Catalyst Co., Ltd., “Seahoster KE-P P250” as an additive with respect to 100 parts by mass of the mixture of the resin composition for forming the curable resin layer 50. ”): An anisotropic diffusion plate 10 of Example 6 was obtained in the same manner as in Example 1 except that 20 parts by mass was added. The elongation at break of the resin layer composition forming the curable resin layer was 7.6%.

(Example 7)
A spherical silica diffuser having an average particle size of 2.5 μm (Seahoster KE-P P250 manufactured by Nippon Catalyst Co., Ltd.) as an additive with respect to 100 parts by mass of the mixture of the resin composition for forming the curable resin layer 50. : An anisotropic diffusion plate 10 was obtained in the same manner as in Example 5 except that the thickness of the coat layer was set to 3 μm in order to form a curable resin layer by adding 20 parts by mass. The elongation at break of the resin layer composition forming the curable resin layer was 10.0%.

(Example 8)
Polysiloxane-based spherical diffuser with an average particle size of 2.0 μm (manufactured by Momentive, TSR9000): 0.5 parts by mass as an additive with respect to 100 parts by mass of the polycarbonate resin prepared for forming the resin base material 40. The anisotropic diffusion plate 10 of Example 8 was obtained in the same manner as in Example 1 except that the above-mentioned Example 1 was added.

(Example 9)
As a mixture (main component) of the resin composition for forming the curable resin layer 50, triacryloxyethyl isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., "A-9300"): 90 parts by mass, bisphenol ethoxylated. A diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., "A-BPE-4"): Performed in the same manner as in Example 1 above, except that 10 parts by mass was prepared to obtain a mixture (main component). The anisotropic diffusion plate 10 of Example 9 was obtained. In addition, a large number of cracks were generated in the curable resin layer 50, and partial peeling failure of the curable resin layer 50 also occurred. The elongation at break of the resin layer composition forming the curable resin layer was 1.2%.

(Comparative Example 1)
A spherical silica diffuser having an average particle size of 2.5 μm (Seahoster KE-P P250, manufactured by Nippon Catalyst Co., Ltd.) as an additive with respect to 100 parts by mass of the mixture of the resin composition for forming the curable resin layer 50. : Shrinkage in the X direction after producing a curable resin layer 50 in which the exit surface 51 is a flat surface on the resin base material 40 in the same manner as in Example 1 except that 35 parts by mass is added. By not stretching in the Y direction, an isotropic diffusion plate of Comparative Example 1 was obtained.

2. 2. Evaluation The anisotropic diffusion plate 10 of each Example and each Comparative Example was evaluated by the following method.

1) Half price length MD, TD, ratio (MD / TD)
For each of the anisotropic diffuser plates 10 of each of the examples and the comparative examples, incident light having a size of 3 mmΦ perpendicular to the incident surface 41 corresponding to the region where the uneven pattern of the exit surface 51 is formed is emitted. It was incident from a light source. Then, at this time, the luminous intensity distribution of the emitted light in the Y direction (front-back direction) and the luminous intensity distribution of the emitted light in the X direction (left-right direction) emitted from the emitting surface 51 are measured by a luminance measuring device (manufactured by HI-LAND). , "RISA-COLOR / ONE").

Then, based on the obtained luminous intensity distribution, the half-value length MD in the luminous intensity distribution in the X direction (left-right direction) of the emitted light and the half-value length TD in the luminous intensity distribution in the Y direction (front-back direction) of the emitted light are obtained. Furthermore, the ratio (MD / TD) was obtained from these half-value lengths.

2) Total light transmittance For each of the anisotropic diffuser plates 10 of each Example and each Comparative Example, a haze meter (manufactured by Murakami Color Technology Research Institute, “HR-100”) was used, and all of them in the thickness direction were used. The light transmittance was measured according to ASTM D1003.

3) Front Luminance of Backlight Unit First, the anisotropic diffuser plates 10 of each Example and each Comparative Example are fixed to the lamp box 31 included in the surface emitting light source 30 so as to close the opening thereof. This made a backlight unit.

Next, the light emitting element 32 included in the lamp box 31 is turned on, and the front luminance in the backlight unit is measured using a luminance measuring device (manufactured by HI-LAND, "RISA-COLOR / ONE"). evaluated.

A: 2200 cd / m ² or more and 2500 cd / m ² or less.
B: less than 2000 cd / ^{m 2} or more 2200cd / ^{m 2.}
C: 1800 cd / m ² or more and less than 2000 cd / m ² .

4) Luminance unevenness of the backlight unit First, the anisotropic diffuser plates 10 of each Example and each Comparative Example are fixed to the lamp box 31 included in the surface emitting light source 30 so as to close the opening thereof. This made a backlight unit.

Next, the light emitting element 32 included in the lamp box 31 was turned on, and the brightness unevenness in the backlight unit was evaluated as follows.

A: In the anisotropic diffuser plate 10, the LED is not scattered without being scattered.
The emitted light is uniformly emitted, and no uneven brightness is observed.
B: In the anisotropic diffuser plate 10, the LED is slightly scattered, but
It can be said that the emitted light is emitted almost uniformly, and no obvious uneven brightness is observed.
C: In the anisotropic diffuser plate 10, the scatteredness of the LED and the brightness shading due to the sample structure defect are slightly generated, and it cannot be said that the emitted light is emitted almost uniformly.
Although slight uneven brightness is observed, there is no problem in practical use.
D: In the anisotropic diffuser plate 10, the interspersed LED is clearly generated.
It cannot be said that the emitted light is emitted uniformly, and remarkable uneven brightness is observed.

The evaluation results of the anisotropic diffusion plate 10 of each Example and each Comparative Example obtained as described above are shown in Table 1 below.

As shown in Table 1, in the anisotropic diffuser plates 10 of Examples 1 to 8, since the front luminance is high and the luminance unevenness does not occur, the interspersedness in which the LEDs can be seen through is suppressed or prevented. However, it was found that the diffused light can be suppressed or prevented from being wasted. Further, in the anisotropic diffusion plate 10 of Example 9, since the curable resin layer 50 having low fracture elongation has cracks and partial peeling fracture, that is, structural defects, the emitted light is emitted substantially uniformly. Although slight unevenness in brightness was observed due to the inability to achieve this, there was no problem in practical use.

On the other hand, in Comparative Example 1, since the isotropic light diffusing plate is used, the light diffusing does not match the shape of the liquid crystal panel, so that the front luminance is not improved, and both the front luminance improvement and the brightness unevenness suppression are achieved. The result was not possible.

According to the present invention, when the incident light incident from the incident surface is emitted as the emitted light diffused from the emitting surface, the anisotropic diffuser has different light diffusing ability in the left-right direction and light diffusing ability in the front-rear direction. Is incident light having a size of 3 mmΦ perpendicular to the incident surface from a light source, and evaluates the diffused light distribution in the left-right direction and the diffused light distribution in the front-rear direction of the emitted light with a brightness meter. The half-value length is twice the distance from the center at the position showing the half-brightness value, which is half the brightness value at the center through which the optical axis of the incident light passes, and the half-value length in the left-right direction. When is MD [mm] and the half-value length in the front-rear direction is TD [mm], the ratio (MD / TD) has a region showing anisotropic diffusion of 1.4 or more and less than 10.0, and The total light transmittance of the emitted light with respect to the incident light having a size of 3 mmΦ is 70% or more and 99% or less. Therefore, it can be said that this anisotropic diffuser has both excellent light diffusivity and excellent light transmission. Therefore, even if an LED is used as an optical element in a liquid crystal display device provided with such an anisotropic diffusion plate, it is possible to accurately suppress or prevent the scatteredness of the LED being seen through the anisotropic diffusion plate. In addition, the diffused light can be accurately suppressed or prevented from being wasted, and the image can be displayed with excellent display characteristics. In addition, when a liquid crystal display device equipped with an anisotropic diffuser is applied to an in-vehicle center information display, the light diffusion angle in the vertical direction can be suppressed as compared with the light diffusion angle in the horizontal direction, so that the image is reflected on the windshield. It is possible to prevent crowding. As a result, the electronic device provided with this liquid crystal display device has excellent reliability. Therefore, the present invention has industrial applicability.

Such an object is achieved by the present invention described in the following (1) to ( 13 ).
(1) An anisotropic diffuser plate in which the light diffusing ability in the left-right direction and the light diffusing ability in the front-rear direction are different when the incident light incident from the incident surface is emitted as the emitted light diffused from the emitting surface. ,
It has a resin base material and a curable resin layer that is laminated on the exit surface side of the resin base material and cured by irradiation with radiation.
The curable resin layer has an uneven pattern along the front-rear direction on the surface on the exit surface side thereof, and the breaking elongation of the resin constituting the curable resin layer is 5% or more.
The resin base material exhibits heat shrinkability that can be shrunk by heating, shrinks in the left-right direction, and is stretched in the front-rear direction.
The incident light having a size of 3 mmΦ perpendicular to the incident surface is incident from the light source, and the diffused light distribution in the left-right direction and the diffused light distribution in the front-rear direction of the emitted light are evaluated by a luminance meter.
The half-value length is twice the distance from the center at the position showing the half-luminance value, which is half the brightness value at the center through which the optical axis of the incident light passes, and the half-value length in the left-right direction is defined as the half-value length. When MD [mm] and the half-value length in the front-rear direction are TD [mm], the ratio (MD / TD) has a region showing anisotropic diffusion of 1.4 or more and less than 10.0, and An anisotropic diffuser having a total light transmittance of 70% or more and 99% or less with respect to the incident light having a size of 3 mmΦ.

(2) said resin substrate, anisotropic diffusion plate according to (1) elongation of not more than 40% 2% against the front-rear direction.

( 3 ) The aspect ratio of the uneven pattern is D / P when the average pitch, which is the average value of the width, is P [μm] and the average depth, which is the average value of the depths, is D [μm]. The anisotropic diffuser according to ( 1 ) or ( 2 ) above, wherein is 0.2 or more and 5.0 or less.

( 4 ) The anisotropic diffusion plate according to any one of ( 1 ) to ( 3 ) above, wherein the resin base material is composed of a polycarbonate resin as a main material.

( 5 ) The anisotropic diffusion plate according to any one of ( 1 ) to ( 4 ) above, wherein the resin base material contains a light diffusing agent.

( 6 ) The anisotropic diffusion plate according to any one of ( 1 ) to ( 5 ) above, wherein the curable resin layer is a UV curable layer that is cured by irradiation with ultraviolet rays.

( 7 ) The anisotropic diffusion plate according to any one of ( 1 ) to ( 6 ) above, wherein the curable resin layer contains a light diffusing agent.

( 8 ) The anisotropic diffuser according to any one of (1) to ( 7 ) above, wherein a low refractive index layer lower than the refractive index of the anisotropic diffuser is formed on the incident surface.

( 9 ) The anisotropic diffusion plate according to any one of (1) to ( 8 ) above, wherein a dielectric multilayer film is formed on the incident surface.

( 10 ) The anisotropic diffuser according to any one of (1) to ( 9 ) above, wherein the anisotropic diffuser has an optical phase difference of 200 nm or less.

( 11 ) The anisotropic diffusion plate according to any one of (1) to ( 10 ) above and a light emitting substrate arranged to face the anisotropic diffusion plate are provided.
The light emitting substrate is a backlight unit having a base substrate and a plurality of light emitting diodes arranged in a grid pattern on a surface of the base substrate facing the anisotropic diffusion plate.

( 12 ) A liquid crystal display device including the backlight unit according to ( 11 ) above and a liquid crystal panel arranged to face the anisotropic diffusion plate side of the backlight unit.
( 13 ) An electronic device including the liquid crystal display device according to the above ( 12 ).

(3) The aspect ratio of the concave-convex pattern is D / P when the average pitch, which is the average value of the width, is P [μm] and the average depth, which is the average value of the depth, is D [μm]. The anisotropic diffuser plate according to (1) or (2) above, wherein is 0.2 or more and 3.0 or less .

Further, when the average pitch P and the average depth D in the uneven pattern formed on the exit surface 51 were measured using a laser microscope (“VK-9700” manufactured by KEYENCE), 10.2 μm and 4. It was 7 μm .

( Comparative Example 2 )
As a mixture (main component) of the resin composition for forming the curable resin layer 50, triacryloxyethyl isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., "A-9300"): 90 parts by mass, bisphenol ethoxylated. A diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., "A-BPE-4"): Compared in the same manner as in Example 1 above, except that 10 parts by mass was prepared to obtain a mixture (main component). The anisotropic diffusion plate 10 of Example 2 was obtained. In addition, a large number of cracks were generated in the curable resin layer 50, and partial peeling failure of the curable resin layer 50 also occurred. The elongation at break of the resin layer composition forming the curable resin layer was 1.2%.

As shown in Table 1, in the anisotropic diffuser plates 10 of Examples 1 to 8, since the front luminance is high and the luminance unevenness does not occur, the interspersedness in which the LEDs can be seen through is suppressed or prevented. However, it was found that the diffused light can be suppressed or prevented from being wasted. Further, in the anisotropic diffusion plate 10 in Comparative Example 2 , since the curable resin layer 50 having low fracture elongation has cracks and partial peeling fracture, that is, structural defects, the emitted light is emitted substantially uniformly. Although slight unevenness in brightness was observed due to the inability to achieve this, there was no problem in practical use.

Claims (14)

An anisotropic diffuser plate in which the light diffusing ability in the left-right direction and the light diffusing ability in the front-rear direction are different when the incident light incident from the incident surface is emitted as the emitted light diffused from the emitting surface.
The incident light having a size of 3 mmΦ perpendicular to the incident surface is incident from the light source, and the diffused light distribution in the left-right direction and the diffused light distribution in the front-rear direction of the emitted light are evaluated by a luminance meter.
The half-value length is twice the distance from the center at the position showing the half-luminance value, which is half the brightness value at the center through which the optical axis of the incident light passes, and the half-value length in the left-right direction is defined as the half-value length. When MD [mm] and the half-value length in the front-rear direction are TD [mm], the ratio (MD / TD) has a region showing anisotropic diffusion of 1.4 or more and less than 10.0, and An anisotropic diffuser having a total light transmittance of 70% or more and 99% or less with respect to the incident light having a size of 3 mmΦ. It has a resin base material and a curable resin layer that is laminated on the exit surface side of the resin base material and cured by irradiation with radiation.
The curable resin layer has an uneven pattern along the front-rear direction on the surface on the exit surface side.
The anisotropic diffusion plate according to claim 1, wherein the breaking elongation of the resin constituting the curable resin layer is 5% or more. The resin base material exhibits heat shrinkability that can be shrunk by heating.
The anisotropic diffusion plate according to claim 2, which is contracted in the left-right direction and stretched in the range of 2% or more and 40% or less in the front-rear direction. The aspect ratio D / P of the concave-convex pattern is 0. When the average pitch which is the average value of the width is P [μm] and the average depth which is the average value of the depth is D [μm]. The anisotropic diffuser according to claim 2 or 3, which is 2 or more and 5.0 or less. The anisotropic diffusion plate according to any one of claims 2 to 4, wherein the resin base material is composed of a polycarbonate resin as a main material. The anisotropic diffusing plate according to any one of claims 2 to 5, wherein the resin base material contains a light diffusing agent. The anisotropic diffusion plate according to any one of claims 2 to 6, wherein the curable resin layer is a UV curable layer that is cured by irradiation with ultraviolet rays. The anisotropic diffusion plate according to any one of claims 2 to 7, wherein the curable resin layer contains a light diffusing agent. The anisotropic diffuser according to any one of claims 1 to 8, wherein a low refractive index layer lower than the refractive index of the anisotropic diffuser is formed on the incident surface. The anisotropic diffusion plate according to any one of claims 1 to 9, wherein a dielectric multilayer film is formed on the incident surface. The anisotropic diffuser according to any one of claims 1 to 10, wherein the anisotropic diffuser has an optical phase difference of 200 nm or less. The anisotropic diffusion plate according to any one of claims 1 to 11 and a light emitting substrate arranged to face the anisotropic diffusion plate are provided.
The light emitting substrate is a backlight unit having a base substrate and a plurality of light emitting diodes arranged in a grid pattern on a surface of the base substrate facing the anisotropic diffusion plate. A liquid crystal display device comprising the backlight unit according to claim 12 and a liquid crystal panel arranged to face the anisotropic diffusion plate side of the backlight unit. An electronic device including the liquid crystal display device according to claim 13.