JP2010217871A - Light control sheet and liquid crystal display device using the light control sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light control sheet capable of emitting a video having satisfactory quality by suppressing color irregularity in a screen, and to provide a liquid crystal display device provided with the light control sheet. <P>SOLUTION: The light control sheet 10 is disposed between a light source 2 and a liquid crystal panel 20 of the liquid crystal display device and has a plurality of layers wherein at least one layer among the plurality of layers is an optical functional sheet layer 11 which has prisms 12, which are arranged side by side along a sheet surface light-transmissibly and have a trapezoidal cross-section shape and light absorption parts 13, formed by filling a material having a light-absorptive property between the prisms, at least one layer among the plurality of layers is made to be a transmissive base film layer 16 to be laminated on the surface of the optical functional sheet layer of a long lower bottom side of the prism having the trapezoidal cross-section shape, and the base film layer has the retardation Re of 15 nm or lower. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light control sheet capable of controlling and emitting light from a light source in a liquid crystal display device such as a liquid crystal display device, and a liquid crystal display device using the light control sheet.

  For example, in a liquid crystal display device or the like, light from a light source is emitted through a liquid crystal panel (hereinafter sometimes referred to as “LCD”) on which image information is represented, thereby providing an image to an observer. At this time, the light from the light source incident on the LCD is preferably parallel to the normal of the panel surface of the LCD as much as possible, thereby improving the quality of the image light provided to the observer.

For this purpose, a light control sheet called a so-called louver is sometimes used. This is composed of a light transmission part having a rectangular cross section arranged in parallel with a predetermined interval along the sheet surface, and a light absorption part having a rectangular cross section provided between the light transmission parts so as to be able to absorb light. Yes. According to this, the light which has entered the light control sheet with a predetermined angle is absorbed by the light absorbing portion. Then, only light that is parallel to or close to the normal to the sheet surface passes through the light transmission part. Thereby, the preferable light as described above can be incident on the LCD.
In the car navigation display, a louver is used to prevent light from being emitted upward in order to prevent the image of the display from being reflected on the windshield at night.

  However, in such a louver type light control sheet, although the direction of light can be controlled, there is a case where the image becomes dark because there is a lot of absorbed light. In order to obtain a bright image, it is necessary to increase the input energy to the light source or to apply a brighter light source.

  On the other hand, a viewing angle control sheet as disclosed in Patent Document 1 is disclosed. According to this, the light transmission part is trapezoidal, and a wedge-shaped part having an inclined surface and capable of absorbing light is formed between them. The inclined surface of the wedge-shaped portion is formed so as to be able to reflect on the basis of the difference in refractive index, and incident light can be emitted close to a parallel one. Therefore, the luminance (brightness) of the emitted light can be made larger than in the case of the louver.

JP 2006-171700 A

  However, when such a viewing angle control sheet is disposed between the light source and the LCD, color unevenness may occur, causing problems.

  Accordingly, an object of the present invention is to provide a light control sheet that can emit a high-quality image while suppressing color unevenness in the screen, and a liquid crystal display device including the light control sheet.

As a result of intensive studies, the inventors have found that color unevenness is prevented by preventing color separation by suppressing retardation of the light control sheet, and interference fringes due to optical adhesion to the liquid crystal panel (polarizing plate) of the light control sheet. The knowledge that it can suppress was acquired.
The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

  The invention according to claim 1 is a light control sheet (10, 110) provided between a light source (2) and a liquid crystal panel (22) of a liquid crystal display device and having a plurality of layers, wherein the plurality of layers At least one of the prism parts (12, 12,...) Having a trapezoidal cross section and a light-absorbing material between the prism parts. And an optical function sheet layer (11) having a light absorption portion (13, 13,...) Formed by filling, at least one of the plurality of layers having a long prism portion having a trapezoidal cross section. A light-transmitting base film layer (16) laminated on the surface of the optical functional sheet layer on the lower bottom side, the base film layer having a retardation Re of 15 nm or less. The problem is solved by providing.

  Here, “retardation Re” means retardation in the plane direction. The retardation Re is preferably 15 nm or less at a wavelength of 400 nm to 700 nm. This is because retardation can be suppressed over the entire visible light range.

  The invention according to claim 2 is a light control sheet (10, 110) provided between the light source (2) of the liquid crystal display device and the liquid crystal panel (22), and having a plurality of layers, the plurality of layers. At least one of the prism parts (12, 12,...) Having a trapezoidal cross section and a light-absorbing material between the prism parts. And an optical function sheet layer (11) having a light absorption portion (13, 13,...) Formed by filling, at least one of the plurality of layers having a long prism portion having a trapezoidal cross section. The light-transmitting base film layer (16) is laminated on the surface of the optical functional sheet layer on the lower bottom side, and the base film layer has a retardation Re of 15 nm or less and the surface of the base film layer Of these, the side on which the optical function sheet layer is laminated and The surface opposite to solve the above problems by the average roughness (Ra) to provide a light control sheet, characterized in that the above rough surface 0.1μm are formed.

  The invention according to claim 3 is characterized in that, in the light control sheet (10, 110) according to claim 1 or 2, the base film layer (16) is mainly composed of polycarbonate.

  The invention according to claim 4 is the light control sheet (110) according to any one of claims 1 to 3, wherein the base film layer (16) of the optical function sheet layer (11) is disposed. Another base film layer (112) is laminated on the surface opposite to the above, and the other base film layer has a retardation Re of 15 nm or less.

Invention of Claim 5 is that the linear expansion coefficient of the light control sheet | seat (10, 110) as described in any one of Claims 1-4 is 1 * 10 < ^-3 > (1 / degreeC) or less. Features.

  The invention according to claim 6 is the light control sheet (10, 110) according to any one of claims 1 to 5, wherein the cross-sectional shape of the light absorbing portion (13, 13, ...) is a base film. It is an isosceles trapezoid having an upper bottom surface with a narrow width on the layer (16) side, or an isosceles triangle having the base film layer side as an apex.

  The invention according to claim 7 is the light control sheet (10) according to any one of claims 1 to 6, wherein the refractive index of the light absorbing portion (13, 13, ...) is Nb, When the refractive index of the material constituting the prism portion (12, 12,...) Is Np, the relationship Nb <Np is established.

  The invention according to claim 8 is the light control sheet (10, 110) according to any one of claims 1 to 7, and a liquid crystal panel disposed on the base film layer (16) side of the light control sheet. (22) and the light source (2) arranged on the side opposite to the base film layer side of the light control sheet are provided to solve the above problem by providing a liquid crystal display device.

  Invention of Claim 9 is the polarizing plate arrange | positioned at the base film layer (16) side of the light control sheet (10,110) as described in any one of Claims 1-7, and a light control sheet. (21), a light source (2) disposed on the side opposite to the base film layer side of the light control sheet, and a reflective polarizing sheet (4) disposed between the light source and the light control sheet. The above-described problems are solved by providing a liquid crystal display device.

  Invention of Claim 10 is a method of manufacturing the light-control sheet | seat (10, 110) as described in any one of Claims 1-7, Comprising: The film used as a base film layer (16), When passing between the mold roll and the pressing roll provided with irregularities corresponding to the shape of the prism portion (12, 12,...) On the surface, between the layer serving as the base film layer and the mold roll. The film that becomes the base film layer is filled with the ionizing radiation curable resin in the space between the film that becomes the base film layer by supplying the ionizing radiation curable resin and the concave portion of the mold roll. The ionizing radiation curable resin filled in the concave portion of the mold roll is cured by irradiating ionizing radiation from the side, and the film to be the base film layer and the cured ionizing radiation curable resin are peeled off from the mold roll. Forming a prism part Thereafter, comprising filling the material having light-absorbing properties during the prism portion, to solve the above problems by providing a method for producing a light control sheet.

  According to the light control sheet and the liquid crystal display device of the present invention, it is possible to emit high-quality images while suppressing color separation and color unevenness in the screen. Here, the color separation is a phenomenon in which colors appear to be divided like a rainbow on the screen.

It is the figure which showed the cross section of the light-control sheet | seat which concerns on one embodiment, and represented the layer structure typically. It is the figure which expanded and showed a part of optical function sheet | seat layer among the light control sheets shown in FIG. It is the figure which showed the other example (polygonal line shape) of the shape of a prism part and a light absorption part. It is the figure which showed the example whose light absorption part is trapezoid. It is the figure which expanded and showed a part of light control sheet | seat shown in FIG. It is a figure explaining an example of the manufacturing method of a light control sheet. It is the figure which showed the cross section of the light-control sheet | seat which concerns on other embodiment, and represented the layer structure typically. It is the figure which showed the cross section of the video source unit among video display apparatuses, and showed the layer structure typically. It is a figure for demonstrating the optical path in a light control sheet. It is the figure which showed the cross section of the video source unit of another example among video display apparatuses, and showed the layer structure typically. It is a figure for demonstrating the optical path in a light-diffusion sheet among the image source units of another example. It is a figure explaining the method of laminating | stacking the other base film layer in an Example.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments.

  FIG. 1 is a view schematically showing a layer structure of a light control sheet 10 according to one embodiment. In the drawings shown below, some repetitive symbols may be omitted for easy viewing.

  The light control sheet 10 includes an optical function sheet layer 11 and a base film layer 16. Each layer maintains the cross section shown in FIG. 1 and extends in the back / front direction. Each layer will be described below.

  The optical function sheet layer 11 includes prism portions 12, 12,... That are substantially trapezoidal in the thickness direction cross section of the light control sheet 10, and a light absorption portion 13 disposed between the prism portions 12, 12,. , 13,... FIG. 2 shows an enlarged view of the optical function sheet layer 11 focusing on the two light absorbing portions 13 and 13 and the prism portions 12, 12 and 12 adjacent thereto. The optical function sheet layer 11 will be described with reference to FIGS. 1 and 2 and the drawings appropriately shown.

The prism portions 12, 12,... Are elements having a substantially isosceles trapezoidal cross section arranged so that one sheet surface side is an upper base and the other sheet surface side is a lower bottom. The prism parts 12, 12,... Are made of a light transmissive resin having a refractive index of Np.
The prism portions 12, 12,... Are usually formed of a resin that is cured by ionizing radiation. The resin can be the same as the binder of the light absorbing portion described later, and is a transparent resin having a predetermined refractive index, such as an ultraviolet curable resin or an electron beam curable resin having an ionizing radiation curing action. Used. There are those that directly cure with ionizing radiation and those that cause a curing reaction through a substance that excites a reaction called a catalyst or an initiator. Examples of ionizing radiation curable resins include reactive oligomers (epoxy acrylate, urethane acrylate, polyether acrylate, polyester acrylate, polythiol, etc.) and reactive monomers (vinyl pyrrolidone, 2-ethylhexyl acrylate, β-hydroxy). Acrylate, tetrahydrofurfuryl acrylate, etc.) are appropriately selected.
Although the magnitude | size of Np is not specifically limited, It is preferable that it is 1.4-1.6 from a viewpoint of the availability of an application material.

  Light can be provided to the liquid crystal panel by transmitting light through the prism portions 12, 12,.

  The light absorbing parts 13, 13,... Are parts disposed between the prism parts 12, 12,. The light absorbing parts 13, 13,... Are substantially isosceles triangles having the upper base side of the prism parts 12, 12,... As the base, and the apex opposite thereto is the lower base side of the prism parts 12, 12,. It is. The light absorption parts 13, 13,... Include a binder part 14 filled with a substance having a refractive index of Nb, and light absorption particles 15, 15,... Mixed in the binder part 14.

  Although the magnitude | size of the refractive index Nb of the binder material with which the binder part 14 is filled is not specifically limited, It is preferable that it is 1.4-1.6 from a viewpoint of the availability of the material to apply.

  As the binder material, for example, an ultraviolet curable resin or an electron beam curable resin having a predetermined refractive index and having an ionizing radiation curing action is used. There are those that directly cure with ionizing radiation and those that cause a curing reaction through a substance that excites a reaction called a catalyst or an initiator. Examples of ionizing radiation curable resins include reactive oligomers (epoxy acrylate, urethane acrylate, polyether acrylate, polyester acrylate, polythiol, etc.) and reactive monomers (vinyl pyrrolidone, 2-ethylhexyl acrylate, β-hydroxy). Acrylate, tetrahydrofurfuryl acrylate, etc.) are appropriately selected.

  Here, the difference between the refractive index Np and the refractive index Nb in the light control sheet 10 of the present invention is not particularly limited, but Np−Nb is preferably larger than zero. As a result, total reflection is appropriately performed at the interface between the prism portions 12, 12,... And the light absorbing portions 13, 13,. ,... Can be absorbed.

  The light absorbing particles 15, 15,... Are particles colored to a predetermined concentration with a pigment such as carbon or a dye such as red, blue, and yellow. For this, for example, commercially available colored resin fine particles can be used. Specifically, a black pigment such as carbon black or a resin particle such as a mixture of black particles such as carbon black described above with transparent particles such as acrylic can be used as the black particles. In addition, a mixture of various pigments and / or dyes of blue, purple, yellow, and red other than black pigments, or a material that is substantially black by mixing and dispersing the black colorant in a blue, purple, yellow, and red colorant May be used. As the blue pigment, copper phthalocyanine, etc., as the purple pigment, dioxazine violet, etc., as the yellow pigment, disazo yellow, etc., as the red pigment, chromophthal red typel, etc. are used. Alternatively, a dye may be used instead of a pigment. Further, a colored pigment or dye obtained by mixing and dispersing a blue, purple, yellow, red, black pigment or dye, and colored particles obtained by coloring transparent particles such as resin particles such as acrylic may be used. Among the above colored particles, in the present invention, black particles are the preferred material because they have the highest light absorption.

The light absorbing particles 15, 15... Are preferably particles having an average particle diameter of 1 μm or more from the viewpoint of availability, optical characteristics, and handling, and in addition, the length of the base that is a triangle of the light absorbing portions 13, 13. More preferably, it is half or less. If the size of the light-absorbing particles 15 is too small as less than 1 μm, there may be many light-absorbing particles on the hypotenuse, and part of the light that should be totally reflected on the hypotenuse may be absorbed. This is because the reflection efficiency may be reduced. Further, at the time of production, the light absorbing particles may remain on the sheet surface, which may cause production problems.
On the other hand, if the size of the light absorbing particles 15 exceeds the half of the length of the bottom of the light absorbing portion 13, it is difficult to fill the inside of the light absorbing portion 13 at the time of manufacture, resulting in a poor filling rate. Furthermore, the filling rate of each light absorption part varies, which is not preferable because of optical unevenness.

  Further, the amount of dispersion of the light absorbing particles 15, 15,... Is preferably 10 to 50% by volume with respect to the total volume of the light absorbing portions 13, 13,. By maintaining this ratio, it is possible to provide easy manufacturing conditions while maintaining a sufficient light absorption effect.

  Further, from the viewpoint of absorbing light, the light absorption performance of the light absorption portions 13, 13,... Can be adjusted as appropriate depending on the purpose, but is formed only from the material constituting the light absorption portions 13, 13,. In measuring the transmittance of a sheet having a thickness of 6 μm, it is preferable that the transmittance is 40 to 70%. The means for setting the transmittance to 40 to 70% is not particularly limited, and examples thereof include adjusting the content of light absorbing particles and light absorbing performance.

  Further, the angle θ of the oblique sides (two sides extending in the sheet thickness direction) of the light absorbing portions 13, 13,... With respect to the sheet surface normal can be changed according to the purpose and is not particularly limited. However, in the case of a normal display device, it is preferably greater than 0 degree and less than or equal to 10 degrees, and more preferably greater than 0 degree and less than or equal to 6 degrees, from the viewpoint of appropriately reflecting and absorbing external light and light. .

As shown in FIGS. 1 and 2, the shape of the optical function sheet layer 11 is such that the prism portions 12, 12,... Have a substantially trapezoidal cross section, and are formed between the light absorbing portions 13, 13, ... has an isosceles triangular cross section. However, if the light can be controlled appropriately, these shapes are not particularly limited, and appropriate shapes are appropriately adopted. FIG. 3 shows a modification. FIG. 3 is a view corresponding to FIG. 2, focusing on the two light absorbing portions 13 ′ and 13 ′ in the optical function sheet layer 11 ′ and the prism portions 12 ′, 12 ′ and 12 ′ disposed on both sides thereof. FIG. As can be seen from FIG. 3, the hypotenuse (the hypotenuses of the prism units 12 ′, 12 ′, 12 ′) in the cross section of the light absorption units 13 ′, 13 ′ is not from one hypotenuse, but two oblique sides 13a ′, 13a ′. ,..., 13b ′, 13b ′. That is, the cross section has a polygonal oblique side. Specifically, the oblique sides 13a ′, 13a ′,... Arranged on the upper base (the bottom on the short side) side (left side of the sheet) of the prism portions 12 ′, 12 ′, 12 ′ are at an angle θ with respect to the normal to the sheet surface. It has _one. On the other hand, the oblique sides 13b ′, 13b ′,... Arranged on the lower bottom (long side bottom) side (right side of the sheet) of the prism portions 12 ′, 12 ′, 12 ′ are at an angle θ _{2 with} respect to the normal of the sheet surface. have.

It is preferable that the angles θ ₁ and θ ₂ have a relationship of θ ₁ > θ ₂ and both are in the range of greater than 0 degree and less than or equal to 10 degrees. A more preferable angle is greater than 0 degree and 6 degrees or less. Further, the two oblique sides 13a ', 13b' intersect at a position dividing the _{Z 1} and _{Z 2} in the thickness direction of the optical functional sheet layer 11 '(left-right direction). Z ₁ and Z ₂ are preferably the same size.

  The modification is an example constituted by two hypotenuses, but may be formed in a polygonal line shape in the cross section by comprising more hypotenuses. Furthermore, this may be curved.

In the present embodiment, the case where the light absorbing portion is substantially triangular has been described and described, but the shape of the light absorbing portion is not limited to this. For example, a trapezoid may be used. FIG. 4 shows the light absorbing portions 13 ″ and 13 ″ of the optical function sheet layer 11 ″ and the prism portions 12 ″ and 12 adjacent thereto among the light control sheets in the example where the light absorbing portion is an isosceles trapezoid. '', 12 ''. Here, as shown in FIG. 4, the light absorbing portions 13 ″ and 13 ″ are trapezoidal. At this time, the long base (lower base) of the trapezoid is the upper base side of the prism portion 12 ″ and the short base (upper base). ) Can be arranged on the lower bottom side of the prism portion 12 ″. Here, the length of the upper base shown by A in FIG. 4 is preferably in the range of 2 μm to 25 μm. Further, the hypotenuse of the trapezoid is formed with an angle of θ ₃ with respect to the normal to the sheet surface. The magnitude of the angle θ ₃ is not particularly limited, but is preferably in the range of greater than 0 degrees and less than 10 degrees. A more preferable angle is greater than 0 degree and 6 degrees or less.

  In the present embodiment, as described above, light absorption performance is obtained by mixing light absorption particles in the light absorption portion from the viewpoint of the efficiency of total reflection on the hypotenuse of the light absorption portion. However, the present invention is not limited to this, and a pigment such as carbon or a predetermined dye may be mixed in the light absorption portion to color the entire light absorption portion to a predetermined concentration.

  Returning to FIG. 1, the configuration of the light control sheet 10 will be described. The base film layer 16 is a film layer as a base layer serving as a base for forming the optical function sheet layer 11 on one surface of the base film layer 16. FIG. 5 shows an enlarged part of FIG.

  As can be seen from FIGS. 1 and 5, a rough surface 16 a is formed on the surface of the base film layer 16 that is not in contact with the optical function sheet layer 11. Thereby, when the said light control sheet | seat 10 is laminated | stacked on a liquid crystal panel, the interference fringe (Newton ring) by what is called optical contact | adherence can be suppressed. In particular, a monitor of a car navigation system is required to have no interference fringes due to partial adhesion with a polarizing plate in a high temperature and high humidity environment. That is, a minute air layer is formed in the optically adhered portion, and the light reflected at the interface immediately before the air layer interferes with the light reflected at the interface after passing through the air layer. This produces interference fringes. On the other hand, since the rough surface 16a is formed, it is possible to suppress the formation of an air layer (for example, an air layer whose layer thickness is minute and constant) in which the interference occurs. Occurrence can be suppressed. Therefore, the surface roughness of the rough surface 16a is not particularly limited as long as the interference fringes can be suppressed. However, the average roughness (Ra) is preferably 0.1 μm or more. This is because if the surface roughness is too small, the above-described effect of forming a rough surface is reduced. On the other hand, from the viewpoint of increasing the light diffusion and reducing the effect of controlling the light emission range, the Ra is preferably 1.5 μm or less.

  A known method can be adopted as a method of forming the rough surface 16a. Examples thereof include transfer by a roll on which embossing is formed, sand blasting, printing, and painting.

Further, the retardation Re in the planar direction of the base film layer 16 is assumed to be 15 nm or less at wavelengths of 400 nm to 700 nm. Here, the retardation Re is represented by Re = (Nx−Ny) × d. Nx is the maximum refractive index in the plane of the base film layer 16, and Ny is the minimum refractive index in the plane of the base film layer 16. D (nm) is the thickness of the base film layer 16.
When the retardation is increased, color unevenness is likely to occur in the image, coupled with the polarizing property of the polarizing plate of the LCD and the liquid crystal panel, and the reflective polarizing sheet for improving the luminance used in the case of the liquid crystal image display device. Therefore, by suppressing the retardation Re to 15 nm or less, it is possible to suppress color unevenness and prevent a decrease in contrast.
Details are as follows. That is, when birefringence (retardation) occurs in the layer, light travels in a plurality of directions. Then, when the separately proceeding light goes out of the layer, it interferes with other separately traveling light. This is observed as so-called color unevenness. This is particularly remarkable when a layer having a large retardation is included between the polarizers. For example, in a liquid crystal display device, having a layer having a large retardation between a reflective polarizing sheet used for the purpose of improving luminance and a polarizing plate of a liquid crystal panel is one cause of color unevenness.
On the other hand, in the light control sheet 10, since the retardation Re is suppressed to 15 nm or less as described above, it is possible to suppress such color unevenness.

  The material used for the base film layer 16 is not particularly limited as long as it has translucency and can suppress retardation to 15 nm or less. Thus, what can suppress retardation low can include a polycarbonate, a cycloolefin, and a TAC film, for example. Among them, polycarbonate is preferable from the viewpoint of availability, cost, and adhesion to ionizing radiation curable resin. In addition, the TAC film is easy to tear, and if it is a processing method such as a normal coating (gravure coating, roll coating, etc.), the film is easily processed by applying a relatively uniform tension in one direction in the film width direction. When releasing the cured resin from the mold roll, a force is applied in the direction perpendicular to the film surface, and the stress generated due to variations in the shape of the mold may be uneven and tear There is.

In addition, the polycarbonate film may be subjected to a primer treatment. The primer has a function of improving the adhesiveness between the base film layer and the ionizing radiation curable resin (optical function sheet layer 11) in the manufacturing process and the use environment of the light control sheet. The polycarbonate used herein is one having polycarbonate as a main polymer, and may include, for example, a filler such as a deterioration inhibitor, a plasticizer, and a softener, or a composite with a methacrylic resin or the like.
The primer coating method is not particularly limited as long as a known means such as a gravure coating method, a spray method, a roll coating method, or the like and a sufficient adhesion can be obtained, but about 1 μm to 10 μm is desirable. As the material of the primer, known materials can be used, for example, acrylic resin, polyvinyl resin, polyester, polyacrylate, polyurethane, and a mixture thereof. Each of them is dissolved and dispersed in a diluting solvent, and then the diluting solvent is evaporated. In the case of curing with ultraviolet rays, it is also possible to use those without containing a diluting solvent.

  Thus, since the retardation Re of the base film layer is set to 15 nm or less, a known method can be used, and the residual stress is reduced by simultaneously heating and pressing the extruded film with a belt press. And forming an amorphous polymer. In addition, although a large facility may be required, it is possible to manufacture without orientation by manufacturing by a casting method.

  In the present embodiment, an example in which the base film layer 16 is provided with the rough surface 16a and the retardation Re is 15 nm or less has been described. However, even if it is a base film layer in which any one of these is comprised, each said effect can be show | played.

The light control sheet 10 as a whole has a linear expansion coefficient of 1 × 10 ⁻³ (1 / ° C.) or less. Thereby, when the light control sheet 10 is incorporated in the video display device, the expansion and contraction of the light control sheet 10 due to the use environment can be suppressed. The expansion and contraction of the light control sheet 10 may cause deformation of the geometric shape of the prism portion 12 and the light absorption portion 13, or may change the relationship with other layers and cause color unevenness. Because there is.
Specifically, linear expansion is achieved by forming a prism portion and a light absorbing portion with a base film that suppresses residual stress as described above and an ultraviolet curable resin or an electron beam curable resin having an ionizing radiation curing action. The coefficient can be kept low.

  The light control sheet 10 can be manufactured including the following processes, for example. FIG. 6 shows a diagram for explanation. The film 41 to be the base film layer 16 is passed between the mold roll 52 and the press rolls 53 and 54. Here, the surface of the mold roll 52 is provided with a shape obtained by inverting the prism portion shape. More details are as follows. The film 41 supplied from the left side of FIG. 6 is transferred so as to be sandwiched between the mold roll 52 and the pressing roll 53. At this time, an ionizing radiation curable resin 42 before curing, which becomes a prism portion, is supplied between the film 41 and the mold roll 52. Thereby, a liquid ionizing radiation curable resin layer in which the surface shape of the mold roll 52 is transferred to the upper surface of the film 41 is formed. In this state, ultraviolet rays are applied to the film 41 and the ionizing radiation curable resin 42 from below by the ultraviolet irradiation device 55. Thereby, the liquid ionizing radiation curable resin is cured to form a prism portion. Then, it moves between the metal mold | die roll 52 and the press roll 54, and releases the film 41 in which the prism part was formed from a metal mold | die roll. The base film layer 11 and the prism parts 12, 12,. Then, in the subsequent process, the light absorbing portions 13, 13,... Are formed by filling a binder mixed with light absorbing particles between the prism portions 12, 12,.

  FIG. 7 is a view schematically showing a layer configuration of a cross section of a light control sheet 110 according to another embodiment. The light control sheet 110 includes an optical function sheet layer 11, a base film layer 16, an adhesive layer 111, and another base film layer 112. Each layer extends in the back / front direction of the paper while maintaining the cross section shown in FIG.

  In the light control sheet 110, the optical function sheet layer 11 and the base film layer 16 are the same as the light control sheet 10 described above, and thus the same reference numerals are given and description thereof is omitted.

  The adhesive layer 111 is a layer in which an adhesive is disposed to adhere the other base film layer 112 to the optical function sheet layer 11. Of the surfaces of the optical function sheet layer 11, the base film layer 16 is disposed. It is provided on the surface opposite to the formed surface. As the adhesive layer 111, a known pressure-sensitive adhesive material or adhesive can be used. The adhesive layer 111 is preferably optically transparent and does not peel or remarkably discolor under the use environment and does not damage other members.

The other base film layer 112 is a layer laminated on the adhesive layer 111. The other base film layer 112 is assumed to have a retardation Re in the plane direction of 15 nm or less at a wavelength of 400 nm to 700 nm, similarly to the base film layer 16 described above.
By suppressing the retardation of both the base film layer 16 and the other base film layer 112 to 15 nm or less, the base film layer 16 and the other base film 112 are laminated regardless of the direction of the slow axis. Have little effect on the optical properties.

The material used for the other base film layer 112 is not particularly limited as long as it has translucency and can suppress retardation to 15 nm or less. Thus, what can suppress retardation low can include a polycarbonate, a cycloolefin, and a TAC film, for example. Among them, polycarbonate is preferable from the viewpoint of availability, cost, and adhesion to ionizing radiation curable resin. In addition, the TAC film is easy to tear, and if it is a processing method such as a normal coating (gravure coating, roll coating, etc.), the film is easily processed by applying a relatively uniform tension in one direction in the film width direction. When releasing the cured resin from the mold roll, a force is applied in the direction perpendicular to the film surface, and the stress generated due to variations in the shape of the mold may be uneven and tear There is.
Further, the other base film layer 112 is preferably the same as the base film layer 16 in order to prevent warpage in the use environment.

  Since the retardation Re of the other base film layer 112 is set to 15 nm or less in this way, a known method can be used, and heating and pressurization are simultaneously performed on the extruded film by a belt press and remain. Mention may be made of reducing the stress and forming an amorphous polymer. In addition, although a large facility may be required, it is possible to manufacture without orientation by manufacturing by a casting method.

  According to the light control sheet 110 as described above, the optical function sheet layer 11 is disposed so as to be sandwiched between the base film layer 16 and the other base film layer 112. Thereby, in addition to the effect which the above-mentioned light control sheet 10 shows, curvature of light control sheet 110 can be prevented.

FIG. 8 is a diagram schematically showing the layer structure of the image display device including the light control sheet 10, showing a cross section focusing on the portion of the image source unit 1 including the light control sheet 10. . The video display device in the present embodiment is a liquid crystal display device, and the video source unit 1 is a liquid crystal display panel unit. In FIG. 8, the right side of the page is the observer side.
Although an example in which the light control sheet 10 is applied will be described here, the light control sheet 110 may be applied instead.

  The video source unit 1 includes a backlight 2, a prism sheet 3, a reflective polarizing sheet 4, a light control sheet 10, a video source 20, and a light diffusion sheet 30.

  The backlight 2 is a light source of the video display device. Here, a backlight used in a normal liquid crystal display panel unit can be used. This includes, for example, a form in which light emitting sources are arranged substantially uniformly in a plane to form a planar light source, or a light emitting source is arranged on an edge and a reflecting surface is used to finally form a planar shape. Examples include an edge input type that emits light.

The prism sheet 3 is a sheet that makes the light from the backlight 2 as uniform as possible using the surface light source. The prism sheet 3 used for a normal liquid crystal display panel unit can be used here.
Here, a layer for diffusing light may be disposed on one surface or both surfaces of the prism sheet 3.

  The reflective polarizing sheet 4 is a polarizing sheet that transmits predetermined polarized light and reflects other light. According to this, since the light that does not pass through is reflected and reused, the luminance can be improved. As the reflective polarizing sheet used here, a known sheet can be used.

  The video source 20 is a part where an image of the video display device is displayed, and includes polarizing plates 21 and 23 and a liquid crystal panel 22 sandwiched between the polarizing plates 21 and 23.

  The polarizing plates 21 and 23 are a pair of optical elements disposed so as to sandwich the liquid crystal panel 22 and absorb polarized light having a vibration surface parallel to the absorption axis direction, while having a vibration surface orthogonal to the absorption axis direction. It has a function of transmitting the polarized light. The light of the backlight 2 that has passed through the polarizing plates 21 and 23 and the liquid crystal panel 22 becomes image light and is emitted to the viewer side.

  The liquid crystal panel 22 displays video information to be emitted here. The liquid crystal panel used for a normal liquid crystal display panel unit can be used here.

The light diffusing sheet 30 is a sheet in which films of various functions for controlling the image from the image source 20 and providing a high-quality image to the observer are laminated. The light diffusion sheet 30 includes an adhesive layer 31, a PET film layer 32, a light diffusion functional sheet layer 33, an adhesive layer 34, a TAC film layer 35, and an antiglare film layer (AG layer) 36.

  The adhesive layers 31 and 34 are layers in which an adhesive is disposed. The material used for the adhesive layers 31 and 34 is not particularly limited as long as it transmits light and can be adhered to other layers. Examples thereof include PSA (Pressure sensitive adhesive). The adhesive force is, for example, about several N / 25 mm to 20 N / 25 mm.

  The PET film layer 32 is a film layer as a base material layer serving as a base for forming the light diffusion functional sheet layer 33 on one surface of the PET film layer 32, and is formed mainly of polyethylene terephthalate (PET). Has been. In the present embodiment, the case where PET is the main component has been described. However, PET is not necessarily used as a material. Polyester resin "can be used. In the present embodiment, it has been described that a resin mainly composed of polyethylene terephthalate (PET) is a preferable material from the viewpoints of mass productivity, price, availability, etc. in addition to performance.

The light diffusion functional sheet layer 33 includes prism portions 33a, 33a,... That are substantially trapezoidal in the section in the thickness direction of the sheet, and cavities 33b, 33b,... Formed between the prism portions 33a, 33a,. It has.
The prism portions 33a, 33a,... Are elements having a substantially trapezoidal cross section arranged so that the image source 20 side is the lower base and the viewer side is the upper base. The prism portions 33a, 33a,... Are made of a light transmissive resin having a refractive index of Nk. This can be formed of the material described in the optical function sheet layer 11 described above. Although the magnitude | size of Nk is not specifically limited, It is preferable that it is 1.49-1.60 from a viewpoint of the availability of an application material. Further, the hypotenuse which is a trapezoid of the prism portions 33a, 33a,... Is set to have a predetermined angle with respect to the normal to the sheet surface.

  The hollow portions 33b, 33b,... Are portions formed between the prism portions 33a, 33a,. Therefore, the hollow portions 33b, 33b,... Have a substantially triangular shape with the upper base side of the prism portions 33a, 33a,... As the base, and the apex facing the prism portions 33a, 33a,. . The cavities 33b, 33b,... Are in a state where air exists and have a refractive index of 1.0.

  The refractive index difference between the prism portions 33a, 33a,... And the cavity portions 33b, 33b,. Further, the hypotenuses of the prism portions 33a and 33a are inclined. As a result, the image light that has reached the hypotenuse can be totally reflected here based on the difference in refractive index and can be emitted in a direction that widens the viewing angle of the image light.

  The TAC film layer 35 is a film formed of triacetyl cellulose and is used as a protective film. The TAC film layer 35 is one of the layers constituting the functional layer provided in the light diffusion sheet 30. As the TAC film used here, one used for a normal liquid crystal image source unit can be applied.

  The AG layer 36 is a film that can prevent glare when the viewer looks at the screen. The AG layer 36 is also one of the layers constituting the functional layer provided in the light diffusion sheet 30. As the antiglare film used here, a film which can be usually obtained can be applied.

In the present embodiment, the TAC film layer 35 and the AG layer 36 are described as the layers provided in the functional layer, but the layers provided in the functional layer are not limited thereto. Any layer having a function capable of improving the quality of incident video light and emitting it can be included in this layer. Examples thereof include an antireflection layer, a hard coat layer, an antistatic layer, a polarizing filter layer, and an antifouling layer.
The antireflection layer is a so-called anti-reflection layer and is also referred to as an AR layer. A film having a function capable of preventing reflection is disposed.
The hard coat layer is also called an HC layer. This is a layer in which a film having a function capable of imparting scratch resistance is provided in order to prevent the image display surface from being scratched.
The antistatic layer is also referred to as an antistatic (AS) layer. This is a layer in which a film having a function capable of preventing charging, that is, preventing static electricity from being charged, is disposed. A commonly available AS film can be applied to this.
The antifouling layer is a layer in which a film having a function capable of preventing the screen surface from being stained is disposed.
The polarizing filter layer is the same as the polarizing filter described above. You may arrange here as needed.

  As can be seen from FIG. 8, in the image source unit 1 including the light control sheet 10, the base film layer 16 of the light control sheet 10 and the image source 20 are in contact with each other by the rough surface 16a. Can be suppressed. Moreover, since the retardation of the base film layer 16 is also suppressed, it is possible to provide appropriate light to the viewer (image source), and color unevenness and contrast reduction can be suppressed.

  The optical path of the light that enters the light control sheet 10 when such an image display device operates will be described. FIG. 9 shows an example of the optical path. The light L1 incident on the vicinity of the central portion of the prism portion 12 from the backlight 2 passes straight through the prism portion 12 and is emitted to the liquid crystal panel side.

  Incident light L2 and L3 incident from the backlight 2 near the end of the prism portion 12 at a predetermined angle are different in refractive index between the prism portion 12 having a refractive index Np and the light absorbing portion 13 having a refractive index Nb. Is totally reflected on the slope, and is emitted toward the liquid crystal panel near an angle parallel to the normal to the sheet surface.

  Further, the light L4 incident on the light absorbing portion 13 from the bottom of the light absorbing portion 13 is absorbed by the light absorbing particles 15. Further, the light L5 incident on the prism portion 12 with a large angle enters the light absorbing portion 13 without being totally reflected by the refractive index difference between the prism portion 12 and the light absorbing portion 13, and Absorbed by the light absorbing particles 15.

  In this way, a light control sheet that can provide light from the backlight 2 to the video source as close to an angle that is parallel to the sheet surface normal as much as possible, and can suppress a decrease in luminance. It becomes possible to provide.

  In addition, since the light L1, L2, and L3 transmitted to the image source side (the right side of FIG. 9) is transmitted through the base film layer, retardation is suppressed, and interference is also suppressed by the rough surface. Less likely to cause color unevenness.

  FIG. 10 shows a video source unit 1 ′ which is a modification of the video source unit 1 described above. FIG. 10 is the same as FIG. 8 and is a diagram schematically showing a layer structure, showing a cross section focusing on the video source unit 1 ′ portion of the video display device. The video display device in the present embodiment is a liquid crystal display device, and the video source unit 1 ′ is a liquid crystal display panel unit. In FIG. 9, the right side of the page is the observer side.

  The image source unit 1 ′ is obtained by replacing the light diffusion function sheet layer 33 in the light diffusion sheet 30 of the image source unit 1 with a light diffusion function sheet layer 33 ′. Accordingly, the other layers are denoted by the same reference numerals as those of the video source unit 1 and description thereof is omitted.

  In the light diffusion functional sheet layer 33 ′, a binder 33 c ′ in which light absorbing particles 33 d ′, 33 d ′,... Are dispersed in the cavities 33 b, 33 b. Here, the binder material used for the binder 33c ′ and the light absorbing particles 33d ′ and 33d ′ are not particularly limited, but the binder 14 used for the light absorbing portion 13 of the optical function sheet layer 11 described above, and The same thing as the light absorption particle | grains 15, 15, ... can be used.

  According to this, the refractive index difference between the prism portions 33a ', 33a',... And the light absorbing portions 33b ', 33b',. Further, the hypotenuses of the prism portions 33a 'and 33a' are inclined. As a result, the image light that has reached the hypotenuse can be totally reflected here based on the difference in refractive index and can be emitted in a direction that widens the viewing angle of the image light.

  Further, the image light incident on the light absorbing portions 33b ′ and 33b ′ with a predetermined angle or more is incident on the light absorbing portions 33b ′ and 33b ′ without being totally reflected by the difference in refractive index. It is absorbed by 33d ′, 33d ′,. Therefore, it is also possible to absorb so-called stray light or the like that is not preferably emitted to the viewer side. Further, since the external light incident on the light absorbing portions 33b ', 33b',... Can be absorbed from the observer side, the contrast can be improved. Details are as follows.

FIG. 11 is an enlarged view of a part of the light diffusion sheet 30 ′ in the video source unit 1 ′ shown in FIG.
According to this, the image light L11 passes through each layer provided in the light diffusion sheet 30 ′ and is normally emitted to the observer. Further, the image lights L12 and L13 are totally reflected at the interface between the prism portions 33a ′, 33a ′,... And the light absorption portions 33b ′, 33b ′,. At this time, the oblique sides of the light absorbing portions 33b ′, 33b ′,... Are inclined as described above, so that the angle of light changes before and after reflection by the oblique sides, and the emission of the image light in the direction of widening the viewing angle is performed. It becomes possible. Thereby, a wide viewing angle can be obtained.

  Further, the image light L14 is not totally reflected at the interface based on the refractive index difference between the prism portions 33a ′, 33a ′,... And the light absorption portions 33b ′, 33b ′,. , 33b ′,... Such image light L14 is absorbed by the light absorbing particles 33d '. Also, stray light can be absorbed in this manner.

  On the other hand, the external light L15 incident on the image display device as external light is incident on the light absorbing portion 33b 'and absorbed by the light absorbing particles 33d'. In this way, a part of the external light is absorbed by the light absorbing portions 33b ', 33b', ..., so that the contrast can be improved.

According to the video source units 1, 1 ′, the video light is condensed by the light control sheet 10 in a direction parallel to the front direction of the observer, and the condensed video light is condensed into the light diffusion sheets 30, 30 ′. A wide viewing angle can be obtained by diffusing.
In addition, since the light diffusion sheets 30 and 30 ′ have a portion common to the configuration of the optical function sheet layer 11 of the light control sheet 10, a part of the material and production can be shared, and the cost can be reduced. It is possible to reduce.

  In the following, the embodiment will be described in more detail. However, the present invention is not limited to the examples.

Example 1
In Example 1, a light control sheet in which the conditions were changed was produced, and the color separation due to retardation and the sticking to the polarizing plate due to the difference in surface roughness were evaluated.

  The layer structure of the light control sheet was composed of a base film layer, an optical function sheet layer, an adhesive layer, and other base film layers as shown in FIG. Details of each layer will be described below. Here, “%” means “mass%”.

<Base film layer>
The base film layer was formed of polycarbonate. As described above, this polycarbonate was produced by a method in which heating and pressurization were simultaneously performed with a belt press on the extruded film, and retardation was adjusted. At this time, one surface was a rough surface. The retardation of each base film layer and the surface roughness (Ra) of the rough surface are shown later in Table 1. Retardation was measured with an automatic birefringence meter (KOBRA, manufactured by Oji Scientific Instruments).
The thickness of the base film layer is a 150 [mu] m, the linear expansion coefficient of 1.1 × ^{10 -4} (℃).

<Primer layer>
In Example 1, the primer layer was formed on the surface of the base film layer opposite to the surface on which the rough surface was formed. For the primer layer, a composition containing 57% polycarbonate-modified urethane acrylate, 3% acetophenone initiator, and 40% toluene was formed at a coating thickness of 3 μm by the gravure berth coating method. After application, the film was dried with warm air of 40 ° C. to 80 ° C. and irradiated with ultraviolet rays at 300 mJ / cm ² .

<Optical function sheet layer>
In the optical functional sheet layer, the prism portion is composed of a composition containing 39% epoxy acrylate, 58% acrylate monomer, and 3% photoinitiator, as described with reference to FIG. Formed. Here, ultraviolet rays were irradiated at 1 J / cm ² . In addition, the prism portion has a trapezoidal shape with an upper base of 0.03 mm, a lower base of 0.06 mm, and a height of 0.15 mm. The refractive index after curing is 1.56.
On the other hand, in the optical function sheet layer, in the light absorbing portion, urethane acrylate is 33.6%, epoxy acrylate is 14, 4%, tripropylene glycol diacrylate is 28.0%, and methoxytriethylene glycol acrylate is 4. A flow material consisting of 0%, photopolymerization initiator 4.0%, and light-absorbing particles 16.0% was filled and irradiated with ultraviolet rays under the condition of 1 J / cm ² . Here, the filling of the fluid was performed by supplying the fluid to the entire surface of the formed prism portion and scraping off the excess fluid with a metal blade. The light-absorbing particles contained in the fluid are acrylic beads containing 30% carbon black, and the average particle size is 5 μm.

<Adhesive layer>
The adhesive layer was coated with a composition containing 55% of an acrylate monomer, 44% of an acrylate oligomer, and 1% of a photopolymerization initiator at a thickness of 50 μm, and another substrate film was bonded, Curing is performed by irradiating with ultraviolet rays under conditions of 700 J / cm ² . The laminating method will be described in the following other base film layer.

<Other base film layers>
The other base film layer was the same as the above base film layer.
Lamination | stacking of the said adhesive bond layer and another base film layer is performed as follows. The figure for demonstrating in FIG. 12 was shown. The composition 72 to be the adhesive layer is supplied between the substrate film layer and optical functional sheet layer laminate 71 and the other substrate film 70, and is passed between the two nip rolls 73 and 74 for adhesion. The nip pressure and the gap are adjusted so that the composition of the agent has a predetermined thickness. Then, the composition of the adhesive is cured by irradiating ultraviolet rays with an ultraviolet irradiation device 75.

Table 1 shows retardation and rough surface roughness of the base film layer of each light control sheet (same for other base film layers), resulting color separation, and sticking under high temperature and high humidity Expressed.
Here, the color separation evaluation was performed using an 8-inch car navigation monitor in which a light guide plate as a light source, a prism sheet, a diffusion layer, a reflective polarizing sheet, a light control sheet, a polarizing plate, a liquid crystal panel, and a polarizing plate were laminated in this order. For such monitoring, the front luminance when no light control sheet disposed totally white display brightness of 500 cd / cm ^2, was visually evaluated. ○ indicates no color separation, Δ indicates slight color separation, and × indicates color separation.
In addition, the sticking test under high temperature and high humidity was performed by sandwiching the light control sheet between two polarizing plates, applying a load with a weight of 3 kg, and leaving it in an environment of 65 ° C. and 95% humidity for 200 hours. The sticking of the light control sheet to the polarizing plate was evaluated. ○ indicates no sticking and × indicates sticking. When there is sticking, interference fringes are generated.

  As can be seen from Table 1, No. having a retardation of 15 μm or less. No color separation occurred in 1, 2, 3, and 6. On the other hand, the rough surface Ra is 0.1 μm or more. 1-No. In 5, there was no sticking.

(Example 2)
In Example 2, No. 1 in Example 1 was obtained. Color unevenness was observed using the light control sheet 1 for a liquid crystal display device. However, the light absorbing particles in the light absorbing portion were 20%. The linear expansion coefficient was 7.3 × 10 ⁻⁵ (1 / ° C.). The linear expansion coefficient was measured in the range of −40 ° C. to 100 ° C. using a thermomechanical analyzer (TMA120 manufactured by Seiko Denshi Kogyo Co., Ltd.) based on JIS K 7197-1991.

  By incorporating the light control sheet as described above into the liquid crystal display device, it was possible to suppress uneven color in the screen and emit a high-quality image. Moreover, both color separation and sticking were good (◯).

  Although the invention has been described with reference to embodiments that are presently practical and preferred, the invention is not limited to the embodiments disclosed herein, but is claimed. The light control sheet and the display device accompanying such changes are also included in the technical scope of the present invention as appropriate without departing from the scope or spirit of the invention that can be read from the scope of the invention and the entire specification. Must be understood.

1 Video source unit 2 Backlight (light source)
DESCRIPTION OF SYMBOLS 3 Prism sheet 4 Reflective polarizing sheet 10 Light control sheet 11 Optical function sheet layer 12 Prism part 13 Light absorption part 14 Binder 15 Light absorption particle 16 Base film layer 16a Rough surface 20 Image source 22 Liquid crystal panel 30 Light diffusion sheet 110 Light Control sheet 111 Adhesive layer 112 Other base film layer

Claims (10)

A light control sheet provided between a light source and a liquid crystal panel of a liquid crystal display device and having a plurality of layers,
At least one of the plurality of layers is arranged in parallel along the sheet surface so as to transmit light, and a prism portion having a trapezoidal cross-sectional shape is filled with a material having a light absorption property between the prism portions. A light absorbing portion to be formed, and an optical functional sheet layer comprising:
At least one of the plurality of layers is a translucent base film layer laminated on the surface of the optical functional sheet layer on the long lower bottom side of the prism portion having a trapezoidal cross section,
The substrate film layer has a retardation Re of 15 nm or less. A light control sheet provided between a light source and a liquid crystal panel of a liquid crystal display device and having a plurality of layers,
At least one of the plurality of layers is arranged in parallel along the sheet surface so as to transmit light, and a prism portion having a trapezoidal cross-sectional shape is filled with a material having a light absorption property between the prism portions. A light absorbing portion to be formed, and an optical functional sheet layer comprising:
At least one of the plurality of layers is a translucent base film layer laminated on the surface of the optical functional sheet layer on the long lower bottom side of the prism portion having a trapezoidal cross section,
The substrate film layer has a retardation Re of 15 nm or less, and the surface of the substrate film layer opposite to the side on which the optical functional sheet layer is laminated has an average roughness (Ra ) Is formed with a rough surface of 0.1 μm or more.   The light control sheet according to claim 1, wherein the base film layer has polycarbonate as a main component.   Another base film layer is laminated on the side of the optical function sheet layer opposite to the side on which the base film layer is disposed, and the retardation Re of the other base film layer is 15 nm or less. The light control sheet according to any one of claims 1 to 3, wherein: The light control sheet according to any one of claims 1 to 4, wherein the light control sheet has a linear expansion coefficient of 1 × 10 ⁻³ (1 / ° C.) or less.   The cross-sectional shape of the light absorption part is an isosceles trapezoid having an upper bottom surface with a narrow width on the base film layer side, or an isosceles triangle having the base film layer side as an apex. The light control sheet according to any one of 1 to 5. When the refractive index of the light absorbing portion is Nb and the refractive index of the material constituting the prism portion is Np,
Nb <Np
The light control sheet according to claim 1, wherein the following relationship is established. The light control sheet according to any one of claims 1 to 7,
A liquid crystal panel disposed on the base film layer side of the light control sheet;
And a light source disposed on the side opposite to the base film layer side of the light control sheet. The light control sheet according to any one of claims 1 to 7,
A polarizing plate disposed on the base film layer side of the light control sheet;
A light source disposed on the side opposite to the base film layer side of the light control sheet;
A liquid crystal display device comprising: a reflective polarizing sheet disposed between the light source and the light control sheet. A method for producing the light control sheet according to claim 1,
When the film to be the base film layer is passed between a mold roll and a pressing roll having unevenness corresponding to the shape of the prism portion on the surface, the layer to be the base film layer and the gold Between the mold rolls, the ionizing radiation curable resin is supplied to fill the space formed by the film serving as the base film layer and the concave portion of the mold roll with the ionizing radiation curable resin,
In the filled state, the ionizing radiation curable resin filled in the concave portion of the mold roll is cured by irradiating ionizing radiation from the film side to be the base film layer,
Peeling the film to be the base film layer and the cured ionizing radiation curable resin from the mold roll to form the prism portion,
Thereafter, a step of filling a light-absorbing material between the prism portions is included.
Manufacturing method of light control sheet.

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