JP2010072556A - Optical equalizing element, optical sheet, backlight unit using the same, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical equalizing element capable of reducing/eliminating a lamp image by equalizing incident light from a plurality of light sources and emitting it and coping with such cases in which the distance between a light source and the optical element, and the optical equalizing element is reduced or in which the interval between the light sources is expanded. <P>SOLUTION: In the optical equalizing element 25 having a structure in which a light propagation layer 23 and an optical deflection element 28 are provided at a light incident surface side of a light diffusion substrate 26, the light diffusion substrate 26 is a light diffusion member in which a light diffusion agent is mixed into a transparent resin. The light diffusion agent is made by mixing a cubic-shaped calcium carbonate particulate and a spherical crosslinked siloxane resin particulate. The weight mixing ratio of the calcium carbonate particulate and the crosslinked siloxane resin particulate is set in a range of 1:0.5 to 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light uniform element used for optical path control, an optical sheet, a backlight unit using the same, and a display device.

  Liquid crystal display devices using a liquid crystal panel are widely used not only for image display means of mobile phones, personal digital assistants, and personal computer displays, but also for televisions as home appliances. Furthermore, in order to make more use of the advantages of liquid crystal display devices, it has spread to general households as an image display device for large-size information appliances that has been difficult with conventional cathode ray tube (CRT) televisions. Developments not only for increasing the size but also for increasing the brightness and reducing the thickness and weight have been proceeding at a very high speed.

  In such a liquid crystal display device, a light source is often built in the device, and in order to obtain the brightness necessary for displaying an image, a backlight unit including the light source is provided on the back side of the liquid crystal panel. It is arranged. The light source employed in this backlight unit is roughly divided into a “light guide plate light guide” that performs multiple reflections of a light source lamp such as a cold cathode tube within a flat light guide plate made of acrylic resin or the like having excellent light transmittance. "Method" (so-called edge light method), and a diffuser plate and an optical film having a strong light scattering property are arranged between the image display element and the light source so that a cold cathode tube, an LED and the like are not directly visible. There is a "direct type", and in particular, the direct type is used for a display device such as a large liquid crystal display in which it is difficult to use a light guide plate.

  The light emitted from the cold cathode tube as the light source is brightest immediately above the cold cathode tube, and darkest between the cold cathode tube and the cold cathode tube. The diffusion plate used in the direct type is mainly intended to reduce the brightness unevenness (lamp image) that is the brightness of this light source, so it contains fine materials that scatter light. Various diffusion plates have been developed to meet the purpose. Moreover, since the diffusion plate plays a role of supporting the optical film disposed thereon, a thickness of about 1 to 3 mm is usually required. Furthermore, liquid crystal display devices tend to be thinner year by year, and a diffusion plate constituting the liquid crystal display device is being demanded to be thinner, and at the same time, further improvement in diffusibility has been demanded.

  As a recent trend of liquid crystal display devices, power consumption suppression for the purpose of reducing energy consumption, which is a part of countermeasures for global environmental problems, has become a major issue. In the liquid crystal display device, the power consumption of the backlight serving as the light source is the largest, and efforts to suppress the power consumption of the backlight have been made in a wide range of fields.

  One approach is to reduce the number of cold-cathode tubes, which are light sources, to reduce power consumption, and the effect of reducing power consumption is widely recognized by society. However, reducing the number of cold-cathode tubes will increase the brightness unevenness (lamp image) that is the brightness of the light source, and it will be difficult to completely erase the lamp image with the combination of the conventional diffuser plate and optical film. It is coming. When diffusing particles are increased in the diffusing plate in order to erase the lamp image, the total light transmittance of the diffusing plate is lowered, and the luminance necessary for image display cannot be obtained. In this case, the required luminance can be obtained by strengthening the light from the cold cathode tube, which is the light source, but there is a problem in that the effect of reducing power consumption is greatly reduced by strengthening the light. become.

Patent Documents 1 to 3 disclose examples in which a lens shape is formed on a light exit surface of a diffusion plate as means for improving diffusion performance. As an example, a lens having a convex curved surface is arranged on the diffusion plate. In such a diffusing plate, it may be necessary to design the shape of the lens in accordance with the arrangement of the light sources and determine the alignment of the lens, which complicates the manufacturing process. Further, by shaping the lens shape on the light exit surface of the diffuser plate, the total light transmittance of the diffuser plate may be lowered, and it may be difficult to obtain the luminance necessary for screen display. Furthermore, there may be a problem that moire interference fringes are generated from the lens sheet disposed on the diffusion plate and the liquid crystal pixels.
JP 2007-103321 A JP 2007-12517 A JP 2006-195276 A

  The present invention has been made in view of the above problems, and can uniformly reduce / extinguish a lamp image by emitting incident light from a plurality of light sources uniformly. The light source, the optical element, and the light It is an object of the present invention to provide an optical uniform element that can cope with a case where the distance to the uniform element approaches or a distance between light sources increases. Furthermore, an optical sheet in which the light emitted from the light uniform element is efficiently emitted to the observer side to improve the luminance toward the observer side, an optical sheet integrally laminated with the light uniform element, and the optical sheet An object of the present invention is to provide a backlight unit and a display device provided.

  In order to solve the above problems, the present invention proposes the following means. That is, claim 1 of the present invention is a light uniform element having a structure in which a light propagation layer and a light deflecting element are provided on the light incident surface side of a light diffusing substrate, wherein the light diffusing substrate is a transparent resin and a light diffusing agent. The light diffusing agent is a mixture of cubic calcium carbonate fine particles and spherical crosslinked siloxane resin fine particles, and the calcium carbonate fine particles and the crosslinked siloxane resin fine particles. The light blending ratio is set in a range of 1: 0.5-10. By optimizing the particle shape and blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles contained in the light diffusing substrate, light can be effectively diffused while maintaining the light transmittance, As a result, it is possible to provide a light uniform element that can maintain luminance and at the same time eliminate luminance unevenness of the light source.

  A second aspect of the present invention is the light uniform element according to the first aspect, wherein the crystal structure of the calcium carbonate constituting the calcium carbonate fine particles is a hexagonal system. The refractive index of the calcium carbonate fine particles that contribute to the light diffusibility can be set in an optimum range, and the light diffusibility can be improved.

  A third aspect of the present invention is the light uniform element according to the first or second aspect, wherein the length of one side of the calcium carbonate fine particles is set in a range of 1 to 10 μm. When the length of one side of the calcium carbonate fine particles is less than 1 μm, it is not preferable because light permeability is poor and only concealing properties are remarkably exhibited. On the other hand, when the diameter is larger than 10 μm, it is difficult to form the calcium carbonate fine particles in a cubic shape, which causes a manufacturing disadvantage. In the present invention, the above disadvantages are eliminated because the length of one side of the calcium carbonate fine particles is set in the range of 1 to 10 μm in consideration of these.

  Claim 4 of the present invention is that the particle diameter of the crosslinked siloxane-based resin fine particles is set in a range of 0.1 to 10 μm, and the light uniform according to any one of claims 1 to 3 It is an element. If the particle size of the crosslinked siloxane-based resin fine particles is smaller than 0.1 μm, the wavelength dependency of the light scattering property is increased, so that yellow may become strong and color unevenness may occur. This is not preferable because unevenness becomes remarkable. In the light diffusing member according to the present invention, since these are taken into consideration, the particle diameter is set in the range of 0.1 to 10 μm, and thus the above-mentioned drawbacks are solved.

  According to a fifth aspect of the present invention, the transparent resin is selected from any one of a polystyrene-based resin, a methacrylic resin, and a polycarbonate-based resin, and is made of one or a combination thereof. The light uniform element according to claim 1. Thereby, the light-diffusion member excellent in the light transmittance and rigidity can be provided.

  According to a sixth aspect of the present invention, in the light uniform element having a structure in which the light propagation layer and the light deflection element are provided on the light incident surface side of the light diffusion substrate, the light deflection element has an arcuate surface or a ridge line. And a first inclined portion from the first top to the light incident surface of the light propagation layer, wherein the refractive index of the light propagation layer is n, the pitch of the light deflection elements is P, and the first inclination When the angle between the tangent to the first inclined surface at the junction where the surface is bonded to the light propagation layer and the light incident surface of the light propagation layer is θ, the thickness T of the light propagation layer is The light uniform element according to claim 1, wherein Formula 1 is satisfied.

  According to a seventh aspect of the present invention, in the light uniform element having a structure in which the light propagation layer and the light deflection element are provided on the light incident surface side of the light diffusion base material, the shape of the light deflection element is the first top portion, The first inclined portion has a shape that has a first curved inclined portion, and an angle formed between a tangent at each point of the first curved inclined portion and the light incident surface side of the light propagation layer is 20 degrees. The light uniform element according to claim 6, wherein the light uniform element continuously changes at 90 degrees or less.

  Claim 8 of the present invention is a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of the light diffusion base material, wherein the top of the light deflection element has a ridge line. The light uniform element according to claim 7.

  Claim 9 of the present invention is a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of the light diffusing substrate, and the light propagation layer on the light incident surface side of the light diffusing substrate. Is formed, a light deflection element is formed on the light incident surface side of the light propagation layer, and the light diffusion base material has a light diffusion region dispersed in a transparent resin, and has a total light transmittance of 10% to 9. The method according to claim 1, wherein the propagation layer has a total light transmittance of 80% or more and a haze value of 95% or less. The light uniform element.

  According to a tenth aspect of the present invention, in a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of the light diffusing substrate, fine irregularities are formed on the light emitting surface side of the light diffusing substrate. The light uniform element according to claim 1, wherein the light uniform element is provided.

  According to an eleventh aspect of the present invention, in a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of the light diffusing substrate, the light diffusing substrate has irregularities on the light emitting surface side. The light uniform element according to any one of claims 1 to 10, further comprising a light diffusing lens.

  According to a twelfth aspect of the present invention, in the light uniform element having a structure in which the light propagation layer and the light deflection element are provided on the light incident surface side of the light diffusing substrate, the light emitting surface side of the diffusing substrate is substantially flat. The light uniform element according to any one of claims 1 to 9, wherein:

  Claim 13 of the present invention is a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of the light diffusion substrate, wherein the light deflection element, the light propagation layer and the light diffusion substrate are The light uniform element according to any one of claims 1 to 12, wherein the light uniform element is integrally formed by a multilayer extrusion method.

  A fourteenth aspect of the present invention is a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on a light incident surface side of a light diffusion base material, wherein the light diffusion base material and the light propagation layer are multilayer extrusion methods. The light according to any one of claims 1 to 13, wherein the light deflection element formed in a sheet shape and the light propagation layer are laminated via a fixed layer. It is a uniform element.

  According to a fifteenth aspect of the present invention, in the light uniform element according to any one of the first to fourteenth aspects, an optical film including a condensing lens and a light transmitting base material is provided on a light exit surface side of the light diffusion base material. A plurality of the condensing lenses are arranged at a constant pitch, and the condensing lens has a convex curved surface, a third top having an arcuate surface, and the light from the third top. And a third inclined surface that reaches the transmission substrate, and the distance between the third inclined surfaces facing each other is gradually decreased as the third top portion is reached. It is an optical sheet.

  According to a sixteenth aspect of the present invention, a plurality of light masks and a light transmission opening for separating the light masks are provided between the optical film composed of a condensing lens and a light transmission substrate and the light uniform element. The light transmission opening is provided corresponding to the third top of the condenser lens, and the optical film and the light uniform element are integrally laminated through the light mask. The optical sheet according to claim 15.

  According to a seventeenth aspect of the present invention, dot-shaped or linear ribs are arranged between the optical film composed of a condensing lens and a light-transmitting substrate and the light uniform element, and the optical film is interposed through the ribs. The optical sheet according to claim 15, wherein the light uniform element is integrally laminated.

  An eighteenth aspect of the present invention is a backlight unit comprising the light uniform element according to any one of the first to fourteenth aspects and a light source.

  A nineteenth aspect of the present invention is a backlight unit comprising the optical sheet according to any one of the fifteenth to seventeenth aspects and a light source.

  According to a twentieth aspect of the present invention, the light source is a linear light source, and the shape of the light deflection element is a lenticular lens. When viewed in plan, the major axis direction of the lenticular lens and the linear light source 20. The backlight unit according to claim 18 or 19, wherein an angle formed with the major axis direction is 20 degrees or less.

  A twenty-first aspect of the present invention includes the image display element that transmits / shields light in pixel units and displays an image, and the backlight unit according to any one of the eighteenth to twentieth aspects. A display device.

  By optimizing the configuration and mixing ratio of the calcium carbonate fine particles and cross-linked siloxane resin fine particles used for the light diffusing material substrate and the composition described so far, the structure where the distance from the light source is close or the distance between the light sources Even with a widened configuration, it is possible to emit uniform light without uneven brightness on the screen display side, and by changing the thickness and material of each layer in a multilayer configuration, the warp due to heat emitted from the light source can be reduced. An optical uniform element that can be prevented can be provided. An optical film that improves the brightness on the viewer side by efficiently emitting light emitted from the light uniform element in the direction of the person observing the liquid crystal display image, and an optical device that integrally laminates the light uniform element. A sheet, a backlight unit including the optical sheet, and a display device can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 12 are examples of schematic cross-sectional views showing the configurations of the light uniform element and the optical path control member according to the present embodiment and the mode of use thereof, and the scales or ratios of the respective parts do not match the actual ones. Moreover, it is not limited to this.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing an example of a light uniform element, a backlight unit, and a display device of the present invention. The display device 70 according to the embodiment of the present invention includes an image display element 35 and a backlight unit 55. In the backlight unit 55 according to the embodiment of the present invention, a plurality of light sources 41 are arranged in a lamp house (reflecting plate) 43, and the light according to the embodiment of the present invention is formed thereon (observer side direction F). The uniform element 25 and the optical member 2 are configured to be single or plural. The light H emitted from the light source 41 is diffused by the light uniform element 25, diffused / reflected / condensed / color-shifted by a single or a plurality of optical members disposed thereon, and emitted from the backlight unit 55. The incident light K enters the image display element 35 and is emitted to the observer side F.

  The light source 41 supplies light to the image display element 35. Therefore, as the light source 41, for example, a plurality of linear light sources can be used. As the plurality of linear light sources, for example, a plurality of fluorescent lamps, cold cathode fluorescent lamps (CCFLs), EEFLs or linearly arranged LEDs can be used. The reflection plate 43 is disposed on the opposite side of the plurality of light sources 41 from the observer side F, and reflects the light emitted in the direction opposite to the observer side F out of the light emitted from the light source 41 in all directions. Can be emitted to the observer side F. As a result, the light H emitted to the observer side F becomes light emitted almost in all directions from the light source 41. By using the reflection plate 43 in this way, the light utilization efficiency can be increased. The reflection plate 43 may be any member that reflects light with high efficiency. For example, a general reflection film, a reflection plate, or the like can be used.

  The light uniform element 25 according to the embodiment of the present invention includes a light deflection element 28, a light propagation layer 23, and a light diffusion base material 26. The light deflection element 28 is arranged toward the light source 41 side of the display device 70, deflects the light H incident from the incident surface of the light deflection element 28, and emits the light H to the light propagation layer 23. The diffused light is emitted from the light exit surface. The light diffusing substrate 26 is formed by superimposing the surface 23b on the viewer side F of the light propagation layer 23 on the surface 26a opposite to the viewer side F. The light uniform element 25 described above can be used not only for a liquid crystal device but also for any device that performs optical path control, such as a rear projection screen, a solar cell, an organic or inorganic EL, and an illumination device.

  FIG. 2A is a diagram for explaining the function of the light uniform element 25 according to the embodiment of the present invention. The light sources 41 are arranged in the lamp house (reflecting plate) 43 at a constant pitch in the Ve direction (the screen vertical direction). The light H emitted from the light source 41 is incident on the surface opposite to the observer side F of the light uniform element 25, that is, the light deflection element 28, and the surface on the observer side F of the light uniform element 25, that is, the light diffusion base material. 26 exits from the face 26b on the viewer side F to the viewer side F. When the diffusion performance of the light uniform element 25 is insufficient, a region facing the light source 41 is bright on the surface 26b on the viewer side F of the light diffusing substrate 26, and a region facing between the light source 41 and the light source 41 is bright. It looks dark and is visually recognized as uneven brightness (light source image). In the light uniform element 25 according to the embodiment of the present invention, the light deflection elements 28 are arranged on the surface opposite to the observer side F. The strong front light H incident from the light source 41 is deflected in the light deflection element 28 in its traveling direction, the incident light deflected in the light propagation layer 23 is spread, and diffused in the light diffusion base material 26, and uniform light is emitted. Inject to the observer side F.

  The light deflection element 28 is preferably a lens having an uneven shape. A tangent m to the first inclined surface at a point 30 where the first inclined surface 28b of the light deflection element 28 is joined to the light propagation layer 23 and a surface 23a opposite to the observer side F of the light propagation layer 23 are formed. When the angle is θ, the pitch of the unit lens of the light deflection element 28 is P, the thickness of the light propagation layer 23 is T, and the refractive index of the light propagation layer 23 is n, it is desirable to satisfy the following formula 1.

  That is, as shown in FIG. 2B, the thickness T of the light propagation layer 23 is such that the light incident on the point 30 where the first inclined surface 28b of the light deflection element 28 is joined to the light propagation layer 23 is angle θ. Is defined as the thickness required to expand the light deflection element 28 in the direction Ve by the pitch P or more in the light propagation layer 23. Here, the pitch P of the unit lenses of the light deflection element 28 is defined as a distance between two points joined to the light propagation layer 23 when the light deflection element 28 is viewed in cross section. In addition, it is desirable that the pitch P of the light deflection elements 28 in which the numerical formula 1 is effective is 10 μm or more and 300 μm or less. This is because when the pitch P of the light deflection elements 28 is smaller than 10 μm, the structure period approaches the wavelength, and the influence of diffraction cannot be ignored. When the pitch P of the light deflection elements 28 exceeds 300 μm, there is no problem in performance, but the thickness T of the light propagation layer 23 becomes very thick. In this case, it is desirable to set the thickness of the light propagation layer 23 to be 2 mm or less.

  Therefore, the front light H incident on the light deflecting elements 28 arranged at a constant pitch is mixed with the light deflected by the light deflecting elements 28 in the light propagation layer 23, diffused by the light diffusion base material 26, and an observer. Injected to side F. When the thickness T of the light propagation layer 23 does not satisfy Equation 1, the light deflected by the light deflection element 28 enters the light diffusion base material 26 without being mixed, and thus the light uniform element 25 has insufficient diffusion performance. .

  Furthermore, it is more preferable that the light deflected by the two adjacent light deflection elements 28 is mixed in the light propagation layer 23. That is, it is desirable to satisfy the following formula 2.

  As shown in FIG. 2C, if the light deflected by the two adjacent light deflecting elements 28 has a thickness T at which the light is mixed in the light propagation layer 23, the diffusion performance is further increased. The lamp image can be reduced / disappeared even when the distance to the lamp approaches 10 mm or less.

  As the light deflection element 28, a triangular prism shape as shown in FIG. This is because lens molding is easy and incident light H from the front can be largely deflected. Further, a convexly curved lens shape as shown in FIG. This is because the tangent line at each point of the first apex portion 28a and the first inclined surface 28b continuously changes, so that the incident light H from the front can be deflected to various angles. The convex curved lens shape is more preferably an aspherical shape as shown in FIG. This is because the radius of curvature of the first apex portion 28a can be reduced, so that the diffusion performance is increased. Furthermore, the light deflection element 28 is preferably a curved triangular prism as shown in FIG. Since the first apex portion 28a is a ridgeline, the incident light H can always be largely deflected regardless of the position of the lens. Moreover, since the tangent line at each point of the first inclined surface 28b continuously changes, the incident light H from the front surface can be diffused to various angles. At this time, as shown in FIG. 3 (d), the angle formed by the tangent line at each point of the first inclined surface 28b and the surface 23b on the side opposite to the observer side F of the light propagation layer 23 is 20 degrees to 90 degrees. It is further desirable that it varies continuously between degrees. If there is a surface below 20 degrees, the deflection angle becomes very small, and the diffusion performance becomes weak. In particular, when there is a surface at 0 degree, the incident light H is transmitted without being deflected at all. In the curved triangular prism, there is no surface in which the angle formed by the tangent line at each point of the first inclined surface 28b and the surface 23b opposite to the observer side F of the light propagation layer 23 is smaller than 20 degrees. It can be deflected at a large angle regardless of where the light enters the surface 28b.

  In addition, when the angle between the tangent line at each point of the first inclined surface 28b and the surface 23b on the opposite side of the light propagation layer 23 from the observer side F does not change significantly, at any point of the first inclined surface 28b light is emitted. Even if it is incident, since the deflection angles are almost the same, the light is concentrated in the same region. In the curved triangular prism, the angle between the tangent line at each point of the first inclined surface 28b and the surface 23b on the opposite side of the light propagation layer 23 from the observer side F greatly changes in the range of 20 degrees to 90 degrees. Therefore, the incident light H can be deflected at various angles to make the light uniform. Further, the light deflection element 28 can be used by combining a plurality of the above lens shapes. For example, as shown in FIG. 3 (e), a shape in which a triangular prism is combined on a convex curved lens may be used. Alternatively, a shape in which two curved triangular prisms are shifted in the Ve direction and overlapped as shown in FIG. This is because the diffusion performance is further increased by the diffusion effect of two or more lens shapes.

  The light deflection element 28 may have a concave lens shape as shown in FIG. The concave lens shape is preferably the reverse shape of the triangular prism, convex curved lens, curved triangular prism, and other combination lenses. In this case, θ in the above-described formulas 1 and 2 is, as shown in FIG. 5, the tangent line m at the point 30 where the first inclined surface 28 b joins the first apex portion 28 a, and the observer side of the light propagation layer 23. It is defined as an angle θ formed with the opposite surface 23a. Therefore, the definition of the thickness T of the light propagation layer 23 is the distance from the first top 28a of the concave lens to the light diffusion base material 26. Therefore, it is desirable because the thickness of the optical element 24 and the light uniform element 25 can be reduced as compared with the convex lens shape. As shown in FIG. 4B, the first apex portion 28a of the concave lens may be a substantially flat surface. This is because the flat surface is less worn and chipped in the mold for molding the light deflection element 28. Furthermore, as shown in FIG. 4C, a light diffusion / reflection layer 28c may be formed on the first top portion 28a which is a substantially flat surface. At this time, the amount of wraparound Δ on the first inclined surface 28b is desirably 30% or less of the width p1 of the first inclined surface 28b. Furthermore, as shown in FIG. 4D, an optical cover layer 28c may be formed on the concave surface of the concave lens. Since the concave surface of the concave lens is a region with a small deflection angle, the diffusion performance is improved by forming the light cover layer 28c on the concave surface. Examples of the forming method include an inkjet method and a water / oil repellent treatment method.

  The light deflection element 28 may be arranged by appropriately combining a plurality of the above-described lenses. Or, as shown in FIGS. 6A and 6B, the pitch P and height of the unit lenses may be changed and arranged. As a result, the farthest intersection α of the light deflection element 28 is unevenly arranged in the light propagation layer 23. FIG. 6C shows a configuration in which the farthest intersection point α is arranged in parallel and on a straight line with respect to the arrangement direction of the unit lenses of the light deflection element 28. When the front light H is incident on the light deflection element 28, a condensing point is generated on the center line of the unit lens, but aberration is generated on the center line. Therefore, in the present invention, in order to simplify the description, the point that is focused at the point farthest from the lens apex is defined as the farthest intersection point α. 6A to 6C show an example in which the farthest intersection point α is a point where light incident on both ends of the unit lens is deflected and intersects.

  In FIG. 6C, for example, when all the light deflection elements 28 have the same shape, the position of the farthest intersection α of the light incident on each light deflection element 28 exists on the same plane. Therefore, since the light H incident from the incident surfaces of the optical element 24 and the light uniform element 25 can obtain the same diffusion performance in any region, the optical element 24 and the light uniform element 25 without unevenness can be provided. . However, as shown in FIGS. 6A and 6B, when the lens shape of the light deflection element 28 is not constant, the farthest intersection α of the light incident on each light deflection element 28 is the same. It does not exist on the surface. Therefore, the thickness T of the light propagation layer 23 is different for each light deflection element 28. At this time, it is desirable to select the thickness T of the light propagation layer 23 that is the thickest among the lenses to be combined. By selecting T that is the thickest, all of the optical deflection elements 28 arranged can satisfy the above-described Expressions 1 and 2, so that the diffusion effect can be reliably obtained. For example, when the light source 41 is extremely close to the optical element 24 and the light uniform element 25, when the distance between the light sources 41 is extremely far away, or when the distance between the light sources 41 is uneven, the light deflection element It is effective to make the 28 farthest intersections α non-uniform. In particular, when a plurality of combinations are combined, they may be regularly arranged in accordance with the position of the light source 41 as shown in FIG. At this time, it is desirable to arrange the light deflection element 28 in the region directly above the light source 41 so that the thickness T of the light propagation layer 23 can be set to be the thinnest. As a result, the diffusion performance in the region directly above the light source 41 can be improved, and thus the luminance unevenness can be further reduced. Although the pitch P of the light deflection element 28 can be determined as appropriate, the larger the pitch P of the light deflection element 28 is, the thicker the thickness T of the light propagation layer 23 is. Therefore, actually, the thickness T is 10 μm or more and 300 μm or less, preferably 10 μm or more. It is calculated | required that it is 200 micrometers or less.

  The light deflection element 28 can be formed on the surface 23 a opposite to the observer side F of the light propagation layer 23 using an electron beam curable resin such as a UV curable resin. For example, the light diffusion base material 26 and the light propagation layer 23 are integrally formed as a plate-like member by an extrusion method or the like, and the light deflection element 28 is placed on the surface 23 a opposite to the observer side F of the light propagation layer 23 by UV. Can be molded. Furthermore, before / after the light propagation layer 23 is formed as a plate-like member by an extrusion method, an injection molding method or the like and integrated with the light diffusion base material 26, the light propagation layer 23 is opposite to the observer side F. The light deflection element 28 can be UV molded on the side surface 23a. PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer), acrylonitrile styrene copolymer, acrylonitrile polystyrene copolymer, etc. The light deflection element 28 can also be formed by a press molding method. Further, the light deflection element 28 can be formed on the surface of the sheet material produced in the same manner using a radiation curable resin.

  The light deflection element 28 and the light propagation layer 23 can be simultaneously produced by extrusion. Further, as shown in FIG. 8A, the light deflection element 28 of the present invention and the light uniform element 25 comprising the light propagation layer 23 and the light diffusion base material 26 may be integrally formed by multilayer extrusion molding or the like. On the other hand, as shown in FIG. 8 (b), after being formed into a sheet shape, the light propagation layer 23 may be bonded to the surface 23a opposite to the observer side F by a fixing layer 20 by lamination or the like. it can. In this case, it is preferable to include an ultraviolet absorber in the light deflection element 28 formed into a sheet shape. By including an ultraviolet absorber in the light deflection element 28 formed into a sheet shape, it is possible to prevent peeling of the fixed layer 20 due to ultraviolet degradation.

  Here, the fixed layer 20 is formed using a pressure-sensitive adhesive or an adhesive. Urethane, acrylic, rubber, silicone, and vinyl resins can be used for the pressure-sensitive adhesive and adhesive. In addition, as the pressure-sensitive adhesive and the adhesive, those which are pressed and adhered in a one-pack type, those which are cured by heat or light can be used, and those which are cured by mixing two liquids or a plurality of liquids are used. be able to. Further, a filler may be dispersed in the fixed layer 20. By dispersing the filler in the fixed layer 20, the elastic modulus of the bonding layer can be increased. As a method for forming the fixed layer 20, there are a method of directly applying to the bonding surface and a method of pasting together those prepared in advance as a dry film. It is preferable to prepare the fixed layer 20 as a dry film because it can be easily handled in the manufacturing process.

  Further, it is desirable that the fixed layer 20 has a warping preventing action. By matching the thermal linear expansion coefficient of the fixed layer 20 so as to be substantially the same as the thermal linear expansion coefficient of the light diffusion base material 26, the warpage of the light uniform element 25 itself can be prevented. Furthermore, the warping of the light uniform device 25 itself can be prevented by matching the thermal linear expansion coefficient of the light deflection element 28 formed into a sheet shape so as to be substantially the same as the thermal linear expansion coefficient of the light diffusion base material 26. Can do. The thickness of the light deflection element 28 formed into a sheet shape is preferably 10 μm to 1 mm. Furthermore, it is desirable that it is 25 micrometers-500 micrometers. This is because if the thickness of the light deflection element 28 formed into a sheet is too thin, wrinkles or the like are generated, and if it is too thick, bonding with the light propagation layer 23 is not easy. Here, the base material region of the light deflection element 28 formed into a sheet shape can be regarded as the light propagation layer 23. Therefore, by forming the light deflection element 28 in a thick sheet shape, the thickness of the light propagation layer 23 can be reduced. Further, it can be directly bonded to the light diffusion base material 26.

  The surface of the light deflection element 28 may have finer irregularities. The fine unevenness can further enhance the deflection effect by the light deflection element 28. At this time, the surface roughness Ra is preferably in the range of 0.1 μm to 10 μm. If the concavo-convex structure is less than 0.1 μm, it is difficult to obtain a deflection effect. As a method for forming fine irregularities, for example, the method of roughening the surface of the light deflection element 28 or the molding die by etching or sandblasting, or the molding die of the light deflection element 28 is further refined. A method such as cutting is used. Further, the light deflection element 28 may not have the lens shape as described above as long as it deflects the incident light H. Further, the light deflection element 28 may not have the lens shape as described above as long as it deflects the incident light H. For example, the light deflection element 28 may be a diffusion layer made of a resin filler or bubbles. This is because the incident light H is deflected by the light deflection element 28, the light deflected by the light propagation layer 23 is expanded, and further diffused by the light diffusion base material 26, thereby improving the diffusion performance.

  The light propagation layer 23 constituting the light uniform element 25 of the present invention preferably has a total light transmittance of 80% or more. If the total light transmittance is 80% or more, the luminance of the light emitted to the observer side F is not lowered. Conversely, if the total light transmittance is less than 80%, the luminance of the light emitted to the observer side F is lowered, which is not preferable. The total light transmittance is a measured value based on JIS K7361-1. The light propagation layer 23 preferably has a haze value of 95% or less. The light propagation layer 23 effectively spreads and propagates the incident light deflected and diffused by the light deflecting element 28 and causes the incident light to enter the light diffusing substrate 26. Therefore, a haze value exceeding 95% is not preferable because a sufficient light diffusion effect cannot be obtained. The haze value is a measured value based on JIS K7136.

  The material used for the light propagation layer 23 is preferably a transparent resin made of a thermoplastic resin. For example, polycarbonate resin, acrylic resin, fluorine acrylic resin, silicone acrylic resin, epoxy acrylate resin, polystyrene resin, cycloolefin polymer, Examples thereof include methyl styrene resin, fluorene resin, PET, polypropylene, acrylonitrile styrene copolymer, acrylonitrile polystyrene copolymer, and the like. Further, the light propagation layer 23 may be extended in at least one axial direction.

  The light propagation layer 23 can have a multilayer structure of at least two layers. At this time, when the refractive index of the layer 23A on the light deflection element 28 side is n1, the refractive index of the layer 23B on the light diffusion base material 26 side is n2, and the refractive index of the light deflection element 28 is n0, Expression 3 is satisfied. Is desirable.

Equation 3 will be described with reference to FIG.
When the light H enters the light deflection element 28, the light H is deflected by the refractive index of air and the refractive index n0 of the light deflection lens 28. At this time, the larger the refractive index n0 of the light deflection element 28, the larger the refraction angle. Therefore, it is desirable that the refractive index n0 of the light deflection element 28 is larger. In FIG. 9A, light is transmitted at each interface of the light deflection element 28, the layer 23A of the light propagation layer 23 on the light deflection element 28 side, and the layer 23B of the light propagation layer 23 on the light diffusion base material 26 side. When proceeding from the light source 41 side to the observer side F, a case where the refractive index at the interface is increased is indicated by a two-dot chain line, a case where the refractive index is not changed is indicated by a dotted line, and a case where the refractive index is reduced is indicated by a solid line. For example, when light deflected by the light deflection element 28 enters the light propagation layer 23, when n0> n1, that is, when the refractive index is low, the light is deflected in the direction shown by the solid line. Since the angle formed between the deflected light and the surface 23a opposite to the observer side F of the light propagation layer 23 is reduced, the diffusion performance is improved.

  On the other hand, when n0 <n1, that is, when the refractive index becomes high, it is deflected in the direction shown by the two-dot chain line. Since the angle formed between the deflected light and the surface 23a opposite to the observer side F of the light propagation layer 23 is increased, the diffusion performance is deteriorated. Similarly, at the interface between the layer 23A on the light deflection element 28 side of the light propagation layer 23 and the layer 23B on the light diffusion base material 26 side of the light propagation layer 23, when n1> n2, that is, when the refractive index is low, diffusion is performed. Performance will be improved. Therefore, it is desirable that the refractive index n0 of the light deflection element 28 and the refractive index n1 of the layer 23A on the light deflection element 28 side of the light propagation layer 23 are equal to each other or the refractive index n0 of the light deflection element 28 is larger. The refractive index n1 of the layer 23A on the light deflection element 28 side of the light propagation layer 23 and the refractive index n2 of the layer 23B on the light diffusion base material 26 side of the light propagation layer 23 are equal or the light deflection element of the light propagation layer 23 It is desirable that the refractive index n1 of the 28-side layer 23A is larger.

  Here, the thickness of the layer 23B on the light diffusion base material 26 side of the light propagation layer 23 is more desirable than the thickness of the layer 23A on the light deflection element 28 side of the light propagation layer 23. This is because the light can be greatly expanded in the layer 23B of the light propagation layer 23 on the light diffusion base material 26 side. Furthermore, as shown in FIG. 9B, the point where the light incident on both ends of the unit lens of the light deflection element 28 is deflected and intersects is located in the layer 23A of the light propagation layer 23 on the light deflection element 28 side. It is desirable to do. Further, when the light propagation layer 23 has a multilayer structure of at least two layers, the farthest intersection α of the light deflection element 28 is the light exit surface of the light deflection element 28 (that is, the observer side F of the light propagation layer 23 and It may be contained in a layer in contact with the opposite surface 23a). As a result, since the farthest intersection point is at a point close to the light deflection element 28 in the light propagation layer 23, light can be diffused greatly.

  The light propagation layer 23 described above can be formed by a plurality of layers having different refractive indexes by a multilayer extrusion method or the like. Further, the light deflection element 28 is formed into a sheet shape using a material having a refractive index higher than that of the light propagation layer 23 on the light propagation layer 23 formed by an extrusion method or an injection molding method, and is bonded by a lamination method or the like. Can also be realized.

  The light propagation layer 23 can be prevented from warping by having a multilayer structure. In this case, warping of the light uniform element 25 can be prevented by matching the thermal linear expansion coefficient of the layer farthest from the viewer side to approximately the same degree as the thermal linear expansion coefficient of the light diffusion base material 26. Further, the warpage of the light uniform element 25 can also be prevented by adjusting the thickness of the light propagation layer 23.

  The light uniform element 25 may be formed by integrating the light diffusion base material 26 and the light propagation layer 23 separately by an extrusion method, injection molding, or the like, and then integrating them with an adhesive or an adhesive material. For example, as the adhesive or the adhesive, the light diffusion base material 26 and the light propagation layer 23 can be bonded using a generally used laminate or the like.

  The light diffusing substrate 26 preferably has a total light transmittance of 10% to 60%. If the total light transmittance is less than 10%, the brightness of the emitted light to the observer side F is lowered, which is not preferable. Conversely, if the total light transmittance exceeds 60%, the diffusion performance is low. This is not preferable because it becomes insufficient and the uniformity of in-plane luminance deteriorates. The light diffusion base material 26 preferably has a haze value of 95% or more. When the haze value is less than 95%, the diffusion performance is insufficient, and the uniformity of in-plane luminance is deteriorated.

  The light diffusing substrate 26 includes a transparent resin and a light diffusing agent mixed and dispersed in the transparent resin, and the refractive index of the transparent resin is different from that of the light diffusing agent. It is supposed to be. As the transparent resin, a thermoplastic resin, a thermosetting resin, or the like can be used. For example, a styrene resin, a polycarbonate resin, a methacrylic resin, a methyl methacrylate resin, glass, a vinyl chloride resin, a polyethylene resin. , Polypropylene resin, polyester resin, fluorene resin, polyethylene terephthalate (PET), polypropylene, acrylonitrile styrene copolymer, acrylonitrile polystyrene copolymer, alicyclic acrylic resin, alicyclic polyolefin resin, olefin / maleimide alternating copolymer A polymer, a cyclohexadiene polymer, an amorphous polyester resin, an amorphous fluorine resin, or the like can be used. Of these, polystyrene resins, methacrylic resins, and polycarbonate resins are preferable. In addition, you may be comprised from 1 type of these, and what was comprised combining 2 or more types may be sufficient.

  In the light diffusing substrate 26 of the present embodiment, a mixture of calcium carbonate fine particles and crosslinked siloxane resin fine particles is used as the light diffusing agent dispersed in the transparent resin. The calcium carbonate fine particles are chemically synthesized in a cubic shape, and the length of one side is set in a range of 1 to 10 μm. When the length of one side is less than 1 μm, the light diffusing base material 26 has poor transparency and concealing properties are remarkably exhibited, which is not preferable as a material for the light diffusing agent. Further, when the length of one side is larger than 10 μm, it is difficult to form the shape into a cubic shape, which is not preferable. Examples of a method for chemically synthesizing calcium carbonate fine particles into a cubic shape include the following methods. First, after dense limestone is baked in an incinerator and decomposed into carbon dioxide and quicklime, water is added to the quicklime and hydrated to obtain lime milk. Cubic calcium carbonate fine particles can be obtained by reacting carbon dioxide gas with this in a batch system. In the present embodiment, as the calcium carbonate fine particles, for example, commercially available Sipron A, Sipron B manufactured by Cypro Kasei Co., Ltd. can be used.

  The crystal structure of calcium carbonate forming such calcium carbonate fine particles is preferably a hexagonal crystal structure, and the refractive index n in that case is in the range of n = 1.486 to 1.658 due to the property of birefringence. Is set.

  The crosslinked siloxane-based resin fine particles are generally called silicone rubber or silicone resin, and are kept in a solid state at room temperature. The siloxane polymer forming the crosslinked siloxane resin fine particles is mainly produced by hydrolysis and condensation of chlorosilane. In the light diffusing substrate 26 of the present embodiment, crosslinking obtained by condensing chlorosilanes represented by dimethyldichlorosilane, diphenyldichlorosilane, phenylmethyldichlorosilane, methyltrichlorosilane, and phenyltrichlorosilane with hydrolysis. Siloxane polymers are used. Further, these cross-linked siloxane polymers are converted into benzoyl peroxide, peroxide 2,4-dichlorobenzoyl, di-p-chlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, 2,5- Cross-linked with a peroxide such as dimethyl-2,5-di (t-butylperoxy) hexane, or a silanol group introduced into the terminal of a polysiloxane compound and condensed and cross-linked with alkoxysilanes. May be. Among these, a crosslinked siloxane polymer in which 2 to 3 organic groups are bonded per silicon atom is preferable. The crosslinked siloxane-based polymer particles of this embodiment can be obtained by forming the crosslinked siloxane-based polymer thus obtained in a spherical shape.

  The particle shape of the crosslinked siloxane-based resin fine particles obtained in this manner is preferably a true spherical shape or an elliptical spherical shape with a particle shape of 0.1 to 10 μm, and particularly a particle shape close to a true spherical shape. Most preferably, the particle diameter is 2 to 6 μm. If the particle size of the crosslinked siloxane-based resin particles is smaller than 0.1 μm, the wavelength dependency of light scattering increases, so that yellow may become strong and color unevenness may occur. This is not preferable because the unevenness of the film becomes remarkable.

  In the light diffusing substrate 26 of the present embodiment, the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles in the light diffusing agent is set in the range of 1: 0.5 to 10, more preferably. It is set in the range of 1: 0.5-5.

  The transparent resin and the light diffusing agent described above are uniformly mixed in a molten state, for example. The mixing ratio of the transparent resin and the light diffusing agent can be prepared as, for example, 9: 1 by weight, but is not limited thereto and can be changed as appropriate. And the plate-shaped light-diffusion base material 26 is shape | molded by performing melt | extrusion extrusion molding or injection molding to the mixture of transparent resin and a light-diffusion agent of this molten state. The plate thickness is set to 0.5 to 5 mm, and particularly 0.5 to 3 mm is most preferable. When the thickness of the light diffusing substrate 26 is less than 0.5 mm, the diffusion performance is insufficient, and the strength of the light diffusing substrate 26 itself cannot be ensured. On the other hand, if the thickness exceeds 5 mm, the amount of resin is large, resulting in a decrease in luminance due to absorption, and the backlight unit 55 and the display device 70 cannot be reduced in thickness, and at the same time, weight reduction is hindered. In addition, the light-diffusion base material 26 may be comprised by the single layer, and may be comprised by the multilayer of two or more layers.

  The light uniform element 25 is preferably formed by integrally forming the light diffusion base material 26, the light propagation layer 23, and the light deflection element 28 by a multilayer extrusion method. The light uniform element 25 may be extended in at least one axial direction. By using the multilayer extrusion method, the manufacturing process can be simplified and made more efficient, and the manufacturing cost can be reduced.

  The light uniform element 25 of the present invention can have a concavo-convex shape on the surface 26 b on the viewer side F of the light diffusing substrate 26. As shown in FIG. 10, the viewer of the light diffusing substrate 26 is provided with a fine concavo-convex shape including, for example, the second top portion 21 a and the second inclined surface 21 b on the emission surface 26 b of the light uniform element 25. Compared with the case where the surface F on the side F is substantially flat, an emission surface of various angles is formed, so that light can be emitted to a wider range, diffusion performance is improved, and a lamp image is reduced / It can be extinguished. Examples of the method for forming such irregularities include mat processing and embossing. According to these methods, the transparent resin that has been softened by heating is pressed against an uneven member to transfer the shape of the member, and then the transparent resin is cured to obtain an uneven shape. . As another method, transparent particles having a particle size of about 30 to 100 μm may be blended in a molten transparent resin, and the transparent particles may be extruded to the outermost layer side to cause unevenness on the surface. When this method is used, it is preferable that the refractive indexes of the transparent resin and the transparent particles are equal.

  The light diffusion lens 21 is mentioned as an uneven | corrugated shape provided to an observer side. As the light diffusion lens 21, a triangular prism shape as shown in FIG. This is because lens molding is easy and the direction of the emitted light can be easily controlled. Further, a convexly curved lens shape as shown in FIG. This is because the emission performance can be improved because the exit surface can be set at various angles. The convex curved lens shape is more preferably an aspherical shape as shown in FIG. This is because the radius of curvature at the top can be reduced, and the diffusion performance is increased. Furthermore, the light diffusion lens 21 is preferably a curved triangular prism as shown in FIG. Since there is no surface parallel to the viewer-side surface 26b of the light diffusing substrate 26 and the exit surface can be set at various angles, the diffusion performance is improved. Further, the light diffusing lens 21 can combine a plurality of the above lens shapes. For example, as shown in FIG. 11 (e), a shape in which a triangular prism is combined on a convex curved lens may be used. This is because the diffusion performance is further increased by the diffusion effect of two or more lens shapes. In addition, the lens shape mentioned as the light deflection element 28 may be used. The light diffusion lens 21 may be arranged by appropriately combining a plurality of the above-described lenses. For example, a diffusion lens 21 having a high diffusion performance may be disposed in a region directly above the light source 41, and a diffusion lens 21 having a low diffusion performance may be disposed between the light source 41 and the light source 41.

  However, when the diffusing lens 21 is disposed on the surface of the light diffusing substrate 26, for example, when the lens sheet 2 is disposed as the optical member 2, moire interference fringes may occur between the diffusing lens 21 and the lens sheet 2. Therefore, a method in which the periodic structure of the diffusing lens 21 and the periodic structure of the lens of the lens sheet 2 are adjusted to a pitch at which moire interference fringes do not occur, an angle is provided, or a diffusing film is further applied as the optical member 2. Is mentioned. When a member having no periodic structure such as a diffusing film or a deflection separation reflection sheet is disposed as the optical member 2, the above-described problem does not occur.

  In the light uniform element of the present invention, it is desirable that the exit surface, that is, the surface 26b on the viewer side F of the light diffusing substrate 26 is substantially flat. The reason will be described with reference to FIG. FIG. 12 is a schematic cross-sectional view illustrating an example of the optical sheet, the backlight unit, and the display device of the present invention. In the optical sheet 52, the optical film 1 and the light uniform element 25 of the present invention are integrally laminated by the fixed layer 20. The optical film 1 includes a light transmitting base material 17 and a condensing lens 16, and a plurality of condensing lenses 16 are arranged at a constant pitch on a surface 17 b on the observer side of the light transmitting base material 17. By forming the condenser lens 16 on the observer-side surface 17b of the light transmitting base material 17, the light passing through the light uniform element 25 is condensed on the observer side F, and the luminance of the observer side F is obtained. Can be improved.

  A surface 17a opposite to the observer side F of the light transmitting substrate 17 is a substantially flat surface, a plurality of light masks 22 are formed, and a light uniform element 25 is bonded via a fixed layer 20. Yes. As the material of the light transmissive substrate 17, a thermoplastic resin, a thermosetting resin, or the like can be used, and the material used for the light uniform element 25 may be used. By joining the materials used for the light uniform element 25, the occurrence of warpage can be suppressed.

  In addition, when unit lenses are formed on one surface and the other surface of one member, moire interference fringes may occur. However, the optical sheet 52 of the present invention is formed by the condensing lens 16 and the light deflection element 28. Since the light diffusion base material 26 is inserted between them, moire interference fringes can be prevented. Here, there is no diffusing element between the condensing lens 16 and the light diffusing substrate 26, and the optical film 1 is bonded to the surface 26b on the observer side F of the light diffusing substrate 26 without unevenness. In addition, it is desirable that the viewer-side surface 26b of the light diffusing substrate 26 is substantially flat.

  The shape of the condensing lens 16 is a convex curved surface shape, and has a third apex portion 16a having an arcuate surface and a third inclined surface 16b extending from the third apex portion 16a to the light transmitting substrate. Moreover, the condensing lens 16 is formed so that the distance between the 3rd inclined surfaces 16b which oppose may decrease gradually as it goes to the 3rd top part 16a. Furthermore, the condenser lenses 16 are spaced apart by the valleys 13 and are formed at a constant pitch.

  Between the optical film 1 and the light uniform element 25, a plurality of light masks 22 and light transmission openings (air layers) 100 that separate the light masks 22 are provided. The pitch of the optical mask 22 and the air layer 15 is substantially the same as the pitch of the condenser lens 16. The position of the optical mask 22 is formed at a position corresponding to the position of the valley portion 13. Therefore, the position of the air layer 100 is provided at a position corresponding to the third top portion 16 a of the condenser lens 16.

  Since the optical mask 22 is made of a material having a high light shielding property and is formed at a position corresponding to the position of the valley portion 13 that separates the condenser lens 16 formed on the surface 17b on the observer side F, Since most of the light incident on the optical film 1 passes through the air layer 100 formed away from the optical mask 22 and enters the condenser lens 16, the light that has passed through the light uniform element 25 is efficiently used. The light is emitted in the front direction (observer side) F.

  Here, the optical mask 22 can be comprised from light-reflective members, such as a metal material and a white reflective material, for example. In this case, the light reflected by the light mask 22 is returned to the light diffusing substrate 26 constituting the light uniform element 25 and is again diffused by the light diffusing substrate 26, and then a part of the light again. Part of the light is emitted from the light uniform element 25 to the light source side, reflected by the reflector constituting the lamp house, and then re-entered the light uniform element and further diffused and re-enter the optical film 1. To do. By repeating this process, most of the light from the light source 41 can be emitted to the observer side F. When the optical mask 22 is made of a light reflective member, the reflectance is desirably 80% or more. If the reflectance is 80% or more, most of the light incident on the optical film 1 can be incident on the condenser lens 16 from the air layer 100, so that the luminance on the observer side F increases. If the reflectance is less than 80%, the amount of light transmitted through the optical mask 22 increases, and the amount of inefficient light incident on the condenser lens 16 increases, thereby causing a decrease in luminance on the viewer side F. .

  Examples of a method for producing the optical film 1 include a method using self-alignment. The condensing lens 16 is formed on the observer-side surface 17b of the light-transmitting substrate 17, and a photosensitive adhesive resin is bonded to the surface 17a opposite to the observer-side F of the light-transmitting substrate 17. By irradiating UV light from the condensing lens 16 side, the photosensitive adhesive resin at a position corresponding to the third top portion 16a of the condensing lens 16 is exposed to cure and lose adhesiveness. Thereafter, by transferring the optical mask 22, the optical mask 22 can be formed at a position corresponding to the valley portion 13 of the condenser lens 16.

  The optical sheet 52 is produced by laminating the optical film 1 produced as described above to the light uniform element 25 by the fixing layer 20 by lamination or the like. At this time, the material of the fixed layer 20 is appropriately selected so that the air layer 100 is maintained.

  The fixed layer 20 is formed using a pressure sensitive adhesive or an adhesive. Urethane, acrylic, rubber, silicone, and vinyl resins can be used for the pressure-sensitive adhesive and adhesive. In addition, as the pressure-sensitive adhesive and the adhesive, those which are pressed and adhered in a one-pack type, those which are cured by heat or light can be used, and those which are cured by mixing two liquids or a plurality of liquids are used. be able to. Further, a filler may be dispersed in the fixed layer 20. By dispersing the filler in the fixed layer 20, the elastic modulus of the fixed layer 20 can be increased. When the elastic modulus of the fixed layer 20 is increased, when the optical film 1 and the light uniform element 25 are integrated, the fixed layer 20 does not enter the region of the air layer 100, so that the air layer 100 can be held. It becomes easy. As a method for forming the fixed layer 20, there are a method of directly applying to the joint surface, and a method of pasting together those prepared in advance as a dry film. It is preferable to prepare the fixed layer 20 as a dry film because it can be easily handled in the manufacturing process.

  However, when a stretched film typified by PET is used as the light-transmitting substrate 17 constituting the optical film 1, the optical sheet 52 is warped in a convex shape toward the light source 41 due to heat generated from the light source 41. There is. At this time, the material of the layer 23A on the light deflection element 28 side of the light propagation layer 23 having a multilayer structure of two or more layers can be used as a warp prevention layer. That is, the layer 23A on the light deflection element 28 side of the light propagation layer 23 generates a moment that warps the optical sheet 52 into a concave shape on the light source side, thereby canceling each moment and preventing warpage. can do. For example, the light deflection element 28 is formed on the same material as the light transmissive substrate 17, and is bonded to the surface 23 a opposite to the observer side F of the light propagation layer 23 by the fixed layer 20 to prevent warping. be able to. Although not shown, dot-shaped or linear ribs may be arranged between the optical film and the light uniform element, and the optical film and the light uniform element may be integrally laminated via the rib.

  Since the display device 70 according to the embodiment of the present invention is configured to use the light K whose light collection / diffusion characteristics are improved by the optical sheet 52 described above, the luminance on the observer side F is improved and the light intensity is increased. An image in which the distribution in the viewing angle direction is smoothed and the lamp image is reduced can be displayed on the image display element 35.

  A display device 70 according to an embodiment of the present invention is an image display element 35 that defines a display image according to transmission / light-shielding in pixel units, and improves the light collection and diffusion characteristics by the backlight unit 55 described above. Therefore, the luminance on the viewer side F can be improved, the distribution of the light intensity in the viewing angle direction can be smoothed, and an image with a reduced lamp image can be obtained. In the backlight unit 55, the light source is a linear light source, the shape of the light deflection element is a lenticular lens, and when viewed in plan, the major axis direction of the lenticular lens and the major axis direction of the linear light source are Is preferably 20 degrees or less from the viewpoint of the effect of the present invention.

  In the display device 70 according to the embodiment of the present invention, the image display element 35 is a liquid crystal display element, and the light K whose light collection / diffusion characteristics are improved by the backlight unit 55 described above is used. It is possible to improve the brightness of the person side F, smooth the distribution of the light intensity in the viewing angle direction, and obtain an image with a reduced lamp image.

  Hereinafter, the present invention will be described in detail based on examples. In addition, this invention is not limited only to these Examples.

  Hereinafter, the optical characteristics of the display device 70 using the light uniform element 25 and the optical sheet 52 of the present invention will be described in Examples.

  A convex lenticular lens was prepared as the light deflection element 28. The pitch P of the convex lenticular lens is 100 μm, the angle θ formed by the tangent m at the junction 30 between the light propagation layer 23 and the convex lenticular lens and the surface 23a opposite to the observer side of the light propagation layer 23 is 65 degrees. The height of the convex lenticular lens was set to 45 μm. The materials of the light deflection lens 28, the light propagation layer 23, and the diffusion base material 26 are all polycarbonate (refractive index = 1.59). As the light diffusing agent used for the diffusion base material 26, spherical crosslinked siloxane resin particles (DY33-719, manufactured by Toray Dow Corning, average particle diameter 2 μm, refractive index 1.42) and cubic calcium carbonate fine particles (Sipron A, manufactured by Sipro Kasei Co., Ltd., average particle diameter of 5 μm, refractive index of 1.486-1.658) was used. As a specific production method, calcium carbonate fine particles and cross-linked siloxane resin fine particles having a predetermined blending ratio were mixed with a Henschel mixer and then pelletized to form a resin composition to produce the light uniform element 25. . Further, according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, the weight blending ratio is 1: 0.1, Example 1, 1: 0.5 is Example 2, and 1: 2. Examples 3 and 1: 5 were designated as Example 4. In these prepared light diffusing plates, the mixing ratio of the light diffusing agent was 10% of the weight of the light diffusing plate.

Example 1
In the set light uniform element 25, the weight blending ratio is 1: 0.1 according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, and the thickness of the light propagation layer 23 is 1.5 mm. The thickness of the light propagation layer 23 was set to 500 μm, and the light uniform element 25 was produced.

(Example 2)
In the light uniform element 25 set as described above, the weight blending ratio is 1: 0.5 according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, and the thickness of the light propagation layer 23 is 1.5 mm. An optical uniform element 25 in which the thickness of the light propagation layer 23 was set to 500 μm was produced.

(Example 3)
In the light uniform element 25 set as described above, the weight blending ratio is 1: 2 according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, the thickness of the light propagation layer 23 is 1.5 mm, and the light propagation is performed. An optical uniform element 25 in which the thickness of the layer 23 was set to 500 μm was produced.

Example 4
In the light uniform element 25 set as described above, the weight blending ratio is 1: 5 according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, the thickness of the light propagation layer 23 is 1.5 mm, and the light propagation is performed. An optical uniform element 25 in which the thickness of the layer 23 was set to 500 μm was produced.

(Comparative Example 1)
Moreover, as Comparative Example 1, a weight ratio of calcium carbonate fine particles and cross-linked siloxane resin fine particles was 0: 1, that is, a comparative example in which the light diffusing agent was composed only of the above-described cross-linked siloxane resin particles was prepared. A light uniform element 25 in which the thickness of the layer 23 was set to 1.5 mm and the thickness of the light propagation layer 23 was set to 500 μm was produced.

(Comparative Example 2)
Further, cubic calcium carbonate fine particles having an average particle diameter of 0.2 μm (Brilliant-1500, manufactured by Shiraishi Kogyo Co., Ltd., average particle diameter of 0.2 μm) are used, and the weight blending of calcium carbonate fine particles and crosslinked siloxane resin fine particles The ratio was set to 1: 0.25, and the other configuration was the same as that of Example 2 as Comparative Example 2. The thickness of the light propagation layer 23 was set to 1.5 mm, and the thickness of the light propagation layer 23 was set to 500 μm. The light uniform element 25 was produced.

(Comparative Example 3)
Finally, the calcium carbonate fine particles have a bell-shaped particle shape, an average particle size of 3 μm (PC, manufactured by Shiraishi Kogyo Co., Ltd., average particle size of 3 μm), and the others are the same as in Example 2. Fabricated as Comparative Example 3, a uniform light element 25 was fabricated in which the thickness of the light propagation layer 23 was set to 1.5 mm and the thickness of the light propagation layer 23 was set to 500 μm.

  On the surface of the observer side F of the light uniform element 25 produced as described above, a diffusion film, a 90-degree triangular prism sheet, and a diffusion film were arranged in this order. These are arranged in the backlight 56 having a CCFL interval of 38 mm, and the distance between the CCFL and the light uniform element 25 is 15 mm, and the liquid crystal panel 35 is arranged on the observer side F of the backlight 56, whereby the display device 70 is arranged. Obtained.

  Next, the condensing lenses 16 are arranged at a pitch of 150 μm on a 75 μm PET substrate on the observer side F surface of the light uniform elements 25 of Examples 1 to 4 and Comparative Examples 1 to 3 prepared above, and the optical mask 22 The optical film 1 formed so that the area was 50% of the pitch of the condenser lens 16 was integrally laminated with an adhesive material, whereby an optical sheet 52 was obtained.

(Example 5)
In the set light uniform element 25, the weight blending ratio is 1: 0.1 according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, and the thickness of the light propagation layer 23 is 1.5 mm. A light uniform element 25 integrated with the optical film 1 was prepared by setting the thickness of the light propagation layer 23 to 500 μm.

(Example 6)
In the light uniform element 25 set as described above, the weight blending ratio is 1: 0.5 according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, and the thickness of the light propagation layer 23 is 1.5 mm. A light uniform element 25 integrated with the optical film 1 was prepared by setting the thickness of the light propagation layer 23 to 500 μm.

(Example 7)
In the light uniform element 25 set as described above, the weight blending ratio is 1: 2 according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, the thickness of the light propagation layer 23 is 1.5 mm, and the light propagation is performed. The light uniform element 25 in which the thickness of the layer 23 was set to 500 μm and integrated with the optical film 1 was produced.

(Example 8)
In the light uniform element 25 set as described above, the weight blending ratio is 1: 5 according to the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles, the thickness of the light propagation layer 23 is 1.5 mm, and the light propagation is performed. The light uniform element 25 in which the thickness of the layer 23 was set to 500 μm and integrated with the optical film 1 was produced.

(Comparative Example 4)
Further, a weight ratio of the calcium carbonate fine particles and the crosslinked siloxane resin fine particles is 0: 1, that is, a comparative example in which the light diffusing agent is composed only of the crosslinked siloxane resin particles is prepared, and the thickness of the light propagation layer 23 is set. The light uniform element 25 integrated with the said optical film 1 was produced by setting 1.5 mm and the thickness of the light propagation layer 23 to 500 micrometers.

(Comparative Example 5)
Further, cubic calcium carbonate fine particles having an average particle diameter of 0.2 μm (Brilliant-1500, manufactured by Shiraishi Kogyo Co., Ltd., average particle diameter of 0.2 μm) are used, and the weight blending of calcium carbonate fine particles and crosslinked siloxane resin fine particles The ratio was set to 1: 0.25, and the other configuration was the same as that of Example 6, and was manufactured as Comparative Example 5. The thickness of the light propagation layer 23 was set to 1.5 mm, and the thickness of the light propagation layer 23 was set to 500 μm. Thus, the light uniform element 25 integrated with the optical film 1 was produced.

(Comparative Example 6)
Finally, as the calcium carbonate fine particles, the particle shape is a spinning type, the average particle size is 3 μm (PC, manufactured by Shiroishi Kogyo Co., Ltd., average particle size 3 μm), and the others are the same as in Example 6. Fabricated as Comparative Example 6, a light uniform element 25 integrated with the optical film 1 was fabricated by setting the thickness of the light propagation layer 23 to 1.5 mm and the thickness of the light propagation layer 23 to 500 μm.

  The samples of Examples 5 to 8 and Comparative Examples 4 to 6 produced as described above were placed in the backlight 56 having a CCFL interval of 38 mm and the distance between the CCFL and the light uniform element 25 being 15 mm. By disposing the liquid crystal panel 35 on the side F, the display device 70 was obtained.

(Optical evaluation)
The display devices of this example and comparative example were evaluated by the following measuring methods.
(Front brightness evaluation)
The display device 70 was set to all white display, and the center of the screen was measured with a spectral radiance meter (SR-3A: manufactured by Topcon Technohouse).
(Luminance unevenness evaluation)
The display device 70 was displayed as all white, and the entire screen was measured with a luminance unevenness measuring device (ProMetric 1200: manufactured by Radiant Imaging), and analysis was performed on the arrangement of a plurality of cold-cathode tubes using luminance distribution data in the vertical direction. Since the luminance distribution can be obtained as a wave distribution corresponding to the cold cathode fluorescent lamps, the luminance data corresponding to the five cold cathode fluorescent lamps at the center is extracted to calculate the average luminance, and then the luminance change with respect to the average luminance is calculated. (%) Was calculated. When the standard deviation σ of the luminance change was within 1%, it was determined that the diffusibility of the optical sheet was good.

  Table 1 shows the measurement results of this example and the comparative example.

In Example 1, there was no decrease in luminance, but the light source image was recognized as thin.
In Example 2, there was no decrease in luminance, and the light source image disappeared well.
In Example 3, there was no decrease in luminance, and the light source image disappeared well.
In Example 4, the light source image disappeared well without a decrease in luminance.
In Comparative Example 1, there was no decrease in luminance, but a light source image was recognized.
In Comparative Example 2, there was no decrease in luminance, but the light source image was recognized as thin.
In Comparative Example 3, there was no decrease in luminance, but the light source image was recognized as thin.
In Example 5, there was no decrease in luminance, but the light source image was recognized as thin.
In Example 6, the light source image disappeared well without a decrease in luminance.
In Example 7, the light source image disappeared well without a decrease in luminance.
In Example 8, there was no decrease in luminance, and the light source image disappeared well.
In Comparative Example 4, the luminance was not decreased, but the light source image was recognized.
In Comparative Example 5, there was no decrease in luminance, but the light source image was recognized as thin.
In Comparative Example 6, there was no decrease in luminance, but the light source image was recognized as thin.

  In Examples 1 and 5 (weight mixing ratio of calcium carbonate fine particles and crosslinked siloxane resin fine particles is 1: 0.1), since the image of the light source was seen through due to insufficient diffusibility, the evaluation items were unsatisfactory. It was a pass. On the other hand, in Comparative Examples 1 and 4 (not including calcium carbonate fine particles), the evaluation item was rejected because the image of the light source was seen through due to insufficient diffusibility. Therefore, it was revealed that the specifications using only the cross-linked siloxane resin fine particles as the light diffusing agent in the light diffusing plate and the weight blending ratio of 1: 0.1 are not preferable in terms of characteristics.

  Comparative Examples 2 and 5 (weight mixing ratio of calcium carbonate fine particles and crosslinked siloxane-based resin fine particles is 1: 0.5 and the particle size of calcium carbonate fine particles is 0.2 μm) and Comparative Examples 3 and 6 The light diffusing plate (weight mixing ratio of calcium carbonate fine particles and crosslinked siloxane resin fine particles is 1: 0.5 and the shape of the calcium carbonate fine particles is spun) until the image of the light source is completely erased. As a result, it was found that the characteristics are not preferable.

Therefore, from the evaluation results of Examples 1 and 5 and Comparative Examples 1 to 4, the weight blending ratio of the calcium carbonate fine particles and the crosslinked siloxane-based resin fine particles is set in the range of 1: 0.5 to 10; It has been found that it is effective to erase the image of the light source by making the particle size of the particles 1 μm or more and making the particle shape a cubic shape.

It is a cross-sectional schematic diagram of the display apparatus which is embodiment of this invention. (A) It is a cross-sectional schematic diagram of the optical uniform element which is embodiment of this invention. (B) It is a figure explaining Numerical formula 1. (C) It is a figure explaining Numerical formula 2. FIG. (A) It is a figure which shows an example of the lens shape of an optical deflection | deviation element. (B) It is a figure which shows an example of the lens shape of an optical deflection | deviation element. (C) It is a figure which shows an example of the lens shape of an optical deflection | deviation element. (D) It is a figure which shows an example of the lens shape of an optical deflection | deviation element. (E) It is a figure which shows an example of the lens shape of a light deflection | deviation element. (F) It is a figure which shows an example of the lens shape of an optical deflection | deviation element. (A) It is a figure which shows an example of the lens shape of an optical deflection | deviation element. (B) It is a figure which shows an example of the lens shape of an optical deflection | deviation element. (C) It is a figure which shows an example which formed the light-diffusion / reflection layer in the 1st top part of the light deflection | deviation element. (D) It is a figure which shows an example which formed the light-diffusion / reflection layer in the recessed part of the light deflection | deviation element. (A) It is a figure explaining Numerical formula 1 in case a light deflection | deviation element is a concave lens. (B) It is a figure explaining Numerical formula 2 in case a light deflection | deviation element is a concave lens. (A) It is a figure explaining the case where the lens height and pitch of a light deflection | deviation element are not constant. (B) It is a figure explaining the case where the lens height of a light deflection | deviation element is not constant. (C) It is a figure explaining the case where the lens height and pitch of a light deflection | deviation element are constant. It is a figure which shows an example at the time of aligning a light deflection | deviation element with a light source. (A) It is a figure which shows the form at the time of integrally forming an optical uniform element. (B) It is a figure which shows the form at the time of shape | molding a light deflection | deviation element in a sheet form. (A) It is a figure explaining the light ray in case a light propagation layer is a multilayer structure. (B) It is a figure explaining the light ray in case a light propagation layer is a multilayer structure. (A) It is a figure explaining the effect by which the unevenness | corrugation was shaped on the emission surface of the light uniform element. (B) It is a figure explaining the case where the emission surface of a light uniform element is flat. (A) It is a figure which shows an example of the lens shape of a light-diffusion lens. (B) It is a figure which shows an example of the lens shape of a light-diffusion lens. (C) It is a figure which shows an example of the lens shape of a light-diffusion lens. (D) It is a figure which shows an example of the lens shape of a light-diffusion lens. (E) It is a figure which shows an example of the lens shape of a light-diffusion lens. (A) It is a cross-sectional schematic diagram of the display apparatus which is embodiment of this invention. (B) It is a cross-sectional schematic diagram of the display apparatus which is embodiment of this invention.

Explanation of symbols

  H, K: light, P: light deflection element pitch, p1: light deflection element first inclined surface pitch, m: tangent, T: thickness of light propagation layer, θ: angle formed by one surface of light propagation layer and tangent m , Θ1, θ2, θ3... Angles formed by tangents at each point of the light deflection element and one surface of the light propagation layer, n... Refractive index of the light propagation layer, n0. Refractive index of the first layer, n2 ... refractive index of the second layer of the light propagation layer, F, F '... observer side, X ... planar view direction, Ve ... image display device vertical direction, Ho ... image display device horizontal direction , Θ41: angle formed by the axial direction j of the lenticular lens with the axial direction k of the linear light source, Δ: light diffusion / reflection layer wrapping amount, α: farthest intersection point, 1 ... optical film, 2 ... optical member, 13 ... Valley, 16 ... Condensing lens, 16a ... Third apex, 16b ... Third inclined surface, 17 ... Light-transmitting substrate, 17a ... Opposite to observer 17b ... observer-side surface (flat surface), 20 ... fixed layer, 21 ... light diffusion lens, 21a ... second top, 21b ... second inclined surface, 22 ... light mask, 23 ... light propagation layer, 23a ... the surface opposite to the observer, 23b ... the surface on the observer side, 23A ... the layer on the light deflection element side of the light propagation layer, 23B ... the layer on the diffusion substrate side of the light propagation layer, 25 ... the light uniform element, 26 ... diffusion substrate, 26a ... surface opposite to the observer, 26b ... surface on the viewer's side, 28 ... light deflection element, 28a ... first top, 28b ... first inclined surface, 30 ... junction point, 31, 33 ... Polarizing plate, 32 ... Liquid crystal panel, 35 ... Image display element, 41 ... Light source, 43 ... Reflector (reflective film), 45 ... Backlight part, 52 ... Optical sheet, 55, 56 ... Backlight unit, 70, 72 ... Display device, 100 ... Air layer.

Claims (21)

  In a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of a light diffusion substrate, the light diffusion substrate is a light diffusion member in which a light diffusion agent is mixed in a transparent resin. The light diffusing agent comprises cubic shaped calcium carbonate fine particles and spherical cross-linked siloxane resin fine particles, and the weight mixing ratio of the calcium carbonate fine particles and the cross-linked siloxane resin fine particles is 1: 0.5. It is set to the range of -10, The light uniform element characterized by the above-mentioned.   2. The light uniform element according to claim 1, wherein a crystal structure of calcium carbonate constituting the calcium carbonate fine particles is a hexagonal system.   3. The light uniform element according to claim 1, wherein a length of one side of the calcium carbonate fine particles is set in a range of 1 to 10 μm.   The light uniform element according to any one of claims 1 to 3, wherein a particle diameter of the crosslinked siloxane-based resin fine particles is set in a range of 0.1 to 10 µm.   5. The uniform light according to claim 1, wherein the transparent resin is selected from any one of a polystyrene resin, a methacrylic resin, and a polycarbonate resin, and is made of one kind or a combination thereof. element. In a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on a light incident surface side of a light diffusion substrate, the light deflection element has an arcuate surface or a ridge line, and the light from the first top. A first inclined portion that reaches the light incident surface of the propagation layer, wherein the refractive index of the light propagation layer is n, the pitch of the light deflection element is P, and the first inclined surface is bonded to the light propagation layer. When the angle between the tangent to the first inclined surface at the joining point and the light incident surface of the light propagation layer is θ, the thickness T of the light propagation layer satisfies the following formula 1. The light uniform element according to any one of claims 1 to 5.

  In a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of the light diffusion base material, the shape of the light deflection element is such that the first top portion and the first inclined portion are curved. The angle formed between the tangent line at each point of the first curved inclined portion and the light incident surface side of the light propagation layer is continuously 20 degrees or more and 90 degrees or less. The light uniform element according to claim 6, wherein the light uniform element is changed.   8. The light uniform element having a structure in which a light propagation layer and a light deflection element are provided on a light incident surface side of a light diffusion base material, wherein the top of the light deflection element has a ridge line. Uniform element.   In a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on a light incident surface side of a light diffusion substrate, a light propagation layer is formed on the light incident surface side of the light diffusion substrate, and the light propagation layer The light diffusing element is formed on the light incident surface side, and the light diffusing substrate has a light diffusing region dispersed in a transparent resin, and has a total light transmittance of 10% to 60% and a haze value of 95%. 9. The light uniform element according to claim 1, wherein the propagation layer has a total light transmittance of 80% or more and a haze value of 95% or less.   In a light uniform element having a structure in which a light propagation layer and a light deflecting element are provided on the light incident surface side of the light diffusing substrate, fine irregularities are provided on the light emitting surface side of the light diffusing substrate, The light uniform element according to any one of claims 1 to 9.   In a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of the light diffusing substrate, a light diffusing lens having irregularities is provided on the light emitting surface side of the light diffusing substrate. The light uniform element according to any one of claims 1 to 10, wherein:   2. The light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of the light diffusing substrate, wherein the light emitting surface side of the diffusing substrate is substantially flat. The light uniform element according to any one of 9.   In a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on a light incident surface side of a light diffusion substrate, the light deflection element, the light propagation layer, and the light diffusion substrate are integrally formed by a multilayer extrusion method. The light uniform element according to claim 1, wherein the light uniform element is a light emitting element.   In a light uniform element having a structure in which a light propagation layer and a light deflection element are provided on the light incident surface side of a light diffusion substrate, the light diffusion substrate and the light propagation layer are integrally formed by a multilayer extrusion method, The light uniform element according to any one of claims 1 to 13, wherein the light deflection element and the light propagation layer formed in a shape are laminated via a fixed layer.   The optical film which consists of a condensing lens and a light transmission base material is provided in the light-projection surface side of the said light-diffusion base material of the light uniform element of any one of Claim 1 to 14, The said condensing A plurality of lenses are arranged at a constant pitch, and the shape of the condensing lens has a convex curved surface shape, a third apex having an arcuate surface, and a third inclination from the third apex to the light transmitting substrate The optical sheet is characterized in that the distance between the opposing third inclined surfaces gradually decreases as going to the third top portion.   A plurality of light masks and a light transmission opening for separating the light masks are provided between the optical film made of a condensing lens and a light transmission base material and the light uniform element, and the light transmission The opening portion is provided corresponding to the third top portion of the condenser lens, and the optical film and the light uniform element are integrally laminated through the optical mask. The optical sheet described.   A dot-shaped or linear rib is arranged between the optical film composed of a condensing lens and a light-transmitting substrate and the light uniform element, and the optical film and the light uniform element are integrally laminated via the rib. The optical sheet according to claim 15, wherein the optical sheet is formed.   A backlight unit comprising the light uniform element according to any one of claims 1 to 14 and a light source.   A backlight unit comprising the optical sheet according to any one of claims 15 to 17 and a light source.   The light source is a linear light source, the shape of the light deflection element is a lenticular lens, and an angle formed by the major axis direction of the lenticular lens and the major axis direction of the linear light source when viewed in plan The backlight unit according to claim 18 or 19, wherein the backlight unit is 20 degrees or less.   21. A display device comprising: an image display element that transmits and blocks light in pixel units to display an image; and the backlight unit according to any one of claims 18 to 20.

Images