JP5282500B2 - Optical element and backlight unit and display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element capable of eliminating a lamp image by equalizing incident light from a plurality of light sources and emitting it, a light equalizing element, an optical sheet, a backlight unit, and a display device in a structure in which the distance between the light source and the optical element or the light equalizing element decreases or the interval between the light sources expands. <P>SOLUTION: The display device is provided, wherein the optical element including a light propagation layer with the diffusion properties and an optical deflection element or the light equalizing element in which a diffusion substrate is integrated with a light emission surface side of the light propagation layer of the optical element is arranged so that the optical element or the optical deflection element of the light equalizing element is at the light source side of the display device, and an optical member or the like is disposed on the light propagation layer of the optical element or the diffusion substrate of the light equalizing element if necessary. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

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

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 configuration in which a diffuser plate and an optical film having a strong light scattering property are disposed between the image display element and the light source so that a cold cathode tube or an LED is 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, suppression of power consumption for the purpose of reducing energy consumption, which is 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), which is the brightness of the light source, and it will be difficult to completely erase the lamp image with the conventional combination of the diffusion plate and the 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 element and a light 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 film that improves the luminance toward the viewer side by efficiently emitting the light emitted from the optical device and the light uniform device to the viewer side is integrated with the optical device and the light uniform device. An object is to provide a laminated optical sheet, a backlight unit including the optical sheet, and a display device.

In order to solve the above problems, the present invention proposes the following means. According to a first aspect of the present invention, there is provided an optical element having a light deflection element and a light propagation layer disposed on a light emission surface side of the light deflection element, the light deflection element or the light propagation layer, or the light deflection element and It includes a substance having a function of diffusing light to the light propagation layer, incident light from the light source from the light incident surface of the light deflection element emits the diffused light from the light exit surface of the light propagation layer, the average of the material A unit selected from fine particles having a particle size in the range of 0.1 μm to 100 μm, wherein the light deflection element has at least one uneven shape, and the light deflection lens is arranged in one dimension. The light propagation layer includes a farthest intersection point, which is a lens and collects light at a point farthest from the lens vertex of each unit lens .

  According to a second aspect of the present invention, in the optical element according to the first aspect, the concentration of the substance having a function of diffusing the light contained in the light deflection element is in the range of 0.001 wt% to 30 wt%. The optical element is characterized in that light from a light source is incident from a light incident surface of the light deflection element and diffused light is emitted from a light exit surface of the light propagation layer.

  A third aspect of the present invention is the optical element according to the first or second aspect, wherein the light propagation layer is composed of at least one layer.

  According to a fourth aspect of the present invention, in the optical element according to any one of the first to third aspects, the light propagation layer has a multilayer structure having at least two different refractive indexes or different haze values. It is.

  According to a fifth aspect of the present invention, the light deflection lens includes a first apex portion having an arcuate surface or a ridge line, and a first inclined portion extending from the first apex portion to a surface opposite to the observer side of the light propagation layer. And the refractive index of the light propagation layer is n, the pitch of the light deflection lens is P, and the tangent to the first inclined surface at the junction where the first inclined surface is bonded to the light propagation layer, The thickness T of the light propagation layer satisfies the following formula 1, where θ is an angle formed with the surface of the light propagation layer opposite to the observer, 5. The optical element according to the item.

  According to a sixth aspect of the present invention, in the optical element according to the fifth aspect, the shape of the light deflection lens includes the first apex portion and a first curved inclined portion formed by bending the first inclined portion. 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 continuously changes from 20 degrees to 90 degrees. It is.

  According to a seventh aspect of the present invention, in the optical element according to the sixth aspect, the first apex portion has a ridge line.

Claim 8 of the present invention includes: the optical deflection element, an optical element according to any one of claims 1 to 7, wherein the optical Propagation layer is characterized by being integrally formed by multi-layer extrusion is there.

Claim 9 of the present invention includes an optical element according to any one of the claims 1 to 8, to have a structure having a light diffusing substrate on the light emitting surface side of the optical Propagation layer of the optical element It is the light uniform element characterized.

Claim 10 of the present invention is a light uniform element for optical path control, wherein the light uniform element comprises a diffusion base material, a light propagation layer, and a light deflection element, and is disposed on the light incident surface side of the diffusion base material. A light propagation layer is formed, the light deflection element is formed on the light incident surface side of the light propagation layer, and the diffusion base material has a light diffusion region dispersed in a transparent resin, and has a total light transmittance. 30% to 80%, and a haze value of 95% or more, the light propagation layer has a total light transmittance of 60% or more state, and are haze values than 95%, the light deflection element or the light propagation layer, or The light deflection element and the light propagation layer include a substance having a function of diffusing light, light from a light source is incident from a light incident surface of the light deflection element, and diffused light is emitted from a light emission surface of the light propagation layer. Selected from fine particles having an average particle size of 0.1 μm to 100 μm, The light deflection element is a light deflection lens having at least one or more concavo-convex shapes, and the light deflection lens is composed of unit lenses arranged in a one-dimensional manner, at a point farthest from the lens vertex of each of the unit lenses. The light uniform element is characterized in that a farthest intersection, which is a point to collect light, is included in the light propagation layer .

  An eleventh aspect of the present invention is the light uniform element according to the ninth or tenth aspect, wherein the diffusion base material, the light propagation layer, and the light deflection element are integrally formed by a multilayer extrusion method. is there.

  According to a twelfth aspect of the present invention, the diffusion base material and the light propagation layer are integrally formed by a multilayer extrusion method, the light deflection element is formed into a sheet shape, and the light deflection sheet, the light propagation layer, The light uniform element according to any one of claims 9 to 11, characterized in that are stacked by a fixed layer.

  A thirteenth aspect of the present invention is the light uniform element according to any one of the ninth to twelfth aspects, wherein a surface on the viewer side of the diffusing member includes a light diffusing lens having irregularities. .

  A fourteenth aspect of the present invention is the light uniform element according to any one of the ninth to thirteenth aspects, wherein a surface on the viewer side of the diffusing substrate is substantially flat.

  According to a fifteenth aspect of the present invention, in the light uniform element comprising the light deflection element according to any one of the ninth to fourteenth aspects, the light propagation layer, and the diffusion base material, the light is incident on the light incident surface side of the light diffusion base material. A propagation layer surface and a light deflecting element are formed, and an optical film composed of a condensing lens and a light transmitting base material is provided on the light exit surface side of the diffusion base material. A plurality of the condensing lenses are arranged at a constant pitch. The condensing lens has a convex curved surface shape, and has a third top portion having an arcuate surface, and a third inclined surface extending from the third top portion to the light-transmitting substrate, The optical sheet is characterized in that the distance between the third inclined surfaces adjacent to each other is gradually reduced as it goes to the three tops.

  According to a sixteenth aspect of the present invention, a plurality of light masks and a light transmission opening for separating the light mask are provided between the optical film and the light uniform element, and the light transmission opening. 16 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 optical mask. It is an optical sheet.

  According to a seventeenth aspect of the present invention, dot-shaped or linear ribs are arranged between the optical film and the light uniform element, and the optical film and the light uniform device are integrally laminated via the rib. The optical sheet according to claim 15.

  An eighteenth aspect of the present invention is a backlight unit comprising the optical element according to any one of the first to eighth aspects, at least one optical member, and a light source.

  A nineteenth aspect of the present invention is a backlight unit comprising the light uniform element according to any one of the ninth to fourteenth aspects and a light source.

  A twentieth aspect of the present invention is a backlight unit comprising the optical sheet according to any one of the ninth to fourteenth aspects and a light source.

  According to a twenty-first aspect of the present invention, the light source is a linear light source, the shape of the light deflection lens is a lenticular type, and when viewed in plan, the major axis direction of the lenticular type lens and the length of the linear light source 21. The backlight unit according to claim 18, wherein an angle formed with the axial direction is 20 degrees or less.

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

With the configuration described so far, even with a configuration in which the distance to the light source is close or a configuration in which the interval between the light sources is increased, it is possible to emit uniform light without uneven brightness on the screen display side. By changing the thickness and material of each layer in the configuration, it is possible to provide an optical element and a light uniform element that can prevent warping due to heat generated from the light source.
Further, the optical element and the optical film for improving the luminance on the viewer side by emitting the light emitted from the light uniform element toward the person who observes the liquid crystal display image efficiently, the optical element, and the optical element An optical sheet integrally laminated with a light uniform element, 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 4 are examples of schematic cross-sectional views showing the configurations of the optical 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 coincide with actual ones. Moreover, it is not limited to this.

(First embodiment)
FIG. 1 is a schematic cross-sectional view illustrating an example of an optical element, 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.
Further, 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 optical according to the embodiment of the present invention is disposed thereon (observer side direction F). The element 24, the light uniform element 25, and the optical member 2 are configured as a single element or a plurality of elements.
The light H emitted from the light source 41 is diffused by the light uniform element 25, diffused / reflected / condensed / color-shifted by one or a plurality of optical members 2 disposed thereon, and from the backlight unit 55. The emitted 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 optical element 24 according to the embodiment of the present invention includes a light deflection element 28 including a substance having a function of diffusing light and a light propagation layer 23.
The light deflection element 28 is arranged toward the light source 41 side of the display device 70.
The function of the optical element 24 is to deflect the light H incident from the incident surface of the light deflecting element 28, emit it to the light propagation layer 23, and emit diffused light from the light exit surface of the light propagation layer 23.
In addition, the light uniform element 25 has the diffusion base material 26 on the optical element 24 described above, and the surface 26a opposite to the observer side F of the diffusion base material 26 has an observer side F on the light propagation layer 23. The surface 23b is formed to overlap.
The optical element 24 and the light uniform element 25 as described above are not limited to a liquid crystal device, but can be any one that performs optical path control, such as a rear projection screen, a solar cell, an organic or inorganic EL, and a lighting device. Can also be used.

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 diffusion base material 26. From the surface 26b on the observer side F to the observer side F.
When the diffusion performance of the light uniform element 25 is insufficient, a region facing the light source 41 is bright and a region facing the light source 41 is dark on the surface 26b on the viewer side F of the diffusion base material 26. Visible and visually recognized as luminance unevenness (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 the traveling direction, the incident light deflected in the light propagation layer 23 is spread, diffused in the diffusion base material 26, and uniform light is observed. It injects to person side F.

The light deflection element 28 is preferably a lens having an uneven shape.
As shown in FIG. 2A, the tangent m to the first inclined surface 28b at the point 30 where the first inclined surface 28b of the light deflection element 28 joins the light propagation layer 23, and the observer side of the light propagation layer 23 When the angle formed by the surface 23a opposite to F 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 Equation 1 below.

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 deflected by the light deflecting elements 28, and further, the light diffused by the light diffusing material inside the light deflecting elements 28 is within the light propagation layer 23. And are diffused by the diffusion base material 26 and injected to the observer side F.
When the thickness T of the light propagation layer 23 does not satisfy Formula 1, the light deflected by the light deflecting element 28 enters the diffusion base material 26 without being mixed, so that the diffusion performance of the light uniform element 25 is insufficient.

  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. 3D, the angle θ formed by the tangent line m 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. It is further desirable that it continuously changes between ˜90 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 where the angle θ between the tangent line m 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 is incident on one inclined surface 28b.

Further, when the angle θ between the tangent line m 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 does not change significantly, at which point of the first inclined surface 28b Even if light is incident, the deflection angles are almost the same, so 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 formulas 1 and 2 is, as shown in FIG. 7, the tangent m at the point 30 where the first inclined surface 28b joins the first apex portion 28a and the observer side of the light propagation layer 23. Is defined as an angle θ formed with the surface 23a on the opposite side.
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 diffusion base material 26.
Therefore, the thickness of the optical element 24 and the light uniform element 25 can be reduced as compared with the convex lens shape, which is desirable.
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 has less wear and chipping of the mold for molding the light deflection lens 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 light diffusing / reflecting layer 28c rotates from the boundary between the first top portion 28a and the first inclined surface 28b to the first inclined surface 28b with the light deflection element 28 (light propagation layer 23) viewed from the thickness direction. The amount of wraparound Δ as the dimension of the recessed portion 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.
FIGS. 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.
Accordingly, 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 Expression 1 and Expression 2, and thus a 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.
Particularly when a plurality of light deflecting elements 28 having different shapes are combined, the light deflecting elements 28 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 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 UV-molded on the surface 23a opposite to the observer side F of the light propagation layer 23. can do.
Furthermore, the light propagation layer 23 is formed as a plate-like member by an extrusion method, an injection molding method, or the like, and before / after the light propagation layer 23 is integrated with the diffusion base material 26, on the side opposite to the observer side F of the light propagation layer 23. The light deflection element 28 can be UV-molded on the 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 optical element 24 of the present invention can be produced by extrusion molding.
Further, as shown in FIG. 8A, the optical element 24 and the diffusion base material 26 may be integrally formed by multilayer extrusion 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 in which the light propagation layer 23 and the light deflection element 28 are directly bonded to each other, and a method in which a dry film prepared in advance is bonded. 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 diffusion base material 26, it is possible to prevent the light uniform element 25 itself from warping.
Furthermore, the warp of the light uniform device (light uniform element) 25 itself is obtained 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 diffusion base material 26. Can be prevented.
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, the light deflection element 28 formed into a sheet shape can be directly bonded to the diffusion base material 26.

As described above, the light deflection element 28 deflects the traveling direction of the strong front light H incident from the light source 41, the light propagation layer 23 spreads the deflected incident light, and is diffused in the diffusion base material 26 to be uniform. Light can be emitted to the observer side F.
Further, by adding a substance having a function of diffusing light to the light deflecting element 28, the traveling direction of the strong front light H incident from the light source 41 is deflected, and at the same time, by the light diffusing substance inside the light deflecting element 28. By further diffusing the front light H and making it uniform, it becomes possible to guide the light uniformed by the light propagation layer 23, and to emit uniform light without uneven brightness on the screen display side. .
Examples of substances that diffuse or scatter light include silicone-based resins, acrylic resins, styrene-based resins, melamine-based resins, high-molecular materials such as silicon-based resins, silica-based materials, calcium carbonate, titanium oxide, and oxidation materials. Examples thereof include inorganic materials represented by magnesium, barium sulfate, alumina, and the like. These materials can be used alone or in combination.

As for the size of the substance that diffuses or scatters light, the average particle size is preferably 0.1 μm to 100 μm, and it is possible to use only the same size, or it is possible to use substances of different sizes in combination.
Examples of the shape of the substance that diffuses or scatters light include a spherical shape, a spherical shape, an elliptical shape, and a needle shape. Furthermore, a material having an indefinite shape or a hollow structure can be used. Although depending on the shape of the substance, when the average particle size is smaller than 0.1 μm, the effect of diffusing or scattering the light becomes low, and the effect of erasing the required image of the light source cannot be obtained. Further, when the average particle size is larger than 100 μm, the dispersibility at the time of addition is lowered, so that the uniform light dispersion is lowered, the light transmittance is greatly lowered, and further, a large aggregate is formed. There is a possibility that this may occur, and there is a high possibility that this will cause a problem of being visually recognized as a bright spot or dark spot.
Further, when a diffusing material having a large particle diameter is exposed on the surface of the light deflection element 28, it becomes a factor that hinders the deflectability of the light deflection element 28 for erasing the image of the light source. Even when the light deflection element 28 is molded, the dispersibility of the substance that diffuses or scatters the light decreases, thereby reducing the uniformity of physical properties such as the viscosity of the material constituting the light deflection element 28, This can be a factor that causes a reduction in the moldability of the light deflection element 28. From the above, the size of the substance that diffuses or scatters light is preferably within the above range.

The content of the light diffusing or scattering material applied to the light deflection element 28 varies depending on the size and shape of the material used, but a preferable content is in the range of 0.01 wt% to 30 wt%. I can do it.
Furthermore, 0.01% by weight to 20% by weight is particularly preferable. This content depends on the shape of the substance, but if it is less than 0.01% by weight, the effect of diffusing or scattering the light becomes low, and the required effect of erasing the image of the light source cannot be obtained. In addition, when it is higher than 30% by weight, the dispersibility at the time of addition is lowered, so that the uniform light dispersion is lowered, the light transmittance is greatly lowered, and the diffusion materials are gathered together. Large agglomerates may occur, which increases the possibility that a problem of being visually recognized as a bright spot or a dark spot will occur.
Further, when a large number of diffusing materials are exposed on the surface of the light deflection element 28, it becomes a factor that impedes the deflectability of the light deflection element 28 for erasing the image of the light source. Even when the light deflection element 28 is molded, the dispersibility of the substance that diffuses or scatters the light decreases, thereby reducing the uniformity of physical properties such as the viscosity of the material constituting the light deflection element 28, This can be a factor that causes a reduction in the moldability of the light deflection element 28. From the above, the size of the substance that diffuses or scatters light is preferably within the above range.

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, and the concavo-convex structure exceeding 10 μm itself becomes the light deflection element 28.
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.

  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.

If is added to a substance having a function of diffusing light to the light Propagation layer 23 plays a role of uniformizing propagated through the optical, joined by effect of diffusely scattered light to the effect of propagation of the light, the more light It can be made uniform.
Examples of substances that diffuse or scatter light include silicone resins, acrylic resins, styrene resins, melamine resins, polymer materials typified by silicon resins, silica materials, calcium carbonate, titanium oxide, magnesium oxide, Examples thereof include inorganic materials represented by barium sulfate, alumina, and the like. These materials can be used alone or in combination.
As for the size of the substance that diffuses or scatters light, the average particle size is preferably 0.1 μm to 100 μm, and it is possible to use only the same size, or it is possible to use substances of different sizes in combination. Examples of the shape of the substance that diffuses or scatters light include a spherical shape, a spherical shape, an elliptical shape, and a needle shape. Furthermore, a material having an indefinite shape or a hollow structure can be used. Although depending on the shape of the material, when the average particle diameter is 0.1μm less than the effect of diffusing or scattering light is lowered, improving the light Propagation effects for erasing the image of the light source that requires Cannot be obtained. In addition, when the average particle size is larger than 100 μm, the dispersibility at the time of addition is lowered, so that the light propagation property is largely inhibited, the light transmittance is greatly reduced, and a large aggregate May occur, and there is a high possibility that this will cause a problem of being visually recognized as a bright spot or a dark spot. In the time of molding the optical Propagation layer 23, by the dispersion of the substance to diffuse or scatter light is reduced, uniformity of physical properties, including materials of viscosity and fluidity which constitute the optical Propagation layer 23 sex reduces the, this may be a factor to increase the variation in the thickness of the molding processability of the reduction and Hikariden transportable layer of the optical Propagation layer 23. From the above, the size of the substance that diffuses or scatters light is preferably within the above range.

The addition amount of the light diffusing or scattering materials is applied to the light - propagation layer 23 is preferably in the range that does not reduce the intensity of light to be emitted to the observer side F.
Therefore, the addition amount of the light diffusing or scattering material varies depending on the size and shape of the material to be used, but a preferable addition amount can be in the range of 0.001 wt% to 10 wt%. Furthermore, 0.001% by weight to 1% by weight is particularly preferable. In this content, it depends on the shape of the material, is lower than 0.001 wt%, the effect of diffusing or scattering light is lowered, for erasing the image of the light source that requires light Propagation effects Improvement cannot be obtained. Further, when the content is higher than 10% by weight, the dispersibility at the time of addition is lowered, so that the uniform light dispersion is lowered, the light transmittance is greatly lowered, and the diffusion materials are gathered together. Large agglomerates may occur, which increases the possibility that a problem of being visually recognized as a bright spot or a dark spot will occur. In the time of molding the optical Propagation layer 23, by the dispersion of the substance to diffuse or scatter light is reduced, uniformity of physical properties, including materials of viscosity and fluidity which constitute the optical Propagation layer 23 sex reduces the, this may be a factor to increase the variation in the thickness of the molding processability of the reduction and Hikariden transportable layer of the optical Propagation layer 23. From the above, the size of the substance that diffuses or scatters light is preferably within the above range.

  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 diffusion base material 26 side is n2, and the refractive index of the light deflection element 28 is n0, Expression 3 is satisfied. 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 emitted from 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 diffusion base material 26 side. When proceeding from the 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 diffusion base material 26 side of the light propagation layer 23, if n1> n2, that is, the refractive index is low, the diffusion 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 diffusion base material 26 side of the light propagation layer 23 are equal or the light deflection element 28 of the light propagation layer 23. It is desirable that the refractive index n1 of the side layer 23A is larger.

Here, it is more desirable that the thickness of the layer 23B on the diffusion base material 26 side of the light propagation layer 23 is thicker 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 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 optical element 24 and 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 as the thermal linear expansion coefficient of the diffusion base material 26. it can. Further, the warpage of the optical element 24 and the light uniform element 25 can be prevented by adjusting the thickness of the light propagation layer 23.

The diffusion base material 26 preferably has a total light transmittance of 30% to 80%. If the total light transmittance is less than 30%, the brightness of the emitted light to the observer side F is lowered, which is not preferable. Conversely, if the total light transmittance exceeds 80%, the diffusion performance is low. This is not preferable because it becomes insufficient and the uniformity of in-plane luminance deteriorates.
Moreover, it is preferable that the diffusion base material 26 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 diffusion base material 26 is formed by dispersing a light diffusion region in a transparent resin. As the transparent resin, a thermoplastic resin, a thermosetting resin or the like can be used. For example, a polycarbonate resin, an acrylic resin, a fluorine acrylic resin, a silicone acrylic resin, an epoxy acrylate resin, a polystyrene resin, a cycloolefin polymer, Methyl styrene resin, fluorene resin, polyethylene terephthalate (PET), polypropylene, acrylonitrile styrene copolymer, acrylonitrile polystyrene copolymer, and the like can be used.

The light diffusion region is preferably made of light diffusion particles. This is because suitable diffusion performance can be easily obtained.
As the light diffusing particles, transparent particles made of an inorganic oxide or a resin can be used. As the transparent particles made of an inorganic oxide, for example, silica, alumina or the like can be used. The transparent particles made of resin include acrylic particles, styrene particles, styrene acrylic particles and cross-linked products thereof, melamine / formalin condensate particles, PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy resin), FEP (tetrafluoroethylene). Fluoropolymer particles such as fluoroethylene / hexafluoropropylene copolymer), PVDF (polyfluorovinylidene), and ETFE (ethylene / tetrafluoroethylene copolymer), silicone resin particles, and the like can be used.
Moreover, you may use combining 2 or more types of transparent particles from the transparent particle mentioned above. Furthermore, the size and shape of the transparent particles are not particularly defined.

  When light diffusing particles are used as the light diffusing region, the thickness of the diffusing substrate 26 is preferably 0.1 to 5 mm. When the thickness of the diffusion base material 26 is 0.1 to 5 mm, optimum diffusion performance and brightness can be obtained. On the other hand, if the thickness is less than 0.1 mm, the diffusion performance is insufficient, and if it exceeds 5 mm, the amount of resin is large and the luminance is reduced due to absorption.

  The light uniform element 25 is preferably formed by integrally forming the 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 may be formed by integrating the 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 material or the adhesive material, the diffusion base material 26 and the light propagation layer 23 can be bonded using a generally used laminate or the like.

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 diffusion base material 26.
As shown in FIG. 10, the uneven surface is provided on the emission surface 26 b of the light uniform element 25, so that the surface 26 b on the observer side F of the diffusion base material 26 is various compared with the case where the surface 26 b is substantially flat. Since the angled emission surface is formed, light can be emitted over a wider range, so that the diffusion performance is improved and the lamp image is reduced / disappeared.
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 diffusing substrate 26 and the exit surface can be set at various angles, the diffusing 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 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 emission surface, that is, the surface 26b on the viewer side F of the diffusion base material 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 device 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 diffusion base material 26 is inserted in between, moire interference fringes can be prevented.
Here, since there is no diffusing element between the condenser lens 16 and the diffusing base material 26, and in order to bond the optical film 1 to the surface 26b on the viewer side F of the diffusing base material 26 without unevenness, It is desirable that the viewer-side surface 26b of the diffusion base material 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 adjacent 3rd inclined surfaces 16b reduces 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 diffusion base material 26 constituting the light uniform element 25, and after being diffused again by the diffusion base material 26, a part of the light again enters the optical film 1. A 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, re-enters the light uniform element, is further diffused, and re-enters the optical film 1. 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.

  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 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.

(Example)
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).
The light deflection lens 28 was added with 5% by weight of a silicone filler having an average particle diameter of 4 μm as a light diffusing material. In the light propagation layer 23, a total of 0.5% by weight of a silicone filler having an average particle diameter of 6 μm and 20 μm was added as a light diffusing material. The diffusion base material 26 contained an appropriate amount of a resin filler so that the total light transmittance was 60%, the haze value was 99%, and the thickness was 1.5 mm.

Example 1
In light uniformity element 25, which is the set, a light diffusing material in addition to the light deflection lens 28 and Hikariden transportable layer 23, to produce a light uniform device 25 by setting the thickness of the light propagation layer 23 to 500 [mu] m.

(Example 2)
In the light uniform element 25 set as described above, a light diffusing material was not added to the light deflection lens 28, and the thickness of the light propagation layer 23 was set to 500 μm to produce the light uniform element 25.

(Example 3)
In the light uniform element 25 set as described above, a light diffusing material was not added to the light propagation layer 23, and the thickness thereof was set to 500 μm to produce the light uniform element 25.

Example 4
In light uniformity element 25, which is the set, without the addition of light diffusing material in the light deflection lens 28 and Hikariden transportable layer 23, to produce a light uniform device 25 by setting the thickness to 500 [mu] m.

  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 element 25 of Examples 1 to 3 manufactured as described above, and the region of the optical mask 22 is the condensing lens 16. The optical film 1 formed so as to be 50% of the pitch was integrally laminated with an adhesive material to obtain an optical sheet 52.

(Example 5)
In light uniformity element 25, which is the set, a light diffusing material in addition to the light deflection lens 28 and Hikariden transportable layer 23, light uniformity that is integrated with the optical film 1 by setting the thickness of the light propagation layer 23 to 500μm Element 25 was produced.

(Example 6)
In the light uniform element 25 set as described above, a light diffusing material is not added to the light deflection lens 28, and the thickness of the light propagation layer 23 is set to 500 μm, and the light uniform element 25 integrated with the optical film 1 is manufactured. did.

(Example 7)
In the light uniform element 25 set as described above, a light diffusing material was not added to the light propagation layer 23, the thickness was set to 500 μm, and the light uniform element 25 integrated with the optical film 1 was produced.

(Example 8)
In light uniformity element 25, which is the set, the light deflection lens 28 and Hikariden transportable layer 23 without adding a light diffusing material, the light uniformity element 25 is integrated with the optical film 1 by setting the thickness to 500μm Produced.

  The samples of 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, and the liquid crystal panel 35 was placed on the observer side F of the backlight 56. By arranging, 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, the light source image disappeared best without a decrease in luminance.
In Example 2, there was no decrease in luminance and the light source image disappeared, but it was slightly inferior to Example 1.
In Example 3, there was no decrease in luminance and the light source image disappeared, but it was slightly inferior to Example 1.
In Example 4, there was no decrease in luminance and the light source image disappeared, but it was inferior to Example 1.
In Example 5, the light source image disappeared best without a decrease in luminance.
In Example 6, there was no decrease in luminance and the light source image disappeared, but it was slightly inferior to Example 4.
In Example 7, there was no decrease in luminance and the light source image disappeared, but it was slightly inferior to Example 4.
In Example 8, there was no decrease in luminance and the light source image disappeared, but it was inferior to Example 4.
From the above, by imparting a light diffusing property to the light deflecting element and Hikariden transportable layer, without decreasing the luminance in the same structure, the effect of erasing the image of the light source was found to improve.

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.

  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: Surface opposite to the observer, 23b: Surface on the observer side, 23A: Layer on the light deflection element side of the light propagation layer, 23B: Layer on the diffusion base material side of the light propagation layer, 24: Optical element, 25 DESCRIPTION OF SYMBOLS ... Light uniform element, 26 ... Diffusing base material, 26a ... Surface opposite to an observer, 26b ... Observer side surface, 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 ... Reflecting plate (reflection film), 45 ... Backlight part, 52 ... Optical sheet, 55, 56 ... Back Light unit, 70, 72 ... display device, 100 ... air layer.

Claims (22)

In an optical element having a light deflection element and a light propagation layer disposed on the light exit surface side of the light deflection element,
A substance having a function of diffusing light into the light deflection element or the light propagation layer, or the light deflection element and the light propagation layer,
The light from the light source is incident from the light incident surface of the light deflection element, and the diffused light is emitted from the light exit surface of the light propagation layer;
Selected from fine particles in which the average particle size of the substance is in the range of 0.1 μm to 100 μm;
The light deflection element is a light deflection lens having at least one uneven shape,
The light deflection lens is composed of unit lenses arranged one-dimensionally, and the farthest intersection point, which is a point that collects light at a point farthest from the lens vertex of each unit lens, is included in the light propagation layer.
An optical element.   2. The optical element according to claim 1, wherein the concentration of the substance is selected from a range of 0.001% by weight to 30% by weight.   The optical element according to claim 1, wherein the light propagation layer includes at least one layer.   The optical element according to any one of claims 1 to 3, wherein the light propagation layer has a multilayer structure having at least two different refractive indexes or different haze values. The light deflection lens has a first apex portion having an arcuate surface or a ridgeline, and a first inclined portion extending from the first apex portion to the light incident surface of the light propagation layer, and the refractive index of the light propagation layer is n. The angle between the tangent to the first inclined surface at the junction where the first inclined surface is bonded to the light propagation layer and the light incident surface of the light propagation layer is θ, where P is the pitch of the light deflection lens The optical element according to any one of claims 1 to 4, wherein the thickness T of the light propagation layer satisfies the following formula (1).

  The shape of the light deflection lens is a shape having the first apex portion and a first curved inclined portion formed by bending the first inclined portion, a tangent at each point of the first curved inclined portion, and the light 6. The optical element according to claim 5, wherein the angle formed by the light incident surface side of the propagation layer continuously changes from 20 degrees to 90 degrees.   The optical element according to claim 6, wherein the top portion has a ridge line. The optical element according to any one of claims 1 to 7, wherein the optical Propagation layer and the light deflection element, characterized in that it is integrally formed by a multilayer extrusion method. An optical element according to any one of the claims 1 to 8, light uniformity element characterized by having a structure having a light diffusing substrate on the light emitting surface side of the optical Propagation layer of the optical element. A light uniform element for optical path control,
The light uniform element is:
It consists of a diffusion substrate, a light propagation layer, and a light deflection element,
A light propagation layer is formed on the light incident surface side of the diffusion base material, and the light deflection element is formed on the light incident surface side of the light propagation layer;
The diffusion base material has a light diffusion region dispersed in a transparent resin,
The total light transmittance is 30% to 80%, the haze value is 95% or more,
The light propagation layer has a total light transmittance of 60% or more state, and are haze value 95% or less,
A substance having a function of diffusing light into the light deflection element or the light propagation layer, or the light deflection element and the light propagation layer,
The light from the light source is incident from the light incident surface of the light deflection element, and the diffused light is emitted from the light exit surface of the light propagation layer;
Selected from fine particles in which the average particle size of the substance is in the range of 0.1 μm to 100 μm;
The light deflection element is a light deflection lens having at least one uneven shape,
The light deflection lens is composed of unit lenses arranged one-dimensionally, and the farthest intersection point, which is a point that collects light at a point farthest from the lens vertex of each unit lens, is included in the light propagation layer.
An optical uniform element characterized by the above.   The light uniform element according to claim 9 or 10, wherein the diffusion base material, the light propagation layer, and the light deflection element are integrally formed by a multilayer extrusion method.   The diffusion base material and the light propagation layer are integrally formed by a multilayer extrusion method, the light deflection element is formed into a sheet shape, and the light deflection sheet and the light propagation layer are laminated by a fixed layer. The light uniform element according to claim 9, wherein the light uniform element is any one of the above.   The light uniform element according to any one of claims 9 to 12, wherein the light emitting surface side of the diffusing member includes a light diffusing lens having irregularities.   The light uniform element according to any one of claims 9 to 13, wherein a light emission surface side of the diffusion base material is substantially flat.   15. The light uniform element according to claim 9, wherein a light propagation layer surface and a light deflection element are formed on a light incident surface side of the light diffusion base material, and a condenser lens is formed on the light output surface side of the diffusion base material. And a third top portion having a plurality of the condensing lenses arranged at a constant pitch, the condensing lens having a convex curved shape, and an arcuate surface. And a third inclined surface extending from the third top to the light-transmitting substrate so that the distance between the adjacent third inclined surfaces gradually decreases as the third top is reached. An optical sheet that is formed.   Between the optical film and the light uniform element, a plurality of light masks and a light transmission opening that separates the light mask are provided, and the light transmission opening is formed by the light condensing lens. The optical sheet according to claim 15, wherein the optical sheet is provided corresponding to a third top portion, and the optical film and the light uniform element are integrally laminated through the optical mask.   The dot-shaped or linear rib is arranged between the optical film and the light uniform element, and the optical film and the light uniform element are integrally laminated through the rib. The optical sheet according to 15.   A backlight unit comprising the optical element according to any one of claims 1 to 8, at least one optical member, and a light source.   A backlight unit comprising the light uniform element according to claim 9 and a light source.   A backlight unit comprising: the optical sheet according to any one of claims 9 to 14; and a light source.   The light source is a linear light source, and the shape of the light deflection lens is a lenticular type. When viewed in plan, the angle formed by the major axis direction of the lenticular lens and the major axis direction of the linear light source is 20 The backlight unit according to any one of claims 18 to 20, wherein the backlight unit is at a degree 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.

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