JPWO2009004696A1 - Lens sheet, optical sheet for display, backlight unit using the same, and display device - Google Patents

Abstract

Provided are a thin, high-strength, high-display quality optical sheet in which a light diffusion film is not required and a lens sheet and a light diffusion layer are integrated, and a backlight unit and a display device using the optical sheet. Objective. The light of a lens sheet comprising a first lens array formed on a single substrate and a second lens array formed on each of the first lens arrays. A backlight unit using an optical sheet 25 in which the lens sheet 1 and the light diffusion layer 25 are integrated with one or more fixing elements 39 in the gap between the incident surface 102 and the light exit surface 101 of the light diffusion plate 25. And a display device. [Selection] FIG.

Description

  The present invention illuminates, from the back side, a liquid crystal panel in which a transmissive / non-transmissive lens sheet and a display optical sheet in pixel units or a display element in which a display pattern is defined according to a transparent state / scattering state is arranged The present invention relates to a backlight unit and a display device.

  In recent years, liquid crystal display devices using TFT liquid crystal panels and STN liquid crystal panels have been commercialized mainly for color notebook PCs (personal computers) in the OA field.

  In such a liquid crystal display device, a so-called backlight method in which a light source is arranged on the back side (observer side) of the liquid crystal panel and the liquid crystal panel is illuminated with light from the light source is employed.

  As a backlight unit employed in this type of backlight system, a light source lamp such as a cold cathode fluorescent lamp (CCFT) is roughly divided into a flat light guide plate made of acrylic resin having excellent light transmittance. There are a “light guide plate light guide method” for reflecting (a so-called edge light method) and a “direct type method” that does not use a light guide plate.

  As a liquid crystal display device on which a light guide plate light guide type backlight unit is mounted, for example, the one shown in FIG. 19 is generally known.

  This is provided with a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73 at the top, and a light guide plate 79 made of a transparent base material such as a substantially rectangular plate-like PMMA (polymethyl methacrylate) or acrylic on the lower surface side. Is installed, and a diffusion film (diffusion layer) 78 is provided on the upper surface (light emission side) of the light guide plate.

  Further, a scattering reflection pattern portion for efficiently scattering and reflecting the light introduced into the light guide plate 79 in the direction of the liquid crystal panel 72 is provided on the lower surface of the light guide plate 79 by printing or the like. A reflection film (reflection layer) 77 is provided below the scattering reflection pattern portion (not shown).

Further, the light guide plate 79 is provided with a light source lamp 76 at the side end, and further covers the back side of the light source lamp 76 so that the light from the light source lamp 76 can be efficiently incident on the light guide plate 79. Thus, a high-reflectance lamp reflector 81 is provided. The scattering reflection pattern portion is formed by printing, drying, and forming a mixture of white titanium dioxide (TiO ₂ ) powder in a solution such as a transparent adhesive in a predetermined pattern, for example, a dot pattern. The light incident on the light plate 79 is imparted with directivity and guided to the light exit surface side, which is a device for increasing the brightness.

  Furthermore, recently, in order to increase the light utilization efficiency and increase the luminance, as shown in FIG. 20, a prism film (prism layer) having a light condensing function between the diffusion film 78 and the liquid crystal panel 72 as shown in FIG. ) 74 and 75 are proposed. The prism films 74 and 75 are configured to collect light emitted from the light exit surface of the light guide plate 79 and diffused by the diffusion film 78 on the effective display area of the liquid crystal panel 72 with high efficiency.

However, in the apparatus illustrated in FIG. 19, the viewing angle is controlled only by the diffusibility of the diffusing film 78, which is difficult to control, and the center in the front direction of the display is bright and becomes darker toward the periphery. This characteristic is inevitable. For this reason, when the liquid crystal screen is viewed from the side, the luminance is greatly reduced, and the light utilization efficiency is reduced.
Furthermore, in the apparatus using the prism film illustrated in FIG. 20, two prism films are required, which not only greatly reduces the amount of light due to film absorption but also increases the cost due to the increase in the number of members. It was also.

  On the other hand, in the direct type, a display device such as a large liquid crystal TV in which the light guide plate is difficult to use is used.

  As a direct liquid crystal display device, a device illustrated in FIG. 21 is generally known. In this, a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73 is provided on the upper side, and is emitted from a light source 51 made of a fluorescent tube or the like on the lower surface side thereof and diffused by an optical sheet such as a diffusion film 82. The light is condensed on the effective display area of the liquid crystal panel 72 with high efficiency. In order to efficiently use the light from the light source 51 as illumination light, a reflector 52 is disposed on the back surface of the light source 51.

  However, even in the apparatus illustrated in FIG. 21, the control of the viewing angle is left only to the diffusibility of the diffusion film 82, which is difficult to control, and the center in the front direction of the display is bright and becomes darker toward the periphery. This characteristic is inevitable. For this reason, when the liquid crystal screen is viewed from the side, the luminance is greatly reduced, and the light utilization efficiency is reduced.

Therefore, as one solution, as shown in FIG. 23, a brightness enhancement film (BEF), which is a registered trademark of 3M USA shown in FIG. A method in which the light diffusion film 84 is disposed on is used. Here, BEF is a film in which unit prisms having a triangular cross section are periodically arranged in one direction on a transparent member.
This prism has a size (pitch) larger than the wavelength of light. BEF collects light from “off-axis” and redirects this light “on-axis” to the viewer, or “recycle”. To do.

When using the display (when observing), the BEF increases the on-axis brightness by reducing the off-axis brightness. Here, “on-axis” is a direction that coincides with the visual direction of the viewer, and is generally on the normal direction side with respect to the display screen.
When the repetitive array structure of prisms is arranged in only one direction, only the direction change or recycling in the parallel direction is possible, and in order to control the luminance of the display light in the horizontal and vertical directions, the parallel direction of the prism groups Are stacked and used in combination so that they are substantially orthogonal to each other.

The adoption of BEF allows display designers to achieve the desired on-axis brightness while reducing power consumption.
As a patent document disclosing that a brightness control member having a repetitive array structure of prisms represented by BEF is adopted for a display, there are many known as exemplified in Patent Documents 1 to 3. Yes.
Japanese Patent Publication No. 1-378001 JP-A-6-102506 In the optical sheet using the BEF as a brightness control member as described above, light from the light source is finally emitted from the film at a controlled angle by refraction. Thus, it is possible to control to increase the light intensity in the visual direction of the viewer.

However, there are unexpected light rays that are unnecessarily emitted laterally without proceeding in the visual direction of the viewer. For this reason, as shown in FIG. 24, the light intensity distribution emitted from the optical sheet using BEF has the light intensity when the viewer's visual direction, that is, the angle with respect to the visual direction F is 0 ° (corresponding to the axial direction). Although most enhanced, there is a problem that a small light intensity peak occurs in the vicinity of ± 90 ° from the front, that is, light (side lobes) emitted from the lateral direction is increased.
A luminance distribution having such a light intensity peak is not desirable, and a smooth luminance distribution having no light intensity peak around ± 90 ° is more desirable.

  In addition, when only the on-axis luminance is excessively improved, the peak width of the luminance distribution curve is remarkably narrowed, and the viewing area is extremely limited. Therefore, in order to increase the peak width appropriately, the prism sheet and There is a problem that it is necessary to newly use a light diffusing film as a separate member, which increases the number of members.

  As described above, this optical sheet is required not only to improve the light utilization efficiency but also to have various functions such as removing unevenness of the light source and securing the viewing area of the display. It is configured by overlapping sheets. However, if the number of optical sheets is large, the work for assembling the display becomes complicated, and there is a problem that it is affected by dust between the optical sheets and hinders miniaturization and thinning.

By the way, in such a liquid crystal display device, light weight, low power consumption, high brightness, and thinning are strongly demanded as market needs, and accordingly, a backlight unit mounted on the liquid crystal display device is also provided. Light weight, low power consumption, and high brightness are required.
In particular, in a color liquid crystal display device that has recently made remarkable progress, the panel transmittance of the liquid crystal panel is remarkably lower than that of a monochrome-compatible liquid crystal panel. It is essential to obtain power consumption.

  However, as described above, it is difficult to say that the conventional apparatus sufficiently satisfies the demand for high luminance and low power consumption, and the user has low price, high luminance, high display quality, and low power consumption. Development of a backlight unit and a display device that can realize a liquid crystal display device with electric power is awaited.

  The present invention has been made in view of such circumstances, and uses a single lens sheet in which a second lens array is formed on a first lens array, and this lens sheet is integrated with a light diffusion plate. It is an object of the present invention to provide an optical sheet that is thin, has sufficient strength, and satisfies optical characteristics, and a backlight unit and a display device using the optical sheet.

In order to achieve the above object, the present invention takes the following measures.
That is, the invention of claim 1 comprises a lens having a first lens array formed on a substrate and a second lens array formed on each of the first lens arrays. It is a sheet.
The invention according to claim 2 is the lens sheet according to claim 1, wherein the first lens array is a lenticular lens group, and the second lens array is a triangular prism group.
In the invention of claim 3, the longitudinal direction of the lenticular lens of the first lens array and the longitudinal direction of the triangular prism of the second lens array intersect at 90 ° ± β (0 ° <β <30 °). The lens sheet according to claim 1, wherein:
According to a fourth aspect of the present invention, when the lens pitch of each lens array of the first lens array is P1, the angle of the lens end is α, and the width of the top of each lens array is W <0.2 < W / P1 <0.8
15 ° <α
The lens sheet according to claim 1, wherein the following relationship is established.
The invention according to claim 5 is the lens sheet according to claim 1 or 2, wherein the lens pitch P2 of each of the second lens arrays is an irregular random pitch.
The invention according to claim 6 is the lens sheet according to claim 1 or 2, wherein the vicinity of the valley portion and the vicinity of the apex of each lens of the first lens array are rounded.
The invention according to claim 7 is the lens sheet according to claim 1 or 2, wherein the vicinity of the valley and the apex of each lens of the second lens array are rounded.
The invention of claim 8 is characterized in that the lens pitch P1 of the first lens array is an irregular random pitch, and the lens height H is constant. It is a lens sheet of description.
The invention according to claim 9 is the lens sheet according to claim 1 or 2, wherein the second lens array has surface diffusion.
The invention of claim 10 is characterized in that the lens pitch P1 of the first lens array is an irregular random pitch, and the lens height H and the width W of the top of the lens array are constant. A lens sheet according to claim 1 or 2.
In the invention of claim 11, the lens pitch P1 of the first lens array is an irregular random pitch, the lens height H is constant, and the width W of the top of the lens array is irregular. The lens sheet according to claim 1 or 2, wherein the lens sheet is a lens sheet.
Invention of Claim 12 heats a thermoplastic resin base material,
Pressurizing with a cooling roll which is a lens mold of the first lens array, forming the first lens array;
Furthermore, it forms by pressing with the cooling roll which is a lens metal mold | die of the said 2nd lens array on the said resin base material in which the said 1st lens array was formed. Or it is a lens sheet of Claim 2.
The invention of claim 13 pressurizes a thermoplastic resin substrate with a heating roll which is a lens mold of the first lens array, and forms the first lens array,
Furthermore, it forms by pressing with the heating roll which is a lens metal mold | die of the said 2nd lens array on the said resin base material in which the said 1st lens array was formed. Alternatively, the lens sheet according to claim 2.
The invention of claim 14 heats a thermoplastic resin substrate,
3. The lens sheet according to claim 1, wherein the lens sheet is formed by pressing with a cooling roll on which a lens-shaped female mold of the lens sheet is formed.
The invention of claim 15 provides a thermoplastic resin substrate,
3. The lens sheet according to claim 1, wherein the lens sheet is formed by pressing with a heating roll in which a lens-shaped female mold of the lens sheet is formed.
A sixteenth aspect of the present invention is an optical sheet for display, wherein the lens sheet according to the first to fifteenth aspects and the light diffusion layer are integrated with a gap therebetween.
The invention according to claim 17 is the optical sheet for display according to claim 16, wherein the surface of the light diffusion layer has a fine uneven shape.
The invention according to claim 18 is the optical sheet for display according to claim 16, characterized in that there is a fine particle layer on the surface of the light diffusion layer.
The invention according to claim 19 is the optical sheet for display according to claim 16, wherein the light diffusion layer has a linear expansion coefficient of 7.0 × 10 ⁻⁵ (cm / cm / ° C.) or less.
The invention according to claim 20 is the optical sheet for display according to claim 16, wherein the gap includes air.
According to a twenty-first aspect of the present invention, the light diffusion layer and the back surface of the surface on which the first lens array and the second lens array of the lens sheet are formed, and the light diffusion layer with one or more fixing elements. The optical sheet for display according to claim 16, which is integrated.
The invention according to claim 22 is the optical sheet for display according to claim 21, wherein the fixing element has an adhesive.
The invention according to claim 23 is the optical sheet for display according to claim 21, wherein the fixing element has an adhesive.
The invention according to claim 24 is characterized in that, when the fixing element is the adhesive or the adhesive, the adhesive and the adhesive contain fine particles. It is a sheet.
The invention according to claim 25 is the optical sheet for display according to claim 21, wherein the fixing element has a rib.
The invention according to claim 26 is the optical sheet for display according to claim 21, wherein the fixing element has a reflective surface.
The invention of claim 27 is characterized in that the optical sheet for display according to claim 21 and a light source for irradiating light from the non-viewing surface side of the liquid crystal panel on the back surface of the optical sheet for display. It is a backlight unit.
The invention of claim 28 comprises the backlight unit;
A display device comprising the liquid crystal panel on a light exit surface side of the optical sheet of the backlight.
The invention according to claim 29 is the display device according to claim 28, wherein each of the backlight device and the display device has a light source, and the light source is a cold cathode fluorescent lamp.
The invention according to claim 30 is the display device according to claim 28, wherein the light source is an LED.
The invention according to claim 31 is the display device according to claim 28, wherein the light source is an EL.
The invention of claim 32 is the display device according to claim 28, wherein the light source is a semiconductor laser.

  As described above, the lens sheet according to the present invention, the optical sheet for display, and the backlight unit and display device using the same are thinner than the conventional configuration and have a desired strength while maintaining sufficient strength. An optical sheet, a backlight unit, and a display device that achieve brightness, light distribution range, uniformity, and the like can be provided.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 15 is a side view showing an example of the backlight unit and the display device according to the embodiment of the present invention.
First, a backlight unit according to an embodiment of the present invention includes a plurality of cylinder-shaped light sources 41 housed in a lamp house 43 and a liquid crystal in which light H from each light source 41 is sandwiched between polarizing plates 31 and 33. An optical sheet 39 to be supplied to the panel 35 is provided. In the figure, reference numeral 45 denotes a light reflecting plate disposed on the back side of the plurality of light sources 41.
The display device according to the embodiment of the present invention is a device that includes the light source 39, the optical sheet 39, and the liquid crystal panel 32 thereon. In this case, the display device is a liquid crystal display device, but is not limited to this, and is a display device that displays an image using light, such as a projection screen device, a plasma display, and an EL display, including the optical sheet 39 described above. There is no limitation on the type.

FIG. 1A is a perspective view illustrating a configuration example of the lens sheet 1. Each unit lens of the lens sheet 1 is configured by forming a second lens array 5 near the top of the first lens array 3 as shown in FIG.
Here, sufficient optical gain cannot be obtained unless the number of unit lenses of the second lens array 5 is two or more with respect to the length U in the longitudinal direction of each lens of the first lens array 3.

FIG. 1E is a view of FIG. 1B viewed from above.
Here, the longitudinal direction of the cylindrical lens of the lens sheet 1 is X (hereinafter referred to as the horizontal direction), and the direction orthogonal to the horizontal direction X is V.
The first lens array 3 and the second lens array 5 are orthogonal to each other. In other words, the trough line (horizontal direction X) of the unit lens of the first lens array 3 and the trough line (vertical direction V) of the unit lens of the second lens array 5 are orthogonal to each other. ing.
Furthermore, the angle formed by the perpendicular line from the concave and convex valleys of the unit lens of the first lens array and the tangent line of the unit lens is α.

  The above-described lens sheet 1 is incident from the incident surface 102 on which the light transmitted from the light source 41 through the light diffusing layer 25 and the gap (air layer) 200 is incident as shown in FIG. Are emitted as light K having an optical gain of 1 or more.

Here, the optical gain is one of indexes indicating the diffusibility of the optical diffusing member, and is expressed as a ratio to the luminance of the light, assuming that the luminance of the diffuser that completely diffuses is 1. When the diffusivity of the diffusing member to be measured is biased depending on the direction, the diffusion characteristic of the diffusing member can be shown by obtaining the optical gain for each direction.
Also, complete diffusion refers to an ideal diffuser that has zero absorption and a constant intensity in any direction. That is, an optical gain of 1 or more indicates that there is an effect of collecting light in the measurement direction, and that the larger the value, the stronger the light collection effect.

FIG. 2 is an explanatory diagram of a lens by optical simulation (RayTracing simulation). FIG. 2A shows a light beam emitted from one unit lens of a normal lenticular lens sheet in the front direction (0 degree). From this, it can be seen that light rays are emitted from the entire surface of the lens.
FIG. 2B shows light that is emitted in the vicinity of a vertical oblique direction (60 degrees to 90 degrees) instead of the front direction of the unit lens of the same lenticular lens sheet as in FIG. From this, it can be seen that the light in the oblique direction in FIG.
That is, a portion called a side lobe that causes a light loss in the entire luminance distribution emitted from the lens sheet is light emitted from the vicinity of the apex of each unit lens of the lens sheet.
Therefore, as one method for emitting the lossy light from the front direction as much as possible, it is possible to emit the above-mentioned light loss from the front of the lens by providing, for example, another lens array near the apex of the unit lens. become. The structure of the lens sheet that embodies this idea is the lens sheet 1 according to the present invention.

FIG.1 (c) and FIG.1 (d) show the front view and side view of Fig.1 (a), respectively. From FIG. 1C and FIG. 1D, the lens pitch of the unit lens is P1, the lens height H, the width W of the lens in which the second lens array is formed, the lens pitch P2, and the lens height H. Then, the following equation holds.
(Formula 1)
0.2 <W / P1 <0.8

The above formula will be described with reference to FIG.
FIG. 4A shows the value of the front luminance when the area ratio (W / P1) of the second lens array 5 with respect to the first lens array 3 is changed.
When the area ratio of the second lens array 5 is close to 0, only the optical function of the first lens array 3 can be obtained, so the front luminance does not increase. However, it can be seen that the front luminance increases when the area ratio of the second lens array 5 is 50% or more and becomes flat at 80%.
Accordingly, when the area ratio (W / P1) of the second lens array 5 is around 50%, the luminance drop is 3% or less, and when the area ratio (W / P1) of the second lens array 5 is smaller than 20%. Since the decrease in luminance is 10% or less, the usable range is preferably such that the area ratio (W / P1) of the second lens array 5 is 20% or more and 80% or less.

  When the area ratio of the second lens array 5 changes, not only the front luminance shown in FIG. 4A but also other optical characteristics, mainly the vertical and horizontal half-value angles of the luminance distribution change. FIG. 4B shows vertical and horizontal half-value angles when the area ratio (W / P1) of the second lens array 5 with respect to the first lens array 3 is changed. FIG. 4B shows that the vertical (V) half-value angle decreases as the area ratio (W / P1) of the second lens array 5 increases, but the horizontal (X) half-value angle increases. When the area ratio (W / P1) of the second lens array 5 is around 50%, the vertical and horizontal half-value angles are substantially equal.

  4A and 4B, when the area ratio (W / P1) of the second stage lens array is 50% or more, the luminance does not change, but the vertical and horizontal half-value angles change. One advantage of this function is that there is no change in luminance, and the half-value angle in the vertical direction (V) and the horizontal direction (X) can be adjusted to the required optical characteristics to some extent.

The thickness of the lens sheet 1 is determined by the manufacturing process or the required physical characteristics of the lens sheet 1 rather than the influence on the optical characteristics.
For example, when the first lens array 3 and the second lens array 5 are made by an ultraviolet curable resin process, since the base material thickness T of the supporting base film is 50 μm or less, wrinkles are generated, so 50 μm. <T needs to be satisfied.
Furthermore, the thickness of the substrate varies depending on the size of the backlight unit or display device used. For example, in a display device having a diagonal size of 37 inches or more, the substrate thickness T is desirably 0.5 mm to 3 mm.

FIGS. 3A and 3B show the results of comparing the light intensity distributions emitted from the lens sheet 1 according to the present invention and the normal lenticular lens sheet obtained by RayTracing simulation.
That is, FIG. 3A shows a comparison between the luminance distribution in the vertical direction of the optical sheet 39 of the present invention and the luminance distribution of a normal lenticular lens sheet.
FIG. 3B shows a comparison between the luminance distribution in the horizontal direction of the optical sheet 39 of the present invention and the luminance distribution of a normal lenticular lens sheet.
3 (a) and 3 (b), it can be seen that the front luminance of the lens sheet 1 of the present invention is higher than that of a normal lenticular lens sheet.
The reason is that there is a second lens array, and the lens directions of the first lens array 3 and the second lens array 5 are orthogonal to each other. In other words, the luminance distribution in the horizontal direction (X) shown in FIG. 3B is abruptly compared with the case of the lenticular lens sheet at about 40 ° to about 50 ° and about −50 ° to about −40 °. Since the amount of the light emitted from the second lens array is emitted from the front direction of the second lens array, it is shown that it contributes to the improvement of the front luminance of the lens sheet 1 after all.
3A and 3B that the optical gain at a position 20 ° away from the front is 1 or more.

In general, many displays have a periodic pixel structure, and the lens sheet also has a periodic structure as shown in FIG. Therefore, a moire of each periodic structure and a high-order moire such as a secondary moire generated in three or more periodic structures are generated, resulting in a defect that impairs the appearance.
Therefore, the first lens array 3 and the second lens array 5 are not limited to the case where the arrangement of the lens arrays is orthogonal to each other, but as shown in FIGS. 5A and 5B, The array 3 and the second lens array 5 may be shifted from each other by an angle β.
Here, β is preferably set to 45 ° <β <135 ° (β∈ 90 ° ± 45 °). Thereby, it is possible to prevent moiré between the horizontal and vertical structures of the periodic pixel structure of the display.

  Further, as a method of preventing the above-described moire, in FIG. 1E, the region of the width W formed at the top of the first lens array 3 is parallel to the horizontal direction X. It is also possible to prevent the above-described moire.

Here, in FIG. 1B, the first lens array 3 has a lenticular lens shape, but is not limited thereto, and may be a concentric cylindrical shape or a parabolic shape. The lens pitch P <b> 1 is a distance when the left and right valley portions (points) having the lowest height H of one unit lens of the first lens array 3 are connected by a straight line. Further, the adjacent unit lenses of the first lens array 3 must be in contact with each other.
That is, if the unit lenses are separated from each other, and the above-described valley is a straight line, the light emitted from the unit lens is diffused light that is not controlled (optical gain is almost 0). It is.

In FIG. 1B, the first lens array 3 has a cylindrical shape, and the second lens array 5 has a prism array having a triangular cross section. The array 3 and the second lens array 5 may be pyramidal microprisms, arc-shaped cylindrical lens arrays, microlens arrays in which hemispherical lenses are arranged, or a combination of these lenses.
In the first lens array 3 described above, the end of the valley and the top of each lens may be rounded.

The first lens array 3 and the second lens array 5 are good in the technical field using PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer), etc. It is formed by a known extrusion molding method, injection molding method, or hot press molding method. In this case, the first lens array 3 and the second lens array 5 may be composed of one base material made of the same material, or may be made from different base materials of different materials. Good.
Further, the first lens array 3 and the second lens array 5 may be molded using UV or radiation curable resin (the type is not particularly limited as long as the resin includes a material curable by UV or radiation). . Furthermore, either one of the first lens array 3 and the second lens array 5 may be manufactured by an extrusion molding method, and the other one may be manufactured by UV molding, and the combination is not limited.

In particular, when the first lens array 3 is a cylindrical lens, the angle formed by the perpendicular from the concave and convex valleys of the unit lens of the first lens array 3 and the tangent of the unit lens is α (15 ° <α). There must be.
The reason is that if the angle 2α formed by the boundary (valley part) between the unit lenses of the first lens array 3 adjacent to each other is less than 30 °, the releasability after molding deteriorates or the molding is repeated. In the meantime, the die tip is bent and it becomes impossible to release the molded product, or the die tip is damaged when handling the die, and the die life tends to be shortened.

  From FIG. 12, there is the following method as a manufacturing method of the lens sheet 1. The heated thermoplastic resin base material 19 is pressurized while being cooled by passing between the cooling roll 11 and the cooling roll 15 which are lens molds of the first lens array 3, and the first lens array 3. The lens shape is molded on a resin substrate. Next, before the temperature of the resin base material 19 is completely lowered, the pressure is applied while cooling by passing between the cooling roll 13 and the cooling roll 17 which are lens molds of the second lens array 5. The lens shape of the second lens array 3 is molded on the resin base material on the lens shape of the lens array 3. As described above, the use of two molds has an advantage that the mold can be easily created.

  In this example, the lens shape was formed by shaping a preheated resin substrate with a cooling roll, but conversely, the resin substrate at room temperature was changed into a lens shape with the first and second heating rolls. It may be formed, or may be prepared by solidifying while forming an ionizing ray curable resin such as an ultraviolet curable resin on a resin base material.

  Further, in the present embodiment, an example of creating with two molds is given, but the lens shape may be formed at a time by molding the female mold of the lens sheet 1 into one lens mold. In this case, there is an advantage that the lens shape becomes more accurate and the molding speed is improved.

  Furthermore, in this embodiment, a highly productive example in which a lens shape is continuously formed by using a cylindrical mold is used, but a lens is formed by intermittent feeding by using a flat mold. May be. When a flat plate mold is used, the production speed is reduced, but there are advantages such that the mold can be easily manufactured and that the mold can be easily duplicated by using an electroforming process.

  As a modification of the lens sheet 1 of the present invention shown in FIG. 6, the second lens array 5 has a shape in which the periphery of the trough and the top of the lens is rounded. In this case, the side surface of the lens array may have a wave shape such as a sine curve. Thereby, there exists an advantage that the lens top part of the 2nd lens array 5 is hard to be damaged.

  As a modification of the lens sheet 1 of the present invention shown in FIG. 7, the second lens array 5 has a convex cylindrical shape with the same lens shape as the first lens.

  As a modification of the lens sheet 1 of the present invention shown in FIG. 8, the second lens array 5 is formed with a unit lens having a random lens pitch. This is one method for reducing the moire between the horizontal or vertical cell structure of the panel when the lens sheet 1 is incorporated in a display.

  As a modification of the lens sheet 1 of the present invention shown in FIG. 9, the second lens array 5 is a microlens array in which hemispherical lenses are arranged. This microlens array has a function of surface diffusing light. Furthermore, the structure having the function of diffusing the surface of light in this case is not limited to the microlens shape of the present embodiment, and includes, for example, a diffusion structure with beads, a surface diffusion structure such as non-glare.

  As a modification of the lens sheet 1 of the present invention, FIGS. 10A and 10B respectively show a side view of the first lens array and a view of the first lens array as viewed from above. . That is, in the first lens array, the lens height h and the width Q of each lens are uniform (Q1 = Q2 = Q3 = Q4), but the lens pitch (S1 to S4) is different, so the distance between the lens widths Q is different. Is non-uniform. This is one method for reducing the moire between the horizontal or vertical cell structure of the panel when the lens sheet 1 is incorporated in a display.

As a modification of the lens sheet 1 of the present invention, FIGS. 11A and 11B show a side view of the first lens array and a view of the first lens array as viewed from above. . Accordingly, the lens height is uniform, but the unit lens height h and the lens pitch P (P1 to P5) are different from each other. Therefore, the lens width T (T1 to T5) is non-uniform, and the lens width T is also different. Different. This is one method for reducing moiré with the horizontal or vertical cell structure of the panel when the lens sheet 1 is incorporated in a display.

FIG. 15 is a perspective view illustrating a configuration example of the optical sheet 39.
The optical sheet 39 includes a light scattering layer 25 that scatters the light H incident from the incident surface 100 to the non-incident surface 101 side.

  Here, the light scattering layer 25 includes a transparent resin and transparent particles dispersed in the transparent resin, and the refractive index of the transparent resin and the refractive index of the transparent particles are different. There is a need. The difference between the refractive index of the transparent resin and the refractive index of the transparent particles is preferably 0.02 or more. If the difference in refractive index is smaller than this, sufficient light scattering performance cannot be obtained. Further, the refractive index difference may be 0.5 or less.

  The light scattering layer 25 needs to transmit the light H incident on the light scattering layer 25 while scattering the light H. For this reason, the average particle diameter of the transparent particles contained in the light scattering layer 25 is preferably 0.5 to 10.0 μm. Preferably it is 1.0-5.0 micrometers. Alternatively, the light diffusion layer 25 may have a structure having a fine cavity containing air in a transparent resin, and the diffusion performance may be obtained by a difference in refractive index between the transparent resin and air.

  As the transparent resin, for example, polycarbonate resin, acrylic resin, fluorine acrylic resin, silicone acrylic resin, epoxy acrylate resin, polystyrene resin, cycloolefin polymer, methylstyrene resin, fluorene resin, PET, polypropylene, etc. should be used. Can do.

Here, the linear expansion coefficients of polycarbonate, polystyrene, methylstyrene resin, and cycloolefin polymer are 6.7 × 10 ⁻⁵ (cm / cm / ° C.), 7 × 10 ⁻⁵ (cm / cm / ° C.), and 7 respectively. It is * 10 < ^-5 > (cm / cm / degreeC) and 6-7 * 10 < ^-5 > (cm / cm / degreeC). On the other hand, when the lens sheet 1 includes, for example, PET, the linear expansion coefficient of PET is 2.7 × 10 ⁻⁵ (cm / cm / ° C.), and the linear expansion coefficient of the light scattering layer is larger. Therefore, when the optical sheet 5 receives heat and deforms, warpage occurs on the light scattering layer 25 side.
However, in the embodiment of the present invention, considering that the linear expansion coefficient of the lens sheet 1 is small, the linear expansion coefficient of the light diffusion layer 25 is 7.0 × 10 ⁻⁵ (cm / cm / ° C.) or less. By doing so, the above-described deformation can be prevented.
In addition, when producing the lens sheet 1 using a polycarbonate as a material by the extrusion method, warpage does not occur because the linear expansion coefficient is substantially equal to that of other transparent resins.

  Moreover, as transparent particles, transparent particles made of inorganic oxide or transparent particles made of resin can be used. For example, examples of the transparent particles made of an inorganic oxide include particles made of silica, alumina or the like. 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 (tetra Examples thereof include fluorine-containing polymer particles such as fluoroethylene-hexafluoropropylene copolymer), PVDF (polyfluorovinylidene), and ETFE (ethylene-tetrafluoroethylene copolymer), and silicone resin particles. These transparent particles may be used as a mixture of two or more.

And the plate-shaped light-scattering layer 25 can be manufactured by disperse | distributing transparent particles in these transparent resins, and extrusion-molding. The thickness is desirably 1 to 5 mm.
When the thickness is less than 1 mm, the light scattering layer 25 is thin and has no drawback, so that it bends. On the other hand, if it exceeds 5 mm, there is a drawback that the transmittance of light from the light source 41 is deteriorated.

Furthermore, the light diffusion layer 25 may have fine unevenness on the surface, and the surface may have light diffusibility due to the fine unevenness on the surface. In this case, the light diffusion layer 25 is formed by an extrusion method, a casting method, or a method using both the extrusion method and the casting method, which are well known in the art. As a specific example, as shown in FIG. 13, FIG. 13A shows a case where fine irregularities are formed on one surface of the light diffusion layer 25, and FIGS. 13B and 13C show light diffusion. An example in which fine irregularities are formed on both surfaces of the layer 25 is shown. Here, examples of the fine unevenness include a convex cylindrical shape, a lens shape, and a triangular prism shape, but are not limited thereto, and the light diffusion function of the light diffusion layer 25 provides fine unevenness. If it is the thing of the uneven | corrugated shape improved compared with before being done, it will not restrict to said shape.
Furthermore, forming fine irregularities on the surface of the light scattering layer 25 is not limited to the above-described light diffusion function, and it is possible to secure a gap 200 described later.
That is, when the light emitting surface 101 of the light diffusing layer 25 and the light incident surface 102 of the lens sheet 1 are joined, the gap 200 can be secured by the fine unevenness formed on the light emitting surface 101 of the light diffusing layer 25. It becomes. In this case, as the fine unevenness, for example, the shape of the fine unevenness includes a rib and a microlens. However, the shape is not limited thereto, and may be any uneven shape that can secure the gap 200.

  Furthermore, FIG.13 (d) shows what attached the fine particle layer 23 to the surface of both surfaces of the light-diffusion layer 25, and this fine particle layer 23 may be attached not only on both surfaces but on one side. The fine particle layer 23 includes, for example, a transparent ink containing beads, spacers, etc., but the thickness of the fine particle layer 23, the type and size of the fine particles are not limited, and the light diffusion function of the light diffusion layer 25 As long as it is improved as compared with before the fine particle layer 23 is applied.

  In addition, when creating the light-diffusion layer 25 with the fine cavity which contains air in transparent resin as mentioned above, you may foam and produce the foaming agent previously contained in transparent resin. The transparent resin contains a resin that is incompatible with each other, and is produced by a method of stretching at least in a uniaxial direction.

  The optical sheet 39 is provided between the light exiting surface 101 side of the light diffusing layer 25 and the light incident surface 102 of the lens sheet 1, and has a fixing element 37 that fixes the light diffusing layer 25 and the lens sheet 1 while maintaining a gap. is doing.

  The fixing element 37 has a plurality of ribs that transmit light scattered by the light scattering layer 25, a contact / adhesive layer, or a plurality of reflective surfaces that reflect light scattered by the light scattering layer 25 toward the light scattering layer 25. Or the rib containing a reflecting material and the contact | adhesion / adhesive layer containing a reflecting material are mentioned. However, the fixing element 37 is not limited to those formed by these methods, and can also be formed by a method of welding, a method using a fixing tool, or a method of room temperature bonding by irradiating an excimer.

Here, the fixing element 37 does not cover all of the non-incident surface 101 of the light diffusion layer 25 and the incident surface 102 of the lens sheet 1.
That is, as a result, a gap 200 is provided between the light diffusion layer 25 and the lens sheet 1 shown in FIG. 15A and transmits light scattered by the light diffusion layer 25 to the lens sheet 1 on the non-scattering layer side. Can be provided. It is possible to collect the light passing through the gap 200 and guide it to the lens sheet 1. The gap 200 is made of a gas such as air or nitrogen, for example.

First, a case where a contact / adhesive layer is used as the fixing element 37 will be described. The position where the adhesive / adhesive layer is applied is at least partly outside the display area of the light diffusion layer 25 and the lens sheet 1 (which means an area other than that used for image display when the lens sheet 1 is incorporated in the display device). Jointly. However, in some cases, the contact / adhesive layer may be in the display region as long as the image display quality of the display (for example, the fixing element 37 is visible from the display) is not affected.
As an example, the position to attach the contact / adhesive layer is shown in FIGS. 14 (a) to 14 (d).
FIG. 14A shows a case where the contact / adhesive layer is applied to the entire periphery of the light diffusion layer 25.
FIG. 14B and FIG. 14C show a case where the adhesive / adhesive layer is applied only to a pair of opposite sides of the light diffusion layer 25.
FIG. 14C shows the case where the contact / adhesive layer is applied to the four corners of the light diffusion layer 25.
FIG. 14 (d) shows a case where the contact / adhesive layer is applied to the entire periphery of the light diffusion layer 25 in the form of dots. Here, also in the case of FIG. 14 (b) and FIG. 14 (c), the contact / adhesive layer may be applied in a dot shape as necessary.
In addition, when using a sticky / adhesive for a rib or white foil, which will be described later, the sticky / adhesive layer may be provided only on the rib or the light reflecting portion, or may be formed on the entire surface of the light diffusion layer 25. I do not care.

Examples of the adhesive / adhesive include acrylic, urethane, rubber, and silicone adhesives / adhesives. In either case, since it is used in a high-temperature backlight, it is desirable that the storage elastic modulus G ′ is 1.0E + 04 Pa or more at 100 ° C. If the value is lower than this, the light diffusion layer 25 and the lens sheet 1 may be displaced during use. In order to secure the gap 200 stably, transparent fine particles, for example, beads may be mixed in the contact / adhesive layer.
The adhesive may be a double-sided tape or a single layer.

  Furthermore, when a contact / adhesive is used in the display area, light absorption must be within 1%. If it exceeds 1%, the integrated light quantity emitted from the optical sheet decreases, and the front luminance decreases regardless of the shape of the lens sheet 1.

  As a method of applying the contact / adhesive layer, various coating apparatuses such as a comma coater, a printing method, a method using a dispenser or a spray, or manual coating using a brush or the like may be used.

  A rib can be used as the fixing element 37. By using this rib, the gap 200 can be fixed uniformly with a constant thickness, so that appearance characteristics such as display quality (optical contact, unevenness, Newton ring) can be improved.

  Here, the rib is made of a transparent resin molded into a certain shape. Further, the transparent resin may contain other effects such as diffusion and coloring by containing inorganic and organic particles and bubbles.

  As a transparent resin for the rib material, for example, a polyester resin, an acrylic resin, a polycarbonate resin, a polystyrene resin, a methylstyrene resin, a polymethylpentene resin, a thermoplastic resin such as a cycloolefin polymer, or a polyester acrylate, urethane acrylate, epoxy acrylate, etc. Transparent resins such as radiation curable resins made of oligomers or acrylates of the above are generally used, but in addition to the above materials, resins that can exhibit rib characteristics can also be used.

  As particles dispersed in the transparent resin, inorganic substances such as silica, alumina, titanium oxide, carbon black, and glass beads, and organic substances such as various resin beads can be used. Various particles dispersed in the transparent rib can be locally disposed, for example, by giving the rib surface a reflection characteristic. Further, bubbles can be dispersed in the resin and used instead of the particles. These particles and bubbles dispersed in the transparent resin may be used in combination of a plurality of types or may not be used depending on the application to be used.

  As for the height of the rib, it is necessary to keep the gap 200 between the lens sheet 1 and the light diffusion layer 25 at 200 nm or more in order to prevent optical adhesion due to distortion of the optical sheet 39. On the other hand, if the thickness of the gap 200 exceeds 2 mm, the visibility of the ribs increases, causing unevenness, and light leakage easily occurs from the side, which is not preferable.

  The ground contact area of the non-incident surface 101 of the rib diffuses the total ground contact area of the rib in contact with the non-incident surface 101 of the light diffusion layer 25 or the incident surface 102 of the lens sheet in order to prevent a decrease in adhesive strength and a decrease in front luminance. It is desirable that the area be 0.01 to 60% with respect to the area of the non-incident surface 101 of the layer 25 or the incident surface 102 of the lens sheet. Furthermore, it is more preferable that the installation area of the light diffusion layer 25 of the rib on the non-incident surface 101 is 1% or more and 20% or less in order to minimize the decrease in luminance.

  Here, when the rib is used, it is limited to the installation position as shown in FIGS. 14 (a) to 14 (d), as in the case of the arrangement of the adhesive / adhesive layer outside the display area as described above. It is not necessary to do this, and it can be installed on the entire incident surface 102 of the lens sheet 1 or the light emitting surface 101 of the light diffusion layer 25.

In addition, the grounding size of one rib (or a group of ribs in some cases) to the non-incident surface 101 of the light diffusion layer 25 extends in one direction from the upper surface of the optical sheet 39 in order to reduce the visibility of rib unevenness. As for the lenticular shape, trapezoidal shape, prism shape, and the like, it is preferable that the line width of the grounded portion of the portion joined to the lens sheet 1 is 50 μm or less. Further, it is preferable that the area of the ground contact portion of a structure such as a cone (or a truncated cone, a truncated cone, or the like), a polygonal column, a cylinder, or the like, a rectangular parallelepiped, a sphere (or hemisphere), or an ellipsoid is 2500 μm ² or less.
In order to further improve the visibility, the line width is more preferably 3 μm and the area is 900 μm ² or less.

  Rib shape, lenticular shape, trapezoidal shape, prism shape, etc., polygonal cones, cones (or polygonal cones, truncated cones, etc.), polygonal columns, columnar cylinders, rectangular parallelepipeds, spherical shapes (or It may be a hemispherical structure or an ellipsoidal structure. Depending on the rib manufacturing method, the shape of the side surface may be an unspecified shape as long as the height of the rib is constant. When securing a space | gap with these ribs, you may use said 1 type rib structure for the whole, or may use it combining multiple types of rib structure. The arrangement of these ribs may be periodic such as a stripe shape or a dotted line, or may be random, and is appropriately selected according to the design.

Regarding the hardness of the rib, it is preferable that the rib has an appropriate flexibility so that the warp between the lens sheet 1 and the light diffusion layer 25 can be minimized even at a high temperature during use of the backlight.
As for the height of the ribs, it is preferable that the ribs are uniformly disposed as a whole, but the height of the lens sheet base material may vary according to the expansion / contraction due to rigidity, heat, water absorption, etc. .

  Then, using these transparent resins, particles, etc., ribs can be formed on the rib itself or the back surface of the lens sheet 1 and the surface of the light diffusing layer 25 at once using various methods such as radiation curing molding, extrusion molding, and hot press molding. Can be produced. Moreover, when bonding together, it can integrate so that it may have a fixed space | gap between the lens sheet 1 and the light-diffusion layer 25 using an adhesive or an adhesive agent on the one or both surfaces of a rib. Furthermore, as another rib forming method, ribs can be prepared in advance by dispersing ribs in an adhesive or adhesive and coating them by various printing methods at once, and then dispersing them. Similarly, it can be integrated so as to have a certain gap.

  Next, the case where a rib having a plurality of reflective surfaces, an adhesive layer containing a reflective material, or an adhesive containing a reflective material is used as the fixing element 37 will be described.

The adhesive / adhesive layer containing the reflective material can be prepared by coating the light diffusion layer 25 with metal particles or high refractive index transparent particles dispersed in the aforementioned adhesive / adhesive.
In the case of a rib having a reflective surface, it can be prepared by mixing metal particles or high refractive index transparent particles in a transparent resin forming the rib. It can also be formed by dry film formation such as vapor deposition or sputtering of a highly reflective metal such as silver, aluminum or nickel on the surface of the rib.

  Furthermore, it can also be created by applying an ink obtained by dispersing and mixing high refractive index transparent particles on the surface of a transparent rib, or an adhesive / adhesive layer obtained by dispersing and mixing high refractive index transparent particles. In addition to the above, as a method of creating the fixing element 37 having reflectivity, it can be formed by transferring a kneaded metal particle or high refractive index transparent particle in a binder, or by forming a white foil or a metal foil laminate. .

  Here, examples of the high refractive index transparent particles include titanium oxide, barium sulfate, magnesium carbonate, zinc oxide, clay, aluminum hydroxide, zinc sulfide, silica, and silicone. Examples of the metal particles or the metal foil include aluminum and silver. One kind of these high refractive index transparent particles, metal particles or metal foil may be used, or a plurality of kinds may be used in combination.

Further, the light absorption by the fixing element 39 having the function of reflecting light must be within 1%. When it exceeds 1%, the integrated light quantity emitted from the optical sheet 37 decreases, and the on-axis luminance decreases regardless of the shape of the lens sheet 1.
In the case of the fixing element 39 having the above-described reflection function, the reflectance thereof needs to be 70% or more, and more preferably 80% or more. If it is lower than 70%, the transmitted light increases too much, so that it may be visually recognized as a bright portion in a low luminance visual field. If it is 80% or more, it is not visually recognized even in a low-luminance visual field.

  The arrangement of the fixing elements 39 having a reflecting function is the same as that of the rib having no reflecting function.

  In the case of using a welding technique as the fixing element 37, for example, a method using heat, ultrasonic waves, or a laser can be used. These methods are easy to process and are suitable for joining outside the display area.

When a fixing tool is used as the fixing element 37, examples of the fixing tool include a resin or metal stopper, a staple, a tape, and the like.
Resin or metal stoppers may be integrated with the backlight housing. These methods are easier to process than welding, and are suitable for joining outside the display area.

  When using a method in which excimer is irradiated and room temperature bonding is used as the fixing element 37, one or both of the two materials to be bonded with 178 nm excimer UV are irradiated, and then the two materials are laminated. Heat may be applied during lamination, or heat may be applied after lamination.

  The optical sheet 39 created by the above description is not limited to the use for improving the luminance of the backlight, but also includes a viewing angle control film for a display such as LCD, EL and PDP, a contrast enhancement film, a light control film for solar cells, It can be used for a projection screen.

  The optical sheet 39 can be used not only in the case of a cold cathode fluorescent lamp as a light source but also in a display device using LEDs, EL, semiconductor lasers and the like that have recently attracted attention as a light source for display.

  Here, when an LED is used as the light source of the display device, as shown in FIG. 18A, an array of red, green, and blue LEDs is used. Are mixed to emit light uniformly as white light, or light from an array of red, green, and blue LEDs using a diffuser as shown in FIG. It can be used also for what can be emitted.

The backlight unit is becoming thinner and the distance between the light source and the optical sheet is shortened accordingly, but if the optical sheet 39 of the present invention is used, a direct type or side edge type backlight is used. Even in the unit, there is no influence of visibility such as a dark spot generated between the light source lamps, and the unit can be used sufficiently.
Furthermore, the size of the optical sheet 39 is also increasing along with the increase in the size of the display device, but the optical sheet 39 of the present invention is thin and strong, and further has excellent display quality. It can be sufficiently used for such a large display device.

FIG. 15 shows an embodiment in which the optical sheet 39 according to the present invention is used in a direct backlight unit and a display device using the backlight unit.

FIG. 16 shows an embodiment in which the optical sheet 39 according to the present invention is used for the side edge type light guide plate 47.

FIG. 17 shows an embodiment in which an EL light source is used as the light source of the display using the optical sheet 39 according to the present invention.

FIG. 18A shows an embodiment in which the LED light source 51 is used with the optical sheet 39 according to the present invention as a light source of a display.
FIG. 18B shows an embodiment in which the LED light source 53 is used with the optical sheet 39 according to the present invention as the light source of the display.

(Lens sheet manufacturing method)
Example 1
A polycarbonate resin, which is a thermoplastic resin, is heated, formed into a film having a thickness of 0.3 mm while being stretched along a roll, and then heated using a cylinder mold in which the shape of the first lens array 3 is cut. The formed film is cooled while being pressurized (the cylinder mold itself is at room temperature 25 ° C.), and before the film on which the shape of the first lens array 3 is molded is completely cured, the second lens array 5 Cooling while pressurizing with a cylinder mold whose shape is cut (the temperature of the cylinder mold whose shape of the second lens array 5 is cut is 10 ° C. with a water-cooled roll) to further reduce the viscosity of the thermoplastic resin. Reduced and fully cured. The lens sheet 1 produced by this method is a lenticular lens group in which the first lens array has a lens pitch of 140 μm, and the second lens array 5 is arranged at 90 degrees with the longitudinal direction of the lenticular lens. However, the shape of the lens sheet 1 having a triangular prism shape with a lens pitch of 20 μm was molded.
In this way, by forming a mold roll having the lens shape of the first lens array 3 and the second lens array 5 on the cooling roll, the extrusion roll is formed once by roll-to-roll (film feed speed 1 m / min). It was possible to produce the lens sheet 1.
Further, when the thus produced lens sheet 1 was measured with an easy contrast (viewing angle measuring device), a viewing angle having almost the same shape as that of the lens sheet of FIG. 3 could be obtained.

(Lens sheet manufacturing method)
(Example 2)
A polycarbonate resin, which is a thermoplastic resin, is heated and formed into a film while being stretched along a roll, and then cooled while pressing the heated film using a cylinder mold cut into the shape of the lens sheet 1 (lens The cylinder mold cut into the shape of the sheet 1 was set to 10 ° C. with a water-cooled roll.) By reducing the viscosity of the thermoplastic resin, the lens sheet 1 was cured while maintaining the shape. The lens sheet 1 produced by this method is a lenticular lens group in which the lens pitch of the first lens array is 140 μm, and the second lens array 5 is arranged at 90 degrees with the longitudinal direction of the lenticular lens. However, the shape of the lens sheet 1 having a triangular prism shape with a lens pitch of 20 μm was molded.
Thus, it was possible to produce the lens sheet 1 at a time by extrusion molding using a roll of roll (film feed speed of 1.5 m / min) with a single lens mold roll.
The lens sheet 1 manufactured in this manner was able to be manufactured substantially the same as the lens sheet of Example 1.
Further, when the thus produced lens sheet 1 was measured with an easy contrast (viewing angle measuring device), a viewing angle having almost the same shape as that of the lens sheet of FIG. 3 could be obtained.

  Here, the manufacturing method of Example 1 can easily change the shape of the lens sheet 1 by replacing one of the two cooling rolls with a lens having a different shape, whereas the method of Example 2 As in the first embodiment, there is an advantage that it is simple because it takes less time to set the cooling temperature of the two cooling rolls and optimize the pressurizing conditions.

(Lens sheet manufacturing method)
(Example 3)
An ultraviolet curable resin (urethane acrylate resin (refractive index: 1.5) made by Nippon Kayaku Co., Ltd.) having a urethane acrylate as a main component for forming a pattern of the lens sheet 1 on an optically biaxially stretchable and easy-adhesive PET film (film thickness 125 μm). 51)) is applied, and UV light is exposed from the PET film side while conveying a film coated with UV curable resin using a cylinder die cut into the shape of the lens sheet 1, thereby UV curable The resin was cured. After curing, the mold is released from the PET film to form a lenticular lens group in which the lens pitch of the first lens array is 140 μm, and the second lenticular lens is arranged at 90 degrees with the longitudinal direction of the lenticular lens. The lens array 5 was able to form the shape of the lens sheet 1 having a triangular prism shape with a lens pitch of 20 μm.
Further, when the thus produced lens sheet 1 was measured with an easy contrast (viewing angle measuring device), a viewing angle having almost the same shape as that of the lens sheet of FIG. 3 could be obtained.

(Lens sheet manufacturing method)
Example 4
A polycarbonate resin, which is a thermoplastic resin, is heated, formed into a film having a thickness of 0.3 mm while being stretched along a roll, and then heated using a cylinder mold in which the shape of the first lens array 3 is cut. The formed film is cooled while being pressurized (the cylinder mold itself is at room temperature 25 ° C.), and before the film on which the shape of the first lens array 3 is molded is completely cured, the second lens array 5 Cooling while pressurizing with a cylinder mold whose shape is cut (the temperature of the cylinder mold whose shape of the second lens array 5 is cut is 10 ° C. with a water-cooled roll) to further reduce the viscosity of the thermoplastic resin. Reduced and fully cured. In this way,
Two types of cylinder molds in which the shape of the second lens array 5 is cut (the shape of the second lens array is the same, but β is 10 ° and 40 ° as shown in FIG. 5B). Using these, two types of lens sheets 1 were produced.
The produced lens sheet 1 is a lenticular lens group in which the lens pitch of the first lens array is 140 μm, the second lens array 5 has a triangular prism shape (β is 10 °) with a lens pitch of 20 μm, The lens array is a lenticular lens group with a lens pitch of 140 μm, and the second lens array 5 has a triangular prism shape (β is 40 °) with a lens pitch of 20 μm.
Next, liquid crystal panels having various cell pitches of 300 μm to 600 μm were prepared for these two types of lens sheets 1, and the lens sheets were assembled in the panel, and it was visually confirmed whether a moire could be visually recognized at a distance of 10 cm from the panel.
As a result, moire did not occur in the lens sheet 1 having β of 10 °, but moire occurred in the lens sheet 1 having β of 40 °.

(Evaluation of lens sheet)
(Example 5)
The following three types of lens sheets were produced by the production method of Example 2 described above. It is a first lens array (a lenticular lens group having a lens pitch P1 of 100 μm and W of 10 μm), a second lens array 5 has a triangular prism shape with a lens pitch of 20 μm, and a first lens array (lens pitch P1). A second lenticular lens group having a lens pitch of 20 μm and a first lens array (a lenticular lens group having a lens pitch P1 of 100 μm and W of 85 μm). The second lens array 5 has a triangular prism shape with a lens pitch of 20 μm.
When the lens sheet 1 of (1) to (3) is measured with an easy contrast (viewing angle measuring device), the lens sheet 1 of (2) obtains a viewing angle having almost the same shape as the lens sheet of FIG. I was able to. However, in the lens sheet 1 of (1), a side rope is generated, and in the lens sheet 1 of (3), the front luminance is lowered and it is difficult to use the display sheet in either case. It was.

(Production method of light diffusion layer)
(Example 6)
There are the following four types of molding methods for the light diffusion layer 25 having surface irregularities.
This time, the resin of the light diffusion layer 25 was MS600 made by Nippon Steel Chemical, and the diffusing agent was a mixture of silica and a commercially available resin filler.
1. It was directly molded when the plate material was extruded. That is, the surface of the first cooling roll or the two-stage cooling roll of the extruder was processed to process the uneven mold on the surface of the cooling roll. At the time of extruding the plate material, the concavo-convex shape was transferred to the plate material by a mold on the surface of the cooling roll.
2. Molded using a mold. It is a well-known technique to block polymerize between flat glass molds using an acrylic monomer to obtain an acrylic plate product. However, in the examples, the surface form of the flat plate was modified, the uneven shape was processed into a metal flat plate shape, and the diffusion plate was molded, and the uneven shape was transferred to the diffusion plate material product.
3. It shape | molded with the hot press to the commercially available diffusion plate prepared beforehand. The concavo-convex shape was formed on a metal to form a mold, and the mold was formed by pressing the mold with a hot press against a commercially available diffusion plate.
4). It was molded on the diffusion plate using a transparent resin. An uneven shape was formed on a metal to form a mold, and a resin was applied onto a commercially available diffusion plate, and the mold was uniformly coated. After the resin was cured, a product was obtained from the mold. As the resin, acrylic, epoxy resin, polyurethane, transparent thermosetting resin or ultraviolet curable resin can be used. This time, a commercially available acrylic resin was used for DM A60.

(Production method of light diffusion layer)
(Example 7)
First, the adhesive which mixed the resin filler with the commercially available diffusion plate was apply | coated. 20% of a polystyrene filler having a particle size of 15 μm was added to a commercially available UV curable adhesive, and a thickness of 15 μm was applied with a roll coater. Thereafter, it was cured with a UV lamp to obtain an uneven surface shape.

(Production method of light diffusion layer)
(Example 8)
A stretched white PP film (Tosero, thickness 30 um) or a stretched white PET film (Toyobo thickness 50 um) and a commercially available transparent MS plate were bonded together with an adhesive. Thereby, a light diffusion layer 25 having light diffusion particles made of air was produced.

(Rib production method)
Example 9
A polycarbonate resin, which is a thermoplastic resin, is heated and stretched along a roll to form a film, and then a cylinder mold cut into a rib shape is used, and the heated film is cooled while being pressurized while being cooled. The resin was reduced in viscosity and cured with the rib shape maintained. After curing, the mold was released from the polycarbonate film to produce a rib having a width of 60 μm and a height of 100 μm.

(Rib production method)
(Example 10)
Application of UV curable resin (urethane acrylate resin (refractive index: 1.51) made by Nippon Kayaku Co., Ltd.) mainly composed of urethane acrylate that forms rib shape on biaxially stretchable and easy-adhesive PET film (film thickness 125μm) The UV curable resin was cured by exposing the UV light from the PET film side while transporting the film using a cylinder mold cut into a rib shape. After curing, the mold was released from the PET film to produce a rib having a width of 60 μm and a height of 100 μm.

(Rib production method)
(Example 11)
After heating the polycarbonate resin, which is a thermoplastic resin in which 20% by weight of titanium oxide (made by DuPont), which is a reflective material, is dispersed with respect to the resin, the film is formed while being stretched along a roll, and then formed into a rib shape. Using a cut cylinder mold, the heated film was cooled while being pressurized to reduce the viscosity of the thermoplastic resin, and was cured while maintaining the rib shape. After curing, the mold was released from the polycarbonate film to produce a reflective rib having a width of 60 μm and a height of 100 μm.

(Rib production method)
(Example 12)
Ultraviolet rays mainly composed of urethane acrylate in which 20% by weight of titanium oxide (made by DuPont), which is a reflective material, is dispersed in order to form a rib shape on a biaxially stretched easily-adhesive PET film (film thickness 125 μm). UV light is exposed from the PET film side while transporting the film using a cylinder mold coated with a curable resin (urethane acrylate resin (refractive index 1.51) manufactured by Nippon Kayaku Co., Ltd.) and cut into a rib shape. As a result, the ultraviolet curable resin was cured. After curing, the mold was released from the PET film to produce a reflective rib having a rib width of 60 μm, a height of 100 μm, and a pitch interval of 600 μm.

(Rib production method)
(Example 13)
Further, a transfer foil (manufactured by Kurz) having a light reflecting function was transferred onto the transparent rib produced in Example 9 while applying pressure and heating to produce a rib shape having a reflective surface on the transparent rib.

(Method of manufacturing optical sheet, backlight unit, liquid crystal display device)
(Example 14)
Apply an adhesive of acrylic resin as the main component with a roll coater to the end 5mm of a 700mm x 900mm diffuser plate (Teijin Chemicals 65HLW (polycarbonate)) (coating amount is 5g / m2), and laminate the lens sheet with a laminator. The adhesive was cured for 30 minutes in a drying oven at 80 ° C. and 50%.
The lens sheet prepared as described above was placed at 80 ° C. for 24 hours. This condition assumes the temperature when the backlight is lit.
As a result, the diffusion plate and the lens sheet were not peeled off, and no bubbles were generated from the adhesive.
In addition, in order to test the vibration state due to transportation, a lamp house containing the prepared optical sheet and cold cathode lamp was assembled in the housing to produce a backlight unit, and a liquid crystal panel was installed on the backlight unit to provide a backlight. The periphery of the light unit and the liquid crystal panel was fixed with a fastener and placed in a housing to produce a liquid crystal display device.
In addition, in order to test the vibration state due to transportation, the liquid crystal display device manufactured as described above has a frequency of 5 to 50 Hz, an acceleration of 1.0 G, 70 minutes in the Z direction, 20 minutes in the X direction, and 20 minutes in the Y direction. For 20 minutes. As a result, no peeling occurred on the lens sheet.

(Method of manufacturing optical sheet, backlight unit, liquid crystal display device)
(Example 15)
A double-sided tape (made by 3M) was pasted in the range of the end face of 5 mm of the diffusion plate (Teijin Chemicals 65HLW (polycarbonate)), and the lens sheet was laminated.
The lens sheet prepared as described above was placed at 80 ° C. for 24 hours. This condition assumes the temperature when the backlight is lit. As a result, the diffusion plate and the lens sheet were not peeled off.
In addition, in order to test the vibration state due to transportation, a lamp house containing the prepared optical sheet and cold cathode lamp was assembled in the housing to produce a backlight unit, and a liquid crystal panel was installed on the backlight unit to provide a backlight. The periphery of the light unit and the liquid crystal panel was fixed with a fastener and placed in a housing to produce a liquid crystal display device.
In addition, in order to test the vibration state due to transportation, the liquid crystal display device manufactured as described above has a frequency of 5 to 50 Hz, an acceleration of 1.0 G, 70 minutes in the Z direction, 20 minutes in the X direction, and 20 minutes in the Y direction. For 20 minutes. As a result, no peeling occurred on the lens sheet.

(Production method of optical sheet)
(Example 16)
As a lens sheet, a PET sheet and a thermoplastic resin polycarbonate resin prepared by an extrusion method were prepared.
Next, an adhesive sheet previously applied at 5 g / m 2 was laminated to each lens sheet, and then the lens sheet and a diffusion plate (Teijin Chemicals (methylstyrene resin)) having a linear expansion coefficient of 7.0 × 10 ⁻⁵ (cm / cm / ° C.)).
Thereafter, the lens sheet was put in an environment from room temperature to 80 ° C., and the warp of the lens sheet due to temperature change was confirmed. The warpage was measured by placing the lens sheet on a flat table with the lens side facing up, and measuring the distance from the square table. The initial value was 0 mm.
Immediately after the introduction of 80 ° C., the lens sheet with PET was warped and became convexly warped toward the diffusion plate. The amount of warpage at the four corners was 10 to 15 mm. On the other hand, in the case of the extruded sheet, it remained at 0 mm.
The above test reproduces the situation when the backlight turns on at high temperatures, but in all samples, the lens sheet side does not become convex, and even if it is incorporated in a liquid crystal panel, it does not cause abnormalities in the displayed image by pressing the panel when it is lit. it is conceivable that.

(Optical sheet manufacturing method)
(Example 17)
Next, the same experiment as in Example 19 was performed using the above-described two types of lens sheets and using a diffusion plate having a linear expansion coefficient of 7.2 × 10 ⁻⁵ (cm / cm / ° C.).
As a result, when the lens sheet was made of PET, warping occurred, and convex warping occurred on the diffusion plate side. The amount of warpage at the four corners was 18 to 40 mm. On the other hand, in the case of the extruded sheet, it was about 5 mm.
Therefore, in order to test the vibration state due to transportation next, the prepared optical sheet is incorporated in the liquid crystal display device, the vibration frequency is 5 to 50 Hz, the acceleration is 1.0 G, 70 minutes in the Z direction, 20 minutes in the X direction, Y Tested in the direction for 20 minutes. As a result, when the lens sheet was made of PET, peeling occurred at the end.

(Method of manufacturing optical sheet, backlight unit, liquid crystal display device)
(Example 18)
When fine particles were mixed in the adhesive: 20% polystyrene filler with a particle size of 15 um was added to a commercially available UV curable adhesive, and 30 μm thick was applied to a diffusion plate (Teijin Chemicals 65HLW (polycarbonate)) with a roll coater. It was cured once with UV until the tack remained. Thereafter, the lens sheet was laminated, and UV was again irradiated to completely cure the adhesive.
The lens sheet prepared as described above was placed at 80 ° C. for 24 hours. This condition assumes the temperature when the backlight is lit. As a result, the diffusion plate and the lens sheet were not peeled off.
As a result, the diffusion plate and the lens sheet were not peeled off, and no bubbles were generated from the adhesive.
In addition, in order to test the vibration state due to transportation, a lamp house containing the prepared optical sheet and cold cathode lamp was assembled in the housing to produce a backlight unit, and a liquid crystal panel was installed on the backlight unit to provide a backlight. The periphery of the light unit and the liquid crystal panel was fixed with a fastener and placed in a housing to produce a liquid crystal display device.
In addition, in order to test the vibration state due to transportation, the liquid crystal display device manufactured as described above has a frequency of 5 to 50 Hz, an acceleration of 1.0 G, 70 minutes in the Z direction, 20 minutes in the X direction, and 20 minutes in the Y direction. For 20 minutes. As a result, no peeling occurred on the lens sheet.

(Method of manufacturing optical sheet, backlight unit, liquid crystal display device)
(Example 19)
A lens sheet made of a polycarbonate resin as a thermoplastic resin by the same extrusion method as in Example 1 was irradiated with 172 nm excimer UV (Iwasaki Electric) for 30 seconds, and then the lens pitch was 140 μm and the lens height was 60 μm. Lamination was performed with a polycarbonate diffusion plate having a thickness of 1 mm on which a lenticular lens was formed and a lami roll at 80 ° C.
The lens sheet prepared as described above was placed at 80 ° C. for 24 hours. This condition assumes the temperature when the backlight is lit. As a result, the diffusion plate and the lens sheet were not peeled off.
In addition, in order to test the vibration state due to transportation, a lamp house containing the prepared optical sheet and cold cathode lamp was assembled in the housing to produce a backlight unit, and a liquid crystal panel was installed on the backlight unit to provide a backlight. The periphery of the light unit and the liquid crystal panel was fixed with a fastener and placed in a housing to produce a liquid crystal display device.
In addition, in order to test the vibration state due to transportation, the liquid crystal display device manufactured as described above has a frequency of 5 to 50 Hz, an acceleration of 1.0 G, 70 minutes in the Z direction, 20 minutes in the X direction, and 20 minutes in the Y direction. For 20 minutes. As a result, no peeling occurred on the lens sheet.

(Method of manufacturing optical sheet, backlight unit, liquid crystal display device)
(Example 20)
A lens sheet prepared in advance with a large size (1000 mm × 1000 mm) and a diffusion plate were stacked, lightly pressed with a static eliminating brush so as not to float between them, and laser cut to a size of 500 mm × 500 mm with a carbon dioxide laser cutting machine. At the end portion of about 5 mm cut by laser irradiation, the color of the lens sheet was slightly changed to yellow.
Therefore, a 25 μm easy-adhesive PET film was laminated as a protective film on the surfaces of the lens sheet and the diffusion plate in advance, and laser cutting was performed in the same manner to peel off the protective film. As a result, the lens sheet and the diffusion plate were not discolored.
The lens sheet prepared as described above was placed at 80 ° C. for 24 hours. This condition assumes the temperature when the backlight is lit. As a result, the diffusion plate and the lens sheet were not peeled off.
In addition, in order to test the vibration state due to transportation, a lamp house containing the prepared optical sheet and cold cathode lamp was assembled in the housing to produce a backlight unit, and a liquid crystal panel was installed on the backlight unit to provide a backlight. The periphery of the light unit and the liquid crystal panel was fixed with a fastener and placed in a housing to produce a liquid crystal display device.
In addition, in order to test the vibration state due to transportation, the liquid crystal display device manufactured as described above has a frequency of 5 to 50 Hz, an acceleration of 1.0 G, 70 minutes in the Z direction, 20 minutes in the X direction, and 20 minutes in the Y direction. For 20 minutes. As a result, no peeling occurred on the lens sheet.

(Method of manufacturing optical sheet, backlight unit, liquid crystal display device)
(Example 21)
A hole was made in the lens sheet and the diffusion plate in advance, and the lens sheet and the diffusion plate were fixed with a metal wire.
In addition, in order to test the vibration state due to transportation, a lamp house containing the prepared optical sheet and cold cathode lamp was assembled in the housing to produce a backlight unit, and a liquid crystal panel was installed on the backlight unit to provide a backlight. The periphery of the light unit and the liquid crystal panel was fixed with a fastener and placed in a housing to produce a liquid crystal display device.
In addition, in order to test the vibration state due to transportation, the liquid crystal display device manufactured as described above has a frequency of 5 to 50 Hz, an acceleration of 1.0 G, 70 minutes in the Z direction, 20 minutes in the X direction, and 20 minutes in the Y direction. For 20 minutes. As a result, no peeling occurred on the lens sheet.

(A) It is explanatory drawing which shows the lens sheet perspective view which concerns on embodiment of this invention. (B) It is explanatory drawing which shows the lens sheet perspective view which concerns on embodiment of this invention. (C) It is explanatory drawing which shows the lens sheet side view which concerns on embodiment of this invention. (D) It is explanatory drawing which shows the lens sheet side view which concerns on embodiment of this invention. (E) It is explanatory drawing which shows the lens sheet top view which concerns on embodiment of this invention. (A) It is explanatory drawing which shows the optical simulation result of the cylindrical lens by a prior art. (B) It is explanatory drawing which shows the optical simulation result of the cylindrical lens by a prior art. (A) It is explanatory drawing which shows the optical simulation result of the lens sheet which concerns on embodiment of this invention. (B) It is explanatory drawing which shows the optical simulation result of the lens sheet which concerns on embodiment of this invention. (A) It is explanatory drawing which shows the simulation result of the front luminance of the lens sheet which concerns on embodiment of this invention. (B) It is explanatory drawing which shows the simulation result of the half value angle of the lens sheet which concerns on embodiment of this invention. (A) It is explanatory drawing which shows the lens sheet perspective view which concerns on embodiment of this invention. (B) It is explanatory drawing which shows the lens sheet top view which concerns on embodiment of this invention. It is explanatory drawing which shows the perspective view of the illustrative lens sheet which concerns on embodiment of this invention. It is explanatory drawing which shows the perspective view of the illustrative lens sheet which concerns on embodiment of this invention. It is explanatory drawing which shows the perspective view of the illustrative lens sheet which concerns on embodiment of this invention. It is explanatory drawing which shows the perspective view of the illustrative lens sheet which concerns on embodiment of this invention. (A) It is explanatory drawing which shows the side view of the illustrative lens sheet which concerns on embodiment of this invention. (B) It is explanatory drawing which shows the top view of the illustrative lens sheet which concerns on embodiment of this invention. (A) It is explanatory drawing which shows the side view of the illustrative lens sheet which concerns on embodiment of this invention. (B) It is explanatory drawing which shows the top view of the illustrative lens sheet which concerns on embodiment of this invention. It is explanatory drawing which shows the lens sheet production method which concerns on embodiment of this invention. (A) It is explanatory drawing which shows the perspective view of the exemplary light-diffusion layer which concerns on embodiment of this invention. (B) It is explanatory drawing which shows the perspective view of the exemplary light-diffusion layer which concerns on embodiment of this invention. (C) It is explanatory drawing which shows the perspective view of the exemplary light-diffusion layer which concerns on embodiment of this invention. (D) It is explanatory drawing which shows the perspective view of the exemplary light-diffusion layer which concerns on embodiment of this invention. (A) It is explanatory drawing which shows arrangement | positioning of the exemplary fixing element which concerns on embodiment of this invention. (B) It is explanatory drawing which shows arrangement | positioning of the exemplary fixing element which concerns on embodiment of this invention. (C) It is explanatory drawing which shows arrangement | positioning of the exemplary fixing element which concerns on embodiment of this invention. (D) It is explanatory drawing which shows arrangement | positioning of the exemplary fixing element which concerns on embodiment of this invention. (E) It is explanatory drawing which shows arrangement | positioning of the exemplary fixing element which concerns on embodiment of this invention. It is explanatory drawing which shows the illustrative display apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows the illustrative display apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows the illustrative display apparatus which concerns on embodiment of this invention. (A) It is explanatory drawing which shows the exemplary display apparatus which concerns on embodiment of this invention. (B) It is explanatory drawing which shows the exemplary display apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows the structural example of the liquid crystal display device by a prior art. It is explanatory drawing which shows the structural example of the liquid crystal display device by a prior art. It is explanatory drawing which shows the structural example of the liquid crystal display device by a prior art. It is explanatory drawing which shows the perspective view of BEF by a prior art. It is explanatory drawing which shows the structural example of the optical sheet for liquid crystal displays by a prior art. It is explanatory drawing which shows the light intensity distribution radiate | emitted from the optical sheet using BEF.

Explanation of symbols

H, K: Light, P1: Arrangement pitch of the first lens array, H: Lens height from the valley to the top of the first lens array, α: Perpendicular from the valley of the irregularities of the unit lens of the first lens array And the angle formed by the tangent line of the unit lens, W: the width of the lens on which the second lens array is formed, P2: the arrangement pitch of the second lens array, h: the lens height from the trough to the top of the second lens array, T: Substrate thickness, V: Vertical direction, X: Horizontal direction, β: Angle formed by the arrangement of the lens arrays of the first lens array 3 and the second lens array 5, Q1 to Q4: Second lens Width of lenses in which the array is formed, R1 to R4... Arrangement pitch of the first lens array, S1 to S5... Arrangement pitch of the first lens array, T1 to T5. ... length of each lens of the first lens array 3 Length in the hand direction, L ... viewing surface (display display surface) 1 ... lens sheet, 3 ... first lens array, 5 ... second lens array, 11 ... cooling roll which is a mold of the first lens array 3, DESCRIPTION OF SYMBOLS 13 ... Cooling roll which is a metal mold | die of 2nd lens array, 15 ... Cooling roll for 1st lens arrays, 17 ... Cooling roll for 2nd lens arrays, 19 ... Thermoplastic resin base material, 21 ... Thermoplastic Processing direction by extrusion method of resin base material, 25 ... Light diffusion layer, 29 ... Fixed element, 31, 33 ... Polarizing plate, 32 ... Liquid crystal panel, 35 ... Liquid crystal layer, 39 ... Display sheet, 41 ... Light source, 43 ... Lamp house, 45 ... light reflecting plate, 47 ... light guide plate, 49 ... EL light source, 51, 53 ... LED light source, 100 ... non-incident surface of light diffusing layer, 101 ... light emitting surface of light diffusing layer, 102 ... lens sheet Light incident surface, 200 ... gap, 3 0 ... light diffusion film, 302 ... vicinity of the apex

Claims (32)

  A lens sheet comprising: a first lens array formed on a base material; and a second lens array formed on each of the first lens arrays.   The lens sheet according to claim 1, wherein the first lens array is a lenticular lens group, and the second lens array is a triangular prism group.   The longitudinal direction of the lenticular lens of the first lens array and the longitudinal direction of the triangular prism of the second lens array intersect at 90 ° ± β (0 ° <β <30 °). Or the lens sheet of Claim 2. When the lens pitch of each lens array of the first lens array is P1, the angle of the lens end is α, and the width of the top of each lens array is W, 0.2 <W / P1 <0.8.
15 ° <α
The lens sheet according to claim 1, wherein the following relationship is established.   The lens sheet according to claim 1 or 2, wherein the lens pitch P2 of each of the second lens arrays is an irregular random pitch.   3. The lens sheet according to claim 1, wherein a vicinity of a valley portion and a vicinity of a vertex of each lens of the first lens array are rounded.   3. The lens sheet according to claim 1, wherein a vicinity of a valley portion and a vicinity of a vertex of each lens of the second lens array are rounded.   3. The lens sheet according to claim 1, wherein a lens pitch P <b> 1 of the first lens array is an irregular random pitch, and the lens height H is constant.   The lens sheet according to claim 1, wherein the second lens array has surface diffusion.   3. The lens pitch P1 of the first lens array is an irregular random pitch, and the lens height H and the top width W of the lens array are constant. The lens sheet described.   The lens pitch P1 of the first lens array is an irregular random pitch, the lens height H is constant, and the top width W of the lens array is irregular. The lens sheet according to claim 1 or 2. Heating the thermoplastic resin substrate,
Pressurizing with a cooling roll which is a lens mold of the first lens array, forming the first lens array;
Furthermore, it forms by pressing with the cooling roll which is a lens metal mold | die of the said 2nd lens array on the said resin base material in which the said 1st lens array was formed. Or the lens sheet of Claim 2. Pressurizing a thermoplastic resin substrate with a heating roll which is a lens mold of the first lens array to form the first lens array;
Furthermore, it forms by pressing with the heating roll which is a lens metal mold | die of the said 2nd lens array on the said resin base material in which the said 1st lens array was formed. Or the lens sheet of Claim 2. Heating the thermoplastic resin substrate,
3. The lens sheet according to claim 1, wherein the lens sheet is formed by applying pressure with a cooling roll on which a lens-shaped female mold of the lens sheet is formed. Thermoplastic resin substrate
3. The lens sheet according to claim 1, wherein the lens sheet is formed by pressing with a heating roll in which a lens-shaped female mold of the lens sheet is formed.   16. An optical sheet for display, wherein the lens sheet of claim 1 and the light diffusion layer are integrated with a gap maintained. The optical sheet for display according to claim 16, wherein the surface of the light diffusion layer has a fine uneven shape. 17. The optical sheet for display according to claim 16, wherein a fine particle layer is present on the surface of the light diffusion layer. 17. The display optical sheet according to claim 16, wherein the light diffusion layer has a linear expansion coefficient of 7.0 × 10 ⁻⁵ (cm / cm / ° C.) or less. The optical sheet for display according to claim 16, wherein the gap contains air.   The back surface of the surface on which the first lens array and the second lens array of the lens sheet are formed and the gap between the diffusion plates are integrated with the light diffusion layer by one or more fixing elements. The optical sheet for display according to claim 16.   The optical sheet for display according to claim 21, wherein the fixing element has an adhesive.   The optical sheet for display according to claim 21, wherein the fixing element has an adhesive.   The optical sheet for display according to claim 21 or 23, wherein, when the fixing element is the adhesive or the pressure-sensitive adhesive, the adhesive and the pressure-sensitive adhesive contain fine particles.   The optical sheet for display according to claim 21, wherein the fixing element has a rib.   The optical sheet for display according to claim 21, wherein the fixing element has a reflective surface. 23. A backlight unit comprising: the optical sheet for display according to claim 21; and a light source for irradiating light from a non-viewing surface side of the liquid crystal panel on a back surface of the optical sheet for display. The backlight unit;
A display device comprising the liquid crystal panel on a light exit surface side of the optical sheet of the backlight.   29. The display device according to claim 28, wherein each of the backlight device and the display device has a light source, and the light source is a cold cathode fluorescent lamp.   The display device according to claim 28, wherein the light source is an LED.   The display device according to claim 28, wherein the light source is an EL.   The display device according to claim 28, wherein the light source is a semiconductor laser.

Images