JP2011059263A - Light control sheet, backlight unit, display device, and method for manufacturing the light control sheet - Google Patents

Abstract

By enabling light distribution adjustment in two directions, it is possible to reduce the number of components and increase the light use efficiency and brightness, and further, adjustment of the light distribution is prepared and the manufacturing method is provided. An easy light control sheet is provided.
A pair of first slopes 3c facing each other connected to a lower bottom surface 3a and an upper bottom surface 3b, respectively, and extending a first trapezoidal first sectional shape 3d in a first direction x. And a pair of bottom surfaces 5a having a substantially polygonal shape located on the upper bottom surface 3b and a bottom surface parallel to the first direction x and opposed to each other. A second inclined surface 5b, a pair of third inclined surfaces 5c having a base parallel to the second direction y intersecting the first direction x and inclined to face each other, and a second inclined surface 5b, The second lens 5 having at least a top connected to the third inclined surface 5c is juxtaposed on the upper bottom surface 3b of the first lens 3 without a gap.
[Selection] Figure 6

Description

  The present invention relates to a light control sheet that emits light with changing optical characteristics of incident light, a backlight unit including the light control sheet, a display device, and a method for manufacturing the light control sheet.

In recent years, display devices using TFT-type liquid crystal panels and STN-type liquid crystal panels have been commercialized mainly in color notebook PCs (personal computers) in the OA field, for example.
Such a display device employs a so-called backlight system in which a light source is arranged on the back side of the liquid crystal panel and the liquid crystal panel is illuminated with light from the light source.

  The backlight units used in this type of backlight system can be broadly divided into multiple light sources such as cold cathode fluorescent lamps (CCFL) within a flat light guide plate made of acrylic resin with excellent light transmission. There are a “light guide plate light guide method” (so-called edge light method) and a “direct type method” that does not use a light guide plate.

For example, a display device shown in FIG. 15 is generally known as a display device on which a light guide plate light guide type backlight unit is mounted.
This display device includes a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73, and a light guide plate 79 made of a transparent base material such as a substantially rectangular plate-like PMMA (polymethylmethacrylate) or acrylic on the back side thereof. A diffusion film (diffusion layer) 78 is provided between the upper surface (light emitting side) of the light guide plate 79 and the polarizing plate 73 on the rear side.

  On the back side of the light guide plate 79, a scattering reflection pattern portion (not shown) is printed for scattering and reflecting the light introduced into the light guide plate 79 so as to be uniform in the direction of the liquid crystal panel 72. A reflective film (reflective layer) 77 is provided on the back side of the scattering reflection pattern portion. Further, a light source lamp 76 is attached to one side end of the light guide plate 79, and further covers the back side of the light source lamp 76 in order to make the light of the light source lamp 76 enter the light guide plate 79 efficiently. In this way, the lamp reflector 81 having a high reflectance is provided. The scattering reflection pattern portion is formed by printing a mixture obtained by mixing white titanium dioxide (TiO2) powder in a transparent adhesive or the like in a predetermined pattern, for example, a dot pattern, and drying and forming it. The directivity is given to the light incident on the light, and the light is guided to the light exit surface side, thereby increasing the brightness.

  Recently, as shown in FIG. 16, a prism film (prism) having a light condensing function is provided between the diffusion film 78 and the liquid crystal panel 72 in order to improve the light utilization efficiency and increase the luminance. It has been proposed to provide layers 74, 75. 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.

On the other hand, a direct-type backlight unit uses a display device such as a large-sized liquid crystal TV in which it is difficult to use a light guide plate. As an example using this backlight unit, for example, a display as shown in FIG. Devices are generally known.
In this display device, a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73 is provided, and a light source 51 including a fluorescent tube is provided on the back side thereof. And the light radiate | emitted from the light source 51 is diffused by the diffusion film 82, and 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.

  Further, in such a direct type backlight unit, in order to increase the front luminance, as shown in FIG. 18, a luminance enhancement film 86 (Brightness Enhancement Film: BEF, registered by 3M Corporation of America, as shown in FIG. 18). Trademarks) are disposed, and as shown in FIG. 19, a diffusion film 82 is disposed thereon (see, for example, Patent Documents 1 to 3).

  The BEF is a film in which unit prisms having a triangular cross-section are periodically arranged in one direction on a transparent member, and a unit prism having a size (pitch) larger than the wavelength of light is adopted. ing. The BEF collects light from “off-axis” and redirects or “recycles” the light “on-axis” toward the viewer. “Yes. “On-axis” is a direction that coincides with the visual direction of the observer, and is generally on the normal direction side with respect to the display screen. The BEF increases the on-axis brightness by reducing the off-axis brightness in this way.

  When such a BEF is used alone, the repetitive array structure of unit prisms is arranged in only one direction, so that only the direction change or recycling in the parallel direction is possible. Therefore, in order to control the luminance of the display light in the horizontal and vertical directions, generally, two sheets are combined and used so that the parallel directions of the unit prism groups are substantially orthogonal to each other.

  In the light control sheet using the BEF as a brightness control member as described above, the light from the light source is refracted and emitted at a controlled angle so as to increase the light intensity in the visual direction of the observer. By adopting this for the backlight unit, it is possible to achieve a desired on-axis brightness while reducing power consumption.

However, in the display device shown in FIG. 15, since the control of the viewing angle depends only on the diffusibility of the diffusing film 78, the control is difficult, and the central portion in the front direction of the display is bright and becomes darker toward the peripheral portion. The phenomenon of becoming is inevitable. For this reason, there is a problem that the luminance is greatly lowered when the liquid crystal screen is viewed from the side, and the light use efficiency is lowered.

  On the other hand, even when the BEF is used as described above, there are unexpected light rays that are wasted in the lateral direction without proceeding in the visual direction of the observer. The light intensity distribution is ideally a smooth convex shape with no light intensity peak around ± 90 ° as shown by the solid line A in FIG. 20, but from the light control sheet using this BEF. In the emitted light intensity distribution, as shown by a broken line B in FIG. 20, a small light intensity peak is recognized around ± 90 ° from the front. This indicates that light (side lobes) emitted from the lateral direction is increased, which is not preferable in terms of the characteristics of the light control sheet.

  In addition, the apparatus using the prism film illustrated in FIG. 16 requires two prism films, so that not only the light quantity is greatly reduced due to absorption of the film, but also the production cost increases due to an increase in the number of members. It was.

  Here, as a method not using two prism films, a square pyramid prism shape as shown in FIG. 21 is arranged, or as shown in FIG. 22, the cross section in a certain direction is sawtooth and orthogonal to a certain direction. There has been proposed a method (hereinafter referred to as a hip roof shape) in which prisms with a trapezoidal cross section are arranged in a lattice (hereinafter referred to as a hip roof shape).

  However, in the quadrangular pyramid prism shape shown in FIG. 21, it is necessary to change the inclination angles θ80 to θ83 in order to adjust the light distribution in two directions. The configuration with the highest brightness is a quadrangular pyramid having an inclination angle θ80 to θ83 of 45 degrees. However, when it is desired to expand or narrow the field of view in either direction, at least one of the inclination angles θ80 to θ83 is increased. Or it needs to be small. However, if the inclination angles θ80 to θ83 are changed from 45 degrees, there arises a problem that the luminance is lowered.

  When the hip roof shape shown in FIG. 22 is adopted, it is possible to adjust the light distribution in two directions by changing the length L of the prism top without changing the inclination angles θ90 to 93. However, the highest luminance is obtained when the prism top is infinitely long. That is, a shape such as BEF has the highest luminance. This is because the shape such as BEF is excellent in efficiency (hereinafter referred to as retroreflectance) in which light incident from the back side is reflected by the prism structure and reflected again to the back side.

The light retroreflected by the prism structure is reflected by the light reflector on the back side of the backlight unit, is incident on the prism structure again, and is condensed on the viewer side, or retroreflected on the back side. .
The probability that the retroreflected light is reflected by the light reflector on the back side of the backlight unit and enters the prism structure again is as high as 90% to 95%, and the utilization efficiency of the retroreflected light is very large.
Therefore, if the light emitted from the prism to the observer side is not deflected in the front direction, it becomes useless light, and the light utilization efficiency is improved by returning it to the back side as retroreflected light.
Therefore, the brightness on the viewer side is increased by using a prism or lens shape having a large retroreflectance.

The reason why the hip roof shape has a small retroreflectance will be described with reference to FIG.
FIGS. 23 (a) and 23 (b) are ray diagrams showing how the light from the BEF is retroreflected. FIG. 23A is a cross-sectional view in the prism direction, and FIG. 23B is a cross-sectional view in the stripe direction.
FIGS. 23C and 23D are ray diagrams showing a state where light in the hip roof shape is retroreflected. FIG. 23C is a sawtooth sectional view, and FIG. 23D is a trapezoidal sectional view.

In the case of BEF, for example, in the cross-sectional view in the prism direction, like the light ray K1, in the cross-sectional view in the stripe direction, when the light is incident at an angle with respect to the front direction, Refracted to become a light ray K2.
Next, the light ray K2 is incident on the prism surface 87, reflected to become the light ray K3, further incident on the opposite prism surface 87, reflected to become the light ray K4, deflected to the back side to become the light ray K4, and refracted from the incident surface. Is emitted to become a light ray K5.

In the case of the hip roof shape, like the light beam K1, the sawtooth cross-sectional view is substantially parallel to the front direction. In the trapezoidal cross-sectional view, the light ray K11 incident at an angle with respect to the front direction, Refracted to become a light ray K12.
The light beam K12 is incident on the hip roof sawtooth-shaped inclined surface 110c and reflected to become the light beam K13, and is incident on the trapezoidal inclined surface 110d without entering the inclined surface 110c opposite to the inclined surface 110c on which the light beam K12 is incident. The light ray K13 is reflected by the inclined surface 110d and deflected to the back side to become the light ray K14. However, unlike the light ray K4, the incident angle on the incident surface is increased, and thus the light ray K13 is reflected by the incident surface to become the light ray K15.

The reason why the incident angle of the light ray K14 with respect to the incident surface is increased is that the inclined surface that deflects the light ray K13 toward the back side is not the inclined surface 110c that faces the inclined surface 110c that reflects the light beam K12 but the inclined surface 110c. This is because the light beam K13 is deflected to the back side by 110d.
The light ray K15 is incident on the inclined surface 110d again, refracted and emitted as the light ray K16.
For this reason, in the hip roof shape, since the retroreflectance is reduced as compared with BEF, there arises a problem that the luminance is lowered as a result.

Furthermore, the square pyramid prism shape shown in FIG. 21 and the hip roof shape shown in FIG. 21 have a problem that the yield when forming the shape is low.
This is because an independent structure is arranged on the lattice, and in a manufacturing method in which a mold and a resin are pressed and cured, such as an extrusion molding method, a UV molding method, or an injection molding, gas is generated in the resin. When mixed, the gas is confined in an independent structure and there is no escape space, so that it remains between the mold and the base material, and bubbles are formed inside the prism sheet (FIG. 13B). When bubbles are formed, a large refractive index difference is generated between the bubbles and the prism sheet, and different light distribution characteristics are generated in regions where bubbles are present and regions where bubbles are absent. Therefore, when it is installed in a display device, there is a problem that an area with bubbles is viewed by an observer and is visually recognized as a defect on the screen.

Japanese Patent Publication No. 1-378001 JP-A-6-102506 Japanese National Patent Publication No. 10-506500 JP-A-6-308485

The present invention has been made in view of such a problem, and enables light distribution adjustment in two directions with a single light control sheet, thereby reducing the number of components and using light efficiently. An object of the present invention is to provide a light control sheet that can increase the luminance, adjust the light distribution, and can be easily manufactured.
In addition, by making it possible to adjust the light distribution in two directions with a single light control sheet, the number of parts can be reduced, the light use efficiency and the brightness can be increased, and the light distribution can be adjusted. An object of the present invention is to provide a backlight unit and a display device that are easy to prepare and easy to manufacture.

In order to solve the above problems, the present invention proposes the following means.
That is, the optical sheet according to the present invention is a light control sheet that emits light by controlling an optical path of light emitted from a light source, and includes a lower bottom surface located on a first reference surface, and the first reference surface. A first cross section having a substantially trapezoidal shape, and an upper bottom surface located on a second reference plane substantially parallel to each other, and a pair of first slopes facing each other connected to the lower bottom surface and the upper bottom surface, respectively. A first lens having a shape extending in a first direction; a bottom surface positioned on the second reference surface and having a substantially polygonal shape; and a base parallel to the first direction. A pair of second inclined surfaces that are inclined to face each other, a pair of third inclined surfaces that have a base parallel to the second direction intersecting the first direction and are inclined to face each other, A second lens having at least a second slope and a top connected to the third slope; Second lens is characterized in that it is without gaps parallel to the bottom surface on the first lens.

  In the optical sheet according to the present invention, when the distance in the third direction orthogonal to the first direction of the lower bottom surface is P1, and the distance in the third direction of the upper bottom surface is P2, 0 <P2 The relationship /P1≦0.8 is established.

  In the optical sheet according to the present invention, when the distance in the third direction orthogonal to the first direction of the lower bottom surface is P1, and the distance in the third direction of the upper bottom surface is P2, 0 <P2 It is preferable that the relationship /P1≦0.5 is satisfied.

  In the optical sheet according to the present invention, it is preferable that the first direction and the second direction are substantially orthogonal to each other, and the second direction and the third direction are substantially coincident with each other.

  The optical sheet according to the present invention includes a first inclination angle formed by the first inclined surface and the second reference surface, and a second inclination angle formed by the second inclined surface and the second reference surface. Are substantially the same.

  In the optical sheet according to the present invention, it is preferable that the first inclination angle is set in a range of 35 to 55 °.

  In the optical sheet according to the present invention, it is preferable that the second inclination angle is set in a range of 35 to 55 °.

  In the optical sheet according to the present invention, it is preferable that a third inclination angle formed by the third inclined surface and the second reference surface is set in a range of 35 to 55 °.

  The backlight unit according to the present invention includes the light control sheet and a light source that emits light to the light control sheet.

  A display device according to the present invention includes the backlight unit and an image display unit that displays an image by irradiating light from the backlight unit.

  The method for manufacturing a light control sheet according to the present invention is a method for manufacturing the light control sheet, in which a resin is pressure-bonded and cured on a mold having a reverse shape of the first lens and the second lens. The first lens and the second lens are formed.

According to the light control sheet of the present invention, it is possible to adjust the light distribution in two directions with one light control sheet, thereby reducing the number of parts and increasing the light use efficiency and the luminance. In addition, it is possible to provide a light control sheet that is prepared for adjustment of the light distribution and easy to manufacture.
In addition, by making it possible to adjust the light distribution in two directions with a single light control sheet, the number of parts can be reduced, the light use efficiency and the brightness can be increased, and the light distribution can be adjusted. It is possible to provide a backlight unit and a display device that are prepared and easy to manufacture.

It is sectional drawing of the display apparatus of this embodiment. It is a figure explaining a point light source. It is a figure explaining a point light source unit. It is a figure explaining the point light source using a semiconductor laser. It is a figure explaining arrangement | positioning of a point light source. It is a figure explaining the light control sheet of this embodiment. It is a graph which shows distribution of the light distribution adjustment of the light control sheet of this embodiment, and the conventional light control sheet. It is a graph which shows distribution of the retroreflectance of the light control sheet of this embodiment, and the conventional light control sheet. It is a figure explaining the reason which retroreflectance improves in the light control sheet of this embodiment. It is a graph which shows distribution of the retroreflectance of the light control sheet of this embodiment, and the conventional light control sheet. It is a graph which shows distribution of the retroreflectance of the light control sheet of this embodiment, and the conventional light control sheet. It is a figure explaining the light control sheet of this embodiment. It is a mold used when producing the light control sheet of this embodiment. It is a figure explaining the shaping | molding method of the light control sheet of this embodiment, and the conventional light control sheet. It is a longitudinal cross-sectional view of a display device on which a conventional light guide plate light guide type backlight unit is mounted. It is a longitudinal cross-sectional view of the display apparatus which provided the prism film of the prior art between the diffusion film and the liquid crystal panel. It is a longitudinal cross-sectional view of the display apparatus provided with the direct-type backlight unit of the prior art. It is a perspective view of the light control sheet | seat provided with the prism film of a prior art. It is a longitudinal cross-sectional view of the principal part of the display apparatus by which the light control sheet provided with the prism film of a prior art is arrange | positioned. It is a figure which shows the light intensity distribution of the light control sheet provided with the prism film of a prior art. It is a figure explaining the light control sheet | seat of a square pyramid shape of a prior art. It is a figure explaining the light control sheet | seat of a hip roof shape of a prior art. It is a figure explaining the fall reason of the retroreflectance of a prior art.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view of the display device of this embodiment. In FIG. 1, the reduced scale of each component does not match the actual one.

  As shown in FIG. 1, the display device 27 according to the embodiment of the present invention is provided by overlapping a display unit (screen display unit) 21 on a backlight unit 13 that irradiates light to the viewer side F. The liquid crystal display device is configured to display a planar image by emitting display light whose display is controlled by an image signal from the display unit 21 toward the observer side F. In the following, the upper direction in FIG. 1 is referred to as an observer side F, and the lower direction is referred to as a back side.

  The backlight unit 13 includes an illumination light path control light control sheet 1, a diffuser plate 25, and a light source 41 that are arranged facing the light incident side of the display unit 21. Further, a light reflection plate 43 for reusing the light reflected by the diffusion plate 25 and the light control sheet 1 is disposed on the back side of the light source 41.

  The light source 41 supplies light H used for image display of the display unit 21. Here, examples of the light source 41 used in the present invention include the following linear light sources and point light sources.

  When the light source 41 is a line light source, a thin rod-shaped cold cathode tube is used. The line light source is not limited to the cold cathode tube, and may be other. That is, the light source 41 includes a normal fluorescent tube, a hot cathode tube, an external electrode tube, a mercury-less rare gas fluorescent lamp, a light emitting diode (hereinafter referred to as an LED) arranged in a row, a semiconductor laser, in addition to a cold cathode tube. Can be used as a linear light source. Among these, it is particularly preferable to use cold cathode tubes, external electrode tubes, or LEDs arranged in a line.

  Alternatively, a light source 41 may be an LED light source using a cylindrical or prismatic transparent light guide having a length equivalent to the parallel grooves of the light guide plate and LEDs arranged on the top and bottom surfaces of the light guide. Good. Such an LED light source can emit LED light from the side surface of the light guide by entering LED light from the top and bottom surfaces of the light guide.

  When a line light source is used as the light source 41, the distance between the centers of adjacent line light sources is preferably set to 15 mm to 150 mm, and more preferably set to 20 mm to 60 mm. By setting the distance between the centers of the line light sources in the above range, the power consumption of the backlight unit 13 can be reduced, the assembly of the backlight unit 13 can be facilitated, and the luminance unevenness of the light emitting surface can be suppressed. .

  In addition, the distance between the centers of adjacent line light sources may be uniformly uniform in all locations, or may be partially changed. The case of partial change is, for example, a case where the distance between point light sources is narrowed at the center of the backlight unit 13 or the like.

  The dimension of the shortest distance between the center position of the line light source as the light source 41 and the incident surface of the diffusion plate 25 is preferably set to 2 mm to 30 mm or less, and more preferably set to 5 mm to 25 mm.

  In the case where the light source 41 is a line light source, the number thereof is not particularly limited. For example, when the backlight unit 13 is used in a 32-inch display device 27, the number of linear light sources may be, for example, an even number such as 16, 14, 12, 8, or an odd number. it can.

  When a point light source is used as the light source 41, it is preferable to adopt an LED that does not contain mercury and has high luminous efficiency.

FIG. 2A shows a white LED 46 used in a mobile device such as a mobile phone. The white LED 46 is configured by covering a blue LED element 50 that emits blue light with an LED lens 46, and a phosphor 51 that emits yellow light is coated on the inner surface of the LED lens 46. Thereby, it emits light as pseudo white. The white LED 46 having this configuration has an advantage that pseudo white light emission can be realized only by covering the phosphor 51 with the monochromatic blue LED element 50.
The light source 41 is not limited to the white LED 46 described above, and may have other configurations as long as one single-color LED element is covered with at least one kind of phosphor.

The phosphor may be a phosphor activated on a crystal matrix with an element called a transition metal ion as the emission center. Alternatively, these metal oxides and organometallic complexes may be used. These include Cr (chromium), Fe (iron), Mn (manganese) and the like.
As the crystal matrix of the phosphor to be the light emitter, ZnS, CaS, SrS, IIa-III-IV type such as BaAl2S4, SrAl2S4, CaAl2S4, IIx-IIIy-IVz type such as BaAl2S4, BaAl4S7, CaAl2S4, Sr2Al2S4, etc. Sulfides, ZnO, BeO, MgO, CdO, Y2O3, CaGa2O3, Zn2GeO4, (Y2O3) 0.6- (GeO2) 0.4, and other oxides, Y-Si-O-N, SrSi6N8, LaAl (Si6- z) N10-zOz (JEM), represented by MSi2O2N2 (M is Ca, Sr, Ba) Alkaline earth nitride, MxSi12- (m + n) Alm + nOnN16-n (M is Ca, Sr, Ba) α-sialon, β 6-Si represented by Si6-zAlzOzN8-z Ron, AlN, GaN, CASN like represented by CaAlSiN3 and the like.

When the white LED 46 that covers the phosphor 51 is used for the blue LED element 50 described above, it is preferable to use a phosphor that emits yellow light. Examples of phosphors that emit yellow light include YAG (yttrium, aluminum, garnet).
By using a phosphor that emits yellow light, a white LED 46 with high luminous efficiency (lm / W) can be obtained. This is because the human eye feels bright (high visibility) even with a small amount of energy when the wavelength spectrum of light is concentrated at a wavelength from orange to yellow (around 555 nm). For this reason, a white LED 46 that is very bright visually can be obtained by combining the yellow phosphor 51 and the blue LED element 50 whose spectrum is concentrated at a wavelength with high visibility.

  The phosphor 51 may be a combination of a phosphor that emits red light and a phosphor that emits green light. By using the phosphors in the above combination, the distribution of the wavelength spectrum emitted by the white LED 46 is widened, so that the displayable color range when used as a display device can be widened, and the image quality is improved.

  FIG. 2 (b) is obtained by adding a prism 53a to the LED lens 53 of FIG. 2 (a). The light distribution of the light emitted from the white LED 46 can be adjusted by the prism 53a.

  FIG. 2 (c) shows a configuration in which pseudo-white light is emitted by combining LED elements (red LED element 48, green LED element 49, blue LED element 50) that emit light in a single color as another method of LEDs emitting pseudo-white light. belongs to. In this case, compared with the case of FIG. 2A as described above, the problem that the phosphor 51 deteriorates due to the heat generated from the LED elements can be avoided, and any color can be achieved by adjusting the light quantity of each LED element. Can be obtained.

  FIG. 3 shows a point light source unit configured by combining single color LEDs (red LED 54, green LED 55, blue LED 56) that emit light in a single color. In this case, the red LED 54, the green LED 55, and the blue LED 56 may be combined one by one as shown in FIG. 3B to constitute the point light source unit 52, or the light output is weak as shown in FIG. 3C. A plurality of (for example, green LEDs 55) may be arranged to constitute the point light source unit 52.

By forming such a point light source unit 52, it is also possible to adopt a configuration in which color display is performed using a field sequential method in which LEDs of each color are colored in a time-sharing manner.
When this point light source unit 52 is formed, the number of LEDs is not limited. When a plurality of point light source units 52 are arranged, it is preferable that adjacent point light source units 52 have different light emission colors of the facing LEDs. This is because, if the light emission colors of the facing LEDs are the same, the intensity of the light emission color is increased, and there is a possibility that the observer side F may visually recognize the color unevenness.

When a point light source is used as the light source 41, in addition to the above-described LED, for example, as shown in FIG. 4, the light of a monochromatic semiconductor laser (red semiconductor laser 57, green semiconductor laser 58, blue semiconductor laser 59) is used. Alternatively, the color may be mixed through the fiber 60 and emitted from the semiconductor laser lens 61.
In addition, a point light source such as a normal fluorescent lamp or a halogen lamp may be used as the light source 41.

  Moreover, you may comprise the above-mentioned point light source unit 52 by combining each said point light source. As an example, a point light source unit may be configured by combining a white LED 46 and a red LED, which is a single color LED. In such a configuration, red light can be complemented to white light of a white LED by emitting red light of the red LED. Therefore, the color reproducibility can be improved.

  Note that the point light source 41 and the point light source unit 52 described above may be divided and driven by arrangement location. As a result, the point light source 41 and the point light source unit 52 at a place where a bright image is displayed are caused to emit light, and the point light source 41 and the point light source unit 52 at a place where a dark image is displayed are turned off or the light emission amount is reduced. The difference can be increased. Therefore, the contrast of the image can be increased.

Next, an arrangement mode when a point light source is used as the light source 41 will be described. FIG. 5 is a plan view schematically showing an arrangement mode of a plurality of light sources 41 or point light source units 52.
As a 1st aspect which arrange | positions the several light source 41 or the point light source unit 52, as shown to Fig.5 (a), the structure arrange | positioned along the surface direction of the backlight unit 13 at predetermined intervals is mentioned.
As a second mode, as shown in FIG. 5 (b), the light source 41 or the point light source unit 52 in FIG. 5 (a) is removed, that is, each of the four vertices of the quadrangle. A configuration in which the point light source 41 or the point light source unit 52 is disposed and the point light source 41 or the point light source unit 52 is disposed at the intersection of the rectangular diagonal lines can be given.
Further, as a third aspect, as shown in FIG. 5C, a configuration in which a light source 41 or a point light source unit 52 is arranged at each vertex of a honeycomb structure in which regular hexagons are continuously formed can be given. It is done.
In addition, as shown in FIG.5 (d), it is good also as a structure which has arrange | positioned the point light source 41 or the point light source unit 52 in linear form.

  In the above aspect, the space | interval of the light source 41 or the point light source units 52 may be uniformly uniform in all the places, and may be changing partially. The case where it changes partially is a case where the space | interval between the light sources 41 narrows in the center location of the backlight unit 13, etc., for example.

  In addition, it is preferable that the distance between the centers of the adjacent point light source units 52 is 15 mm-150 mm, and it is more preferable that it is especially 20 mm-60 mm. By setting it as such a range, while the power consumption of the backlight unit 13 can be reduced, the assembly of the said apparatus becomes easy and the brightness nonuniformity of the light emission surface can be suppressed.

  The dimension of the shortest distance between the center of the point light source 41 or the point light source unit 52 and the incident surface of the diffuser plate 25 may be designed in consideration of the thickness of the backlight unit 13 and the uniformity of brightness, but is 1 mm to 30 mm. It is preferable that the thickness is 3 mm to 25 mm. As a result, luminance unevenness can be reduced, and reduction in the light emission efficiency of the light source 41 can be prevented. In addition, the entire thickness of the backlight unit 13 can be reduced.

  In the present embodiment, the direct-type backlight unit 13 as described above is employed, but instead, a plurality of light sources are arranged in the reflector, and incident from the light sources on the sides thereof. An edge light system in which a light guide plate that emits light to the viewer side F may be employed. It is composed of that.

  A part of the light emitted from the light source 41 enters the reflection plate 43 installed on the back side of the light source 41 and is reflected to the front side. The reflection plate 43 may be formed of any material that can reflect the light from the light source 41. For example, a void is formed by stretching a filler or air in PET, PP (polypropylene) or the like and then stretching it. Resin sheet with high reflectivity formed, sheet with mirror surface formed by vapor deposition of aluminum on transparent or white resin sheet surface, resin sheet carrying metal foil or metal foil such as aluminum, or sufficient reflection on the surface It can form with the metal thin plate which has property.

  The reflection plate 43 is preferably diffuse reflection instead of specular reflection. By making the diffuse reflection, when the light retroreflected from the light control sheet 1 is diffusely reflected, the polarization of the light is randomized or the incident angle is randomized. This makes it possible to improve the probability of condensing on the observer side F when the light enters the light control sheet 1 again.

  The light emitted from the light source 41 is incident on the incident surface of the diffusion plate 25 directly or through reflection by the reflection plate 43. The light incident on the diffusion plate 25 is diffused by the uneven structure of the incident surface of the diffuser plate 25, the refractive index difference between the diffusion region inside the diffuser plate 25 and the transparent resin, and the uneven structure of the exit surface of the diffuser plate 25. The

The diffusion plate 25 is configured by dispersing a light diffusion region in a transparent resin.
As the transparent resin, a thermoplastic resin, a thermosetting resin or the like can be used. For example, a polycarbonate resin, an acrylic resin, a fluorine acrylic resin, a silicone acrylic resin, an epoxy acrylate resin, a polystyrene resin, a cycloolefin polymer, Methyl styrene resin, fluorene resin, polyethylene terephthalate (PET), polypropylene, acrylonitrile polystyrene copolymer, and the like can be used.

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

  When the above light diffusing particles are used as the light diffusing region, the thickness of the diffusing plate 25 is preferably 0.1 to 5 mm. When the thickness of the diffusion plate 25 is 0.1 to 5 mm, optimum diffusion performance and brightness can be obtained. On the other hand, if the thickness is less than 0.1 mm, the diffusion performance is insufficient, and if it exceeds 5 mm, the amount of resin is large and the luminance is reduced by absorption, which is not preferable.

In the case where a thermoplastic resin is used as the transparent resin, air bubbles may be used as the light diffusion region. The internal surface of the bubble formed inside the thermoplastic resin causes diffused reflection of light, and a light diffusing function equivalent to or higher than that when light diffusing particles are dispersed can be expressed. Therefore, it becomes possible to make the film thickness of the diffusion plate 25 thinner.
Examples of the diffusion plate 25 include white PET and white PP. White PET is obtained by dispersing a resin incompatible with PET, fillers such as titanium oxide (TiO2) and barium sulfate (BaSO4) in PET, and then stretching the PET by a biaxial stretching method. It is formed by generating bubbles around the filler.

  Note that the diffusion plate 25 made of thermoplastic resin only needs to be stretched in at least one axial direction. This is because if it is stretched in at least one axial direction, bubbles can be generated around the filler.

  Examples of the thermoplastic resin include polyethylene terephthalate (PET), polyethylene-2, 6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, cyclohexanedimethanol copolymer polyester resin, isophthalic acid copolymer polyester resin, and spiroglycol copolymer polyester resin. , Polyester resins such as fluorene copolymerized polyester resins, polyolefin resins such as polyethylene, polypropylene, polymethylpentene, alicyclic olefin copolymer resins, acrylic resins such as polymethyl methacrylate, polycarbonate, polystyrene, polyamide, polyether, Polyester amide, polyether ester, polyvinyl chloride, cycloolefin polymer, acrylonitrile polystyrene copolymer Beauty These copolymer as a component, or the like can be used a mixture of these resins are not particularly limited.

  When bubbles are used as the light diffusion region, the thickness of the diffusion plate 25 is preferably 25 to 500 μm. When the thickness of the diffusing plate 25 is less than 25 μm, it is not preferable because the sheet is insufficiently squeezed and wrinkles are easily generated in the manufacturing process and display. In addition, when the thickness of the diffusion plate 25 exceeds 500 μm, there is no particular problem in optical performance. However, since the rigidity is increased, it is difficult to process into a roll shape and the slit cannot be easily formed. This is not preferable because the merit of the thinness obtained is reduced.

Furthermore, an uneven shape (not shown) may be formed on the surface of the diffusion plate 25. With this uneven shape, the light emitted from the diffusion plate 25 can be diffused to further improve the uniformity of the light. In this case, the concavo-convex shape is preferably a prism shape or a lens shape having a center line average roughness Ra of 3 μm to 1,000 μm. In the case of the prism shape, the prism shape is preferably polygonal, the prism apex angle is preferably 40 ° to 170 °, and the prism pitch is preferably 20 μm to 700 μm. The prism shape may be a pyramid shape or a truncated pyramid shape. The uneven shape described above may change its shape in accordance with the illuminance or brightness of light incident on the uneven shape. For example, in the region where the illuminance or brightness of light incident on the uneven shape is large, the prism tops described above may be used. You may make a corner small.
The uneven shape may be formed on a matte surface such as a satin finish. Furthermore, the total light transmittance of the diffusion plate in this case is preferably 40% or more and 98% or less, the haze is preferably 20% to 100%, and the water absorption is preferably 0.25% or less.

The diffusing plate 25 as described above can be manufactured using a known technique such as a co-extrusion molding method, an injection molding method, a hot press method, a cast polymerization method, or the like.
In addition, as a method for forming the uneven shape on the diffusion plate 25, during the formation of the diffusion plate 25 by the above-described coextrusion forming method or injection molding method, pressure is applied to the mold for forming the uneven shape. Uneven shape can be transferred. Alternatively, the incident surface or the exit surface of the diffusion plate 25 can be molded using a radiation curable resin such as a UV curable resin. For example, after the diffusion plate 25 is formed as a plate-like member by a coextrusion method, an uneven shape can be formed by UV molding on the incident surface or the emission surface of the diffusion plate 25.

  Alternatively, the film having the uneven shape may be formed as a separate body, and the film having the uneven shape and the diffusion plate 25 may be bonded to each other through a bonding layer made of an adhesive or an adhesive material.

As the above-described method for producing a concavo-convex film, the film may be formed on a translucent film using UV or radiation curable resin (the type is not particularly limited as long as the resin includes a material that is cured by UV or radiation). Here, as the translucent film, PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate) PMMA (polymethyl methacrylate), benzyl methacrylate, MS resin, other acrylic resins, or COP (cycloolefin polymer) It is preferable to use an optically transparent member such as.
Alternatively, the technology using PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer), PAN (polyacrylonitrile copolymer), AS (acrylonitrile styrene copolymer), etc. It may be formed by an extrusion molding method, injection molding method, or hot press molding method well known in the field.

  The light emitted from the diffusion plate 25 enters the incident surface of the light control sheet 1. The light control sheet 1 controls at least one of the optical characteristics of light, that is, the emission direction, the range, the color, and the luminance distribution when the incident light is emitted from the emission surface.

As shown in FIGS. 1 and 6, the light control sheet 1 of the present embodiment has a plurality of first lenses 3 formed on the surface of the light-transmitting substrate 6 facing the observer side F, and further the first lens 3. The second lens 5 is formed on the lens 3.
6A is a perspective view of the lens shape of the light control sheet of the present embodiment, and FIG. 6B is a top view of the lens shape of the light control sheet of the present embodiment. ) Is a cross-sectional view orthogonal to the x-direction of the lens shape of the light control sheet of the present embodiment, and FIG. 6D is a cross-sectional view orthogonal to the y-direction of the lens shape of the light control sheet of the present embodiment.

As shown in FIG. 1, the light-transmitting substrate 6 is a transparent member having a substantially plate shape or sheet shape, and one surface facing the back side is an incident surface 6a, and the other surface facing the front direction. Is the exit surface 6b.
The exit surface 6b of the light transmissive substrate 6 is disposed on the flat first reference surface 2, and a plane spaced apart from the first reference surface 2 by a certain distance in the front direction is the first reference surface 2. The second reference surface 4 is substantially parallel to the reference surface 2.

As shown in FIG. 6 (c), the first lens 3 includes a lower bottom surface 3 a located on the first reference surface 2, that is, on the emission surface 6 b of the light transmitting substrate 6, and the second reference surface. An upper bottom surface 3b located on the surface 4 and a pair of first inclined surfaces 3c connected to the lower bottom surfaces 3a and 3b and facing each other are provided. That is, when the direction along the x direction is the first direction x, the first lens 3 emits the first cross-sectional shape 3d having a substantially trapezoidal shape shown in FIG. It has a substantially trapezoidal prism shape extending in the first direction x along the surface 6b (first reference surface 2).
As shown in FIG. 1, a plurality of such first lenses 3 are arranged in parallel on the emission surface 6 b of the light-transmitting substrate 6 in parallel with each other without a gap.

  The lower bottom surface 3a, the upper bottom surface 3b, and the first inclined surface 3c each have a rectangular shape, and the first cross-sectional shape 3b has the lower bottom surface 3a as the lower bottom and the upper bottom surface 3b longer than the lower bottom. It has an isosceles trapezoidal shape with a short upper base and a pair of first inclined surfaces 3c having a pair of oblique sides having the same length.

The second lens 5 has a quadrangular bottom surface 5a located on the second reference surface 4, that is, the upper bottom surface 3b of the first lens 3, and a base parallel to the first direction x. A pair of second slopes 5b that are inclined to face each other and a pair of third slopes 5c that have a base parallel to the second direction y intersecting the first direction x and are inclined to face each other. And a top 5d connected to the second inclined surface 5b and the third inclined surface 5c.
In the above description, the case where the bottom surface 5a is rectangular has been described. However, if the second lens 5 has a structure having at least the second inclined surface 5b, the third inclined surface 5c, and the top portion 5d, the bottom surface 5a is not rectangular. It may be a polygon.
For example, the bottom surface 5a may be a triangle, and the triangular pyramid-shaped second lens 5 may be disposed on the first lens 3 without a gap.

Here, the second direction y is a direction that intersects the first direction x and is along the second reference plane 4. In particular, in the present embodiment, the direction that is orthogonal to the first direction x. It is said that. The second direction y only needs to intersect the first direction x, and does not necessarily have to be orthogonal to the first direction x.
Further, the bottom surface 5a of the second lens 5 is a quadrangle having four sides along the first direction x and the second direction y, and the four sides of the quadrangle are along the first direction x. The two sides are connected to the upper ends of the pair of first slopes 3 c in the first lens 3.
As shown in FIG. 6 (d), a plurality of such second lenses 5 are arranged in parallel along the first direction on the upper bottom surface 3 b of the first lens 3 without gaps. .

Here, a direction orthogonal to the first direction x and along the first reference plane 3 and the second reference plane 4 is defined as a third direction y. In the present embodiment, since the second direction y is orthogonal to the first direction x, the third direction and the second direction are both directions along the y direction.
Further, the distance in the third direction y of the lower bottom surface 3a is P1, the distance in the third direction y of the upper bottom surface 3b is P2, and one second lens 5 in the portion where the bottom surface 5a and the first inclined surface 3c are in contact with each other. Is the distance P3, the first inclination angle formed by the first slope 3c and the second reference plane 4 is θ1, and the second inclination angle formed by the second slope 5b and the second reference plane 4 is θ2. The third inclination angle formed by the third inclined surface 5c and the second reference surface 4 is θ3, and the distance in the third direction y of the top portion 5d is L.

  The light incident on the first lens 3 and the second lens 5 is incident on the first inclined surface 3c, or the second inclined surface 5c or the third inclined surface 5d, and a part of the light is refracted to the observer side. The light is emitted to F, and the other light is reflected, emitted to the back side, and retroreflected.

Here, in the light control sheet 1, in order to efficiently collect light, it is preferable not to provide a flat surface that is not given to the light collection. Therefore, in the light control sheet 1 of the present embodiment, the second lens 5 is arranged on the first lens 3 without a gap so that there is no flat surface that does not impart light collection. . Thereby, a condensing function can be improved with respect to two directions.
Furthermore, since the first lenses 3 are arranged without gaps on the light-transmitting substrate 6 of the light control sheet 1, there is no flat surface that does not give light collection, and the light collection function is improved. It has been.

  The light control sheet 1 of the present embodiment can increase the range in which the light distribution can be adjusted by arranging the second lens 5 on the first lens 3. Furthermore, by adjusting the parameters θ1 to θ3 or the ratio of L and P1, it is possible to adjust the light distribution in the x direction and the light distribution in the y direction.

Even in the hip roof shape shown in FIG. 21, it is possible to adjust the light distribution in the x direction and the light distribution in the y direction by adjusting the ratio of θ90 to 93 or L and P1. Compared with, the adjustment range of light distribution is small.
This is because even if the ratio of L and P1 is changed, the light collecting ability in the trapezoidal cross-sectional direction cannot be made larger than the light collecting ability in the cross-sectional direction of the sawtooth shape.
The light collecting ability in the cross-sectional direction of the trapezoidal shape is greatest when θ90 and θ91 are 45 degrees and L / P1 is 0%, that is, a quadrangular pyramid shape. If L / P1 is increased from here, the light collecting ability in the cross-sectional direction of the trapezoidal shape decreases. By changing the values of θ92 and θ93 from 45 degrees, the light collecting ability in the sawtooth cross-sectional direction is reduced, and the light collecting ability in the trapezoidal cross-sectional direction is relatively reduced. However, it is not preferable because the light collecting ability of the entire hip roof shape is lowered and the luminance is reduced.

FIG. 7 shows a graph of light distribution adjustment distribution of the light control sheet 1. In FIG. 7, the horizontal axis indicates L / P1, and the vertical axis indicates the half-value angle.
For the light control sheet 1 of the embodiment, θ1 to θ3 are 45 degrees, P3 / P1 is 1/6, and L / P1 is changed from 0% to 80%.
In addition, as a comparative example, a simulation result in which the hip roof shape is used and θ90 to 93 is set to 45 degrees and L / P1 is changed from 0% to 90% is plotted by ×.
The half-value angle is an angle at which the luminance is half of the reference luminance when observed from an observer side F and observed with an angle on the basis of the luminance in the front direction (angle 0).

From FIG. 7, in the light control sheet 1 of this embodiment, by adjusting L / P1, when L / P1 is 0% to 30%, the light collecting ability in the third direction y is relatively large, and L / P1 is 50. From 80% to 80%, the light collecting ability in the third direction y is relatively large, and when L / P1 is 40%, the light collecting ability in the first direction x and the second direction y are equal. It was.
On the other hand, when the L / P1 is 10% to 80%, the hip roof has a relatively large converging ability in the sawtooth cross-sectional direction. When the L / P1 is 0%, the sawtooth cross-sectional direction and the trapezoidal cross-sectional direction are used. The light condensing capacity is the same. However, it was found that the light collecting ability in the trapezoidal cross-sectional direction is not larger than the light collecting ability in the cross-sectional direction of the sawtooth shape.
Therefore, it was found that the light control sheet 1 of the present embodiment has a range in which the light distribution can be adjusted larger than the hip roof shape.

  The light distribution characteristics may be appropriately designed according to the installation location of the backlight unit 13 and the display device 27 and the required characteristics, and the light distribution is adjusted by setting θ1 to θ3 and L / P1 to arbitrary values. Is possible.

  For example, when the display device 27 of the present embodiment is used for television, it is desirable that the horizontal half-value angle of the display device is wide. This is because when observing the television, the observer observes the television from various positions in the horizontal direction. However, when the display device 27 of the present embodiment is used for advertising billboards or the like, it may be desirable that the half-value angle in the vertical direction is wide.

Moreover, according to the light control sheet 1 of the present embodiment, the retroreflectance is high, and the luminance can be improved.
FIG. 8 shows a graph of the retroreflectance distribution for each incident angle on the light control sheet 1. In FIG. 8, the horizontal axis indicates the incident angle of light, and the vertical axis indicates the retroreflectance.
As for the light control sheet 1, θ1 to θ3 is 45 degrees, P3 / P1 is 1/6, L / P1 is 10% (FIG. 8A), and L / P1 is 80%. The simulation result in the case (FIG. 8B) is shown.
In addition, as a comparative example, when the hip roof shape is set, θ90 to 93 is set to 45 degrees, L / P1 is set to 10% (FIG. 8A), and L / P1 is set to 80% (FIG. 8B). )) Simulation results are shown.

From FIG. 8A, in the light control sheet 1 of the present embodiment, the retroreflectance is larger than the hip roof shape having the same L / P1 in the light incident angle range of 35 to 85 degrees. I understand that.
The reason for this will be described with reference to FIGS. 9B and 9C.

  9 shows a conventional prism (FIG. 9A), a hip roof shape (FIG. 9B), and a light control sheet 1 of the embodiment (FIGS. 12C to 12D) having an incident angle of 60. It is a figure which shows the optical path of the light ray in the case of entering at a degree.

  In FIG. 9, the optical paths of the light rays K21, K31, K41, and K51 are shown as an example of the light rays when incident at an incident angle of 60 degrees. The light rays K21, K31, K41, and K51 are light rays that are incident at an angle of 60 degrees with respect to the front direction in the y direction without an angle in the x direction.

FIG. 9A is a diagram showing the light path of the light beam in the conventional prism.
In the x direction, there is no angle and it is substantially parallel to the front direction, and in the y direction, the incident light ray K21 having an angle of 60 degrees with respect to the front direction is refracted at the incident surface to become the light ray K22. Reflected to become a light ray K23. The light ray K23 is incident on the inclined surface 87 opposite to the inclined surface 87 on which the light beam K22 is incident at a small incident angle, so that the light beam K23 is transmitted without being reflected by the inclined surface 87, and is emitted as the light beam K24.
Since the light K24 is emitted with a large angle with the front direction, the light use efficiency does not increase without improving the luminance in the front direction.

FIG. 9B is a diagram showing the light path of the light beam in the hip roof shape.
A light ray K31 incident at an angle of 60 degrees with respect to the front direction in the y direction without being angled in the x direction is refracted at the incident surface to become a light ray K32, and is incident on the inclined surface 110b. Reflected to become a ray K33.
The light beam K33 is reflected by the inclined surface 110c intersecting the inclined surface 110b to become the light beam K34, reflected by the inclined surface 110c opposite to the inclined surface 110c on which the light beam K33 is incident, deflected to the back side, and incident on the incident surface. Become.
Since the light ray K35 has a large incident angle with respect to the incident surface, the light ray K35 is reflected without being transmitted and deflected to the observation side F to become a light ray K36. The light beam K36 is refracted by being incident on the inclined surface 110b opposite to the inclined surface 110b on which the light beam K32 is incident, and is emitted to the viewer side as the light beam K37. Since the light beam K37 is emitted with a large angle with the front direction, the light utilization efficiency is reduced without giving the luminance improvement in the front direction.

FIG.9 (c) is the figure which showed the optical path of the light ray in the light control sheet 1 of this embodiment.
A light ray K41 incident at an angle of 60 degrees with respect to the front direction in the y direction without an angle in the x direction is refracted at the incident surface to become a light ray K42. The light beam K43 is reflected by the inclined surface 3c.
The light ray K43 is transmitted through the first lens 3, reflected by the third slope 5c of the second lens 5 to become the light ray K44, and the third slope 5c facing the third slope 5c on which the light ray K43 is incident. And is deflected to the back side to become a light ray K45.

Unlike the light beam K35 in the hip roof shape of FIG. 9B, the light beam K45 does not enter the incident surface, and the first inclined surface 3c facing the first inclined surface 3c on which the light beam K42 is incident, or the second inclined surface 5b. (In the figure, it is incident on the first inclined surface 3c)
This is because the probability of deflecting to the back side before entering the second lens 5 is low, and the probability of deflecting to the back side by the second lens 5 is high. Therefore, the moving distance of the light ray K43 in the y direction is larger than that of the light ray K33, and as a result, the first inclined surface 3c or the second inclined surface 5b facing the first inclined surface 3c on which the light ray K42 is incident. Since the light ray K44 is deflected to the back side in the vicinity, the light ray K45 has a high probability of being incident on the first inclined surface 3c opposite to the first inclined surface 3c on which the light ray K42 is incident or the second inclined surface 5b. Become.
The light ray K45 is reflected by the first inclined surface 3c or the second inclined surface 5b, and becomes the light ray K46 whose incident angle to the incident surface is smaller than the light ray K45. Since the incident angle with respect to the incident surface is small, the light ray K46 has a high probability of being transmitted without being reflected, and is refracted to become the light ray K47 to be retroreflected light.

As described above, the third lens 3 deflects the light beam K43 in the x-direction cross section on the first lens 3 having no slope for deflecting the light beam K43 in the cross-section in the x direction. By providing the second lens 5 having the inclined surface 5c, the moving distance of the light beam K43 in the y direction is increased, and the light beam K45 deflected to the back side is transmitted by the first inclined surface 3c or the second inclined surface 5b. Further, the light is reflected, and the incident angle on the incident surface can be reduced.
As a result, as shown in FIG. 8A, the retroreflectance in the range of the incident angle of 35 degrees to 85 degrees is increased, and the retroreflectance of the entire light control sheet 1 is increased. As a result, the light utilization efficiency is improved and the luminance is improved.

  However, when L / P1 is set to 80% in FIG. 8B, the retroreflectance in the range of the incident angle of 35 degrees to 85 degrees becomes small, and as a result, the L / P1 is retroreflected more than the hip roof shape. The rate is reduced.

The reason for this will be described with reference to FIG. In the light control sheet 1 shown in FIG. 9D, the height of the first lens is small and P2 is large compared to the light control sheet 1 shown in FIG.
A light ray K51 incident at an angle of 60 degrees with respect to the front direction in the y direction without being angled in the x direction is refracted at the incident surface to become a light ray K52. It is reflected by the inclined surface 3c and becomes a light ray K53.
In FIG. 9, a light ray K53 is transmitted through the first lens 3, reflected by the third slope 5c of the second lens 5 to become a light ray K54, and is opposed to the third slope 5c on which the light ray K53 is incident. 3 is reflected by the inclined surface 5c and deflected to the back side to become a light ray K55.

The light ray K55 is different from the light ray K45 of FIG. 9C, and the light ray K55 is incident on the first inclined surface 3c opposite to the first inclined surface 3c on which the light ray K52 is incident or the second inclined surface 5b. Incident on the surface. This is because, unlike FIG. 9C, since the light ray K53 enters the second lens 5 at a short distance, the probability that the light ray 53 is deflected to the back side with a small movement distance in the y direction increases. is there.
As a result, the light ray K54 is deflected to the back side at a distance from the first inclined surface 3c or the second inclined surface 5b opposite to the first inclined surface 3c on which the light ray K52 is incident. The probability of entering the incident surface without entering the first inclined surface 3c facing the incident first inclined surface 3c or the second inclined surface 5b is increased.

  When the light is not incident on the first inclined surface 3c or the second inclined surface 5b and is not reflected, the incident angle of the light ray K55 is larger than the incident angle of the light ray K45. The light beam K56 is deflected in the right direction. The light ray K56 is incident on the first inclined surface 3c or the second inclined surface 5b facing the first inclined surface 3c on which the light ray K52 is incident. Since the light ray K56 is incident on the first inclined surface 3c or the second inclined surface 5b at a small incident angle, the light ray K56 is refracted and transmitted without being reflected to become a light ray K57. The light beam K57 is emitted at a large angle with the front direction, and thus is not imparted to improving the luminance in the front direction, resulting in a decrease in light use efficiency.

As described above, when the height of the first lens 3 is not sufficiently high, the moving distance of the light beam K53 in the y direction is insufficient, so that the light beam K55 faces the first inclined surface 3c on which the light beam K52 is incident. The light does not enter the first inclined surface 3c or the second inclined surface 5b, and as a result, the light ray K55 is incident on the incident surface at a large incident angle and reflected, and thus does not become retroreflected light.
Therefore, as shown in FIG. 11B, the retroreflectance in the range of the incident angle of 35 degrees to 85 degrees becomes small, and the retroreflectance of the entire light control sheet becomes small. As a result, the light use efficiency is reduced and the luminance is reduced.

  10 and 11 and Table 1 are simulations in the light control sheet 1 where θ1 to θ3 are 45 degrees, P3 / P1 is 1/3 to 1/20, and L / P1 is in the range of 0% to 90%. It is a result.

  In FIG. 10, the chain line indicates the retroreflectance of the conventional prism having a light collecting action only in one direction, and the alternate long and short dash line indicates the retroreflectance of the quadrangular pyramid prism. Moreover, the plot of x shows the retroreflectance of the hip roof shape. The rhombus plot is a retroreflectance of P3 / P1 of 1/3 of the light control sheet 1 of this embodiment, and the round plot is a recursion of P3 / P1 of the light control sheet 1 of this embodiment of 1/6. The triangular plot is a retroreflectance in which P3 / P1 of the light control sheet 1 of this embodiment is 1/10, and the square plot is P3 / P1 of the light control sheet 1 of this embodiment is 1. / 20 retroreflectivity.

  In the plot of the light control sheet 1 in FIG. 10, P2 / P1 is 0% or more and 50% or less when the plot points are outlined, and P2 / P1 is when the plot points are displayed relatively large. P1 exceeds 80%.

  In FIG. 11, the chain line indicates the retroreflectance of the conventional prism having a light collecting action only in one direction, and the alternate long and short dash line indicates the retroreflectance of the prism having a quadrangular pyramid shape. The rhombus plot is a retroreflectance of P3 / P1 of 1/3 of the light control sheet 1 of this embodiment, and the round plot is a recursion of P3 / P1 of the light control sheet 1 of this embodiment of 1/6. The triangular plot is a retroreflectance in which P3 / P1 of the light control sheet 1 of this embodiment is 1/10, and the square plot is P3 / P1 of the light control sheet 1 of this embodiment is 1. / 20 retroreflectivity.

As shown in FIGS. 10 and 11, the light control sheet 1 of the present embodiment exceeds the retroreflectance of the quadrangular pyramid shape regardless of the values of P2 / P1 and L / P1.
That is, by using the configuration of the light control sheet 1 of the present embodiment, a light control sheet that can adjust light distribution in two directions, has a higher retroreflectivity than a quadrangular pyramid, and has high light utilization efficiency as a result. It becomes possible to do.

Also, as shown in FIG. 10, the light control sheet 1 of the present embodiment has the same retroreflectance when P2 / P1 is 0% or more and 80% or less when L / P1 is the same as compared with the hip roof shape. That's it.
That is, in the configuration of the light control sheet 1 of the embodiment, by adjusting P2 / P1 to 0% or more and 80% or less, light distribution adjustment in two directions is possible, and the retroreflectivity is compared with the hip roof shape. As a result, it is possible to provide a light control sheet having a light use efficiency equal to or higher than that of the hip roof shape.

Furthermore, as shown in FIGS. 10 and 11, the light control sheet 1 of the present embodiment is retroreflective when P2 / P1 is 0% or more and 50% or less as compared with a conventional prism having a light collecting function only in one direction. The rate is equal or better.
That is, in the configuration of the light control sheet of this embodiment, when P2 / P1 is 0% or more and 50% or less, light distribution adjustment in two directions is possible, and a conventional light collecting function is provided only in one direction. As a result, it is possible to provide a light control sheet that has a retroreflectance equal to or higher than that of the prism and has a light use efficiency equal to or higher than that of the conventional prism.

Here, in the light control sheet 1 of the present embodiment, the inclination angles θ1 to θ3 for obtaining the high-luminance display device 27 are preferably set in a range of 35 degrees to 55 degrees. It is more preferable that the angle is set in a range of 50 degrees to 50 degrees.
By setting it as the above range, it is possible to obtain a sufficient retroreflectance, and as a result, it is possible to obtain a light control sheet with high light use efficiency.

  Further, as shown in FIG. 6B, it is desirable that the angle formed by the first direction x and the second direction is approximately 90 degrees. That is, it is desirable that the second direction coincides with the third direction and is a direction along the y direction. Thereby, when the display device 27 is viewed from the observer side F in a plan view, a light collecting effect is obtained in the horizontal direction and the vertical direction, so that the light utilization efficiency is increased.

Furthermore, in the light control sheet 1 of the present embodiment, it is preferable that the first inclination angle θ1 and the second inclination angle θ2 are set to be the same as shown in FIG.
This makes it possible to match the light collecting ability and the retroreflective ability of the first lens 3 and the second lens 5 in the third direction y, so that the light use efficiency of the entire light control sheet 1 can be improved. Can be improved.

So far, the case where the cross section of the first lens 3, that is, the first cross sectional shape 3 d is an isosceles trapezoid and the cross section of the second lens 5 is a triangular shape has been described. These lens shapes and the lens shape of the second lens 5 can be arbitrarily selected.
For example, the shape of the first lens 3 and the second lens 5 can be a convex lenticular shape. When the convex lenticular is formed only in one direction, a display device 27 having a wide visual field range can be obtained. In this regard, by forming a convex lenticular as the second lens on the top of the convex lenticular, a condensing effect in two directions of the first direction x and the third direction y can be obtained, so that the visual field range is wide and A display device 27 with high brightness can be obtained.

  As a manufacturing method of the light control sheet 1, a light control sheet 1 of the present embodiment is prepared by preparing a mold 7 for producing the light control sheet 1 as shown in FIG. 1 can be produced. The first lens 3 is formed by the first convex portion 7a in FIG. 13, and the second lens 5 is formed by the second convex portion 7b.

  The lens shape as described above may be molded on the translucent substrate 6 using UV or radiation curable resin, or PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate). ), COP (cycloolefin polymer), PAN (polyacrylonitrile copolymer), AS (acrylonitrile styrene copolymer), etc., which are well known in the art, such as extrusion molding, injection molding, or heat You may shape | mold by the press molding method.

  The light control sheet 1 of the present embodiment uses the above-described mold and resin by forming the second lens 5 on the first lens 3 having a shape in which the first cross section 3d is extended. The effect of improving the yield of the manufacturing method can be obtained.

That is, the square pyramid prism shape shown in FIG. 21 and the hip roof shape shown in FIG. 22 have a problem that the yield when forming the shape is low.
This is because in order to arrange independent structures on the lattice, in the manufacturing method in which the mold 7 and the resin are pressure-bonded and cured, such as extrusion molding, UV molding, or injection molding, bubbles are formed in the resin. When 9 is mixed, the bubble 9 is confined in an independent structure and there is no escape space, so that it remains between the mold 9 and the base material and bubbles are formed inside the prism sheet 110 ( FIG. 14 (b)). When bubbles are formed, a large refractive index difference is generated between the bubbles and the prism sheet, and different light distribution characteristics are generated in regions where bubbles are present and regions where bubbles are absent. Therefore, when it is installed in a display device, there is a problem that an area with bubbles is viewed by an observer and is visually recognized as a defect on the screen.

In this regard, in the light control sheet 1 of the present embodiment, as shown in FIG. 14A, when bubbles are generated between the resin and the mold, the bubbles 9 are not confined in the second lens 5, Move into the first lens 3. Since the first lens 3 has an extended shape, the bubbles 9 are not confined. Therefore, it is possible to prevent bubbles from forming inside the light control sheet 1.
As a result, it is possible to improve the yield in the manufacture of the light control sheet 1 having a light collecting effect in two directions.

The above-mentioned method for preventing the generation of bubbles is particularly effective for a method in which a sheet-shaped resin is pressure-bonded to a cylinder-shaped mold used in an “R to R method” such as an extrusion molding method or a UV molding method. It is. In the cylinder-shaped mold used in the “R to R” method, the mold and the resin are pressure-bonded in a short time, and therefore there is no time for performing a defoaming process for removing bubbles between the mold and the resin.
Therefore, by adopting the shape of the light control sheet 1 of the present embodiment, it is possible to efficiently manufacture without introducing air bubbles in the manufacturing method using the cylinder-shaped mold used in the “R to R method”. preferable.

  Furthermore, in the case of a manufacturing method such as a UV molding method in which a resin is applied on a transmissive substrate such as PET and the resin and the mold are pressed and bonded, the bubbles cannot move into the transmissive substrate. In the pyramidal prism shape or the hip roof shape shown in FIG. 22, the probability that the bubbles 9 are confined in an independent structure is increased. Therefore, it is preferable to improve the yield by adopting the shape of the present embodiment, which becomes relatively large. Since the UV molding method has a higher molding accuracy than the extrusion molding method, the light control sheet 1 having a high shape accuracy and a high yield can be manufactured by using this embodiment.

Moreover, in the light control sheet 1 of this embodiment, it is desirable that each P1 and each P3 are set substantially equal to each other.
Note that P1 or P3 may be non-uniform. By making it non-uniform, it is possible to further reduce the occurrence of moire interference fringes between the periodic structure of the display unit 21 and the structure of the light control sheet 1.
However, it is not preferable to make P1 and P3 non-uniform when each P1 and each P3 are set to be approximately equal and the above-described moire interference fringes are not generated. The reason is that when P1 and P3 are made non-uniform, unevenness occurs in the light control sheet 1, and when used for the display device 27, there is a possibility that a problem may be observed from the observer side F.

In the light control sheet 1 of the present embodiment, the first direction x or the third direction y is installed with an angle of 0 degree to 45 degrees with respect to the horizontal direction or the vertical direction of the display device 27. In particular, it is preferable to set the angle in a range of 3 degrees to 20 degrees.
By installing with the above-mentioned angle, it is possible to further reduce the occurrence of moire interference fringes between the periodic structure of the display unit 21 and the lens shape of the light control sheet 1.
However, when the above-described moire interference fringes are not generated in a state where the first direction x or the third direction y is substantially coincident with the horizontal direction or the vertical direction of the display device 27, the light has an angle. It is not preferable to install the control sheet 1. When the light control sheet 1 is installed with an angle, for example, when the display device 27 is used as a television application, the viewing angle in the Ho direction cannot be maximized. Not desirable.

In the light control sheet 1 of the present embodiment, the first direction x may be substantially parallel to the horizontal direction of the display device 27, or the third direction y may be substantially parallel. Similarly, the first direction x may be substantially parallel to the vertical direction of the display device 27, or the third direction y may be substantially parallel.
Whether the first direction x or the third direction y is set substantially parallel to the horizontal direction or the vertical direction of the display device 27 is set according to the light distribution required for the display device 27. do it.
For example, when the display device 27 of the present invention is used for television, it is desirable that the horizontal half-value angle of the display device is wide. This is because when observing the television, the observer observes the television from various positions in the horizontal direction. However, when the display device 27 of the present invention is used for advertising billboards or the like, it may be desirable that the half-value angle in the vertical direction is wide.

Further, whether the first direction x or the third direction y is set to be substantially parallel to the horizontal direction or the vertical direction of the display device 27 may be set according to the periodic structure of the display unit 21. Good.
In the case of a display device that performs color display, each pixel of the display unit 21 is divided into three colors (red, green, blue) or five colors (red, green, blue, cyan, yellow). Therefore, the periodic structure of the display unit 21 includes a direction in which the pitch of the periodic structure is small and a direction in which the pitch of the periodic structure is large in the orthogonal direction.
In order to reduce the occurrence of moire interference fringes between the lens shape of the light control sheet 1 and the periodic structure of the display unit 21, the direction in which the value of P1 or P3 of the lens shape of the light control sheet 1 is small, and the display unit 21 It is preferable that the periodic structure is substantially parallel to the direction in which the pitch is small.
That is, it is preferable that the third direction y is substantially parallel when P1 is small, and the first direction x is substantially parallel when the pitch of the periodic structure of the display unit 21 is small when P3 is small.
In particular, if P3 is made smaller than P1, the range of P2 / P1 can be widened. Therefore, P3 is made smaller than P1, and the first direction x is a direction in which the pitch of the periodic structure of the display unit 21 is small. It is preferable to make it substantially parallel.

  Furthermore, in the light control sheet 1, the value of P1 is preferably set in the range of 30 μm to 200 μm, and more preferably 50 μm to 150 μm. When P1 exceeds 200 μm, moire interference fringes between the periodic structure of the display unit 21 and the first lens 3 of the light control sheet 1 are not preferable. When the pitch P1 is less than 30 μm, in the manufacture of the mold used for manufacturing the light control sheet 1, more manufacturing time is required as the pitch P1 decreases, and the influence of shape change due to scratches increases. This is not preferable because the production efficiency is lowered and the cost is increased.

  In the light control sheet 1 of the present embodiment, the value of P3 is preferably set in a range of 10 μm to 200 μm, and more preferably 15 μm to 150 μm. If P3 exceeds 200 μm, moire interference fringes between the periodic structure of the display unit 21 and the second lens 5 are generated, which is not desirable. When P3 is less than 10 μm, in the manufacture of the mold used for manufacturing the light control sheet 1, more manufacturing time is required as P3 becomes smaller, and the influence of the shape change due to scratches becomes larger. This is not preferable because it lowers the cost and causes an increase in cost.

  The thickness of the light control sheet 1 is determined by the manufacturing process or the required physical characteristics of the light control sheet 1 rather than the influence on the optical characteristics. For example, when the light control structure is formed by UV molding, the thickness of the light-transmitting substrate 6 is wrinkled if it is 50 μm or less, so it needs to exceed 50 μm. Furthermore, the thickness of the substrate varies depending on the size of the backlight unit or display device used. For example, in the display device 27 having a diagonal size of 37 inches or more, the thickness of the light transmissive substrate 6 is preferably set in the range of 0.05 mm to 3 mm.

  The light emitted from the light control sheet 1 as described above enters the display unit 21. By emitting display light whose display is controlled by an image signal from the display unit 21 toward the observer side F, a planar image is displayed.

The display unit 21 includes two polarizing plates (polarizing films) 31 and 33 and a liquid crystal panel 32 sandwiched therebetween. The liquid crystal panel 32 is configured, for example, by filling a liquid crystal layer between two glass substrates.
The light emitted from the backlight unit 13 is incident on the liquid crystal unit 32 through the polarizing plate 33 and is emitted to the viewer side F through the polarizing plate 31.

  The display unit 21 is preferably an element that displays an image by transmitting / blocking light in pixel units. If the image is displayed by transmitting / blocking light in pixel units, the light control sheet 1 improves the luminance toward the viewer side F and reduces the viewing angle dependency of the light intensity. It is possible to display an image with high image quality by effectively using the light whose lamp image is reduced.

  The display unit 21 is preferably a liquid crystal display element. A liquid crystal display element is a typical element that transmits / shields light in pixel units and displays an image, and can improve image quality and reduce manufacturing cost compared to other display elements. Can do.

  Although the display device 27 is a liquid crystal display device including the display unit 21 as described above, as long as it includes at least the backlight unit 13, a projection screen device, a plasma display, an EL display, etc. The type of the image display unit that displays an image using the light from the backlight unit 13 as display light is not limited.

  In the present embodiment, the display device 27 may be provided with a diffusion film, a prism sheet, a polarization separation / reflection sheet, and the like. Thereby, the image quality can be further improved.

  Since the display device 27 in the present embodiment uses the light whose light collection / diffusion characteristics are improved by the light control sheet 1 described above, the luminance on the observer side F is improved and the distribution of the light intensity in the viewing angle direction is improved. And an image with a reduced lamp image can be displayed on the display unit 21.

  Further, in the display device 27, the display unit 21 that defines a display image according to transmission / shielding in pixel units uses light whose light collection / diffusion characteristics are improved by the backlight unit 13 described above. With this configuration, it is possible to improve the brightness on the viewer side F, smooth the distribution of the light intensity in the viewing angle direction, and obtain an image with a reduced lamp image.

  Further, in the display device 27, since the display unit 21 is a liquid crystal display element and uses the light whose light collection / diffusion characteristics are improved by the backlight unit 13, the luminance on the observer side F is improved, It is possible to obtain an image in which the distribution of the intensity in the viewing angle direction is smoothed and the lamp image is reduced.

  As described above, the embodiment in the present embodiment has been described in detail. However, the present invention is not limited to this, and some design changes can be made without departing from the technical idea of the present embodiment.

Example 1
The light control sheet 1 was produced by extrusion molding using polycarbonate (refractive index: 1.585) with the thickness of the light transmissive substrate 6 being 250 μm. The first cross-sectional shape 3d of the first lens 3 is trapezoidal, the bottom surface of the second lens 5 is rectangular, the first inclination angle θ1 is 45 degrees, the second inclination angle θ2 is 45 degrees, and the third inclination The angle θ3 was 45 degrees, P1 was 100 μm, P2 was 83.3 μm, P3 was 33.3 μm, L was 50 μm, P2 / P1 was 83.3%, and L / P1 was 50%.

(Example 2)
The light control sheet 1 was produced by extrusion molding using polycarbonate (refractive index: 1.585) with the thickness of the light transmissive substrate 6 being 250 μm. The first cross-sectional shape 3d of the first lens 3 is trapezoidal, the bottom surface of the second lens 5 is rectangular, the first inclination angle θ1 is 45 degrees, the second inclination angle θ2 is 45 degrees, and the third inclination The angle θ3 was 45 degrees, P1 was 100 μm, P2 was 70 μm, P3 was 20 μm, L was 50 μm, P2 / P1 was 70%, and L / P1 was 50%.

(Example 3)
The light control sheet 1 was produced by extrusion molding using polycarbonate (refractive index: 1.585) with the thickness of the light transmissive substrate 6 being 250 μm. The first cross-sectional shape 3d of the first lens 3 is trapezoidal, the bottom surface of the second lens 5 is rectangular, the first inclination angle θ1 is 45 degrees, the second inclination angle θ2 is 45 degrees, and the third inclination The angle θ3 is 45 degrees, P1 is 100 μm, P2 is 40 μm, P3 is 20 μm, L is 20 μm, P2 / P1 is 40%, and L / P1 is 20%.

Example 4
Using the same mold as in Example 3, a light control sheet 1 was prepared by a UV molding method using a UV curable resin having a refractive index of 1.585.

(Comparative Example 1)
Using a polycarbonate (refractive index: 1.585), a substrate having a thickness of 250 μm, an apex angle of 90 degrees, an inclination angle of 45 degrees, and a pitch prism of 50 μm was formed by a extrusion method.

(Comparative Example 2)
Using a polycarbonate (refractive index of 1.585) and a substrate thickness of 250 μm, a quadrangular pyramid-shaped light control sheet with an apex angle of 90 degrees, an inclination angle of 45 degrees, and a pitch of 50 μm is formed by extrusion. Produced.

(Comparative Example 3)
Polycarbonate (refractive index 1.585) is used, the thickness of the substrate is 250 μm, the inclination angle is 45 degrees, the trapezoidal pitch is 100 μm, the sawtooth-shaped pitch is 50 μm, L is 50 μm, and L / P1 is 50%. A hip roof-shaped light control sheet was prepared by extrusion molding.

The light control sheets 1 produced in Examples 1 to 4 and Comparative Examples 1 to 3 were placed in the backlight 13 and the luminance was measured. The backlight 13 has a configuration in which a CCFL is disposed as the light source 41 on the observer side F of the reflector 43, and the diffusion plate 25 and the light control sheet 1 are sequentially disposed thereon (observer side F).
Moreover, it was confirmed by visual evaluation whether or not bubbles were formed in the light control sheet 1. The measurement results are shown in Table 2. The luminance value is a relative value with reference to Comparative Example 2.

  From Table 2, when Examples 1-4 and Comparative Examples 2-3 were compared, in the Example, it turned out that there was no bubble generation and the light control sheet 1 was able to be created.

  Comparing Examples 1 to 4 with Comparative Example 2, the light control sheet 1 of Examples 1 to 4 corresponding to the embodiment is adopted, so that the luminance is higher than that of the light control sheet having a quadrangular pyramid lens shape. Was confirmed to rise.

  Comparing Examples 1 and 2 with Comparative Example 3, in the example, the light control sheet having the same L / P1 hip roof shape lens shape by satisfying 0 <P2 / P1 ≦ 0.8. As a result, it was confirmed that the luminance increased.

Comparing Examples 2 and 3 with Comparative Example 1, in the example, a light control sheet in the shape of a conventional prism having a light collecting function only in one direction by satisfying 0 <P2 / P1 ≦ 0.5. As a result, it was confirmed that the luminance increased. .
It was also confirmed that the lens shape accuracy was improved and the luminance was increased by adopting the UV molding method.

DESCRIPTION OF SYMBOLS 1 Light control sheet 2 1st reference surface 3 1st lens 3a Lower bottom surface 3b Upper bottom surface 3c 1st slope 3d 1st cross-sectional shape 4 2nd reference surface 5 2nd lens 5a Bottom surface 5b 2nd slope 5c Third slope 13 Backlight unit 25 Diffuser 27 Display device 53a Prism

Claims (11)

A light control sheet that controls and outputs optical characteristics of incident light,
A lower bottom surface located on the first reference plane;
An upper bottom surface located on a second reference plane substantially parallel to the first reference plane;
A first lens having a pair of first slopes facing each other and connected to the lower bottom surface and the upper bottom surface, and extending a first trapezoidal cross-sectional shape in a first direction; Have
A bottom surface positioned on the upper bottom surface and having a substantially polygonal shape;
A pair of second slopes having a base parallel to the first direction and inclined to face each other;
A pair of third slopes having a base parallel to a second direction intersecting the first direction and inclined to face each other;
A second lens having a top connected to the second slope and the third slope;
The light control sheet, wherein a plurality of the second lenses are arranged side by side on the upper bottom surface of the first lens without a gap. A distance in a third direction orthogonal to the first direction of the lower bottom surface is P1,
When the distance in the third direction of the upper bottom surface is P2,
0 <P2 / P1 ≦ 0.8
The light control sheet according to claim 1, wherein the relationship is established. A distance in a third direction orthogonal to the first direction of the lower bottom surface is P1,
When the distance in the third direction of the upper bottom surface is P2,
0 <P2 / P1 ≦ 0.5
The light control sheet according to claim 1, wherein the relationship is established.   The first direction and the second direction are substantially orthogonal to each other, and the second direction and the third direction are substantially coincident with each other. Light control sheet.   The first inclination angle formed by the first inclined surface and the second reference surface and the second inclination angle formed by the second inclined surface and the second reference surface are substantially the same. The light control sheet according to claim 1, wherein the light control sheet is a light control sheet.   The light control sheet according to any one of claims 1 to 5, wherein the first inclination angle is set in a range of 35 to 55 °.   The light control sheet according to any one of claims 1 to 6, wherein the second inclination angle is set in a range of 35 to 55 °.   8. The third inclination angle formed by the third inclined surface and the second reference plane is set in a range of 35 to 55 °, according to claim 1. Light control sheet. The light control sheet according to any one of claims 1 to 8,
A backlight unit comprising: a light source that emits light to the light control sheet. A backlight unit according to claim 9;
A display device comprising: an image display unit configured to display an image by light irradiation from the backlight unit. It is a manufacturing method of the light control sheet according to any one of claims 1 to 10,
The light control sheet is characterized in that the first lens and the second lens are formed by pressing and curing a resin on a mold having a reverse shape of the first lens and the second lens. Manufacturing method.

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