JP4467840B2 - Illumination device and light guide plate manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lighting device, an image display device, a liquid crystal monitor, a liquid crystal television, a liquid crystal information terminal, and a method for manufacturing a light guide plate.
[0002]
[Prior art]
A liquid crystal display device, which is an example of a conventional image display device, has, for example, a predetermined interval such that two laminated glass substrates on which electrodes made of a transparent conductive thin film and an alignment film are laminated are opposed to each other. And a liquid crystal display element in which a liquid crystal is sealed between both glass substrates and a polarizing plate is provided outside both glass substrates, and disposed below the liquid crystal display element to transmit light to the liquid crystal display element. It includes a backlight to be supplied, a circuit board for driving a liquid crystal display element, and the like.
[0003]
FIG. 32A shows a conventional liquid crystal display device and a backlight used therefor, and FIGS. 33 and 34 show another conventional backlight.
[0004]
As shown in FIGS. 32 (a), 33, and 34, the backlight guides light emitted from the light emitter 1001, for example, away from the light emitter 1001, and emits light to the entire liquid crystal display element 1006. A light guide plate 1003 made of a transparent synthetic resin plate for uniform irradiation, a fluorescent tube which is a light emitter 1001 disposed in the vicinity of the end surface of the light guide plate 1003 in parallel with the end surface, and a fluorescent tube And a reflector 1002 that constitutes a light source and covers the fluorescent tube substantially over its entire length. The backlight 1000 is disposed on the light guide plate 1003 and diffuses a sheet (not shown) that diffuses the light from the light guide plate 1003. The backlight 1000 is disposed below the light guide plate 1003 and transmits the light emitted from the light guide plate 1003. A reflection plate 1005 or the like is further provided that reflects the light back into the light guide plate 1003 again.
[0005]
So-called scattering dots 1004 are formed in a predetermined pattern on the lower surface of the light guide plate 1003, and the surface of the scattering dots 1004 is a scattering surface. An example of the pattern of the scattering dots 1004 is shown in FIG. Therefore, the light incident on the scattering dots 1004 is scattered, and part of the scattered light is emitted from the upper surface of the light guide plate 1003. Further, the light incident on the portion other than the scattering dots 1004 on the lower surface of the light guide plate 1003 travels inside the light guide plate 1003 while repeating multiple reflections by the internal reflection action according to the incident angle.
[0006]
By changing the distribution of the scattering dots 1004, the luminance distribution on the light exit surface (upper surface) of the light guide plate 1003 can be changed. Light entering the light guide plate 1003 from the light source travels through the light guide plate 1003 while repeating internal reflection so that it is emitted to the outside at a constant rate. Smaller as you leave. Therefore, as shown in Japanese Utility Model Laid-Open No. 60-76387, on the light source side, for example, the area ratio of the scattering dots 1004 to the lower surface of the light guide plate 1003 is reduced. Then, the ratio of the light traveling toward the lower surface of the light guide plate 1003 that is scattered by the scattering dots 1004 and emitted from the upper surface of the light guide plate 1003 is reduced. On the other hand, when the area ratio is increased as the distance from the light source increases, the ratio of the light that is scattered by the scattering dots 1004 and emitted from the upper surface of the light guide plate 1003 increases at a position away from the light source. As a result, on the upper surface of the light guide plate 1003, the ratio of the amount of light emitted from each part to the amount of light emitted from the whole (hereinafter referred to as light intensity distribution) becomes equal, and the uniformity of luminance can be improved.
[0007]
Further, in the liquid crystal display device using such a backlight 1000, the uniformity of the luminance of the display screen of the liquid crystal display element 1006 can be improved.
[0008]
By the way, the current mainstream transmissive liquid crystal display devices require illumination from behind using a backlight as described above. However, since the incident light is random light whose polarization directions are not uniform, about half of the light is absorbed by the polarizing plate on the incident side, and the light use efficiency is lowered. For this reason, a prism sheet is used that efficiently condenses the diffused light of the backlight within the viewing angle to increase the front luminance.
[0009]
FIG. 35 shows a liquid crystal display device using such a prism sheet. In FIG. 35, light from light sources 1002 arranged above and below enters the light guide plate 1003. The reflection sheet 1005 is used to effectively return the light leaked from the light guide plate 1003 back to the light guide plate 1003. Light scattered by the diffusion sheet 1031 is collected by the prism sheet 1033 and enters the liquid crystal cell 1035. Before and after the liquid crystal cell 1035, polarizing plates 1034 and 1035 having polarizing axes orthogonal to each other are arranged. The prism sheet 1033 has different transmittance depending on the polarization direction of incident light. This is determined by the relationship between the angle of the irregularities on the surface of the prism sheet 1033 and the vibration direction of the incident light, and this characteristic is as shown in FIG. FIG. 26A shows the change in transmittance with respect to the incident angle in the vertical direction with respect to the prism sheet 1033, that is, in the direction orthogonal to the ridge line direction 1045 of the prism sheet 1033. On the other hand, FIG. 26B shows the transmittance with respect to the incident angle in the ridge line direction 1045 of the prism sheet 1033. From the result of FIG. 26, the transmittance is different between the P-polarized light and the S-polarized light, and the transmittance of the P-polarized light is high in any direction in the front direction, that is, in the direction where the viewing angle is in the range of about −10 degrees to +10 degrees. I understand. Therefore, when priority is given to the front luminance, the luminance can be increased by preferentially using the P-polarized light. An attempt to increase the light use efficiency in the liquid crystal panel by setting the transmission axis of the polarizing plate on the incident side in accordance with the light in a specific vibration direction transmitted through the prism sheet is disclosed in Japanese Patent Application Laid-Open No. 2000-122046. Is disclosed.
[0010]
[Problems to be solved by the invention]
However, in the conventional backlight described above, as indicated by a dotted line in FIG. 34, a part of the light emitted from the light source 1002 is emitted from the opposite end face without hitting the scattering dots 1004. This light becomes lost light leaking outside the light guide plate 1003. In this case, it is conceivable to provide a reflective tape on the opposite end face and return it to the light guide plate 1003 again. However, in recent years, as shown in FIGS. Often provided at both ends of 1003. In such a case, a reflective tape cannot be provided, and a part of the light reaching the opposite end face is reflected by the fluorescent tube 1001 and the reflector 1002 and reentered into the light guide plate 1003 for use. However, there are some that disappear without re-incident. In the experiments and simulation results performed by the present inventors, about half of the light reaching the opposite end face of the light guide plate 1003 is lost. In addition, about 18% of the light emitted from the fluorescent tube 1001 penetrates to the opposite side, and about half of the light was lost. In order to reduce the light penetrating light from the light guide plate, the scattering dots 1004 may be arranged densely. In general, the scattering dots 1004 are formed by printing. However, the density of the scattering dots 1004 has an upper limit due to manufacturing stability. In other words, if the scattering dots 1004 are formed densely, the adjacent scattering dots 1004 adhere to each other at the time of printing, and printing with an area as designed cannot be performed. In addition, the degree of sticking differs every time printing is performed and cannot be stably manufactured. For this reason, a certain amount of space is required between adjacent scattering dots 1004. When this is represented by the ratio of the area of the scattering dot 1004 to the area of the surface on which the scattering dot 1004 is formed (hereinafter referred to as area ratio), the upper limit is 80%. Further, the area of the scattering dots 1004 that can be printed stably also has a lower limit, and this lower limit is 20% in terms of area ratio. In the backlight 1000, since there is an upper limit in the area ratio of the scattering dots 1004, the light penetrating through the light guide plate 1003 as described above is generated. Therefore, the light from the light source 1002 cannot be fully utilized.
[0011]
On the other hand, Japanese Patent Application Laid-Open No. 8-146231 discloses a configuration in which a diffusing material is mixed in a light guide plate and light is scattered thereby to be used for display.
However, in such a system in which a diffusing material is mixed and scattered in the light guide plate, the scattering efficiency in the light guide plate can be improved, but it is difficult to simultaneously control the luminance distribution on the light exit surface of the light guide plate.
[0012]
In recent years, liquid crystal display devices are becoming widespread as monitors for PCs (personal computers). Furthermore, the application to the use as a liquid crystal television which displays a moving image of a movie is also progressing. In liquid crystal display devices for monitors and the like, higher definition and higher brightness are progressing. Since the monitor mainly displays characters and drawings, uniformity of luminance is required over the entire display screen. Actually, the luminance distribution over the entire area of the display screen also has a high uniformity of 80% or more with respect to the central portion in the portion where the luminance in the peripheral portion is low.
[0013]
On the other hand, a television using a conventional CRT (hereinafter referred to as a TV) generally has a high luminance at the center of the display screen, and some of the peripheral portions have a luminance reduced to about 50%. This is because, on a moving image surface such as a movie, an observer tends to gaze at the center portion, and even if the luminance difference in the luminance distribution of the display screen is large, an unnatural feeling is hardly felt. Rather, even if the luminance of the peripheral portion is lowered, it is felt brighter when the luminance of the central portion is increased.
[0014]
As described above, the display has several settings suitable for display characteristics such as luminance distribution depending on applications such as a monitor and a TV. Also, in the field of liquid crystal display devices, AVPC (audio video personal computer) compatible devices that can be used for both monitors and TVs have recently been developed. The liquid crystal display device displays an image by illumination from a backlight. Therefore, in order to change the luminance distribution, it is necessary to change the light emission characteristic of the backlight so that the luminance has a distribution.
[0015]
In an edge light type backlight using a light guide plate that is usually used well, the luminance distribution is controlled by the scattering dots formed on the lower surface of the light guide plate as described above. However, since the scattered dot pattern is fixed and formed by printing, the setting of the luminance distribution of the backlight cannot be arbitrarily changed. Therefore, in a conventional liquid crystal display device using a backlight, the setting of the luminance distribution cannot be changed depending on the application.
[0016]
Furthermore, the conventional liquid crystal display device generally has a lower luminance than a CRT or the like, and is required to have a higher luminance than the current situation. In order to increase the brightness, it is necessary to increase the output of the light source. At this time, in the configuration of the conventional liquid crystal panel 1006 as shown in FIG. 35, half of the light from the light source 1002 is absorbed by the incident side polarizing plate 1034. As the output of the light source 1002 increases, this amount of absorption also increases, so that the uniformity of the polarizing plate 1034 is lost due to heat shrinkage or the like due to the absorbed light, and unevenness in black display occurs.
[0017]
In addition, since unpolarized random light is incident on the prism sheet 1033, the proportion of the light having low transmittance in P-polarized light and S-polarized light is not negligible. As a result, there is a problem such as deterioration of light collecting characteristics due to deformation of the prism sheet 1033 due to heat generation.
[0018]
Furthermore, in FIG. 35, the polarizing axis of the polarizing plate is disposed at an angle of about 45 degrees with respect to the liquid crystal cell 1035 for the following reason. That is, the TN liquid crystal widely used in the liquid crystal display element 1006 has a biased contrast viewing angle characteristic, and is wide in the left-right direction and narrow in the vertical direction. Therefore, the contrast viewing angle characteristic is adjusted by inclining the transmission axis direction of the polarizing plate at an angle of 45 degrees. Accordingly, if the transmission axis of the polarizing plate on the incident side is set in accordance with the light in a specific vibration direction transmitted through the prism sheet, there arises a problem that the contrast viewing angle characteristic is impaired.
[0019]
The present invention has been made to solve the above-described problems. An illumination device, an image display device, a liquid crystal monitor, a liquid crystal television, a liquid crystal information terminal, and a method of manufacturing a light guide plate used for these can be achieved. The first purpose is to provide.
[0020]
The present invention also provides an illuminating device, an image display device, a liquid crystal monitor, a liquid crystal television, a liquid crystal information terminal, and a method of manufacturing the light guide plate used in these devices capable of reducing light penetration of the light guide plate and controlling the luminance distribution. This is the second purpose.
[0021]
The third object of the present invention is to provide an illumination device, an image display device, a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal capable of changing the luminance distribution.
[0022]
In addition, a fourth object of the present invention is to provide an illumination device, an image display device, a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal that can reduce the loss of light in the light collecting means.
[0023]
In addition, a fifth object of the present invention is to provide an image display device, a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal capable of reducing light loss in a polarizing plate of a liquid crystal display element.
[0076]
[Means for Solving the Problems]
  The present inventionOne aspectThe method of manufacturing a light guide plate according to the present invention includes a step of heating and melting the material of the substrate in the method of manufacturing a light guide plate in which scatterers that scatter incident light are dispersed in a transparent substrate, and the molten substrate. Mixing the scatterer with the material, and heating the molten substrate material so that the temperature varies depending on the part while holding the plate, and then curing the material. The scatterer is dispersed in the substrate so that the density varies depending on the part.
[0077]
  With such a configuration, it is possible to easily obtain a light guide plate whose scattering rate varies depending on the part.In addition, since the viscosity of the melted base material changes depending on the temperature, and the density of the scatterer changes accordingly, a light guide plate in which the dispersion density of the scatterer changes depending on the part can be easily manufactured.
[0080]
  Further, in a method of manufacturing a light guide plate in which a scatterer that scatters incident light is dispersed in a transparent substrate, a photoreactive foaming agent is dispersed in the substrate material, and then the light irradiation intensity varies depending on the part. , Thereby generating bubbles as the scatterer in the substrate so that the density varies depending on the site, and thereby dispersing the scatterer in the substrate so that the density varies depending on the site. May be.
[0082]
With such a configuration, the molten base material mixed with the foaming agent can be foamed so that the density changes depending on the part by irradiating light so as to have an intensity distribution in the irradiation surface. Thus, it is possible to easily manufacture a light guide plate in which the dispersion density of the scatterers changes.
[0083]
  In addition, the present inventionOne aspectThe illuminating device according to the present invention includes a light guide plate that guides light from the light source to the light emitting surface, and a luminance distribution of the light emitting surface in the illuminating device including a light source and a light emitting surface from which light from the light source is emitted. Brightness distribution changing means for changing the light source, and the light guide plate is disposed so that light from the light source is incident from an end face, and light emitted from one main surface of the light guide plate is applied to the one main surface. By forming the reflecting surface so as to return, the other main surface of the light guide plate constitutes the light emitting surface, and the luminance distribution changing means is viewed from the light emitting surface of the light guided by the light guide plate. A scattering ratio distribution changing means for changing the distribution of the scattering ratio, wherein the scattering ratio distribution changing means is formed so as to be distributed on one main surface of the light guide plate; Between one main surface of the light guide plate and the reflective surface And scattering control structures scattered or transmitted by the switching light passing through, it is made of a second scattering region formed so as to be distributed in the reflecting surface.
[0084]
  With this configuration, the luminance distribution on the light exit surface can be changed to a required one according to the application. As a result, it is possible to increase the luminance.Further, since the luminance distribution on the light exit surface is changed by changing the distribution of the scattering ratio, the brightness distribution on the light exit surface can be changed to a required one in the edge light type illumination device according to the application. it can. Also,The first and second scattering regions can be formed by printing dots, for example, and the scattering control structureIn addition, since the mode is switched so as to uniformly scatter or transmit the incident light, a simple configuration is sufficient. Therefore, the scattering ratio distribution changing means can be configured easily and at low cost.
[0114]
  With such a configuration, the luminance distribution of the display screen corresponds to the luminance distribution of the light emitting surface of the lighting device, so the luminance distribution of the display screen can be used by changing the luminance distribution of the light emitting surface of the lighting device. It can be changed according to. As a result, it is possible to increase the luminance.In addition, since it is easy to calculate the histogram and determine the brightness of the screen from the calculation result, the luminance distribution on the light exit surface can be easily associated with the video signal.
[0163]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1
Embodiment 1 of the present invention shows a configuration example of a lighting device capable of arbitrarily setting a luminance distribution.
[0164]
FIG. 1 is a diagram schematically showing a configuration of an illumination device and an image display device using the illumination device according to the present embodiment, where (a) is a cross-sectional view and (b) is a diagram of a dispersed liquid crystal element of (a). FIG. 2 is a block diagram showing a configuration of a control system of the image display apparatus of FIG. 1 (a). In FIG. 1A, for convenience, the X direction is the upward direction of the image display device.
[0165]
In FIG. 1A, in the present embodiment, the liquid crystal display device 1 is illustrated as an image display device, and the backlight 100 for the liquid crystal display device is illustrated as an illumination device.
[0166]
The backlight 100 is disposed below a liquid crystal panel (hereinafter referred to as a liquid crystal display element) 106 that constitutes the liquid crystal display element 1. The backlight 100 includes a light guide plate 103 made of a transparent rectangular synthetic resin plate, and a pair of light emitting elements disposed in the vicinity of the pair of end surfaces 103a of the light guide plate 103 along the end surfaces 103a and substantially in parallel with the end surfaces 103a. A cold cathode fluorescent lamp 101 as a body, a pair of reflectors 102 covering the pair of cold cathode fluorescent lamps 101 over their entire length, a dispersed liquid crystal element 104 disposed on the lower surface of the light guide plate 103, and a dispersed liquid crystal element 104 And a reflecting plate 105 disposed below. The cold cathode tube 101 and the reflector 102 constitute a light source 151. In FIG. 1A, for convenience of explanation, the reflector 105 is shown to be positioned away from the dispersed liquid crystal element 104, but this is usually disposed so as to be in contact with the lower surface of the dispersed liquid crystal element 104. .
[0167]
The dispersed liquid crystal element 104 includes an electrode made of a dot matrix, and is configured such that a drive signal for generating a predetermined dot pattern as shown in FIG. More specifically, the dispersion liquid crystal element 104 has a structure similar to that of a liquid crystal cell, and a substrate having a common electrode formed on the inner surface and a substrate having a pixel electrode formed on the inner surface face each other with the liquid crystal interposed therebetween. It is arranged and configured. Then, as shown in FIG. 2, a drive signal 35 is input from the luminance distribution setting circuit 32 to the dispersed liquid crystal element 104. The luminance distribution setting circuit 32 includes, for example, a CPU 34 and a main memory 33, and a plurality of dot patterns are stored in the main memory 33 in advance. The operation switch 31 is connected to the CPU 34. When a dot pattern selection command is input from the operation switch 31, the CPU 34 reads the selected dot pattern from the main memory 33, and reads the read dot pattern. A drive signal 35 corresponding to the pattern is generated and input to the dispersed liquid crystal element 104. Then, a voltage corresponding to the input drive signal 35 is applied to the liquid crystal of each pixel, and the orientation of the liquid crystal molecules of each pixel changes according to the applied voltage. As a result, the selected dot pattern is generated in the dispersed liquid crystal element 104.
[0168]
As shown in FIG. 1B, this dot pattern is composed of circular dots 41 and other portions 42. The portion of the dot 41 of the dispersed liquid crystal element 104 is a portion to which no voltage is applied, and the orientation of the liquid crystal molecules of each pixel is random, while the portion 42 of the dispersed liquid crystal element 104 other than the dot 41 Is a portion to which a voltage is applied, and the alignment of liquid crystal molecules in each pixel is aligned in one direction and is transparent. Therefore, the light incident on the dot 41 is scattered, the scattered light is scattered and reflected by the reflecting plate 105, and a part of the scattered and reflected light passes through the light guide plate 103 and is emitted from the upper surface. On the other hand, light incident on the portion 42 other than the dots 41 is transmitted, reflected by the reflecting plate 105 according to the incident angle, and returned to the inside of the light guide plate 103 again. The dot pattern has a smaller area ratio with respect to the main surface of the dispersed liquid crystal element 104 (corresponding to the display screen of the liquid crystal display element) in the vicinity of the light source 151 on the main surface, and as it approaches the central portion. It is formed to be large. For this reason, according to this dot pattern, the ratio (light intensity distribution) of the amount of light emitted from each part to the amount of light emitted from the entire upper surface of the light guide plate 103 is increased at the central portion, and thus the luminance is increased at the central portion. . Since the dispersed liquid crystal element 104 has almost no light absorption characteristic, it does not reduce the amount of light emitted from the light guide plate, and has the same scattering function as the scattering dots formed on the conventional light guide plate.
[0169]
The plurality of dot patterns stored in the main memory 33 of the luminance distribution setting circuit 32 are those in which the backlight 100 has a luminance distribution suitable for the use according to a plurality of predetermined uses of the liquid crystal display device 1. Each is set to be. In the present embodiment, for example, a dot pattern for monitoring that requires a relatively small luminance distribution between the peripheral portion and the central portion of the display screen, and a luminance difference between the peripheral portion and the central portion of the display screen. A TV dot pattern that requires a relatively large luminance distribution is stored in the main memory 33.
[0170]
Next, the operation of the backlight 100 configured as described above will be described.
[0171]
1 and 2, first, the operation switch 31 is operated to select a desired dot pattern. Here, it is assumed that a dot pattern for monitoring is selected. Then, the luminance distribution setting circuit 32 outputs a drive signal 35 corresponding to the selected monitor dot pattern, and the dispersed liquid crystal element 104 generates a monitor dot pattern corresponding to the output drive signal 35. . On the other hand, light emitted from the cold cathode fluorescent lamp 101 is incident on the light guide plate 103 directly or after being reflected by the reflector 102 from the end face 103a. Of the incident light, light incident on the dots 41 of the dispersed liquid crystal element 104 is scattered, and part of the scattered light is emitted from the upper surface of the light guide plate 103. On the other hand, of the incident light, the light incident on the portion 42 other than the dot 41 of the dispersed liquid crystal element 104 is transmitted, reflected by the reflecting plate 105 according to the incident angle, and returned to the inside of the light guide plate 103. As a result, the light intensity distribution of the light emitted from the upper surface of the light guide plate 103 corresponds to the dot pattern for monitoring, and as a result, the luminance distribution of the backlight 100 has a peripheral portion and a central portion of the light emitting surface 103b. The luminance difference between them becomes a relatively small luminance distribution. Further, when a TV dot pattern is selected with the operation switch 31, the luminance distribution of the backlight 100 becomes a luminance distribution in which the luminance difference between the peripheral portion and the central portion of the light emitting surface 103b is relatively large by the same operation. .
[0172]
As described above, in the illumination device according to the present embodiment, the dispersed liquid crystal element 104 is disposed on the lower surface of the light guide plate 103, and the dot pattern set and selected by the luminance distribution setting circuit 32 is generated in the dispersed liquid crystal element 104. Since it is configured as possible, an arbitrary luminance distribution according to the application can be obtained. For example, it is possible to arbitrarily set the luminance distribution for display of a moving image on TV or the like, or make the luminance distribution uniform for a monitor for displaying characters.
[Example 1]
In FIGS. 1A and 1B, the dot pattern generated in the dispersed liquid crystal element 104 is set as follows. That is, when the dots 41 are arranged in a lattice pattern and the diameter of the dots 41 is y, the function “y” in which the diameter y is linearly proportional to the distance r from the light emitters 101 arranged at the left and right ends of the light guide plate 103. = A × r ”(a: proportional coefficient). The proportionality coefficient a was set so that the diameter of the central dot 41 having the maximum diameter was about 2 mm, and the pitch of the dots 41 was set to about 1.5 to 3 mm.
[0173]
The light guide plate 103 is a rectangular plate having a diagonal length of 7 inches (hereinafter, the diagonal length is expressed as ○ inch size) and a thickness of about 10 mm. Further, a cold cathode tube having an output of about 100 W was used as the light emitter 101.
[0174]
Then, when the luminance distribution on the upper surface of the light guide plate 103 as the light emitting surface 103b was measured, the luminance was about 4500 to 5000 candela over the entire surface, and a uniform luminance distribution was obtained.
[Example 2]
In the present embodiment, the diameter of the dot 41 changes in accordance with a function “y = a × r × r” in which y is proportional to the square of the distance r from the light emitter 101 disposed at the left and right ends of the light guide plate 103. To do. The other points are the same as in the first embodiment. Then, when the luminance distribution on the upper surface of the light guide plate 103 was measured, the luminance at the center was about 6000 candela, the luminance at the position 0.9 inches in the diagonal direction from the corner was about 3000 candela, and the peripheral luminance was 50 of the central luminance. A luminance distribution having a large luminance difference between the periphery and the center of about% was obtained.
[0175]
From Examples 1 and 2, it was found that the luminance distribution can be arbitrarily changed by forming a specific scattering pattern by the electric field applied to the dispersed liquid crystal element 104. The dot patterns of Examples 1 and 2 are suitable for monitoring and TV, respectively.
[0176]
Next, a modification of the present embodiment will be described. In the above configuration example, a dot matrix is generated in the dispersed liquid crystal element 104 to generate a dot pattern. However, as another configuration example, in the backlight 100 of FIGS. The (Indiumu Tin Oxide) electrode may be formed in a predetermined dot pattern, and the voltage applied to the dispersed liquid crystal element 104 may be turned on / off. In this case, the ITO electrode is formed in a shape corresponding to the portion 42 other than the dots 41 in FIG. Then, scattering dots having a pattern corresponding to the necessary luminance distribution are formed in advance on the lower surface of the light guide plate 103 by printing.
[0177]
With such a configuration, when no voltage is applied to the dispersed liquid crystal element 104, the light incident on the dispersed liquid crystal element 104 is uniformly scattered over the entire surface. The scattered light is reflected by the reflection plate 105 and returns to the inside of the light guide plate 103, is scattered by the printed scattering dots, and is emitted from the upper surface of the light guide plate 103. On the other hand, when a voltage is applied to the dispersed liquid crystal element 104, a predetermined dot pattern is generated in the dispersed liquid crystal element 104, so that light incident on the light guide plate 103 is finally printed on the predetermined dot pattern. The light is emitted from the upper surface of the light guide plate 103 in a form multiplied by the scattering characteristics of the scattered dots.
[0178]
Therefore, two luminance distributions can be selected by turning on / off the voltage applied to the dispersed liquid crystal element 104. Moreover, the dispersed liquid crystal element 104 only needs to be formed so that the ITO corresponds to a predetermined dot pattern, and voltage application may be performed only by an on / off operation. For this reason, it is possible to configure the dispersed liquid crystal element 104 at a lower cost than in the case where the electrodes are formed in a dot matrix.
[0179]
It is desirable to perform optical matching that encloses a liquid having the same refractive index between the dispersed liquid crystal element 104 and the light guide plate 103 or between the dispersed liquid crystal element 104 and the reflective plate 105. .
[0180]
Further, the reflection plate 105 may be omitted, and instead, a reflective film made of a metal such as aluminum may be formed on the lower substrate of the dispersion liquid crystal element 104 to have a function as a reflection surface.
[0181]
Further, in the above configuration example, polymer dispersed liquid crystal is used as the liquid crystal of the dispersed liquid crystal element 104, but instead of this, for example, nematic liquid crystal, ferroelectric liquid crystal, antiferroelectric liquid crystal, or the like may be used.
[0182]
Further, in the above configuration example, the dispersion liquid crystal element 104 is used as the means for switching the scattering characteristics of the light incident on the light guide plate 103. Instead of this, lithium niobate that can electrically change the light transmittance is used. Or BSO crystals may be used.
Embodiment 2
The second embodiment of the present invention shows another configuration example of a lighting device capable of arbitrarily setting the luminance distribution.
[0183]
FIG. 3 is a cross-sectional view schematically showing a configuration of the illumination device according to the present embodiment and an image display device using the same. 3, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.
[0184]
As shown in FIG. 3, unlike the first embodiment, in this embodiment, scattering dots 114 are formed on the lower surface of the light guide plate 103, and a scattering control plate 107 is disposed below the scattering dots 114. A scattering reflection plate 201 is disposed below the scattering control plate 107. The other points are the same as in the first embodiment. In FIG. 3, for convenience of explanation, the light guide plate 103, the control plate 107, and the scattering reflection plate 201 are shown to be positioned apart from each other, but these are usually arranged so as to be in contact with each other.
[0185]
More specifically, the scattering control plate 107 is configured by disposing a pair of glass substrates having ITO electrodes formed on the inner surface thereof and sealing a polymer-dispersed liquid crystal between the two glass substrates. The scattering control plate 107 is connected to a drive circuit (not shown) for applying a voltage of about 10 to 30 V between the ITO electrodes and driving it. When this voltage is turned on / off, the alignment state of the liquid crystal molecules on the scattering control plate 107 is switched to “aligned state” / “random state” accordingly.
[0186]
A dot pattern as shown in FIG. 1B is formed on the lower surface of the light guide plate 103.
[0187]
The scattering reflector 201 is configured by forming scattering dots 201b as shown in FIG. 3 on the reflecting surface of the reflector 201a. The pattern of the scattering dots 201b is different from the pattern of the scattering dots 114 formed on the light guide plate 103.
[0188]
According to the above configuration, the light emitted from the light emitter 01 enters the light guide plate 103 directly or after being reflected by the reflector 102. The incident light is scattered by the scattering dots 114 on the lower surface of the light guide plate 103 while repeating multiple reflections inside the light guide plate 103.
[0189]
Here, when no voltage is applied to the scattering control plate 107 by the voltage application circuit, the orientation of liquid crystal molecules on the scattering control plate 107 is in a random state, so that scattering control is performed from the lower surface of the light guide plate 103. The light incident on the plate 107 is scattered over the entire surface. Therefore, the light is reflected by the scattering reflection plate 107 without being affected by the scattering dots 201b formed on the reflection surface of the scattering reflection plate 201, and is reflected in the light guide plate 103. Return to. As a result, the luminance distribution of the light exit surface 103b of the light guide plate 103 corresponds to the pattern of the scattering dots 114 formed on the lower surface of the light guide plate 103.
[0190]
On the other hand, when the voltage is applied to the scattering control plate 107 by the voltage application circuit, the alignment of the liquid crystal molecules of the scattering control plate 107 is in a uniform state. The light incident on 107 is transmitted therethrough, reflected by the scattering reflector 107 in a manner corresponding to the pattern of the scattering dots 201b formed on the reflecting surface of the scattering reflector 201, and returned into the light guide plate 103. As a result, the luminance distribution of the light exit surface 103b of the light guide plate 103 is affected by the influence of the patterns of both the scattering dots 114 formed on the lower surface of the light guide plate 103 and the scattering dots 201b of the scattering reflector 201. , The characteristics of both patterns are multiplied.
[0191]
As described above, according to the present embodiment, the luminance distribution of the light exit surface 103b of the light guide plate 103 can be switched between two types by switching the scattering / transmission of incident light in the scattering control plate 107. it can. Therefore, for example, by setting one of the two types of luminance distributions to a highly uniform one, it can be used when the liquid crystal display device 1 is used as a monitor. Further, by setting the other to have a large luminance difference between the peripheral portion and the central portion, it can be used when the liquid crystal display device 1 is used as a TV.
[0192]
Moreover, since the scattering control plate 107 can be composed of a glass substrate in which polymer dispersed liquid crystal is sealed between each other, and its drive circuit can be composed of a simple circuit that turns on and off a predetermined voltage, A configuration that switches between two luminance distributions can be realized at a very low cost.
[Example 3]
A light guide plate 103 having a size of 7 inches and a thickness of about 10 mm was used as in Example 1 of the first embodiment. Further, a cold cathode tube having an output of about 100 W was used as the light emitter 101. Further, in the scattering reflector 201, the area ratio of the scattering dots 201b is very large in the central part and small in the peripheral part. Then, the voltage distribution applied to the scattering control plate 107 was turned on / off, and the luminance distribution on the light exit surface 103b of the light guide plate 103 was measured. As a result, when no voltage was applied, a uniform luminance distribution with a luminance of about 4000 to 5000 candela was obtained over the entire light emitting surface 103b. On the other hand, when an electric field was applied to the scattering control plate 107, the luminance at the center of the light exit surface 103b was 6000-6500 candela, and the luminance at the periphery thereof was about 3000-3500 candela. That is, in this case, a luminance distribution in which the luminance is large in the central portion and small in the peripheral portion is obtained under the influence of the configuration in which the area ratio of the scattering dots 201b is very large in the central portion of the scattering reflector 201. It was.
[0193]
As described above, according to the present embodiment, it has been found that an illumination device that can obtain two luminance distributions by switching the optical characteristics of the scattering control plate 107 can be realized.
[0194]
In the above configuration example, the polymer dispersed liquid crystal is used as the optical property variable body of the scattering control plate 107, but this is not limited to the liquid crystal, and any material can be used as long as the light transmittance can be switched. In addition, when liquid crystal is used, it is needless to say that other liquid crystal such as twisted nematic liquid crystal as described in Embodiment 1 can be used without being limited to polymer dispersed liquid crystal.
Embodiment 3
FIG. 4 is a cross-sectional view schematically showing a configuration of an illumination apparatus and an image display apparatus using the illumination apparatus according to Embodiment 3 of the present invention. 4, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.
[0195]
As shown in FIG. 4, in the present embodiment, unlike the first embodiment, the first reflective polarizing plate 301a, the polarization modulation element 302, and the second are disposed above the light emitting surface 103b of the light guide plate 103. Reflective polarizing plates 301b are arranged in this order. The first and second reflective polarizing plates 301a and 301b and the polarization modulation element 302 constitute a light quantity modulation structure 305. Further, scattering dots (not shown) are formed on the lower surface of the light guide plate 103 by printing, and a reflection plate 105 is disposed so as to be in contact with the lower surface. The dot pattern of the scattered dots is as shown in FIG. The other points are the same as in the first embodiment.
[0196]
More specifically, the first and second reflective polarizing plates 301a and 301b are composed of chiral liquid crystals and have a characteristic of transmitting or reflecting incident light depending on the polarization direction depending on the helical pitch of the liquid crystals. . Here, the first reflective polarizing plate 301a is configured to transmit only the P-polarized light and reflect the S-polarized light out of the P-polarized light and S-polarized light contained in the light emitted from the light guide plate 103. The first and second reflective polarizing plates 301a and 301b are arranged so that their polarization axes coincide with each other.
[0197]
For example, the polarization modulation element 302 has a configuration in which the twisted nematic liquid crystal is used instead of the polymer dispersed liquid crystal in the dispersion liquid crystal element 104 of the first embodiment. A driving signal for applying a voltage to a predetermined region is input to the polarization modulation element 302 by the luminance setting circuit 32 and the operation switch 31 shown in FIG. Here, as shown in the enlarged view of the light amount modulation structure in FIG. 4, driving is performed such that a voltage is applied to the central portion 303 of the polarization modulation element 302 and no voltage is applied to other portions, that is, the peripheral portion 304. A signal is output.
[0198]
In the backlight 100 configured as described above, the light reflected and scattered by the lower surface of the light guide plate 103 and emitted from the upper surface 103b of the light guide plate 103 undergoes light amount modulation by the light amount modulation structure 305. That is, as shown in the enlarged view of the light amount modulation structure 305 in FIG. 4, the first reflective polarizing plate 301a transmits only the P-polarized light out of the light emitted from the upper surface 103b of the light guide plate 103, and the S-polarized light. Reflect. Here, in the polarization modulation element 302, it is assumed that the above drive signal is input, a voltage is applied to the central portion 303, and no voltage is applied to the peripheral portion 304. Then, among the transmitted P-polarized light, the light incident on the central portion 303 is transmitted while maintaining its polarization direction, passes through the second reflective polarizing plate 301b, and enters the liquid crystal display element 106. . On the other hand, the light incident on the peripheral portion 304 is emitted with its polarization direction twisted by approximately 90 degrees, and is therefore reflected by the second reflective polarizing plate 301b. The reflected light passes through the polarization modulator 302 again, and its polarization direction is twisted by 90 degrees, and then passes through the first reflective polarizing plate 301a and returns to the light guide plate 103. The returned light is scattered and reflected in the light guide plate 103 and its polarization direction is also modulated, and is emitted again from the upper surface 103b of the light guide plate 103 as recycled light shown in FIG.
[0199]
If the recycled light passes through the first reflective polarizing plate 301a and enters the portion 303 to which the voltage of the polarization modulation element 302 is applied, as shown in FIG. 4, for example, the polarization modulation element 302 and the second The light passes through the reflective polarizing plate 301b in order and enters the liquid crystal display element. That is, the light intensity modulation structure 305 can have a light intensity distribution such that the light emitted from the upper surface 103b of the light guide plate 103 has a large amount of light at the central portion and a small amount of light at the peripheral portion. As a result, the backlight 100 has a luminance distribution in which the luminance is high in the central portion and the luminance is low in the peripheral portion. In addition, the light emitted from the light guide plate 103 can be incident on the liquid crystal display element 106 with its polarization direction aligned with almost no loss of the original light amount. Further, since the polarization directions of the light incident on the liquid crystal display element 106 are uniform, it is possible to omit the polarizing plate conventionally disposed on the incident side of the liquid crystal display element 106.
[0200]
When a drive signal that applies a voltage across the entire area is input to the polarization modulator 302, the light emitted from the light guide plate 103 passes through the polarization modulator 302 and is incident on the liquid crystal display element 106. Therefore, the luminance distribution of the backlight 100 corresponds to the scattered dots printed on the lower surface of the light guide plate 103, and the luminance distribution is substantially uniform over the entire surface. As described above, the two types of luminance distributions can be obtained by switching the drive signal input to the polarization modulation element 302 in the same manner as in the first embodiment.
[Example 4]
In this example, as in the example of the first embodiment, a rectangular light guide plate 103 having a size of 7 inches and a thickness of about 10 mm is used, and a cold cathode tube having an output of about 100 W is used as the light emitter 101. Using. In the polarization modulation element 302, a voltage is applied to the central portion and no voltage is applied to the peripheral portion. Then, when the luminance distribution on the exit surface of the second reflective polarizing plate 301b was measured, it was about 6000 candela in the central part and about 3000 candela in the peripheral part. In addition, as a result of comparing the total light quantity with the case where the light quantity modulation structure 305 is not provided, it is almost the same. From this, it is understood that the light quantity loss due to the provision of the light quantity modulation structure 305 hardly occurs. It was.
[0201]
As described above, according to the present embodiment, the light intensity modulation structure 305 is provided, and the voltage is applied to the central portion of the polarization modulation element 302, whereby the luminance is high in the central portion and the luminance in the peripheral portion. It has been found that a low luminance distribution can be obtained with almost no loss of light.
[0202]
In the above configuration example, twisted nematic liquid crystal is used as the liquid crystal of the polarization modulation element 302, but other than this, ferroelectric liquid crystal, antiferroelectric liquid crystal, or the like can be used. In addition, the polarization modulator of the polarization modulation element 302 is not limited to liquid crystal, and materials and configurations capable of polarization modulation other than liquid crystal can be used.
Embodiment 4
In the first to third embodiments, light is applied to the liquid crystal display element from behind. However, a front light type liquid crystal display device using a reflective liquid crystal display element is also used in the first to third embodiments. It is possible to obtain the effect by applying the described configuration. The fourth embodiment of the present invention has such a configuration and obtains the same effects as the first to third embodiments.
[0203]
In this embodiment, a reflective liquid crystal display element having a size of about 5 inches is used. In this liquid crystal display element, a reflection plate is disposed behind (below) the liquid crystal cell, and includes the reflection type polarizing plate and the polarization modulation element described in the third embodiment between the liquid crystal cell and the reflection plate. A light intensity modulation structure was arranged. And the light source was arrange | positioned at the edge part of the front surface (upper surface) of the said liquid crystal display element. As a result, on the display screen of the liquid crystal display element, a uniform luminance distribution in which the peripheral luminance is 80% or more with respect to the central luminance, and the luminance in which the peripheral luminance drops to about 50% with respect to the central luminance. Two types of luminance distribution with a large difference were obtained. Therefore, it has been found that the configuration of arbitrarily changing the luminance distribution of the present invention can be applied to the front light type.
Embodiment 5
FIG. 5 is a plan view schematically showing the configuration of the illumination apparatus according to Embodiment 5 of the present invention. 5, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.
[0204]
As shown in FIG. 5, in the present embodiment, a plurality of LEDs 401 are used as the light emitter instead of the cold cathode tube. Other points are the same as in the embodiment.
[0205]
More specifically, when a cold cathode tube is used as the light emitter, the luminance is substantially uniform over the entire length of the incident surface 103a at the end of the light guide plate 103, but when a plurality of LEDs 401 are used as the light emitter, By changing the density of the LEDs 401 in the longitudinal direction of the incident surface 103a, the luminance of the entire light emitter can be changed. Therefore, in the present embodiment, for example, the LED 401 is disposed in the longitudinal direction of the incident surface 103a so that the density is high at the center and low at both ends, and thereby a light emitting body composed of a plurality of LEDs 401 The overall luminance is set to be large at the center and small at both ends in the longitudinal direction of the incident surface 103a.
[0206]
With such a configuration, on the incident surface 103 of the light guide plate 103, the amount of incident light increases at the central portion and the amount of incident light decreases at both ends thereof. As a result, on the light exit surface of the light guide plate 103, the luminance increases at the central portion, and conversely, the luminance decreases at the peripheral portion. Therefore, since the configuration and the operation of changing the luminance of the light emitter itself in the longitudinal direction of the incident surface 103 of the light guide plate 103 are added to the configuration of the first embodiment, the luminance distribution of the light emitting surface of the backlight 100 is increased. The degree of freedom of pattern creation can be further increased.
[Example 5]
In this example, about 10 white LEDs 401 on each side were used as light emitters instead of cold cathode tubes. Then, the white LED 401 is set so that the density becomes uniform and the density changes in the longitudinal direction of the incident surface 103a of the light guide plate 103, corresponding to Examples 1 and 2 of the first embodiment. did. Then, when the luminance distribution of the backlight 100 was measured, when the density of the white LED 401 was set uniformly, the luminance was set to about 2000 candela over the entire surface, and the density of the white LED 401 was changed. In this case, the luminance was about 5000 candela in the central part and the luminance was about 1000 candela in the peripheral part.
[0207]
As a result, it has been found that a luminance distribution with a larger luminance difference can be set by using a plurality of LEDs as the light emitter and changing the density of the LEDs in the longitudinal direction of the incident surface 103a of the light guide plate 103. .
Embodiment 6
In the sixth embodiment of the present invention, an image display device is configured using the illumination devices of the first to fifth embodiments.
[0208]
First, the case where the lighting device of Embodiment 1 is used will be described.
[0209]
As shown in FIGS. 1 and 2, in the liquid crystal display device 1 as the image display device according to the present embodiment, a backlight 100 is disposed below the liquid crystal display element 106. Here, the liquid crystal display element 106 is formed of a well-known TFT (Thin Film Transistor) type, a counter substrate 111 having a common electrode (not shown) formed on the inner surface, a pixel electrode and a gate line not shown on the inner surface. The TFT substrate 112 on which the source line and the switching element are formed is disposed so as to face each other with the liquid crystal 113 interposed therebetween, and polarizing plates (not shown) are provided on both sides of the opposed substrate 111 and the TFT substrate 112 disposed opposite to each other. Etc. are pasted. In the TFT substrate, gate lines and source lines are arranged in a matrix, and a pixel electrode and a switching element are formed for each pixel defined by the gate lines and source lines. The source line and gate line of the liquid crystal display element 106 are driven by a source driver and a gate driver, respectively, and the source driver and gate driver are controlled by a controller. Hereinafter, the source driver, the gate driver, and the controller are collectively referred to as a drive circuit 36.
[0210]
In the liquid crystal display element 1 configured as described above, in the drive circuit 36, the controller outputs control signals to the gate driver and the source driver, respectively, according to the video signal 25 input from the outside. Then, the gate driver outputs a gate signal to the gate line to sequentially turn on the switching elements of each pixel, while the source driver applies a source signal including a video signal to the pixel electrode of each pixel through the source line in synchronization with the timing. Enter sequentially. Thereby, the liquid crystal is modulated, the transmittance of the light emitted from the backlight 100 is changed, and an image corresponding to the video signal 25 is displayed to the eyes of a person observing the liquid crystal display device 1. Hereinafter, the gate signal and the source signal are collectively referred to as a drive signal 37.
[0211]
At this time, the luminance distribution of the display screen of the liquid crystal display element 106 corresponds to the luminance distribution of the backlight 100. Therefore, by switching the luminance distribution of the backlight 100 according to the application of the liquid crystal display element 1 as described in the first embodiment, it is possible to obtain the luminance distribution of the display screen optimum for the application. Also, by setting a desired dot pattern in the luminance distribution setting circuit 32 of FIG. 2, an image corresponding to the video signal 25 input to the liquid crystal display element 106 can be displayed on the display screen with a desired luminance distribution. .
[0212]
2, a video composition circuit 901 is provided, a plurality of video signals 25 are input to the video composition circuit 901, and a plurality of videos corresponding to each video signal 25 are displayed on one screen. It is also possible to compose so as to display on a multi-screen, and to input the synthesized video signal to the drive circuit 36. With such a configuration, it is possible to perform display on a multi-screen, and by appropriately setting the dot pattern of the luminance distribution setting circuit 32, it is possible to obtain a preferable luminance distribution for each area constituting the multi-screen of the display screen. The luminance distribution of the display screen can be set so that
[0213]
Next, the case where the illuminating device of Embodiment 2-5 is used is demonstrated.
[0214]
In these cases, in the above configuration, instead of the backlight 100 of the first embodiment, the backlight 100 of FIG. 3 (second embodiment), the backlight 100 of FIG. 4 (third embodiment), By using the front light (Embodiment 4) and the backlight 100 (Embodiment 5) in FIG. 5, a liquid crystal display device as an image display device can be configured. In any liquid crystal display device, as in the above configuration, the luminance distribution of the display screen that is optimal for the application can be obtained by switching the luminance distribution of the illumination device in accordance with the application of the liquid crystal display element.
[Example 6]
In this example, as in Examples 1 and 2 of the first embodiment, a cold cathode tube of about 100 W was used as the light emitter. A liquid crystal display element having a size of about 10 inches was used. Then, when the luminance distribution was measured via the liquid crystal display element 106, the luminance was about 200 candela over the entire display screen in the setting in which the uniformity of luminance was enhanced for monitoring purposes.
[0215]
On the other hand, in a setting for increasing the luminance difference between the central portion and the peripheral portion for TV use, the luminance of the central portion is about 300 candela and the luminance of the peripheral portion is about 150 candela. The total amount of light was almost the same for all luminance distribution settings. Further, the power consumption of the entire light emitter was almost the same in any luminance distribution setting. Furthermore, when an image was observed when the luminance difference between the central portion and the peripheral portion was set large, the TV moving image felt brighter than when the luminance distribution was set uniformly. This confirmed the effectiveness of the setting to brighten the center of the display screen.
[0216]
In addition, when the luminance difference between the central portion and the peripheral portion is set to be large, the power consumption of the light emitter can be reduced correspondingly if the central luminance is the same as when the luminance distribution is set uniformly. .
[0217]
As described above, according to the present embodiment, it has been found that an image display device can be configured using the illumination device of the present invention, and the luminance distribution can be arbitrarily set according to the application.
Embodiment 7
FIG. 6 is a perspective view schematically showing a configuration of an illumination device and an image display device according to Embodiment 7 of the present invention. 6, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.
[0218]
As shown in FIG. 6, in this embodiment, a so-called direct-type backlight configuration is employed, and a plurality of liquid crystal display elements 106 that directly irradiate the liquid crystal display element 106 as a backlight 100 behind (downward) the liquid crystal display element 106. The light emitter 501 is arranged. A reflector (not shown) is disposed behind the plurality of light emitters 501 so as to surround them. Therefore, the plurality of light emitters 501 and the reflector constitute a light source, and the back surface of the liquid crystal display element 106 constitutes the light emission surface of the light source. A scattering film or the like for making the luminance uniform may be disposed between the light emitter 501 and the liquid crystal display element 106. In the present embodiment, the light emitter 501 is formed of a cold cathode tube, and a plurality of the cold cathode tubes 501 are arranged on the back surface (lower surface) of the liquid crystal display element 106 at a constant pitch parallel to a predetermined side. . As in the first embodiment, a luminance distribution setting circuit 32 and an operation switch 31 as shown in FIG. 2 are provided. In the present embodiment, the luminance distribution setting circuit 32 can preset the output patterns of the plurality of cold cathode tubes 501, and when the output pattern is selected by the operation switch 31, the plurality of cold cathode tubes 501 A voltage that causes the output to correspond to the selected output pattern is output to each cold cathode tube 501 as the drive signal 35. Here, as in the first embodiment, a uniform luminance distribution and a luminance distribution with a large luminance difference between the peripheral portion and the central portion of the display screen are set in the luminance distribution setting circuit 32. Thus, when a uniform luminance distribution is selected, the outputs (luminances) of the plurality of cold cathode fluorescent lamps 501 are all the same, while there is a luminance distribution with a large luminance difference between the peripheral portion and the central portion of the display screen. When selected, the outputs of the plurality of cold cathode fluorescent lamps 501 are larger as they are arranged at the center and smaller as those arranged at the periphery.
[Example 7]
In this example, a cold cathode tube 501 having about 100 W as in the first embodiment was used. A liquid crystal display element 106 having a size of about 10 inches was used. Then, when the luminance of the display screen of the liquid crystal display element 106 was measured, the luminance was about 200 candela over the entire display screen when a uniform luminance distribution was selected. On the other hand, when a luminance distribution having a large luminance difference between the peripheral portion and the central portion of the display screen is selected, the luminance at the central portion is about 300 candela, and the luminance at the peripheral portion is about 150 candela. In addition, the power consumption of the entire cold cathode tube 501 at this time was almost the same as when the uniform luminance distribution was selected. Further, when the image at this time was observed, it was felt that the moving image of TV was brighter than when the uniform luminance distribution was selected. By setting the luminance distribution to brighten the center, it seems that the sense of brightness is improved in appearance.
[0219]
Further, if the luminance at the center of the display screen is made the same as in the case of a uniform luminance distribution, the power consumption of the cold cathode tube 501 can be reduced accordingly.
[0220]
As described above, according to the present embodiment, in the configuration of the direct type backlight, it is possible to arbitrarily set the luminance distribution of the display screen by changing the luminance of the light emitter according to the arrangement position. It was.
[0221]
As another configuration example of the present embodiment, the light quantity modulation structure 305 of the third embodiment is disposed between the cold cathode tube 501 and the liquid crystal display element 106 without changing the output of the cold cathode tube 501. You may comprise.
Embodiment 8
FIG. 7 is a perspective view schematically showing the configuration of the illumination device and the image display device according to Embodiment 8 of the present invention. 7, the same reference numerals as those in FIG. 6 denote the same or corresponding parts.
[0222]
As shown in FIG. 7, in the present embodiment, a plurality of cold-cathode tubes 501 are arranged so that the density is high at the center and low at both ends (peripherals) in the arrangement direction, and all The output of the cold cathode fluorescent lamp 501 is configured to be constant. The other points are the same as in the seventh embodiment.
[0223]
With such a configuration, in the display screen of the liquid crystal display element 106, the central portion where the cold cathode fluorescent lamps 501 are densely arranged has a relatively high light output and a high luminance. The sparsely arranged peripheral part has a relatively small light output and a low luminance. That is, by providing a distribution in the arrangement density of the cold cathode fluorescent lamps 501, it is possible to provide a distribution in the luminance of the liquid crystal display device.
[0224]
Then, when the luminance was actually measured using the same cold cathode fluorescent lamp and liquid crystal display element as in the seventh embodiment, the same result as in the seventh embodiment was obtained. Accordingly, it has been found that an arbitrary luminance distribution can be set even in the configuration of FIG.
[0225]
In the configuration of the present embodiment, it is needless to say that the output of the light emitter can be changed according to the arrangement position as in the seventh embodiment.
Embodiment 9
FIG. 8 is a perspective view schematically showing the configuration of the illumination device and the image display device according to Embodiment 9 of the present invention. 8, the same reference numerals as those in FIG. 6 denote the same or corresponding parts.
[0226]
As shown in FIG. 8, in the present embodiment, a surface light source 502 is disposed behind the liquid crystal display element 106 as the direct type backlight 100. Similar to the sixth embodiment, a luminance distribution setting circuit 32 and an operation switch 31 as shown in FIG. 2 are provided. The luminance distribution setting circuit 32 can set the luminance pattern of the surface light source 501 in advance, and when the luminance pattern is selected by the operation switch 31, the luminance distribution of the surface light source 501 corresponds to the selected luminance pattern. The control signal that is the same is output to the surface light source 501 as the drive signal 35. Here, as in the sixth embodiment, a uniform luminance distribution and a luminance distribution with a large luminance difference between the peripheral portion and the central portion of the display screen are set in the luminance distribution setting circuit 32. Thereby, when a uniform luminance distribution is selected, the luminance distribution of the surface light source 501 becomes uniform, while when a luminance distribution with a large luminance difference between the peripheral portion and the central portion of the display screen is selected, The luminance distribution of the surface light source 501 has a large luminance at the central portion and a small luminance at the peripheral portion.
Embodiment 10
The tenth embodiment of the present invention exemplifies an image display device that controls the luminance distribution of a lighting device in accordance with the screen of a video signal input from the outside.
[0227]
FIG. 9 is a block diagram showing the configuration of the control system of the image display apparatus according to the present embodiment. 9, the same reference numerals as those in FIG. 2 denote the same or corresponding parts.
[0228]
As shown in FIG. 9, unlike the first embodiment, the liquid crystal display device 1 as the image display device according to the present embodiment is based on a video signal 25 input to a drive circuit 36 that drives a liquid crystal display element 106. A signal processing circuit 38 for determining the brightness of the screen (frame), and a luminance distribution setting circuit 32 for controlling the luminance distribution by outputting a drive signal 35 to the illumination device 100 according to the determined screen brightness. And. Moreover, the illuminating device 100 of Embodiment 1-5, 7-9 can be used as the illuminating device 100. FIG. The other points are the same as in the first embodiment.
[0229]
In the liquid crystal display device 1 configured as described above, when the video signal 25 is input, the signal processing circuit 38 calculates a histogram of the luminance of the pixel for each screen of the video signal 25, and the image is obtained from the distribution. Is a bright scene (screen) or a dark scene, and the determination result is output to the luminance distribution setting circuit 32. In response to this determination result, the luminance distribution setting circuit 32 operates as follows. That is, the luminance distribution setting circuit 32 stores, for example, a normal TV luminance distribution and a luminance distribution with a higher central luminance in the main memory 33, and displays a determination result that the scene is bright. Upon receipt, a luminance distribution with an increased central luminance is selected, and a drive signal 35 corresponding to the luminance distribution is output to control the illumination device 100 so as to obtain such a luminance distribution. As a result, the display screen of the liquid crystal display element 106 has a luminance distribution with an increased central luminance. On the other hand, upon receiving the determination result that the scene is dark, the lighting device 100 outputs a drive signal 35 that controls the normal luminance distribution and controls it. As a result, the display screen of the liquid crystal display element 106 has a luminance distribution for a normal TV.
[Example 8]
Actually, when the display was performed using the liquid crystal display device configured as described above, a movie screen in which a person was displayed at the center felt brighter due to the effect of increasing the luminance at the center.
[0230]
As described above, according to the present embodiment, it is possible to perform optimum settings according to the scene to be displayed by controlling the luminance distribution of the illumination device according to the image to be displayed. As a result, it has been found that visibility can be improved.
Embodiment 11
In the eleventh embodiment of the present invention, in the liquid crystal display device 1 of FIG. 9, the signal processing circuit 38 and the luminance distribution setting circuit 32 are configured to perform the following operations, and the lighting device 100 is the same as that of the first embodiment. It consists of a backlight 100.
[0231]
That is, the signal processing circuit 38 divides the screen of the input video signal 25 into a plurality of blocks, and obtains a pixel luminance histogram for each block. Then, the luminance of each block is obtained from the obtained histogram, thereby obtaining the general luminance distribution of the screen. The pixel luminance histogram for each block is obtained for each screen here, but may be obtained over a plurality of continuous screens. In that case, the general luminance distribution is a total of the plurality of screens. Then, the block having the luminance peak, that is, the position on the screen where the luminance peak exists is detected from the general luminance distribution, and this is output to the luminance distribution setting circuit 32. The luminance distribution setting circuit 32 receives this output, and drives the lighting device 100 so that the luminance distribution on the light exit surface is high in the vicinity of the position corresponding to the detected peak. Output a signal. Referring also to FIGS. 1 and 2, illumination device 100 is configured with backlight 100 according to the first embodiment. Therefore, the dot pattern of dispersed liquid crystal element 104 is arbitrary in time according to the drive signal. Therefore, when the drive signal 35 is input, the dot pattern of the dispersed liquid crystal element 104 changes according to the drive signal 35. As a result, the luminance distribution of the liquid crystal display element 1 corresponds to the drive signal 35, and as a result, the luminance distribution of the liquid crystal display device 1 is higher in the vicinity of the luminance peak position on the screen of the video signal. It will be like that.
[Example 9]
When the image was actually displayed using the liquid crystal display device 1 configured as described above, the position where the person's face moved was always displayed brightly on the screen where the person's face was displayed. In a screen on which a person is displayed, a person tends to gaze at the face of the person, and in this embodiment, the portion corresponding to the gaze area is always displayed brightly. It was recognized as a bright image.
[0232]
As described above, in the present embodiment, as a result of controlling the luminance distribution of the lighting device in accordance with the luminance distribution on the screen of the video signal, an excellent display in terms of brightness for the observer of the liquid crystal display device It turns out that an effect is acquired.
Embodiment 12
The twelfth embodiment of the present invention shows a configuration example of an illuminating device that can reduce the amount of light penetrating the light guide plate.
[0233]
FIG. 10 is a cross-sectional view schematically showing the configuration of the lighting apparatus according to the present embodiment. 10, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.
[0234]
As shown in FIG. 10, in this embodiment, a constant scattering layer (hereinafter referred to as a semi-transmissive layer) 121 that transmits incident light so as to be scattered at a predetermined rate is formed on the lower surface 103a of the light guide plate 103. The scattering dots (distributed scattering structure) 114 are formed in a predetermined pattern on the lower surface of the semi-transmissive layer 121. A reflective plate 105 is disposed below the semi-transmissive layer 121. Note that the semi-transmissive layer 121 has a substantially uniform transmittance over the entire region. Here, the light emitters 101 are composed of cold cathode fluorescent lamps, and are arranged so that two light guides 101 are arranged in the thickness direction of the light guide plate 103. The other points are the same as in the first embodiment.
[0235]
More specifically, the light guide plate 103 is made of, for example, a synthetic resin such as acrylic.
[0236]
The semi-transmissive layer 121 is configured, for example, by dispersing SiO2 fine particles in a synthetic resin. The synthetic resin of the semi-transmissive layer 121 needs to have a refractive index different from that of SiO 2 and substantially the same as the refractive index of the material of the light guide plate 103. In order for the SiO2 fine particles to exhibit the scattering function in the semi-transmissive layer 121, the refractive index thereof needs to be different from the refractive index of the synthetic resin of the semi-transmissive layer 121. This is because the refractive index of the synthetic resin of the semi-transmissive layer 121 needs to be substantially equal to the refractive index of the light guide plate 103 in order to prevent reflection at the interface with the transmissive layer 121. The semi-transmissive layer 121 is formed by printing ink formed by mixing SiO2 fine particles in a synthetic resin on the lower surface 103c of the light guide plate 103. Further, the transmittance of the semi-transmissive layer 121 is adjusted by controlling the thickness thereof.
[0237]
The scattering dots 114 are the same as those in the conventional example, and are formed by printing a resin containing a pigment or glass. The pattern of the scattering dots 114 is, for example, such that the scattering dots 114 are dense at the center and directed toward the periphery so that the light emitted from the upper surface 103b of the light guide plate 103 has a uniform intensity distribution. To be sparse.
[0238]
Next, the operation of the lighting device configured as described above will be described. Light emitted from the light source 151 enters the light guide plate 103. This incident light propagates inside the light guide plate 103. At this time, when the light enters the semi-transmissive layer 121, a part of the incident light is scattered by the SiO2 fine particles according to the transmittance, and the remaining light is transmitted therethrough. . Of this transmitted light, light incident on the scattering dots 114 is scattered there, and the remaining light is totally reflected on the lower surface of the semi-transmissive layer 121 (interface with air) and returns to the light guide plate 103. To be exact, some of the light transmitted through the semi-transmissive layer 121 is not totally reflected by the lower surface of the semi-transmissive layer 121, but this is reflected by the reflective plate 107 and is reflected inside the light guide plate 103. Returned to
[0239]
The light scattered by either the semi-transmissive layer 121 or the scattering dots 114 is emitted from the upper surface 103b of the light guide plate 103. On the other hand, light that is not scattered by either the semi-transmissive layer 121 or the scattering dots 114 propagates while repeating total reflection between the upper surface 103b of the light guide plate 103 and the lower surface of the semi-transmissive layer 121, and a part of the light is scattered. The light source 151 is reached without facing. Here, when attention is paid to the light emitted from the light source 151 on one side, the light scattered by the semi-transmissive layer 121 and the scattering dots 114 is increased as compared with the case where the semi-transmissive layer 121 is not provided. The light emitted from the light emitting surface 103b increases, and the light reaching the light source 151 on the opposite side decreases. Therefore, the light loss in the vicinity of the light source 151 on the opposite side is reduced, and the light use efficiency is increased. As a result, an illuminating device having a high brightness on the light exit surface can be obtained. Further, since the semi-transmissive layer 121 can be formed at a time by printing or the like, a structure that increases the light utilization efficiency can be obtained at a low cost by a simple method.
[0240]
In addition, since the semi-transmissive layer 121 is formed over the entire surface of the lower surface 103c of the light guide plate 103, the amount of light incident on the scattering dots 114 is reduced at any location on the lower surface 103c, further reducing light loss. Can be reduced.
[0241]
The proportion of the light propagating through the light guide plate 103 is scattered by the scattering dots 114 toward the center, and is totally reflected between the upper surface 103b of the light guide plate 103 and the lower surface of the semi-transmissive layer 121. Therefore, the intensity distribution of light emitted from the upper surface 103b of the light guide plate 103, that is, the luminance distribution of the upper surface 103b is corrected.
[0242]
Next, the relationship between the amount of light penetrating the light guide plate (hereinafter referred to as light guide plate penetrating light amount) and the transmittance of the semi-transmissive layer 121 will be described.
[0243]
FIG. 11 is a graph showing a change in the amount of light passing through the light guide plate with respect to the transmittance of the semi-transmissive layer. The graph shown in FIG. 11 is obtained by calculating the penetration light amount when the present inventor changes the transmittance of the semi-transmissive layer by simulation. In this simulation, the amount of light penetrating the light guide plate is the amount of light leaked (lost) to the outside from the end surface 103a of the light guide plate 103 on which the two light sources 151 are disposed, and the light amount output from the two light sources 151 Expressed as a percentage. As shown in FIG. 5, the amount of light penetrating the light guide plate is about 18% when the semi-transmissive layer does not exist (transmittance of 100%), but is reduced to zero by reducing the transmittance of the semi-transmissive layer to 50%. Become. That is, there is no loss of light. In this way, the transflective layer has a transmissivity below a certain level, in other words, has a scattering rate above a certain level, so that the light incident on the light guide plate 103 from the two light sources 151 and 151 facing each other is a light source on the opposite side. The light utilization efficiency can be made 100%.
[0244]
In the above configuration example, the semi-transmissive layer 121 and the scattering dots 114 are arranged in this order on the lower surface of the light guide plate 103, but these may be arranged in the reverse order.
[0245]
Further, what is dispersed in the semi-transmissive layer 121 is not limited to the SiO2 fine particles but may be a pigment such as TiO2 or may be composed of a plurality of materials.
[0246]
The semi-transmissive layer 121 only needs to have a function of partially reflecting incident light, and may be formed of a diffraction grating, a hologram film, a scattering anisotropic film, or the like.
[0247]
Further, the semi-transmissive layer 121 may be composed of a plurality of layers, or may be partially disposed on the lower surface of the light guide plate 103.
Embodiment 13
FIG. 12 is a cross-sectional view schematically showing a configuration of a lighting apparatus according to Embodiment 13 of the present invention. 12, the same reference numerals as those in FIG. 10 denote the same or corresponding parts.
[0248]
As shown in FIG. 12, in this embodiment, the semi-transmissive layer 121 is not provided on the lower surface 103c of the light guide plate 103 as in the tenth embodiment, but the scatterers 122 are dispersed in the light guide plate 103. I'm hurt. The other points are the same as in the tenth embodiment.
[0249]
The light guide plate 103 is made of, for example, an acrylic material, and a large number of scatterers (scatterers) 122 are mixed therein. The scatterer 122 may be, for example, a gas such as air, argon Ar, oxygen O 2, or nitrogen N 2 or a vacuum bubble, or may be a resin containing a material such as glass or white pigment having a refractive index different from that of the light guide plate 103.
[0250]
According to the above configuration, the light incident on the light guide plate 103 from the light source 151 diffuses (scatters) when it hits the scatterer 205 in the light guide plate 103, and a part of the scattered light is applied to the upper surface 103b of the light guide plate 103. Exit. Thereby, the amount of light penetrating from the light source 151 on one side to the light source 151 on the opposite side is reduced, and light can be efficiently propagated to the light emitting surface 103b of the light guide plate 103, so that a bright illumination device is obtained.
[0251]
Note that the scatterer 122 dispersed in the light guide plate 103 only needs to have a diffusing function, and is not particular about the material. Further, the dispersion of the scatterers 122 may be either uniform or non-uniform.
Embodiment 14
FIG. 13 is a cross-sectional view schematically showing a configuration of a lighting apparatus according to Embodiment 14 of the present invention. 13, the same reference numerals as those in FIG. 10 denote the same or corresponding parts.
[0252]
As shown in FIG. 13, in this embodiment, the semi-transmissive layer 121 is not provided on the lower surface 103c of the light guide plate 103 as in the tenth embodiment, but is formed on the lower surface 103c of the light guide plate 103. The scattering dot 123 is composed of two types of scattering dots 123a and 123b. The other points are the same as in the tenth embodiment.
[0253]
The scattering dots 123 are formed in the same pattern as in the first embodiment, that is, so as to be dense at the center and sparse toward the periphery. The scattering dot 123 is composed of a first scattering dot 123a disposed at the center and a second scattering dot 123b disposed at the periphery, that is, a portion close to the light source 151. The first scattering dots are configured to include SiO2 fine particles, and the second scattering dots 123b are configured to include TiO2 fine particles. As a result, the first scattering dot 123a is more scattering than the second scattering dot 123b. The reason for this configuration is to achieve both uniformity and scattering of light propagating in the light guide plate 103. That is, in order to make the illumination device 1 bright, it is advantageous to use scattering dots with increased scattering properties, but if the scattering properties are too high, there is a lower limit on the printable size of the scattering dots. In spite of the fact that the low scattering property is necessary, the scattering property cannot be kept below a certain level, and as a result, the uniformity of the luminance distribution on the light exit surface may be impaired. Therefore, in such a case, by combining at least two types of scattering dots having different scattering properties, the scattering property is improved while maintaining the uniformity of the luminance distribution on the light exit surface.
[0254]
For the first and second scattering dots 123a and 123b, an ink in which SiO2 fine particles and TiO2 fine particles are mixed with resin is prepared, and ink containing SiO2 fine particles is first printed on the lower surface 103b of the light guide plate 103, and then It can be easily formed by printing ink containing TiO2 fine particles. Alternatively, the ink containing TiO2 fine particles may be printed first, and the ink containing SiO2 fine particles may be printed later.
[0255]
In the illuminating device 1 configured as described above, when light is incident on the light guide plate 103 from the light source 151, the incident light is scattered when it is incident on the scattering dots 123, and is not incident on the scattering dots 123 when the light is incident on the light guide plate. The light propagates so as to be totally reflected by the lower surface 103c of 103. At this time, the second scattering dots 123b having a relatively low scattering property are formed sparsely in the portion near the light source on the lower surface 103c of the light guide plate 103, and conversely the first having a relatively high scattering property in the central portion. Since the scattering dots 123b of the light guide plate 103 are densely formed, the ratio of the light propagating through the light guide plate 103 is scattered in the central portion is higher than the portion near the light source 151 of the light guide plate. As a result, the luminance distribution on the light exit surface 103b of the light guide plate 103 is uniform. In addition, in this case, the relative scattering property of the scattering dot formed in the central portion with respect to that formed in the portion close to the light source 151 is higher than that in the case where the scattering dot 123 is formed of one kind. Can be set. Therefore, a brighter lighting device 1 can be obtained.
Embodiment 15
FIG. 14 is a cross-sectional view schematically showing the configuration of the illumination apparatus according to Embodiment 15 of the present invention. 14, the same reference numerals as those in FIG. 13 denote the same or corresponding parts.
[0256]
As shown in FIG. 14, in this embodiment, the scattering properties of the two types of scattering dots 123a and 123b are not made different from each other as in the case of the fourteenth embodiment, but the two types of scattering dots 1234 and 124b. The scattering property is made different depending on the dispersion density of the scattering material in the scattering dots 234 and 124b. That is, the first scattering dots 124a contain the SiO2 fine particles densely, and the second scattering dots 124b contain the SiO2 fine particles sparsely, whereby the first scattering dots 124a are the second scattering dots. Scattering is higher than 124b. Other points are the same as in the fourteenth embodiment.
[0257]
The first and second scattering dots 124a and 124b are formed by printing on the lower surface 103c of the light guide plate 103, ink in which SiO2 fine particles are mixed with resin at different mixing ratios.
[0258]
According to the above configuration, the same material is used for the two types of scattering dots 124a and 124b to improve the scattering property while maintaining the uniformity of the luminance distribution on the light exit surface 103c, and as a result, a brighter illumination device can be obtained. Can do.
Embodiment 16
FIG. 15 is a cross-sectional view schematically showing the configuration of the illumination apparatus according to Embodiment 16 of the present invention. 15, the same reference numerals as those in FIG. 13 denote the same or corresponding parts.
[0259]
As shown in FIG. 13, in this embodiment, a scattering region 125 is formed instead of the 14 scattering dots 123 of the embodiment. The scattering region 125 is formed by providing a large number of minute irregularities on the lower surface 103c of the light guide plate 103. The first scattering region 125a and the second scattering region 125b are made to have different scattering properties by making the unevenness density different. The scattering region 125 is formed by performing mechanical processing and chemical processing on a predetermined region on the lower surface of the light guide plate 103 to form unevenness. The other points are the same as in the tenth embodiment.
[0260]
Even with this configuration, the same effect as in the fourteenth embodiment can be obtained.
[0261]
In Embodiments 12 to 15, it goes without saying that the scattering region of this embodiment may be formed instead of the scattering dots.
[0262]
In the twelfth to sixteenth to sixteenth embodiments, the lower surface 103 of the light guide plate 103 is illustrated as being flat, but may be uneven.
[0263]
Further, the position of the light emitter 101 may be anywhere within the reflector 102, and the number of light emitters 101 may be any number.
[0264]
Further, the number of the light sources 151 may be one and may have a luminance distribution.
Embodiment 17
In the seventeenth embodiment of the present invention, an image display device is configured using the illumination devices of the twelfth to sixteenth embodiments. In order to obtain the image display device according to the present embodiment, a liquid crystal display element 106 is disposed above the illumination device 100 of FIGS. 10, 12, 13, 14, and 15, as shown in FIG. The liquid crystal display element 106 may be driven by the drive circuit 36 shown in FIG.
[0265]
With such a configuration, it is possible to obtain an image display device that exhibits the effects described in the twelfth to sixteenth embodiments.
Embodiment 18
The eighteenth embodiment of the present invention shows a configuration example of an illumination device that can reduce the light penetrating light from the light guide plate and control the luminance distribution on the light exit surface.
[0266]
FIG. 16 is a cross-sectional view schematically showing a configuration of the illumination device according to the present embodiment and an image display device using the same. 16, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.
[0267]
As shown in FIG. 16, in the backlight 100 as the illumination device according to the present embodiment, a large number of scatterers 126 are dispersed in the light guide plate 103, and the scattering having a predetermined pattern on the lower surface 103b of the light guide plate 103 is performed. Dots (distributed scattering structures) 104 are formed.
[0268]
The scatterer 126 is made of a material that is present in the material constituting the light guide plate 103 and that reflects or refracts incident light. The scattering dots 104 have the same pattern as the pattern shown in FIG. 1B, and are formed so that the area ratio increases from the portion near the light source of the light guide plate 103 toward the central portion.
[0269]
The scattering rate of the light guide plate 103 and the total scattering rate of the scattering dots 104 are larger than the scattering effect of the light guide plate 103 in terms of the contribution of the scattering action by the scattering dots 104 to the amount of light emitted from the upper surface 103b of the light guide plate 103. Set to be larger. Specifically, it is desirable that the scattering action by the scattering dots 104 is approximately twice or more that of the scattering action by the light guide plate 103 in the contribution. This is because the greater the scattering action by the light guide plate 103, the greater the effect of reducing the light penetration of the light guide plate, but the influence of the scattering action by the scattering dots 104 is relatively reduced, and the luminance at the light exit surface 103b This is because the ability to control the distribution decreases.
[0270]
Next, the operation of the lighting device configured as described above will be described. Light that has entered the light guide plate 103 from the light source 151 is efficiently scattered by the scatterers 126 dispersed in the light guide plate 103. Therefore, as in the conventional example, there is almost no light that passes through the light guide plate and is emitted from the opposite end face to be lost.
[0271]
Further, of the light propagating through the light guide plate 103, the light incident on the scattering dots 104 is scattered there and emitted from the upper surface 103b of the light guide plate 103. On the other hand, those not incident on the scattering dots 104 propagate through the light guide plate 103 while repeating total reflection inside the light guide plate 103. Therefore, when light enters the light guide plate 103, the amount of light that reaches the light source 151 decreases from the portion close to the light source 151 toward the central portion. It becomes smaller as it goes to the central part.
[0272]
On the other hand, the scattering dots 104 are formed so that the area ratio is small at a portion near the light source 151 of the light guide plate 103 and the area ratio increases toward the center. Therefore, the ratio of the light propagating through the light guide plate 103 to the light emitted from the upper surface 103b of the light guide plate 103 is small near the light source 151 and increases toward the center. Therefore, the intensity of light scattered by the scattering dots 104 and emitted from the upper surface 103b of the light guide plate 103 is uniform throughout the light guide plate 103.
[0273]
Further, by forming the scattering dots 104 so that the area ratio in the vicinity of the light source 151 is smaller than the area ratio in the central portion, more light is collected in the central portion and the central luminance is increased. It is also possible to do. Specifically, for example, the area ratio of the scattering dots 104 can be set so as to change according to an exponential function, a Gaussian function, a sine function, or the like with respect to the distance from the light source 151.
[0274]
As described above, according to the present embodiment, the scattering efficiency of light incident on the light guide plate 103 from the light source 151 can be improved by dispersing the scatterers 126 inside the light guide plate 103. As a result, light penetrating the light guide plate can be reduced. Further, the luminance distribution on the light exit surface 103b of the light guide plate 103 can be arbitrarily controlled by the scattering dots 104 formed on the lower surface 103c of the light guide plate 103. That is, it is possible to improve the light utilization rate by using the light from the light source 151 without omission in the light guide plate 103 and to set the luminance distribution on the light exit surface to a desired one.
[Example 10]
In this embodiment, the light guide plate 103 is 7 inches in size and about 10 mm thick made of acrylic resin. The light guide plate 103 was mixed with a scatterer as the scatterer 126 by a method described later, and scattering dots 104 were formed on the lower surface thereof. As the scatterer mixed in the light guide plate 103 made of acrylic resin, a scatterer that reflects or refracts incident light and exhibits almost no absorption characteristics is preferable. Specifically, for example, metal powder or glass beads can be used. In this embodiment, since visible light having a wavelength of about 0.5 μm is targeted, in order for the scatterer 126 to cause scattering, the scatterer 126 needs to be larger than the wavelength of the visible light. There is. Further, since the size of the scatterer 126 cannot exceed the thickness of the light guide plate 103, it is about several mm to several tens of mm at the maximum, and considering the uniformity at the time of mixing, about several μm to several tens of μm. It is desirable that
[0275]
Further, when the bubbles are dispersed inside the acrylic plate, a scattering action is generated due to a difference in refractive index from the acrylic plate. Therefore, the acrylic plate and the bubbles may be used as the light guide plate 103 and the scatterer 126, respectively. Good. In addition, since an acrylic plate that is usually used for the light guide plate 103 has a refractive index of about 1.5, the scatterer 126 has a refractive index of about 0 for the member to exhibit scattering characteristics due to the difference in refractive index. It is preferable to have a refractive index difference of 1 or more. In this example, beads having a size of about 10 μm and a refractive index of about 1.7 were used as the scatterer 126. In FIG. 16, the scatterers 126 are randomly dispersed, but they may be regularly dispersed. In addition, the shape of the scatterer 126 is spherical in FIG. 16, but may be any shape, for example, an ellipse, a rectangle, a triangle, or the like having a combined cross-sectional shape can be used. .
[0276]
The pattern of the scattering dots 104 was formed such that the scattering dots 104 were arranged in a lattice shape and the diameter thereof was about 0.5 mm to 2 mm at a pitch of about 1.5 mm to 3 mm. A cold cathode tube with an output of about 100 W was used as the light emitter 101.
[0277]
In addition, as a comparative example (conventional example), a light guide plate made of an acrylic plate having the same size as that of the present example was used, and an illuminating device in which scattering dots were formed in the same pattern as that of the present example on its lower surface was created.
[0278]
And both compared the light intensity radiate | emitted from the upper surface of a light-guide plate. This comparison was performed by measuring the luminance on the upper surface of the light guide plate at nine locations on the surface. As a result, in this example, the luminance (emitted light intensity) increased by an average of 5 to 10% at the nine places as compared with the comparative example. In addition, the luminance distribution at these nine locations is almost equal between the two, and therefore, it can be said that the present embodiment is the same as the conventional example in terms of the luminance distribution.
[0279]
As described above, according to the present embodiment, by dispersing the scatterer in the light guide plate 103 and using it together with the scattering dots, the scattering efficiency is improved and the luminance on the light exit surface of the light guide plate is increased and desired. It has been found that it is possible to obtain a luminance distribution.
Embodiment 19
FIG. 17 is a cross-sectional view schematically showing a configuration of an illumination apparatus and an image display apparatus using the illumination apparatus according to Embodiment 19 of the present invention. 17, the same reference numerals as those in FIG. 16 denote the same or corresponding parts.
[0280]
As shown in FIG. 17, in the present embodiment, unlike the eighteenth embodiment, no scattering dots are formed on the lower surface of the light guide plate 203, and the light guide plate 203 is a first in which the scatterers 126 are dispersed. The unit light guide plate 204 and the second unit light guide member 205 in which the scatterers are not dispersed are composed of a composite light guide plate (hereinafter simply referred to as a light guide plate). The other points are the same as in the eighteenth embodiment.
[0281]
The first unit light guide member 204 and the second unit light guide member 205 are configured to form a rectangular plate-shaped light guide plate 203 by combining both. In other words, the first unit light guide member and the second unit light guide member are arranged in a cross section perpendicular to the end surface on which the light source 151 of the rectangular plate-shaped light guide plate 203 is disposed, and the middle point of the upper side and the lower left and right sides. The first and second regions 204, 205 formed by dividing the cross section into two by a straight line connecting the corners on the side are formed. The first unit light guide member 204 and the second unit light guide member 205 are joined to form the light guide plate 203. The joint between the first unit light guide member 204 and the second unit light guide member 205 is subjected to an optical refractive index matching process by a method to be described later. Therefore, light is reflected at this joint surface. Not to be. Accordingly, the interface between the unit light guide members 204 and 205 is shown in FIG. 17, but this is only shown for convenience of description of the structure, and this interface is not actually visible. The first and second unit light guide members 204 and 305 can be created by cutting out one rectangular light guide plate into a shape as shown in FIG.
[0282]
The scatterers 126 are dispersed in the first unit light guide member 204 in the same manner as the light guide plate of the eighteenth embodiment. On the other hand, the scatterer is not dispersed in the second unit light guide member 205.
[0283]
In the illumination device 100 configured as described above, the light emitted from the light source 151 enters the light guide plate 203 from the end face 203a. The incident light is transmitted through the second unit light guide member 205 in which the scatterer is not dispersed, and hits the scatterer 126 in the first unit light guide member 204 in which the scatterer 126 is dispersed. And scattered on its surface. Then, the scattered light is emitted from the upper surface 203b of the light guide plate 203, while the light that has not hit the scatterer 126 is totally reflected by the upper and lower inner surfaces (interface with air) of the light guide plate 203 while being guided. Propagates through the optical plate 203. However, since the interface between the second unit light guide member 205 and the first unit light guide member 205 is formed so as to be inclined with respect to the light propagation direction in the light guide plate 203, the first unit light guide member 205 is formed. The volume ratio of the light member 204 to the light guide plate 203 is small in the portion close to the light source 102 and increases toward the center. Accordingly, the light incident on the light guide plate 203 has a small ratio of being scattered by the scatterer 126 in the portion close to the light source, and the ratio of being scattered by the scatterer 126 increases toward the center. On the other hand, the proportion of light incident on the light guide plate 203 reaches a large portion near the light source, and the proportion reaching the central portion decreases. As a result, the intensity of light emitted from the upper surface 203b of the light guide plate 203 is substantially uniform throughout the light guide plate 203.
[Example 11]
In this example, as in the eighteenth embodiment, a light guide plate 203 having a size of 7 inches and a thickness of about 10 mm made of acrylic was used. As the scatterer 126 of the first unit light guide member 204, beads having a size of about 10 μm and a refractive index of about 1.7 were used. Further, as the light emitter 101, a cold cathode tube having an output of about 100 W was used.
[0284]
Then, the luminance was measured at nine points on the line connecting the center and the four corners of the upper surface 203b of the light guide plate 203, and the uniformity of the luminance in the plane was examined. As a result, when the luminance in the vicinity of the center of the upper surface 203b of the light guide plate 203 is 100%, the luminance at other locations is distributed in the range of about 85% to 95%. In addition, the sum of luminance at all points was the same as that of the lighting device according to Example 10 of the eighteenth embodiment. Therefore, according to the present Example, it turned out that the uniformity of a brightness | luminance can be raised while improving a light utilization factor.
Embodiment 20
FIG. 18 is a cross-sectional view schematically showing a configuration of an illumination apparatus and an image display apparatus using the illumination apparatus according to Embodiment 20 of the present invention. 18, the same reference numerals as those in FIG. 17 denote the same or corresponding parts.
[0285]
As shown in FIG. 18, in the present embodiment, unlike the nineteenth embodiment, the light guide plate 203 is a composite composed of first, second, and third unit light guide members 206, 207, and 208 having different dispersion densities of the scatterers 126. It is composed of a light guide plate. Other points are the same as in the nineteenth embodiment.
[0286]
The first, second, and third unit light guide members are formed by dividing a cross section perpendicular to the end surface on which the light source 151 of the rectangular plate-shaped light guide plate 203 is divided into three in the left-right direction. The second and third regions 206, 207, and 208 are formed so as to constitute the respective regions. In the first and third light guide plates 206 and 208, the dispersion density of the scatterers 126 is equal to each other. The second unit light guide member 207 has a higher dispersion density of the scatterers 126 than the first and third light guide plates 206 and 208. Here, the scatterers 126 are uniformly and regularly dispersed in the unit light guide members 206, 207, and 208.
[0287]
In the illuminating device 100 configured as described above, light that has entered the light guide plate 203 is scattered when it strikes the scatterer 126, exits from the upper surface 203 b of the light guide plate 203, and is guided when it does not strike the scatterer 126. The light propagates through the light guide plate 203 while being totally reflected by the upper and lower inner surfaces of the light plate 203. However, the dispersion density of the scatterer 126 is low in the first and third unit light guide members 206 and 208 close to the light source 151 and high in the second unit light guide member 208 located in the center. Therefore, the ratio of the light propagating through the light guide plate 203 is small in the first and third unit light guide members 206 and 208 close to the light source 151 and high in the second unit light guide member 208 located in the center. On the other hand, the rate at which the light incident on the light guide plate 203 reaches is large in the first and third unit light guide members 206 and 208 close to the light source 151, and is small in the second unit light guide member 208 located in the center. . As a result, the intensity of light emitted from the upper surface 203b of the light guide plate 203 is substantially uniform throughout the light guide plate 203.
[0288]
In the above configuration example, the light guide plate 203 is divided into three parts having different dispersion densities of the scatterers. However, this may be divided into a plurality of parts having different dispersion densities of the scatterers. By increasing the number of parts in this way, the scattering ratio at each position in the light guide plate 203 can be set more finely according to the distance from the light source 102, so the luminance distribution on the light exit surface can be controlled more accurately. can do.
[0289]
In the above configuration example, the scatterers 126 are regularly dispersed. However, the scatterers 126 may be dispersed randomly.
[Example 12]
In this example, similar to Example 11 of the nineteenth embodiment, a light guide plate 203 having a size of 7 inches and a thickness of about 10 mm made of acrylic was used. Further, as the scatterer 126, beads having a size of about 10 μm and a refractive index of about 1.7 were used. The amount of beads added to the second unit light guide member 207 is twice that of the first and third unit light guide members 206 and 208. Further, as the light emitter 101, a cold cathode tube having an output of about 100 W was used.
[0290]
Then, the luminance on the upper surface 203b of the light guide plate 203 was measured at a total of nine locations for each unit light guide member 206, 207, 208, and the luminance uniformity on the upper surface 203b was examined. As a result, when the luminance near the center of the unit light guide member 207 located at the center is 100%, the luminance at the unit light guide members 206 and 208 located at both ends is distributed in a range of about 70 to 85%. In addition, the sum of the luminance at each measurement location was the same as that of the illumination device according to Example 10 of the eighteenth embodiment. Therefore, according to this embodiment, it has been found that the light utilization rate can be improved and the luminance distribution can be controlled.
Embodiment 21
FIG. 19 is a cross-sectional view schematically showing a configuration of an illumination apparatus and an image display apparatus using the illumination apparatus according to Embodiment 21 of the present invention. 19, the same reference numerals as those in FIG. 16 denote the same or corresponding parts.
[0291]
As shown in FIG. 19, in the present embodiment, unlike the eighteenth embodiment, the density of the scatterers 126 in the light guide plate 103 is low near the light source 151 and increases toward the center. It is dispersed in. Further, no scattering dots are printed on the lower surface of the light guide plate 103. The other points are the same as in the eighteenth embodiment.
[0292]
In the illuminating device 100 configured as described above, light that has entered the light guide plate 103 is scattered when it strikes the scatterer 126, exits from the upper surface 103 b of the light guide plate 103, and is guided when it does not strike the scatterer 126. The light propagates through the light guide plate 103 while being totally reflected by the upper and lower inner surfaces of the light plate 103. However, the dispersion density of the scatterers 126 is low near the light source 151 and high at the center. Therefore, the rate at which light propagating in the light guide plate 103 is scattered is small in the portion near the light source 151 and is high in the central portion, while the rate at which the light incident on the light guide plate 103 reaches is a portion near the light source 151. It becomes large at and becomes small at the central part. As a result, the intensity of light emitted from the upper surface 103b of the light guide plate 103 is substantially uniform throughout the light guide plate 103.
[0293]
In the above configuration example, the scatterers 126 are regularly dispersed. However, the scatterers 126 may be irregularly dispersed.
[Example 13]
In this example, a light guide plate 103 having a size of 7 inches and a thickness of about 10 mm was used as the light guide plate 103 as in Example 10 of the eighteenth embodiment. As the scatterer 126, beads having a size of about 10 μm and a refractive index of about 1.7 were used. The scatterers 126 were dispersed by a manufacturing method described later so that the density increases substantially linearly with respect to the distance from the end face of the light guide plate 103 toward the center. As the luminous body 101, a cold cathode tube having an output of about 100 W was used.
[0294]
Then, the luminance was measured at nine points on the line connecting the center and four corners of the upper surface 103b of the light guide plate 103, and the uniformity of the luminance in the surface was examined. As a result, when the luminance in the vicinity of the center of the upper surface 103b of the light guide plate 103 is 100%, the luminance at other locations is distributed in a range of about 85% to 95%. Further, the sum of the luminances at all points was the same as that of the lighting apparatus according to Example 10 of the eighteenth embodiment. Therefore, according to the present example, it was found that the light utilization rate can be improved and the luminance uniformity can be increased.
Embodiment 22
FIG. 20 is a cross-sectional view schematically showing a configuration of an illumination apparatus according to Embodiment 22 of the present invention and an image display apparatus using the same. 20, the same reference numerals as those in FIG. 19 denote the same or corresponding parts.
[0295]
As shown in FIG. 20, in the twenty-second embodiment, the light guide plate 203 is composed of a composite light guide plate formed by joining first and second unit light guide members 210 and 211. The first and second unit light guide members are respectively composed of parts 210 and 211 formed by dividing the light guide plate 103 of FIG. 19 (Embodiment 21) into two at the center in the left-right direction. Surface 209 is formed as a reflective surface. The reflection surface 209 is formed by sticking a reflection tape on the joint surfaces of the unit light guide members 210 and 211 or depositing a reflective material such as aluminum Al. The reflecting surface 209 has a function of reflecting or scattering incident light, and here has a function of scattering and reflecting. The other points are the same as in the twenty-first embodiment.
[0296]
In the illumination device 100 configured as described above, the intensity of light emitted from the upper surface 203b of the light guide plate 203 becomes substantially uniform over the entire light guide plate 203 by the action of the scatterers 126 as in the twenty-first embodiment.
[0297]
Further, since the reflection surface 209 is provided on the joint surface between the two unit light guide members 210 and 211, the light incident on the light guide plate 203 from the light source 151 is not sufficiently scattered in the inside from the end surface on the opposite side. Lost light that is emitted can be reduced. That is, a part or all of the incident light is scattered and reflected by the reflection surface 209 provided at the center of the light guide plate 203. The scattered and reflected light is scattered again by the scatterer 126 dispersed in the original unit light guide members 210 and 211. Therefore, light that is not sufficiently scattered in the light guide plate 203 and penetrates to the opposite end face to be lost is further suppressed. When the reflection surface 209 is configured to have a function of scattering and transmitting, the light scattered through the reflection surface 209 and scattered in the other unit light guide member unit light guide members 210 and 211 is scattered. It is further scattered by the body 126. Therefore, since the light incident on the light guide plate 203 is sufficiently scattered, the light penetrating to the opposite end face is further suppressed.
[Example 14]
In this example, a light guide plate 203 having a size of 7 inches and a thickness of about 10 mm was used as the light guide plate 203 as in Example 10 of the eighteenth embodiment. As the scatterer 126, beads having a size of about 10 μm and a refractive index of about 1.7 were used. The scatterers 126 were dispersed by a manufacturing method to be described later so that the density increases substantially linearly with respect to the distance from the end face of the light guide plate 203 toward the center. As the luminous body 101, a cold cathode tube having an output of about 100 W was used. The reflection surface 209 has a scattering reflection function by sticking a reflection tape to the joint surface of each unit light guide member 210, 211.
[0298]
Then, the luminance was measured at nine points on the line connecting the center and the four corners of the upper surface 203b of the light guide plate 203, and the uniformity of the luminance in the plane was examined. As a result, when the luminance in the vicinity of the center of the upper surface 203b of the light guide plate 203 is 100%, the luminance at other locations is about 80% to 95%, which is the same as that in the twenty-first embodiment. In addition, the total luminance at each measurement point increased by about 5% compared to the twenty-first embodiment. Therefore, according to the present example, it was found that the light utilization rate can be improved and the luminance uniformity can be increased.
Embodiment 23
In the twenty-third embodiment of the present invention, the joint surface between the first unit light guide member 210 and the second unit light guide member 211 in FIG. 20 (Embodiment 22) is a refractive index matching surface. Other points are the same as in the twenty-second embodiment. In the present embodiment, the first and second unit light guide members 210 and 211 are made of an acrylic plate, and the joint surfaces thereof are bonded together using an adhesive having a refractive index substantially equal to these. Since acrylic has a refractive index of about 1.5, an epoxy adhesive having a refractive index of about 1.5 was used as the adhesive.
[0299]
With such a configuration, the joint surface does not function as a boundary surface that reflects light, and functions in the same manner as when optical matching is performed.
[0300]
Further, in Embodiment 19 or 20, by applying this refractive index matching process to the joint surfaces of the unit light guide members, the joint surfaces can be obtained by the difference in transmittance and reflectance without using a scattering sheet or the like. It is thought that it can be prevented from being seen as a boundary line. Although the adhesive is used in the above configuration example, the same effect can be obtained by simply applying a liquid having a refractive index equal to that of the unit light guide members 210 and 211 to the joint surfaces and bringing the joint surfaces into close contact with each other.
[0301]
Actually, as a result of measuring the luminance at the light exit surface 203a of the light guide plate 203 in the above configuration, a result substantially similar to the measurement result in the twenty-second embodiment was obtained. Further, even when the light exit surface 203b of the light guide plate 203 was observed without using the scattering sheet, an unnatural boundary such as a line was not observed. Therefore, according to this embodiment, it was found that the light utilization rate can be improved and the luminance uniformity can be increased.
Embodiment 24
FIG. 21 is a plan view schematically showing the configuration of the illumination apparatus according to Embodiment 24 of the present invention. 21, the same reference numerals as those in FIG. 17 denote the same or corresponding parts.
[0302]
FIG. 21 is a view as seen from the light exit surface side of the light guide plate. As shown in FIG. 21, in the present embodiment, unlike the nineteenth embodiment, the light guide plate 203 is composed of first and second unit light guide members 204 and 205 each of which is divided into two parts in plan view. In addition, the light emitter 101 is disposed on the four end faces of the light guide plate 203. Other points are the same as in the nineteenth embodiment. In FIG. 21, the reflector is omitted.
[0303]
The first unit light guide member in which the scatterers 126 are dispersed is composed of a diamond-shaped part 204 formed by connecting the midpoints of the sides of the rectangular light guide plate 203 with a straight line, and the second scatterers are not dispersed. The unit light guide member is composed of the remaining part 205 of the rectangular light guide plate 203. Accordingly, the occupation ratio of the first unit light guide member 204 in which the scatterers 126 are dispersed to the light guide plate 203 is increased from the portion near the light emitter 101 of the light guide plate 203 toward the central portion. . The first and second unit light guide members 204 and 205 are bonded to each other by performing the refractive index matching process described in the twenty-third embodiment. The mode of the scatterer 126 is the same as that of the nineteenth embodiment.
[0304]
The shape of the first unit light guide member 204 is such that the occupying ratio of the first unit light guide member 204 to the light guide plate 203 increases from the portion close to the light emitter 101 toward the center portion. If it is sufficient, it is not restricted to a rhombus. The light emitter 101 may be configured such that two L-shaped light emitters 101 are arranged on the four end faces of the light guide plate 203, and the U-shaped light emitter 101 and the linear light emitter. 101 may be arranged on the four end faces of the light guide plate 203.
[Example 15]
In this example, similarly to Example 10 of the eighteenth embodiment, the material and shape of the light guide plate, the light emitter, and the like were configured. Further, a diamond-shaped portion as shown in FIG. 21 was cut out from a rectangular acrylic plate in which the scatterers 126 were previously dispersed, and this was used as the first unit light guide member 204. Further, four right triangle portions as shown in FIG. 21 are cut out from an acrylic plate having the same shape as the acrylic plate for the first unit light guide member 204 and having no scatterers dispersed therein, The unit light guide member 205 was used. Then, the joining surfaces of the first and second unit light guide members 204 and 205 were bonded together using an epoxy adhesive.
[0305]
As a result of measuring the luminance at the light emitting surface 203b of the light guide plate 203 in the same manner as in Example 10 of the eighteenth embodiment, when the luminance near the center of the light emitting surface 203b is 100%, The luminance was about 80% to 95%. Therefore, it was found that the luminance distribution on the light exit surface can be controlled by this embodiment.
Embodiment 25
In the twenty-fifth embodiment of the present invention, an image display apparatus is configured by using the illumination devices according to the eighteenth to twenty-fourth embodiments. Specifically, in the configuration of the image display device described in the sixth embodiment, instead of the backlight 100 in the first embodiment, the backlight 100 in FIG. 16 (the eighteenth embodiment) and the backlight in FIG. Light 100 (Embodiment 19), backlight 100 (Embodiment 20) in FIG. 18, backlight 100 (Embodiment 21) in FIG. 19, backlight 100 (Embodiments 22 and 23) in FIG. By using the backlight 100 (Embodiment 24) of FIG. 21, the liquid crystal display device 1 as an image display device can be configured. As the liquid crystal element 106, a twist nematic type having a size of about 7 type was used. In addition, polarizing plates (not shown) are arranged in crossed Nicols on both sides of the liquid crystal element 106.
[0306]
Then, when the luminance distribution of the display screen was measured through the liquid crystal element 106, the result was obtained by multiplying the luminance measured by only the lighting device 100 by about 5 to 7% of the transmittance of the liquid crystal element 106. Accordingly, it has been found that even when an image display apparatus is configured using the lighting apparatus according to Embodiments 18 to 24, it is possible to improve the light utilization rate and control the luminance distribution.
Embodiment 26
Embodiment 26 of the present invention exemplifies a method for manufacturing a light guide plate in which scatterers are dispersed.
[0307]
FIG. 22 is a cross-sectional view showing a method for manufacturing a light guide plate according to the present embodiment. In FIG. 22, reference numeral 702 indicates a mold for forming the light guide plate by heating and melting. On the surface of the mold 702, a recess 702 having a plane shape substantially the same as the plane shape of a desired light guide plate and having a predetermined depth is formed. The mold 702 is made of a metal such as aluminum Al.
[0308]
In the present embodiment, the product is a light guide plate in which scatterers are dispersed in an acrylic resin. As the scatterer, a scatterer that has a reflection and refracting action on incident light and hardly exhibits absorption characteristics is preferable. Specifically, metal powder, glass beads, or the like can be used as the scatterer. Since the scattering target is visible light having a wavelength of about 0.5 μm, the scatterer needs to be larger than this wavelength in order to cause scattering. Further, since the size of the scatterer cannot exceed the thickness of the light guide plate, it is about several mm to several tens mm at the maximum. Therefore, considering the uniformity at the time of mixing, the size of the scatterer is preferably about several μm to several tens of μm.
[0309]
To manufacture the light guide plate, first, an acrylic resin is heated and melted, and beads having a refractive index of about 1.7 are added thereto. Next, a mixture (hereinafter simply referred to as a mixture) 701 of the beads and acrylic resin 701 is poured into the recess 702a of the mold 702. Next, the temperature of both end portions a and c of the mold 702 is set higher by about 50 to 100 ° C. than the temperature of the central portion b. Then, the viscosity of the portion where the temperature of the mixture 701 is high becomes low, and the degree of diffusion of the beads serving as the additive increases. For this reason, the dispersion density of beads becomes low at both ends a and c where the temperature is high, and the dispersion density becomes higher toward the center. Next, the mixture 701 is rapidly cooled in this state. Then, a light guide plate is obtained in which the dispersion density of beads is low at both ends and the dispersion density of beads is increased toward the center.
[0310]
Note that a photocuring agent may be added to the mixture 701 in advance, and the mixture 701 may be cured by light irradiation.
[0311]
Further, if the heating temperature of the mold 702 is made uniform, it is possible to obtain a light guide plate having a uniform dispersion density of scatterers.
[0312]
The light guide plate created as described above and having a different dispersion density depending on the location was used as the light guide plate 103 in the twenty-first embodiment. As described in the twenty-first embodiment, the optical characteristics of the lighting device 100 using the light guide plate 103 can be improved and the luminance distribution can be controlled. The effectiveness of the light guide plate 103 was confirmed.
Embodiment 27
FIG. 23 is a cross-sectional view showing a method for manufacturing a light guide plate according to Embodiment 27 of the present invention. 23, the same reference numerals as those in FIG. 22 denote the same or corresponding parts.
[0313]
In the present embodiment, the product is a light guide plate in which bubbles are dispersed as scatterers in an acrylic resin. The bubbles are made of air and have a refractive index of 1.0. On the other hand, the refractive index of acrylic resin is about 1.5. Accordingly, the air bubbles dispersed in the acrylic resin substrate scatter incident light due to the difference in refractive index of each other, and thereby function as a scatterer.
[0314]
To manufacture the light guide plate, first, the acrylic resin is heated and melted, and a foaming agent is added thereto. Next, as shown in FIG. 23, the molten acrylic resin 703 to which the foaming agent is added is poured into the recess 702a of the mold 702. Next, in this state, the molten acrylic resin 703 is irradiated with light 704.
[0315]
Here, the foaming agent has a property of generating bubbles in accordance with the intensity of irradiated light. Therefore, the dispersion density of the bubbles in the molten acrylic resin 703 can be changed depending on the location by setting the intensity of the irradiated light 704 to be distributed on the irradiated surface. Therefore, in the present embodiment, for example, the intensity of the irradiation light 704 is set to be small at both ends of the surface of the molten acrylic resin 703 and increase toward the center.
[0316]
Therefore, by this light irradiation, bubbles are generated in the molten acrylic resin 703 such that the dispersion density is low at both ends and the dispersion density increases toward the center.
[0317]
Next, the molten acrylic resin 703 is rapidly cooled in this state. Then, a light guide plate is obtained in which the dispersion density of bubbles is low at both ends and the dispersion density of bubbles is increased toward the center.
[0318]
A curing agent that reacts with ultraviolet rays may be added to the molten acrylic resin 703 in advance, and the molten acrylic resin 703 may be cured by irradiating the molten acrylic resin 703 with ultraviolet rays.
[0319]
Further, if the intensity distribution in the irradiation surface of the irradiation light 704 is made uniform, it is possible to obtain a light guide plate with a uniform dispersion density of bubbles. Furthermore, by selecting the intensity distribution in the irradiation surface of the irradiation light 704, the dispersion density of the bubbles in the light guide plate can be arbitrarily controlled.
[0320]
The light guide plate produced as described above was used as the light guide plate 103 in the twenty-first embodiment. As described in the twenty-first embodiment, the optical characteristics of the lighting device 100 using the light guide plate 103 can be improved and the luminance distribution can be controlled. The effectiveness of the light guide plate 103 was confirmed.
Embodiment 28.
Twenty-eighth embodiment of the present invention exemplifies an illumination device and an image display device that use a reflective polarizing plate to improve the light utilization rate and increase the luminance.
[0321]
FIG. 24 is an exploded perspective view schematically showing the configuration of the illumination device and the image display device according to the present embodiment, FIG. 25 is a schematic view showing the operation of the reflective polarizing plate of FIG. FIG. 26 is a cross-sectional view showing the case where the reflective polarizing plate has a multilayer film structure, FIG. 26B shows the case where the reflective polarizing plate is made of cholesteric liquid crystal, and FIG. 26 shows the change in transmittance with respect to the viewing angle of the prism sheet of FIG. (A) is a diagram showing a change in the direction perpendicular to the ridge line direction of the prism sheet, (b) is a diagram showing a change in the ridge line direction of the prism sheet. 24, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. In FIG. 24, for convenience, the Y direction is defined as the forward direction.
(Lighting device)
As shown in FIG. 24, in lighting device 100 according to the present embodiment, light sources 102 are provided on the upper end surface and the lower end surface of rectangular light guide plate 103, respectively. A reflection sheet 105 is disposed behind the light guide plate 103, and a diffusion sheet 131, a reflective polarizing plate 132, and a prism sheet 133 are disposed in this order in front of the light guide plate 103. The prism sheet 133 is arranged so that the ridge line direction 145 is a horizontal direction.
[0322]
As shown in FIG. 25 (a), the reflection-type polarizing plate 132 has an interface formed so as to extend in a triangular wave shape in the left-right direction in the cross section, and a multilayer film composed of a number of films having different refractive indexes is formed on the interface. Is formed. Since such an interface has a function similar to that of the polarization beam splitter, the P-polarized light of the incident light 137 is transmitted and the S-polarized light is reflected at the interface. The reflected S-polarized light is returned to the incident side, that is, the light guide plate 103. The reflective polarizing plate 132 is arranged so that the polarized light (here, “P-polarized light in the reflective polarizing plate 132”) enters the prism sheet 133 as “P-polarized light in the prism sheet 133”. Yes. That is, the polarization axis (polarization plane) of P-polarized light in the prism sheet 133 is a direction perpendicular to the ridge line direction 145, that is, a vertical direction. Therefore, the reflective polarizing plate 132 is configured such that the polarization axis of the P-polarized light emitted from the reflective polarizing plate 132 is in the vertical direction. Specifically, the interface is formed vertically.
[0323]
Next, the operation of the illumination device 100 configured as described above will be described. The light emitted from the light source 102 enters the light guide plate 103, is scattered by scattering dots (not shown) formed on the back surface of the light guide plate 103 while repeating internal reflection, and is emitted from the front surface of the light guide plate 103. . At this time, light leaking from the back surface of the light guide plate 103 is returned to the inside of the light guide plate 103 by the reflection sheet 105. The light emitted from the light guide plate 103 passes through the scattering sheet 131 while being scattered, and then enters the reflective polarizing plate 132. Then, among the incident light, P-polarized light is transmitted through the reflective polarizing plate 132, and S-polarized light is reflected by the reflective polarizing plate 132. The reflected S-polarized light is reflected by the scattering dots or the reflection sheet 105 of the light guide plate 103 and is incident on the reflective polarizing plate 132 again. At that time, the polarization direction is also modulated in the reflection process. Therefore, a part of the re-incident light can pass through the reflective polarizing plate 132 as it is. By repeating this process, the light emitted from the light source 102 is aligned in the polarization direction to the P-polarized light by the reflective polarizing plate 132.
[0324]
This P-polarized light is incident on the prism sheet 133 as P-polarized light in the prism sheet 133 and is condensed in the central direction at the viewing angle.
[0325]
Here, as shown in FIGS. 26 (a) and 26 (b), in the prism sheet 133, the P-polarized light transmittance 141 is higher than the S-polarized light transmittance 142 in the light emitted at an angle close to vertical. It is high. Specifically, the transmittance 141 for P-polarized light is approximately 6.5% higher than the transmittance 142 for S-polarized light within a viewing angle range of −10 degrees to +10 degrees. On the other hand, since the light incident on the prism sheet 133 is aligned with the P-polarized light by the reflective polarizing plate 132, the transmittance of the incident light is improved as compared with the case of passing the S-polarized light as in the conventional example. As a result, effective use of light can be achieved.
[0326]
Next, as a modification of the present embodiment, in FIG. 24, a phase plate such as a quarter wavelength plate is disposed on the light incident side of the reflective polarizing plate 132 and reflected by the reflective polarizing plate 132. S-polarized light may be passed twice back and forth. As a result, the polarization direction of the reflected S-polarized light is rotated by 90 ° and can be transmitted through the reflective polarizing plate 132. Therefore, the polarization directions can be more easily aligned as compared with the above configuration example.
[0327]
Further, as shown in FIG. 25B, the reflective polarizing plate 132 may be configured to have a film structure including cholesteric liquid crystal. In such a reflection type polarizing plate 132, the right-handed polarized light of the incident light 137 is transmitted and the left-handed polarized light is reflected according to the helical pitch of the cholesteric liquid crystal. In this case, since the light that has passed through the reflective polarizing plate 132 does not become linearly polarized light, it is necessary to use a phase plate such as a quarter-wave plate in combination.
(Image display device)
27 is a cross-sectional view showing the configuration of the liquid crystal cell of FIG. 24, where (a) shows a state where no voltage is applied, and (b) shows a state where a voltage is applied. 27, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. FIGS. 27A and 27B show one pixel.
[0328]
As shown in FIG. 24, in the image display device 1 according to the present embodiment, a liquid crystal display element 106 is disposed in front of the illumination device 100, and a drive circuit (not shown) that drives the liquid crystal display element 106 is provided. Is arranged. Since the configuration and operation of the drive circuit are the same as those in Embodiment 1, the description thereof is omitted.
[0329]
The liquid crystal display element 106 includes a liquid crystal cell 135, an incident side polarizing plate 134 provided on the back side of the liquid crystal cell 135, and an output side polarizing plate 136 provided on the front side of the liquid crystal cell 135. Yes. The incident side polarizing plate 134 is arranged so that its polarization axis (transmission axis) 146 is vertical corresponding to the polarization axis of the P wave transmitted through the reflective polarizing plate 132, and the output side polarizing plate 136 is The shaft 147 is disposed so as to be perpendicular to the polarization axis 146 of the incident side polarizing plate 134.
[0330]
As shown in FIG. 27A, the liquid crystal cell 135 has a liquid crystal mode in which the alignment direction of the liquid crystal molecules 113a for each pixel 139 has different pretilt angles with respect to the center plane 139a of the pixel without applying a voltage. have. Here, the pretilt angle is substantially symmetric with respect to the center plane 139a of the pixel. In this liquid crystal mode, when a voltage is applied by the power source 148, the liquid crystal molecules 113a rise in a direction perpendicular to the substrates 111 and 112 as shown in FIG. In such a liquid crystal mode, when the liquid crystal cell 135 is viewed from two directions (indicated by arrows A and B in FIG. 27A) inclined opposite to the normal lines of the substrates 111 and 112, FIG. As apparent from the above, the apparent refractive index is substantially the same in any direction. Therefore, the contrast is the same in any direction, and a wide viewing angle characteristic can be obtained.
[0331]
In such a liquid crystal mode, the substrates 111 and 112 are rubbed in directions opposite to each other in a state where the other side is masked for each region divided by the center plane 139a of the pixel 139 shown in FIG. Can be realized. In addition, a partition made of a polymer material is formed in a space between the substrates 111 and 112 on which the liquid crystal layer is arranged so as to partition the pixel 139 into a plurality of regions, and the liquid crystal is along the partition when the voltage is turned on / off. You may comprise so that a movement of a molecule | numerator may arise. This partition wall can be formed by irradiating a mixture of liquid crystal and a photocurable polymer material with light using a photomask having a predetermined pattern. The liquid crystal mode can also be realized by such a configuration. In addition, the liquid crystal mode can be realized by the following configuration. In other words, it is possible to form a concavo-convex pattern on the inner surface of one of the opposing substrates 111 and 112, for example, in a comb pattern, and to align liquid crystal molecules in different directions along the concavo-convex pattern. Also, the switching of the liquid crystal alignment is not performed by applying a voltage between the opposing substrates, but the switching electrode is formed on one substrate, and the liquid crystal alignment is switched in a direction parallel to the substrate. May be. In this case, the switching electrode pattern may be formed in a comb shape.
[0332]
Next, as described above, since the liquid crystal cell 135 has the same contrast when viewed from either direction, the axial direction of the polarizing plate 134 does not have to be inclined 45 degrees with respect to the longitudinal direction of the panel as in the conventional example. Good viewing angle characteristics can be obtained. Therefore, in the present embodiment, the polarization axis 146 of the incident-side polarizing plate 134 is set to the same vertical direction as the polarization axis of the P wave transmitted by the reflective polarizing plate 132, and accordingly, the polarization axis of the output-side polarizing plate 136 147 is level.
[0333]
In the image display device 1 configured as described above, the light emitted from the prism sheet 133 of the illumination device 100 sequentially passes through the incident-side polarizing plate 134, the liquid crystal cell 106, and the outgoing-side polarizing plate 136. An image corresponding to the video signal input to the drive circuit is displayed on the display screen. At this time, since the polarization axis of the incident-side polarizing plate 134 coincides with the polarization axis of the P-polarized light, most of the incident light passes through the incident-side polarizing plate 134 so that no absorption loss occurs. . Therefore, even when a high-output light source is used, heat generation due to light absorption at the incident side polarizing plate 134 is prevented, and heat generation at the prism sheet 133 is reduced as described above. Deterioration of the sheet 133 such as heat shrinkage and non-uniform optical characteristics is prevented. Therefore, according to the present embodiment, an image display apparatus that can improve the light utilization rate and increase the luminance can be obtained.
[0334]
In the above configuration example, the case where the image display device displays a monochrome image has been described. However, when the image display device displays a color image, the pixels (dots) of the respective colors constituting the pixel are replaced with the pixel. What is necessary is just to comprise similarly.
[0335]
In the above configuration example, the prism sheet is used as the light condensing means. However, any prism may be used as long as it collects incident light in a predetermined direction using refraction or reflection of the interface. In this way, a plurality of ridges may be arranged on the main surface of the flat member, and the cross-section of the ridges may be a shape other than a triangle.
Embodiment 29.
FIG. 28 is an exploded perspective view schematically showing the configuration of the illumination apparatus according to Embodiment 29 of the present invention, in which (a) shows a case where a point light emitter is used as a light source, and (b). FIG. 4 is a diagram showing a case where a linear light emitter is used as a direct light source, and FIG. 5C is a diagram showing a case where a planar light emitter is used as a light source. 28, the same reference numerals as those in FIG. 27 denote the same or corresponding parts.
[0336]
This embodiment mode shows a specific configuration example of the light source 102 in Embodiment Mode 28.
[0337]
In the first configuration example, as shown in FIG. 28A, for example, a large number of point light emitters 101 such as LEDs (light emitting diodes) are arranged on the upper end surface and the lower end surface of the light guide plate 103, respectively.
[0338]
In the second configuration example, as shown in FIG. 28B, a plurality of linear light emitters 101 such as cold cathode tubes are arranged behind the light guide plate 103, respectively. That is, it is configured as a direct type illumination device.
[0339]
In the third configuration example, as shown in FIG. 28C, a planar light emitter 10 is disposed instead of the light guide plate.
[0340]
It is also possible to obtain a new configuration by combining the above configurations. For example, by arranging a plurality of cold cathode tubes behind the light guide plate 103 to form a direct type, and by arranging a plurality of LEDs that emit several kinds of colors on the upper and lower end faces of the light guide plate 103, the luminance is further increased. Can do. In addition, for example, the color balance can be improved by configuring the LED so as to compensate for a color portion having a low light emission intensity in the emission spectrum of the cold cathode tube.
[Example 16]
In this embodiment, a direct-type illumination device is used as in the second configuration example. A cold cathode tube having an output of about 100 W was used. A light guide plate having a size of about 10 inches was used.
[0341]
And when the brightness | luminance in the output surface of the prism sheet 133 was measured, it is 10000 cd / mm.²A high brightness output was obtained. In this state, even if illumination was continued for 100 hours or more, the luminance distribution was not made nonuniform due to thermal deformation of the prism sheet 132 or the like. From this, it was found that the lighting device according to the present example can obtain stable performance even when operated at high luminance.
[0342]
It goes without saying that an image display device can be obtained by combining the lighting device according to this embodiment with a liquid crystal display element and a drive circuit in the same manner as in Embodiment 28.
Embodiment 30
FIG. 29 is an exploded perspective view schematically showing the configuration of the illumination device and the image display device according to Embodiment 30 of the present invention. 29, the same reference numerals as those in FIG. 24 denote the same or corresponding parts.
[0343]
As shown in FIG. 29, in the present embodiment, the polarization axis 146 of the incident side polarizing plate 134 is inclined 45 degrees with respect to the horizontal direction, and the polarization axis 147 of the outgoing side polarizing plate 136 is the polarization of the incident side polarizing plate 134. The ridge line directions 145A and 145B of the prism sheets 133A and 133B and the polarization axis of the P wave are set in directions corresponding thereto. The liquid crystal cell 135 is a TN liquid crystal mode. Other points are the same as in the twenty-eighth embodiment.
[Example 17]
In this embodiment, in FIG. 29, only the prism sheet 133A is disposed, and the prism sheet 133A is disposed obliquely so that the ridge line direction 145A is perpendicular to the polarization axis 146 of the incident side polarizing plate 134. . The reflection type polarizing plate 132 is configured such that the polarization axis of the P wave, which is the transmission axis, coincides with the polarization axis 146 of the incident side polarizing plate 134. Then, cold cathode tubes of about 100 W were disposed on the upper and lower end faces of the light guide plate 103 as light emitters. Further, as a comparative example (conventional example), a configuration in which the ridge line direction 133A of the prism sheet 133A was set to the horizontal direction and the reflective polarizing plate 132 was removed in the configuration of this example was created.
[0344]
As a result of measuring the front luminance on the display screen, the front luminance was improved by about 5 to 10% in this example as compared with the comparative example.
[0345]
From the above results, it is possible to arrange the polarizing plate so that it can be applied to the TN mode liquid crystal currently widely used. It was found that the brightness can be improved.
[Example 18]
In Example 17, the effect of improving the front luminance was obtained as described above. However, since the prism sheet 133A was disposed obliquely, non-uniformity occurred in the viewing angle characteristics (contrast viewing angle characteristics) in the left-right direction. Therefore, in this embodiment, in order to eliminate this, a prism sheet 133B is further added in front of the prism sheet 133A, and this is arranged so that the ridge line direction 145B coincides with the polarization axis 146 of the incident side polarizing plate 134. did.
[0346]
As a result of measuring the luminance of the display screen, the left and right viewing angle characteristics were almost symmetrical. As for the front luminance, the opposite of the case where the ridge line direction 145B of the one 133B close to the liquid crystal cell 135 is perpendicular to the polarization axis 146 of the incident side polarizing plate 134 is the opposite ( It was confirmed that the luminance was increased by several percent compared to the configuration shown in FIG. If two prism sheets are used and they are arranged so that the ridge directions are perpendicular to each other, the transmittance by polarized light should be equal. However, in reality, the medium of the prism sheet itself has some refractive index anisotropy. Therefore, the combination of the arrangement and the incident side polarizing plate 134 is considered to affect the transmittance of the liquid crystal cell 135.
[0347]
As described above, according to the present embodiment, the two prism sheets 133A and 133B are used, both ridge line directions are perpendicular to each other, and one ridge line direction is parallel to the direction of the polarization axis 146 of the incident-side polarizing plate 134. It was confirmed that the left and right viewing angle characteristics can be made symmetric while improving the front luminance.
Embodiment 31
In the inventions according to Embodiments 28 and 30, a reflective polarizing plate is inserted on the optical path of the illumination device, the ridge line direction of the prism sheet and the polarization of the polarizing plate of the liquid crystal display element are on the polarization axis of the P wave that is the transmission axis. It is essential that the axes correspond to each other. Therefore, the present invention can be applied to various types of lighting devices by adding this essential configuration. Therefore, in the present embodiment, the configurations of Embodiments 28 and 30 except for the reflective polarizing plate 132 and the prism sheet 133 in the illumination device 100 are replaced with the illumination devices of Embodiments 1 to 27, respectively. . By adopting such a configuration, in addition to the effects of Embodiments 28 and 30, the effects of Embodiments 1 to 27 can be obtained together.
[0348]
It goes without saying that an image display device can be obtained by combining the lighting device according to this embodiment with a liquid crystal display element and a drive circuit in the same manner as in Embodiment 28.
Embodiment 32.
Embodiment 32 of the present invention relates to a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal device using the image display devices (liquid crystal display devices) of Embodiments 6 to 11, 17, 25, and 28 to 31 as display units. This is just an example.
[0349]
FIG. 30 is an external view showing the configuration of the liquid crystal monitor according to the present embodiment. Referring also to FIG. 2, the liquid crystal monitor 601 includes a display unit including the liquid crystal display device 1 using the illumination device 100 according to the first embodiment, and a signal processing unit that processes a monitor signal input from the outside ( The monitor video signal output from the signal processing unit is input to the drive circuit 36 of the liquid crystal display device 1 as the video signal 25. With such a configuration, a liquid crystal monitor capable of controlling the luminance distribution can be obtained.
[0350]
Here, as the liquid crystal display device, another liquid crystal display device of the sixth embodiment and the liquid crystal display devices of the seventh to eleventh, seventeenth, twenty-fifth and twenty-fifth embodiments may be used, and the liquid crystal exhibiting effects corresponding to the respective embodiments. You can get a monitor.
[0351]
FIG. 31 is an external view showing a configuration of the liquid crystal television according to the present embodiment. Referring also to FIG. 2, liquid crystal television 602 is a tuner that selects a display unit composed of liquid crystal display device 1 using lighting device 100 of Embodiment 1 and a channel of a television broadcast signal input from the outside. Unit 603, and the TV video signal of the channel selected by the tuner unit 603 is input to the drive circuit 36 of the liquid crystal display device 1 as the video signal 25. Note that. In FIG. 31, wiring between the liquid crystal display device 1 and the tuner unit 603 is omitted. With such a configuration, a liquid crystal television in which the luminance distribution can be controlled can be obtained.
[0352]
Here, as the liquid crystal display device, another liquid crystal display device of the sixth embodiment and the liquid crystal display devices of the seventh to eleventh, seventeenth, twenty-fifth and twenty-fifth embodiments may be used, and the liquid crystal exhibiting effects corresponding to the respective embodiments. You can get a TV.
[0353]
The liquid crystal information terminal device according to the present embodiment includes transmission / reception means for transmitting / receiving communication information in place of the tuner unit 603 in the liquid crystal television 602, and an image signal including required information output from the transmission / reception means is displayed on the liquid crystal display. The video signal 25 is input to the drive circuit 36 of the display device 1. With such a configuration, an information terminal device capable of controlling the luminance distribution can be obtained.
[0354]
Here, as the liquid crystal display device, another liquid crystal display device according to the sixth embodiment and the liquid crystal display devices according to the seventh to eleventh, seventeenth, twenty-fifth and twenty-fifth embodiments may be used. A terminal device can be obtained.
[0355]
Note that the embodiment of the present invention is not limited to the above-described Embodiments 1 to 32, and it is needless to say that a configuration for improving or modifying them can be used. Further, although a configuration example using a liquid crystal display element as an image display device has been described, this is not limited to a liquid crystal display element, and any element of a display type using a backlight or a front light may be used.
[0356]
【The invention's effect】
The present invention is implemented in the form as described above, and has the following effects.
(1) It is possible to provide an illumination device, an image display device, a liquid crystal monitor, a liquid crystal television, a liquid crystal information terminal, and a method of manufacturing a light guide plate used in these devices that can increase the luminance.
(2) It is possible to provide an illuminating device, an image display device, a liquid crystal monitor, a liquid crystal television, a liquid crystal information terminal, and a method of manufacturing the light guide plate used in these devices capable of reducing light penetration of the light guide plate and controlling the luminance distribution. .
(3) An illumination device, an image display device, a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal capable of changing the luminance distribution can be provided.
(4) It is possible to provide an illuminating device, an image display device, a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal that can reduce light loss in the light collecting means.
(5) It is possible to provide an image display device, a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal capable of reducing light loss in a polarizing plate of a liquid crystal display element.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams schematically illustrating a configuration of an illumination device and an image display device using the illumination device according to Embodiment 1 of the present invention, in which FIG. 1A is a cross-sectional view, and FIG. It is a top view which shows the dot pattern of a dispersion | distribution liquid crystal element.
FIG. 2 is a block diagram showing a configuration of a control system of the image display apparatus of FIG.
FIG. 3 is a cross-sectional view schematically showing a configuration of an illumination device and an image display device using the illumination device according to a second embodiment of the present invention.
FIG. 4 is a cross-sectional view schematically showing a configuration of an illumination apparatus according to Embodiment 3 of the present invention and an image display apparatus using the same.
FIG. 5 is a plan view schematically showing a configuration of a lighting apparatus according to Embodiment 5 of the present invention.
FIG. 6 is a perspective view schematically showing configurations of an illumination device and an image display device according to Embodiment 7 of the present invention.
FIG. 7 is a perspective view schematically showing a configuration of an illumination device and an image display device according to Embodiment 8 of the present invention.
FIG. 8 is a perspective view schematically showing a configuration of an illumination device and an image display device according to Embodiment 9 of the present invention.
FIG. 9 is a block diagram showing a configuration of a control system of an image display apparatus according to Embodiment 10 of the present invention.
FIG. 10 is a cross-sectional view schematically showing a configuration of a lighting apparatus according to Embodiment 12 of the present invention.
11 is a graph showing a change in the amount of light passing through the light guide plate with respect to the transmittance of the semi-transmissive layer in FIG.
FIG. 12 is a cross-sectional view schematically showing a configuration of a lighting apparatus according to Embodiment 13 of the present invention.
FIG. 13 is a cross-sectional view schematically showing a configuration of a lighting apparatus according to Embodiment 14 of the present invention.
FIG. 14 is a cross-sectional view schematically showing a configuration of a lighting apparatus according to Embodiment 15 of the present invention.
FIG. 15 is a cross-sectional view schematically showing a configuration of a lighting apparatus according to Embodiment 16 of the present invention.
FIG. 16 is a cross-sectional view schematically showing a configuration of an illumination device and an image display device using the same according to an eighteenth embodiment of the present invention.
FIG. 17 is a cross-sectional view schematically showing a configuration of an illumination apparatus and an image display apparatus using the illumination apparatus according to a nineteenth embodiment of the present invention.
FIG. 18 is a cross-sectional view schematically showing a configuration of an illumination device and an image display device using the same according to a twentieth embodiment of the present invention.
FIG. 19 is a cross-sectional view schematically showing a configuration of an illumination apparatus according to Embodiment 21 of the present invention and an image display apparatus using the illumination apparatus.
FIG. 20 is a cross-sectional view schematically showing a configuration of an illumination apparatus and an image display apparatus using the same according to a twenty-second embodiment of the present invention.
FIG. 21 is a cross-sectional view schematically showing a configuration of a lighting apparatus according to Embodiment 24 of the present invention.
FIG. 22 is a cross sectional view showing a method for manufacturing the light guide plate according to Embodiment 26 of the present invention.
FIG. 23 is a cross-sectional view showing the method for manufacturing the light guide plate according to Embodiment 27 of the present invention.
FIG. 24 is an exploded perspective view schematically showing a configuration of an illumination apparatus and an image display apparatus according to a twenty-eighth embodiment of the present invention.
25 is a schematic diagram showing the operation of the reflective polarizing plate of FIG. 24, where (a) is a cross-sectional view showing a case where the reflective polarizing plate has a multilayer film structure, and (b) is a schematic diagram of the reflective polarizing plate. It is a figure which shows the case where it consists of a cholesteric liquid crystal.
26 is a graph showing a change in transmittance with respect to the viewing angle of the prism sheet of FIG. 24, where (a) shows a change in the direction perpendicular to the ridge line direction of the prism sheet, and (b) shows a change in the prism sheet. It is a figure which shows the change in a ridgeline direction.
27 is a cross-sectional view showing the configuration of the liquid crystal cell of FIG. 24, in which (a) shows a state in which no voltage is applied, and (b) shows a state in which a voltage is applied.
FIG. 28 is an exploded perspective view schematically showing a configuration of an illumination apparatus according to Embodiment 29 of the present invention, in which (a) shows a case where a point light emitter is used as a light source; (B) is a figure which shows the case where a linear light-emitting body is used as a direct light source, (c) is a figure which shows the case where a planar light-emitting body is used as a light source.
FIG. 29 is an exploded perspective view schematically showing a configuration of an illumination device and an image display device according to a thirtieth embodiment of the present invention.
FIG. 30 is an external view showing a configuration of a monitor device according to Embodiment 31 of the present invention.
FIG. 31 is an external view showing a configuration of a television device according to Embodiment 31 of the present invention.
32A and 32B are diagrams schematically showing a configuration of a conventional illumination device and an image display device using the same, wherein FIG. 32A is a cross-sectional view, and FIG. FIG.
FIG. 33 is a cross-sectional view schematically showing a configuration of a conventional lighting device.
FIG. 34 is a cross-sectional view schematically showing a configuration of a conventional lighting device.
FIG. 35 is an exploded perspective view schematically showing a configuration of a conventional image display apparatus.
[Explanation of symbols]
1 Liquid crystal display device
25 Video signal
31 Operation SW
32 Luminance distribution setting circuit
33 Main memory
34 CPU
35,37 Drive signal
36 Drive circuit
38 Signal processing circuit
41 dots
Area other than 42 dots
100 Lighting equipment (backlight)
101 Light emitter (cold cathode tube)
102 reflector
103 Light guide plate
103a End face
103b Top view
103c bottom
104 Dispersed liquid crystal element
105 Reflector (reflective sheet)
106 Liquid crystal display elements
107 Scatter control board
111 Counter substrate
112 TFT substrate
113 LCD
114 scattering dots
121 translucent layer
122 Scatterer
123,124 scattering dots
123a, 124a First scattering dot
123b, 124b Second scattering dot
125 scattering region
125a First scattering region
125b Second scattering region
126 Scatterer
131 Diffusion sheet
132 Reflective polarizing plate
133,133A, 133B Prism sheet
134 Incident-side polarizing plate
135 Liquid crystal display elements
136 Output-side polarizing plate
137 Incident light
139 pixels
139a Pixel center plane
141 P-polarized light transmittance
142 S-polarized light transmittance
145,145A, 145B Prism sheet ridge direction
146 Polarization axis of incident side polarizing plate
147 Polarization axis of the output-side polarizing plate
151 Light source
201 Scattering reflector
203 Light guide plate
204 ~ 208,210,211 Unit light guide member
209 Reflective surface
301 reflective polarizing plate
302 Polarization modulator
305 Light modulation structure
401 LED
501 illuminant
502 Planar light emitter
601 LCD monitor
602 LCD TV
603 tuner
701 mixture
702 formwork
702a recess
703 Molten acrylic resin
901 Video signal synthesis circuit
1000 backlight
1001 Light emitter
1002 reflector
1003 Light guide plate
1004 scattering dots
1005 reflector
1006 LCD device

Claims (3)

A method of manufacturing a light guide plate in which scatterers that scatter incident light are dispersed in a transparent substrate,
  Heating and melting the substrate material;
  Mixing the scatterer into the molten substrate material;
  Heating the melted substrate material in a plate-like manner while maintaining the temperature different depending on the site, and then curing the material, whereby the density of the scatterer varies depending on the site. A method for producing a light guide plate dispersed in a substrate. A method of manufacturing a light guide plate in which scatterers that scatter incident light are dispersed in a transparent substrate, wherein a photoreactive foaming agent is dispersed in the substrate material, and then the light irradiation intensity varies depending on the site. , Thereby generating bubbles as the scatterer in the base so that the density changes depending on the part, and thereby dispersing the scatterer in the base such that the density changes depending on the part. Manufacturing method . A lighting device comprising a light source and a light emitting surface from which light from the light source is emitted, wherein the light guide plate guides the light from the light source to the light emitting surface and the luminance for changing the luminance distribution of the light emitting surface The light guide plate is arranged so that light from the light source is incident from an end surface, and light emitted from one main surface of the light guide plate is reflected so as to return to the one main surface. By forming a surface, the other main surface of the light guide plate constitutes the light emitting surface,
  The luminance distribution changing means is composed of scattering ratio distribution changing means for changing the distribution of the scattering ratio of the light guided by the light guide plate as viewed from the light exit surface. A scattering control structure that scatters or transmits light by switching between a first scattering region formed so as to be distributed on one main surface of the light plate and the one main surface of the light guide plate and the reflection surface And a second scattering region formed so as to be distributed on the reflection surface.

Images