JP2002208307A - Manufacturing method of illumination device, image display device, liquid crystal monitor, liquid crystal tv, liquid crystal information terminal and light guide plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination device, an image display device or the like that allow high luminance. SOLUTION: The illumination device 100 comprises a light source 102, a light guide plate 103 that is arranged so that the light from the light source 102 may enter from the end face 103a, and a reflection face 105 that is formed so as to be opposed to one of the main face 103c of the light guide plate 103. In the illumination device, a constant scattering layer 121 that transits so that the entering light may be scattered at a prescribed rate on one of the main face 103c of the light guide plate 103 is formed, and a distribution scattering structure 114 that transmits so that the entering light may be scattered at a varying rate on the surface of the constant scattering layer 121 according to the distance from the above light source 102 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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]

2. Description of the Related Art In a liquid crystal display device, which is an example of a conventional image display device, for example, two transparent glass substrates on each of which an electrode made of a transparent conductive thin film and an alignment film are stacked are opposed to each other. A liquid crystal display element comprising a liquid crystal display element having a liquid crystal sealed between the two glass substrates, a polarizing plate provided outside the both glass substrates, and a liquid crystal display element arranged below the liquid crystal display element. It is configured to include a backlight for supplying light to the display element, a circuit board for driving the liquid crystal display element, and the like.

FIG. 32A shows a conventional liquid crystal display device and a backlight used therein, and FIGS. 33 and 34 show another conventional backlight.

As shown in FIGS. 32 (a), 33, and 34, a backlight guides light emitted from, for example, a luminous body 1001 to a direction away from the luminous body 1001, and a liquid crystal display element.
A light guide plate 1003 made of a transparent synthetic resin plate for uniformly irradiating light to the entire surface of the light guide 1006, and a luminous body 1001 arranged near the end face of the light guide plate 1003 and substantially parallel to the end face along the end face. It has a fluorescent tube and a reflector 1002 which constitutes a light source together with the fluorescent tube and covers the fluorescent tube over substantially the entire length thereof. In addition, the backlight 1000 includes a diffusion sheet (not shown) disposed on the light guide plate 1003 and diffusing light from the light guide plate 1003, and a light diffused from the light guide plate 1003 disposed below the light guide plate 1003. Reflector that reflects and returns to light guide plate 1003 again
It further has 1005 mag.

On the lower surface of the light guide plate 1003, so-called scattering dots
1004 is formed in a predetermined pattern, and the scattering dots
The surface of 1004 is a scattering surface. This scattering dot 1004
An example of the pattern is shown in FIG. Therefore, light incident on the scattering dots 1004 is scattered, and a part of the scattered light is emitted from the upper surface of the light guide plate 1003. Light incident on a 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 due to an internal reflection action according to the incident angle.

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 that has entered the light guide plate 1003 from the light source travels through the light guide plate 1003 while repeating internal reflection so as to be emitted to the outside at a fixed rate, so that the light amount is usually large near the light source from the light source. It gets smaller as you move away. Therefore, as shown in Japanese Utility Model Laid-Open No. 60-76387, for example, the area ratio of the scattering dots 1004 to the lower surface of the light guide plate 1003 is reduced on the light source side. Then, among the light traveling to the lower surface of the light guide plate 1003, the scattering dots
The ratio of light scattered by 1004 and emitted from the upper surface of light guide plate 1003 is reduced. On the other hand, if the area ratio is increased as the distance from the light source increases, the ratio of light 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.

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 currently mainstream transmissive liquid crystal display device requires illumination from behind using a backlight as described above. However, since the incident light is random light whose polarization direction is not uniform, about half of the light is absorbed by the polarizing plate on the incident side, and the light use efficiency is reduced. 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.

FIG. 35 shows a liquid crystal display device using such a prism sheet. In FIG. 35, light from light sources 1002 arranged vertically enters a light guide plate 1003. The reflection sheet 1005 is used for returning light leaked from the light guide plate 1003 to the light guide plate 1003 for effective use. The light scattered by the diffusion sheet 1031 is collected by the prism sheet 1033 and enters the liquid crystal cell 1035. Before and after this liquid crystal cell 1035, polarizing plates 1034 and 103 whose polarization axes are arranged orthogonally to each other.
5 are located. The transmittance of the prism sheet 1033 varies 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, the direction orthogonal to the ridgeline 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 direction 1045 of the prism sheet 1033. 26, the transmittance of the P-polarized light is different from that of the S-polarized light, and the transmittance of the P-polarized light is higher in any direction in the front direction, that is, in the direction in which the viewing angle is in a range of about −10 degrees to +10 degrees. I understand. Therefore, when the front luminance is emphasized, the luminance can be increased by preferentially using the P-polarized light. As described above, Japanese Patent Application Laid-Open No. 2000-1220 has attempted to increase the light use efficiency of the liquid crystal panel by setting the transmission axis of the polarizing plate on the incident side in accordance with the light in the specific vibration direction transmitted through the prism sheet.
46 publication.

[0010]

However, in the above-described conventional backlight, as shown by a dotted line in FIG. 34, a part of the light emitted from the light source 1002 does not hit the scattered dots 1004 and the end face on the opposite side. Some are emitted from. This light becomes loss light leaked to the outside of the light guide plate 1003. In this case, a reflective tape is provided on the opposite end face, and the light guide plate 1003 is again provided.
It is conceivable to return the light source 1002 to the light guide plate 10 as shown in FIGS.
It is often provided at both ends of 03. In such a case, a reflective tape cannot be provided, and a part of the light reaching the end face on the opposite side is reflected by the fluorescent tube 1001 and the reflector 1002 and re-enters the light guide plate 1003 and is used. However, there are some that disappear without re-entering. According to the results of experiments and simulations performed by the inventor, the light guide plate 1003
Approximately half of the light reaching the opposite end face is lost. In addition, about 18% of the light emitted from the fluorescent tube 1001 penetrated to the opposite side, and about half of the light was lost. In order to reduce the penetration light of the light guide plate, the scattering dots 1004 may be densely arranged. Generally, the scattering dots 1004 are formed by printing. However, the density of the scattering dots 1004 has an upper limit due to manufacturing stability. That is, when trying to form the scattering dots 1004 densely, the adjacent scattering dots 1004 are stuck together at the time of printing, and printing cannot be performed with the designed area. Also,
The degree of sticking differs every time printing is performed, and stable production cannot be performed. Therefore, some space is required between adjacent scattering dots 1004. This is called scattering dots 10
The upper limit was 80% in terms of the ratio of the area of the scattering dots 1004 to the area of the surface on which 04 was formed (hereinafter, referred to as area ratio). In addition, scattering dots 10 that can be printed stably
The area of 04 also had a lower limit, and the lower limit was 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, light penetrating the light guide plate 1003 as described above is generated. Therefore, the light of the light source 1002 cannot be sufficiently utilized.

On the other hand, with respect to this problem,
No. 231 discloses a configuration in which a diffusing material is mixed into a light guide plate to scatter light 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.

In recent years, a liquid crystal display device is a PC (persona).
l Computer) is becoming widespread. Further, the application to liquid crystal televisions for displaying moving images of movies is also progressing. In a liquid crystal display device for a monitor or the like, higher definition and higher luminance have been developed. The monitor is
In order to mainly display characters and drawings, uniformity of luminance is required over the entire area of the display screen. Actually, the luminance distribution over the entire display screen also has high uniformity of 80% or more of the central part in the peripheral part where the luminance is low.

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 the luminance at the peripheral portion is reduced to about 50% of that. is there. This is because, on a moving image such as a movie, the observer tends to gaze at the central portion, and even if the luminance difference in the luminance distribution of the display screen is large, the observer rarely feels unnatural. Rather, even if the brightness of the peripheral portion is reduced, the brightness of the central portion is increased when the brightness is increased.

As described above, the display has several settings suitable for display characteristics such as luminance distribution depending on the application such as a monitor or a TV. In the field of liquid crystal display devices, AVP can be used for both monitors and TVs.
A computer compatible with C (audio video personal computer) has 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 characteristics of the backlight so that the luminance has a distribution.

In an edge light type backlight using a light guide plate which is generally used, as described above,
The distribution of the brightness is controlled by scattering dots formed on the lower surface of the light guide plate. However, since the pattern of the scattering dots is a fixed pattern 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 according to the application.

Further, the conventional liquid crystal display device has a CR
In general, the luminance is still lower than that of T or the like, and higher luminance than the current state is required. 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.
At 34, half of the light from light source 1002 is absorbed. light source
If the output of 1002 increases, the amount of absorption also increases, so that the polarizing plate 1034 loses uniformity due to thermal contraction or the like due to the absorbed light, causing a problem that unevenness in black display occurs.

Also, since unpolarized random light is incident on the prism sheet 1033, the rate of absorption of low P-polarized light and S-polarized light having low transmittance cannot be ignored. As a result, the prism sheet
Degradation of the light-collecting characteristics due to deformation of 1033 and the like poses a problem.

Further, in FIG. 35, the polarization axis of the polarizing plate is arranged at an angle of about 45 degrees with respect to the liquid crystal cell 1035 for the following reason. That is, the TN type liquid crystal widely used in the liquid crystal display element 1006 has a bias in the contrast viewing angle characteristic, and is wide in the left-right direction and narrow in the up-down direction. Therefore, the viewing angle characteristic of the contrast is adjusted by inclining the transmission axis direction of the polarizing plate at an angle of 45 degrees. Therefore, if the transmission axis of the polarizing plate on the incident side is set in accordance with the light in the specific vibration direction transmitted through the prism sheet, there arises a problem that the contrast viewing angle characteristic is impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to a lighting device, an image display device, a liquid crystal monitor, a liquid crystal television, a liquid crystal information terminal, and a light guide plate used for these devices, which can achieve high luminance. First to provide a manufacturing method of
The purpose is.

Further, the present invention provides an illuminating 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 used for the same, which can reduce the penetration light through the light guide plate and control the luminance distribution. The second purpose is to provide

A third object of the present invention is to provide a lighting device, an image display device, a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal that can change the luminance distribution.

Further, the present invention provides an illumination device, an image display device, a liquid crystal monitor,
A fourth object is to provide a liquid crystal television and a liquid crystal information terminal.

It is a fifth object of the present invention 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 device.

[0024]

In order to achieve the above object, an illumination device according to the present invention comprises a light source, a light guide plate arranged so that light from the light source enters from an end face, and one of the light guide plates. In a lighting device having a reflection surface formed so as to face the main surface of the light guide plate, a constant scattering layer that transmits incident light to be scattered at a predetermined rate is formed on one main surface of the light guide plate, A distributed scattering structure is formed on the surface of the constant scattering layer so as to transmit incident light so as to be scattered at a rate that varies according to the distance from the light source (claim 1).

With this configuration, light incident on the light guide plate propagates so that light not scattered in the light guide plate is totally reflected, but light scattered by the constant scattering layer increases. The amount of light penetrating through is reduced. Therefore, the light utilization rate is improved, and high luminance can be achieved. Moreover,
The luminance distribution on the other main surface of the light guide plate, which is the light emitting surface, can be controlled by the scattering action of the distribution scattering structure.

In this case, the constant scattering layer may be formed on the entire surface of one main surface of the light guide plate.

With this configuration, it is possible to reduce the penetration light amount more effectively.

The distributed scattering structure may be a scattering region formed on the surface of the constant scattering layer such that the area ratio changes according to the distance from the light source.

In this case, the scattering region may be a scattering dot formed on the surface of the constant scattering layer.

With this configuration, since the scattering dots can be formed by printing, the scattering region can be easily formed.

Further, the scattering region may be a region in which irregularities on the surface of the constant scattering layer are formed.

Further, the lighting device according to the present invention comprises: a light source;
In a lighting device including a light guide plate arranged so that light from the light source is incident from an end face, and a reflection surface formed to face one main surface of the light guide plate, the light guide plate includes:
A distributed scattering structure is formed that scatters light propagating inside at a certain rate, and transmits incident light on one main surface of the light guide plate so as to be scattered at a rate that varies according to the distance from the light source. (Claim 6).

With this configuration, light penetrating the light guide plate from the light source to the opposite end face is reduced by the scattering action of the light guide plate, and the luminance distribution on the other main surface of the light guide plate, which is the light exit surface, is reduced by a distributed scattering structure. Can be controlled by the scattering action. As a result, the light utilization rate is improved, and high luminance can be achieved.

In this case, the scattering effect of the distributed scattering structure may be greater than the scattering effect of the light guide plate in the degree of contribution to the amount of light emitted from the other main surface of the light guide plate.

With this configuration, it is possible to reduce the penetration light of the light guide plate without impairing the control of the luminance distribution on the light emitting surface.

In this case, the scattering effect of the distributed scattering structure may be approximately twice or more the scattering effect of the light guide plate.

With this configuration, the luminance distribution on the light emitting surface can be controlled more appropriately.

In the above case, the distributed scattering structure is:
A scattering region may be formed on one main surface of the light guide plate such that an area ratio changes according to a distance from the light source.

With this configuration, the distributed scattering structure can be easily configured.

In this case, the scattering area may be a scattering dot.

With this configuration, the distributed scattering structure can be configured more easily.

In the above case, the light guide plate may scatter light by a scatterer dispersed in the light guide plate.

With this configuration, a light guide plate having a scattering function can be easily configured.

Further, the distributed scattering structure may scatter the incident light at a smaller rate as the light is closer to the light source.

With this configuration, it is possible to correct the luminance distribution on the light exit surface, in which the luminance becomes higher as the light source is closer to the light source.

Further, the lighting device according to the present invention comprises: a light source;
In a lighting device including a light guide plate arranged so that light from the light source is incident from an end face, and a reflection surface formed to face one main surface of the light guide plate, the light guide plate includes:
Light that propagates inside is scattered at a rate that varies according to the distance from the light source (claim 13).

With this configuration, since the scattering rate of the light guide plate changes according to the distance from the light source, it is possible to reduce the penetration light of the light guide plate and to control the luminance distribution on the light emitting surface. As a result, the light utilization rate is improved, and higher luminance can be achieved.

In this case, the light guide plate is constituted by a plurality of unit light guide members having different scattering rates, and the plurality of unit light guide members are arranged such that the scattering rate of the entire light guide plate depends on the distance from the light source. It may be arranged so as to be changed (claim 14).

With such a configuration, it is not necessary to change the scattering rate in the unit light guide member, so that the light guide plate can be easily manufactured.

In this case, the plurality of unit light guide members may include one having no scattering function.

With this configuration, a part of the unit light guide members can be formed in the same manner as a general light guide plate, so that the manufacture becomes easier.

[0052] The junction between the unit light guide members may be configured to reflect or scatter incident light.

With such a configuration, the chances of scattering of light propagating in the light guide plate increase, so that light penetrating the light guide plate can be further reduced.

In this case, the reflection or scattering may be at least one of total reflection, scattering reflection, and scattering transmission (claim 17).

In the above case, the plurality of unit light guide members may be joined so as to be in a refractive index matching state.

With this configuration, the light guide plate can be made to function optically as a single light guide plate.

In this case, the plurality of unit light-guiding members may be joined to each other via a member having a refractive index of about 1.5 so as to be in a refractive index matching state. Item 19).

With this configuration, the unit light guide member can be made of a commonly used acrylic resin.
A light guide plate that is optically similar to a single light guide plate can be easily obtained.

In the above case, the light guide plate scatters light by a scatterer dispersed in the light guide plate, and the scatterer has a density varying with a distance from the light source. They may be distributed (claim 2
0).

With this configuration, it is possible to easily configure a light guide plate in which the scattering rate varies depending on the location.

Further, the light guide plate may scatter light propagating in the inside at a smaller rate as the light is closer to the light source.

With such a configuration, it is possible to correct the luminance distribution on the light exit surface, in which the luminance becomes higher as the light source is closer to the light source.

Further, the plurality of light sources may be arranged so as to make each of the outgoing lights enter each of the plurality of end faces of the light guide plate.

With this configuration, the luminance can be improved.

In the above case, the scatterer may reflect or refract incident light.
3).

Further, the size of the scatterer may be substantially larger than the wavelength of visible light.

With this configuration, the scatterer can suitably scatter the incident light in the illumination device for visible light.

The size of the scatterer is substantially sub-μm
It may be set to a few mm (claim 25).

Further, the scatterer is made of beads, SiO 2,
Alternatively, it may be constituted by bubbles.
6).

Further, the lighting device according to the present invention comprises: a light source;
A light guide plate arranged so that light from the light source is incident from an end face, and a lighting device including a reflection surface formed to face one main surface of the light guide plate, wherein one of the light guide plates A plurality of scattering regions that scatter incident light on the main surface are formed so that the area ratio changes according to the distance from the light source, and the plurality of scattering regions are formed of a plurality of types having different scattering properties from each other. (Claim 27).

With this configuration, it is possible to prevent the uniformity of the luminance distribution on the light emitting surface from being impaired by appropriately selecting the scattering properties of the plurality of scattering regions. Further, by selecting the scattering property, it is possible to increase the light brightness.

In this case, the plurality of types of scattering regions may have different scattering properties due to the difference in the material constituting the scattering regions.

Further, the plurality of types of scattering regions are formed by dispersing a scatterer having a different refractive index from that of the substrate in a substrate that transmits incident light, and the scattering property is varied due to a difference in the dispersion density of the scatterers. It may be different (claim 2
9).

Further, an image display device according to the present invention includes the lighting device according to any one of claims 1, 6, 13, and 27, and uses light emitted from the lighting device as light for image display. (Claim 30).

With this configuration, an image display device capable of reducing the penetration light of the light guide plate and controlling the luminance distribution of the display screen or preventing the uniformity of the luminance distribution of the screen from being impaired is obtained. be able to. As a result, an image device capable of increasing luminance can be obtained.

Further, the method for manufacturing a light guide plate according to the present invention comprises:
In a method for manufacturing a light guide plate in which scatterers that scatter incident light are dispersed in a transparent substrate, the scatterers are dispersed in the substrate such that the density varies depending on the site.

With this configuration, it is possible to easily obtain a light guide plate whose scattering rate varies depending on the position.

In this case, the step of heating and melting the base material, the step of mixing the scatterer into the melted base material, and the step of holding the molten base material in a plate shape Heat so that the temperature differs depending on the part,
And thereafter curing the same (claim 32).

With this configuration, the viscosity of the molten base material changes with temperature, and the density of the scatterers changes accordingly. Therefore, a light guide plate in which the dispersion density of the scatterers changes depending on the portion is easily manufactured. be able to.

Further, the bubbles as the scatterer may be generated in the substrate so that the density varies depending on the portion.

In this case, the air bubbles may be generated by using a foaming agent.

With this configuration, the molten base material mixed with the foaming agent is irradiated with light so as to have an intensity distribution within the irradiation surface, so that the foam can be formed so that the density changes depending on the portion. Therefore, it is possible to easily manufacture a light guide plate in which the dispersion density of the scatterer changes depending on the location.

The lighting device according to the present invention comprises a light source,
An illumination device having a light exit surface from which light from the light source exits, further comprising a luminance distribution changing means for changing a luminance distribution of the light exit surface (claim 35).

With this configuration, the luminance distribution on the light emitting surface can be changed to a required one according to the application. Eventually, high luminance can be achieved.

In this case, a light guide plate for guiding the light from the light source to the light exit surface is provided, and the luminance distribution changing means controls the distribution of the scattering ratio of the light guided by the light guide plate as viewed from the light exit surface. (Claim 36).

With this configuration, the luminance distribution on the light emitting surface changes by changing the distribution of the scattering ratio. Therefore, in the edge light type illuminating device, the luminance distribution on the light emitting surface is required in accordance with the application. Can be changed to

In this case, the light guide plate is arranged so that the light from the light source enters from the end face, and the reflection surface is formed such that the light emitted from one main face of the light guide plate returns to the one main face. By being formed, the other main surface of the light guide plate constitutes the light exit surface, and between the one main surface of the light guide plate and the reflection surface, is parallel to the light exit surface of incident light. A light dispersion structure for changing the distribution of the scattering ratio in a suitable plane may be provided as the scattering ratio distribution changing means (claim 37).

With this configuration, the distribution of the scattering ratio can be changed only by the light dispersion structure, so that the scattering ratio distribution changing means can be easily configured.

In this case, the light dispersion structure is provided between one main surface of the light guide plate and the reflection surface so as to transmit or scatter incident light depending on the position in the plane where the liquid crystal extends. The liquid crystal device may include a liquid crystal element capable of switching the orientation of the liquid crystal, and control means for switching the orientation of the liquid crystal of the liquid crystal device depending on the position.

In such a configuration, the liquid crystal element has the same structure as a normal liquid crystal cell, so that the light dispersion structure can be easily formed.

In this case, the light dispersion structure may cause the liquid crystal element to generate a region for scattering the incident light such that an area ratio of the region changes according to a distance from the light source. Good (claim 39).

With this configuration, the distance from the light source on the light emitting surface differs depending on the position. Therefore, by appropriately selecting the area ratio of the scattering region of the light dispersion structure, the distance from the light source to the position on the light emitting surface can be reduced. By canceling the difference, a desired luminance distribution on the light emitting surface can be obtained.

Further, the liquid crystal of the liquid crystal element may include a polymer-dispersed liquid crystal.

With this configuration, the liquid crystal element can be suitably configured.

In the above case, the light guide plate is arranged so that light from the light source enters from the end face, and light emitted from one main face of the light guide plate returns to the one main face. By forming the reflection surface, the other main surface of the light guide plate constitutes the light emitting surface, and the scattering ratio distribution changing means is formed so as to be distributed on one main surface of the light guide plate. A first scattering region, a scattering control structure that scatters or transmits light passing between one of the main surface of the light guide plate and the reflection surface by switching, and a second light distribution plate that is formed to be distributed on the reflection surface. And two scattering regions (claim 41).

With this configuration, the first and second scattering regions can be formed by, for example, printing dots, and the scattering control structure switches modes so as to uniformly scatter or transmit incident light. Thus, since a simple configuration is sufficient, the scattering ratio distribution changing means can be configured simply and at low cost.

Further, the brightness distribution changing means may be constituted by a light intensity distribution changing means for changing a light intensity distribution of the light traveling toward the light exit surface within the light exit surface. ).

With this configuration, the present invention can be applied to a direct-type lighting device.

In this case, the light intensity distribution changing means may change the light intensity distribution by transmitting or reflecting the light depending on a position in a plane parallel to the light emitting surface ( Claim 43).

With this configuration, since the light intensity distribution changing means does not cause absorption, the light intensity distribution can be changed with almost no loss.

In the above case, the brightness distribution changing means may change the brightness distribution on the light emitting surface of the light source.

In this case, the light source may be composed of a plurality of light emitters, and the brightness distribution changing means may change the light emission amount of each light emitter according to the arrangement position of each light emitter. 45).

With this configuration, since the amount of light emitted from the light emitter is changed, the luminance distribution on the light emitting surface can be changed efficiently.

In this case, the brightness distribution changing means may change the amount of light emitted from each of the light-emitting members by changing the power supplied to each of the light-emitting members.

Further, the luminous body may be constituted by an LED (claim 47).

With such a configuration, the light emitting body can be easily configured.

In the above case, the light source may be constituted by a surface light emitter, and the luminance distribution changing means may change the luminance distribution on the light emitting surface of the surface light emitter. 48).

With this configuration, it is possible to easily configure a light source capable of changing the luminance distribution on the light emitting surface.

Further, the lighting device according to the present invention comprises: a light source;
A lighting device provided with a light exit surface from which light from the light source exits, wherein the light source is composed of a plurality of luminous bodies, and the plurality of luminous bodies are arranged so as to vary in density. (Claim 49).

With this configuration, the luminous bodies need only be arranged so as to change the density, so that the configuration is simplified.

In this case, the luminous body may be constituted by an LED (claim 50).

With this configuration, the light emitting body can be easily formed.

Further, the image display device according to the present invention provides a lighting device and a liquid crystal display for displaying an image by transmitting light emitted from the lighting device to a liquid crystal layer forming a display screen while changing transmittance. An image display device comprising: an element; and a driving unit that changes a transmittance of the liquid crystal display element so as to display an image corresponding to a video signal, wherein the lighting device emits light from the light source and light from the light source. It has a light emitting surface and a brightness distribution changing means for changing the brightness distribution of the light emitting surface (claim 51).

With this configuration, the luminance distribution of the display screen corresponds to the luminance distribution of the light exit surface of the lighting device. Therefore, the luminance distribution of the display screen is changed by changing the luminance distribution of the light exit surface of the lighting device. Can be changed according to the application. As a result, higher luminance can be achieved.

In this case, the brightness distribution changing means includes a brightness distribution setting means capable of setting the brightness distribution of the plurality of light emitting surfaces, and a selecting means for selecting the set brightness distribution of the plurality of light emitting surfaces. (Claim 52).

With this configuration, it is only necessary to select a preset luminance distribution, so that the desired luminance distribution can be easily changed.

In this case, the brightness distribution changing means may change the brightness distribution on the light emitting surface according to the video signal.

With such a configuration, the luminance distribution of the display screen can be made suitable for the displayed screen by appropriately associating the luminance distribution of the light emitting surface with the video signal.

Further, the brightness distribution changing means may obtain the general brightness distribution of the screen of the video signal, and may change the brightness distribution of the light emitting surface in accordance with the obtained general brightness distribution. Good (claim 54).

With this configuration, for example, the brightness peak position is obtained from the general brightness distribution and the brightness near the peak position on the display screen is increased, so that the apparent brightness feeling can be improved.

Further, the brightness distribution changing means may obtain a brightness histogram of the pixels of the video signal, and change the brightness distribution of the light exit surface based on the obtained histogram. 55).

With this configuration, it is easy to calculate the histogram and determine the brightness of the screen from the calculation result, so that the luminance distribution on the light exit surface can easily correspond to the video signal. .

Further, the image display device according to the present invention comprises a lighting device and a liquid crystal display for displaying an image by transmitting light emitted from the lighting device to the liquid crystal layer forming the display screen while changing the transmittance. An image display device comprising: an element; and a driving unit that changes a transmittance of the liquid crystal display element so as to display an image corresponding to a video signal, wherein the lighting device emits light from the light source and light from the light source. A light emission surface, and a brightness distribution changing unit that changes a brightness distribution of the light emission surface, and converts a plurality of input video signals into an image corresponding to the plurality of video signals in one screen. A video signal synthesizing means for synthesizing the image so as to be displayed in a plurality of regions and inputting the synthesized signal as the image signal to the driving means is provided (claim 56).

With this configuration, it is possible to perform display in a plurality of regions within one screen, that is, a multi-screen, and furthermore, it is preferable that the luminance distribution changing means provides a preferable luminance for each region constituting the multi-screen of the display screen. The luminance distribution of the display screen can be set to be a distribution. As a result, it is possible to increase the brightness of the multi-screen.

Further, the image display device according to the present invention comprises a lighting device and a liquid crystal display for displaying an image by transmitting light emitted from the lighting device to the liquid crystal layer forming the display screen while changing the transmittance. An image display device comprising: an element; and a driving unit that changes a transmittance of the liquid crystal display element so as to display an image corresponding to a video signal, wherein the lighting device emits light from the light source and light from the light source. And a light emitting surface, wherein the light source is composed of a plurality of luminous bodies, and the plurality of luminous bodies are arranged so as to change in density.
7).

With such a configuration, it is sufficient to dispose the light emitters so that the density changes, so that the configuration of the lighting device is simplified.

Further, the lighting device according to the present invention comprises: a light source;
A light condensing means for condensing the light emitted from the light source, comprising: a polarizing means for polarizing the light emitted from the light source to be P-polarized light and entering the light into the light condensing means. (Claim 58).

With this configuration, when the light condensing means has a higher transmittance for the P-polarized light than for the S-polarized light, the transmittance of the light condensing means is improved, thereby enabling higher brightness. . Further, light loss in the light condensing means is reduced.

In this case, the condensing means may be formed of a prism sheet.

With such a configuration, in the prism sheet, since the transmittance of the P-polarized light is higher than that of the S-polarized light, a particularly remarkable effect can be obtained.

Further, the above-mentioned polarizing means is capable of detecting P
It may be made of a reflective polarizing plate that transmits polarized light and reflects S-polarized light.

With this configuration, the incident light is hardly absorbed when it is polarized, so that the loss can be reduced.

In this case, the reflective polarizing plate may have a multilayer structure including a plurality of films having different refractive indexes.

With this configuration, it is possible to easily configure a structure for p-polarizing incident light.

Further, the reflection type polarizing plate may include a cholesteric liquid crystal.

Also, A phase plate may be provided in front of the reflective polarizing plate (claim 63).

With this configuration, the polarization direction of the S-polarized light reflected by the reflective polarizing plate can be changed.

In the above case, the light source may include a plurality of point light emitters.

Further, the light source may include a linear illuminant (claim 65).

Further, the light source may include a planar light-emitting body.

Further, the light source may include a combination of a plurality of point light emitters, linear light emitters, and planar light emitters.

The image display device according to the present invention is characterized in that, in the image display device using light emitted from the illumination device as light for image display, the illumination device comprises a light source and a condenser for condensing incident light. Means, and light emitted from the light source is P
And polarizing means for polarizing the light so as to become polarized light and making the light incident on the light collecting means.

With such a configuration, when the light condensing means has a higher transmittance for the P-polarized light than for the S-polarized light, the transmittance is improved, thereby increasing the brightness of the image display apparatus. Can be obtained. Further, light loss in the light condensing means is reduced.

In this case, it has an incident side polarizing plate, a liquid crystal cell, and an emitting side polarizing plate which are sequentially arranged on the optical path of the outgoing light of the condensing means. The polarization axes of the plates may be substantially parallel and substantially perpendicular to the polarization axis of the P-polarized light, respectively.

With this configuration, light having a polarization axis substantially coinciding with the polarization axis of the light enters the incidence-side polarizing plate.
Loss due to absorption in the incident-side polarizing plate can be reduced.

In this case, the polarization axis of the P-polarized light may be set so as to be inclined at approximately 45 degrees with respect to the longitudinal direction of the display screen of the liquid crystal cell.

With such a configuration, the present invention can be applied to a general TN mode liquid crystal display device.

In this case, the pair of light-collecting means are provided so that the directions perpendicular to the planes including the respective light-collecting directions are perpendicular to each other, and the one light-collecting means is perpendicular to the plane including the light-collecting directions. May be substantially parallel to the polarization axis of the incident-side polarizing plate (claim 71).

With this configuration, in a general TN mode liquid crystal display device, the contrast viewing angle characteristics in the longitudinal direction of the display screen can be made symmetric.

In this case, the direction perpendicular to the plane including the light-collecting direction of the light-collecting means closer to the incident-side polarizing plate may be substantially parallel to the polarization axis of the incident-side polarizing plate. 7
2).

With this configuration, it is possible to improve the front luminance of the display screen as compared with the case where the condensing means is arranged in reverse.

Further, in the above case, it is assumed that the liquid crystal in the region constituting each pixel or picture element of the liquid crystal cell is oriented in different directions from each other on a plane substantially perpendicular to the substrate of the liquid crystal cell. (Claim 73).

Further, the liquid crystal may be oriented substantially symmetrically with respect to the plane (claim 74).

With this configuration, since the contrast viewing angle characteristics of the display screen become substantially symmetric, it is not necessary to set the polarization axes of the polarizing plates disposed before and after the liquid crystal cell in the diagonal direction of the display screen.

The polarization axis of the P-polarized light may be set substantially perpendicular to the longitudinal direction of the display screen of the liquid crystal cell.

With this configuration, the light-collecting direction of the light-collecting means is substantially perpendicular to the longitudinal direction of the display screen of the liquid crystal cell.
Only one light collecting means is required. Therefore, the configuration is simplified.

A liquid crystal monitor according to the present invention uses the image display device according to any one of claims 51, 56, and 57 as a display section (claim 76).

With this configuration, it is possible to obtain a liquid crystal monitor capable of controlling a luminance distribution, a liquid crystal monitor capable of displaying a multi-screen with a desired luminance distribution, or a liquid crystal monitor with a simplified configuration of a lighting device.

Further, a liquid crystal television according to the present invention uses the image display device according to any one of claims 51, 56 and 57 as a display section (claim 77).

With this configuration, it is possible to obtain a liquid crystal television capable of controlling the luminance distribution, a liquid crystal television capable of multi-screen display with a desired luminance distribution, or a liquid crystal television with a simplified configuration of the lighting device.

A liquid crystal information terminal according to the present invention uses the image display device according to any one of claims 51, 56, and 57 as a display unit.

With this configuration, it is possible to obtain a liquid crystal information terminal capable of controlling a luminance distribution, a liquid crystal information terminal capable of displaying a multi-screen with a desired luminance distribution, or a liquid crystal information terminal having a simplified configuration of a lighting device. .

[0163]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 Embodiment 1 of the present invention shows an example of a configuration of a lighting device capable of arbitrarily setting a luminance distribution.

FIGS. 1A and 1B are diagrams schematically showing a configuration of an illumination device according to the present embodiment and an image display device using the same, wherein FIG. 1A is a cross-sectional view, and FIG. FIG. 2 is a plan view showing a dot pattern of the liquid crystal element, and FIG. 2 is a block diagram showing a configuration of a control system of the image display device of FIG. FIG.
In (a), for convenience, the X direction is the upward direction of the image display device.

FIG. 1A illustrates a liquid crystal display device 1 as an image display device and a backlight 100 for a liquid crystal display device as an illumination device in this embodiment.

The back light 100 is a liquid crystal display element 1
Liquid crystal panel (hereinafter referred to as liquid crystal display element) 10
Located below 6. The backlight 100 includes a light guide plate 103 made of a transparent rectangular synthetic resin plate, and a pair of light-emitting members disposed near the pair of end surfaces 103a of the light guide plate 103 and substantially parallel to the end surfaces 103a along the end surfaces 103a. Cold cathode fluorescent tube 101
And a pair of reflectors 102 respectively covering the pair of cold cathode tubes 101 over substantially the entire length thereof, a dispersed liquid crystal element 104 disposed on the lower surface of the light guide plate 103, and disposed below the dispersed liquid crystal element 104. And a reflection plate 105. The cold cathode tube 101 and the reflector 102 constitute a light source 151. In FIG. 1A, for convenience of explanation, the reflection plate 105 is shown to be located away from the dispersion liquid crystal element 104, but usually, it is arranged so as to be in contact with the lower surface of the dispersion liquid crystal element 104. .

The dispersed liquid crystal element 104 is provided with an electrode composed of a dot matrix, and is configured such that a drive signal for generating a predetermined dot pattern as shown in FIG. I have. More specifically, the dispersed liquid crystal element 104 has a structure similar to that of a liquid crystal cell, and a substrate in which a common electrode is formed on the inner surface and a substrate in which a pixel electrode is formed on the inner surface are opposed to each other with the liquid crystal interposed therebetween. It is arranged and configured. Then, as shown in FIG. 2, a driving 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, CP
It has a U34 and a main memory 33, in which a plurality of dot patterns are stored in advance. And
An operation switch 31 is connected to the CPU 34, and 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 applies the read dot pattern to the read dot pattern. A corresponding drive signal 35 is generated, and this is
Enter 4 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.

This dot pattern is composed of circular dots 41 and other parts 42 as shown in FIG. 1 (b). The dots 41 of the dispersed liquid crystal element 104 are parts to which no voltage is applied, and the orientation of the liquid crystal molecules of each pixel is random. Is a portion to which a voltage is applied, and the alignment of the liquid crystal molecules of each pixel is aligned in one direction and is transparent. Therefore, the light incident on the dot 41 is scattered, and the scattered light is scattered and reflected by the reflection plate 105, and a part of the scattered reflection light is used as the light guide plate 103.
And exits from the upper surface. On the other hand, the light incident on the portion 42 other than the dots 41 is transmitted, reflected by the reflection plate 105 according to the incident angle, and returned to the inside of the light guide plate 103 again. The area ratio of the dot pattern to the main surface of the dispersed liquid crystal element 104 (corresponding to the display screen of the liquid crystal display element) is small in the vicinity of the light source 151 on the main surface, and as it approaches the central part. It is formed to be large. For this reason, according to this dot pattern, the ratio 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 (light intensity distribution) increases in the central portion, and therefore, the luminance increases in the central portion. . Since the dispersed liquid crystal element 104 has almost no light absorption characteristics, 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.

The plurality of dot patterns stored in the main memory 33 of the luminance distribution setting circuit 32 correspond to the plurality of predetermined uses of the liquid crystal display device 1 so that the backlight 100 has a luminance distribution suitable for the use. Are respectively set so as to have. In the present embodiment, for example, a monitor dot pattern that requires a luminance distribution in which the luminance difference between the peripheral part and the central part of the display screen is relatively small, and the luminance difference between the peripheral part and the central part of the display screen are different. The main memory is a dot pattern for TV that requires a relatively large luminance distribution.
33 is stored.

Next, the operation of the backlight 100 configured as described above will be described.

In FIGS. 1 and 2, first, the operation switch
Operate 31 to select a desired dot pattern. Here, it is assumed that a dot pattern for monitoring is selected. Then, the brightness 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 tube 101 enters the light guide plate 103 from the end face 103a directly or reflected by the reflector 102. Of the incident light, the light incident on the dots 41 of the dispersion 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 dots 41 of the dispersion liquid crystal element 104 is transmitted and the reflection plate 105
Is reflected according to the incident angle and returned to the inside of the light guide plate 103. As a result, the light intensity distribution of 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 is reduced at the peripheral portion and the central portion of the light emitting surface 103b. The luminance difference is relatively small. Operation switch 31
When a dot pattern for TV is selected, the luminance distribution of the backlight 100 becomes a luminance distribution in which the luminance difference between the peripheral part and the central part of the light emitting surface 103b is relatively large by the same operation.

As described above, in the lighting device according to the present embodiment, the dispersed liquid crystal element 104 is provided on the lower surface of the light guide plate 103, and the dots set and selected by the luminance distribution setting circuit 32 are provided on the dispersed liquid crystal element 104. Since the configuration is such that a pattern can be generated, it is possible to obtain an arbitrary luminance distribution according to the application.
For example, it is possible to arbitrarily set such that the luminance distribution is increased for displaying a moving image of a TV or the like and the luminance distribution is made uniform for a monitor for displaying characters. Example 1 In FIGS. 1 (a) and 1 (b), the dot patterns generated in the dispersion liquid crystal element 104 were set as follows. That is, assuming that the dots 41 are arranged in a grid 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 luminous bodies 101 arranged on both the left and right ends of the light guide plate 103. = A × r ”(a: proportional coefficient). The proportional coefficient a was set such that the diameter of the central dot 41 having the largest diameter was about 2 mm, and the pitch of the dots 41 was set to about 1.5 to 3 mm.

A rectangular light guide plate 103 having a diagonal length of 7 inches (hereinafter, the diagonal length is イ ン チ inch is referred to as ○ inch size) and a thickness of about 10 mm. Using. Further, a cold cathode tube having an output of about 100 W was used as the light emitting body 101.

When the luminance distribution on the upper surface of the light guide plate 103 serving as the light exit surface 103b was measured, the luminance was about 4500 to 5000 candela over the entire surface, and a uniform luminance distribution was obtained. [Embodiment 2] In this embodiment, a function "y = a * r * r" in which the diameter y of the dot 41 is proportional to the square of the distance r from the luminous body 101 disposed at the left and right ends of the light guide plate 103 is obtained. In response to Other points are the same as in the first embodiment. 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 a position 0.9 inch diagonally 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 was obtained.

According to Examples 1 and 2, the dispersion liquid crystal element 10
It was found that the luminance distribution can be changed arbitrarily by forming a specific scattering pattern by the electric field applied to 4. The dot patterns of the first and second embodiments are suitable for a monitor and a TV, respectively.

Next, a modification of this embodiment will be described.
In the above configuration example, a dot matrix is formed on the dispersed liquid crystal element 104 to generate a dot pattern. However, as another configuration example, the backlight 100 shown in FIGS.
In the above, the ITO (Indiumu Tin Oxid
e) The electrodes 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 portion 4 other than the dot 41 in FIG.
An ITO electrode is formed in a shape corresponding to 2. Then, scattering dots having a pattern corresponding to the required luminance distribution are formed on the lower surface of the light guide plate 103 by printing in advance.

With such a configuration, the dispersion liquid crystal element 10
When no voltage is applied to 4, the light incident on the dispersion liquid crystal element 104 is uniformly scattered over the entire surface. The scattered light is reflected by the reflection plate 105, 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, and the light incident on the light guide plate 103 is finally printed on this 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 scattering dots.

Therefore, by turning on / off the voltage applied to the dispersed liquid crystal element 104, two luminance distributions can be selected. In addition, the dispersed liquid crystal element 104 only needs to form ITO so as to correspond to a predetermined dot pattern, and the application of a voltage may be performed only by an on / off operation. For this reason, compared with the case where the electrodes are formed in a dot matrix, the dispersed liquid crystal element 104 can be configured at a lower cost.

It should be noted that optical matching is performed between the dispersion liquid crystal element 104 and the light guide plate 103 or between the dispersion liquid crystal element 104 and the reflection plate 105 so as to seal a liquid having the same refractive index. It is desirable.

Further, the reflection plate 105 may be omitted, and instead, a reflection 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.

In the above configuration example, the dispersed liquid crystal element 104
Although a polymer-dispersed liquid crystal is used as the liquid crystal, a nematic liquid crystal, a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or the like may be used instead.

In the above configuration example, the dispersion liquid crystal element 104 is used as a means for switching the scattering characteristic of light incident on the light guide plate 103.
However, instead of this, lithium niobate, BSO crystal, or the like that can electrically change the light transmittance may be used. Embodiment 2 Embodiment 2 of the present invention shows another configuration example of a lighting device capable of arbitrarily setting a luminance distribution.

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 indicate the same or corresponding parts.

As shown in FIG. 3, in the present embodiment, unlike the first embodiment, scattering dots 114 are formed by printing on the lower surface of the light guide plate 103, and the scattering control plate 107 is provided below the scattering dots 114. Are provided, and a scattering reflection plate 201 is provided below the scattering control plate 107. Other points are the same as the first embodiment. In FIG. 3, for convenience of explanation, the light guide plate 103, the control plate 107, and the scattering reflector 201 are shown as being separated from each other, but they are usually arranged so as to be in contact with each other.

More specifically, the scattering control plate 107 is configured by disposing a pair of glass substrates each having an ITO electrode 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 driving a voltage by applying a voltage of about 10 to 30 V between the ITO electrodes. Then, when this voltage is turned on / off, the orientation state of the liquid crystal molecules of the scattering control plate 107 is switched between “aligned state” and “random state”.

A dot pattern as shown in FIG. 1B is formed on the lower surface of the light guide plate 103.

The scattering reflector 201 has a structure in which scattering dots 201b as shown in FIG. 3 are formed on the reflecting surface of the reflector 201a. The pattern of the scattering dots 201b is
Is different from the pattern of the scattered dots 114 formed in FIG.

According to the above configuration, the light emitted from the light emitting body 01 is directly reflected by the reflector 102 or is reflected by the light guide plate 103.
Incident on. The incident light is scattered dots 1 on the lower surface of the light guide plate 103 while repeating multiple reflections inside the light guide plate 103.
Scattered at 14.

When no voltage is applied to the scattering control plate 107 by the voltage application circuit, the orientation of the liquid crystal molecules of the scattering control plate 107 is in a random state. The light incident on the scattering control plate 107 is scattered over the entire surface, and therefore,
The light is reflected by the scattering reflection plate 107 and returned to the light guide plate 103 without being affected by the scattering dots 201b formed on the first reflection surface. Thereby, the brightness distribution of the light emitting surface 103b of the light guide plate 103 is in accordance with the pattern of the scattering dots 114 formed on the lower surface of the light guide plate 103.

On the other hand, when a voltage is applied to the scattering control plate 107 by the voltage application circuit,
7 are aligned, the light incident on the scattering control plate 107 from the lower surface of the light guide plate 103 is transmitted therethrough, and the scattering dots 201b formed on the reflection surface of the scattering reflection plate 201 The light is reflected by the scattering reflection plate 107 and returns to the inside of the light guide plate 103 in a mode according to the pattern of (1). As a result, the brightness distribution of the light exit surface 103b of the light guide plate 103 becomes smaller than 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.
And the effects of both patterns are superimposed, and the characteristics of both patterns are multiplied.

As described above, according to the present embodiment, by switching the scattering / transmission of the incident light in the scattering control plate 107, the luminance distribution of the light exit surface 103b of the light guide plate 103 is reduced by two.
You can switch between types. Therefore, for example, by setting one of the two types of luminance distribution to one having high uniformity, it can be used when the liquid crystal display device 1 is used as a monitor. In addition, by setting the other to have a large difference in luminance between the peripheral portion and the central portion, the liquid crystal display device 1 can be used when used as a TV.

Moreover, the scattering control plate 107 can be constituted by a glass substrate in which polymer dispersed liquid crystal is sealed between each other, and its driving circuit can be constituted by a simple circuit for turning on / off a predetermined voltage. Therefore, a configuration for switching between two luminance distributions can be realized very inexpensively. Example 3 As in Example 1 of Embodiment 1, a light guide plate 103 having a size of 7 inches and a thickness of about 10 mm was used. Further, a cold cathode tube having an output of about 100 W was used as the light emitting body 101. Further, in the scattering reflector 201, the area ratio of the scattering dots 201b was very large in the central part and small in the peripheral part. And the scattering control plate 10
Turn on / off the voltage applied to 7 and the light exit surface of light guide plate 103
The luminance distribution at 103b 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 area of the light emitting surface 103b. On the other hand, when an electric field is applied to the scattering control plate 107, the luminance at the center of the light exit surface 103b becomes 60%.
The brightness was about 00 to 6500 candela, and the luminance in the periphery thereof was about 3000 to 3500 candela. That is,
In this case, under the influence of the configuration in which the area ratio of the scattering dots 201b is very large in the central part of the scattering reflector 201, a luminance distribution was obtained in which the luminance was large in the central part and small in the peripheral part.

As described above, according to the present embodiment, it has been found that an illumination device capable of obtaining two luminance distributions can be realized by switching the optical characteristics of the scattering control plate 107.

In the above configuration example, a polymer-dispersed liquid crystal is used as the variable optical characteristic of the scattering control plate 107. However, the liquid crystal is not limited to the liquid crystal, but may be any as long as it can switch the light transmittance. When liquid crystal is used, it is needless to say that other liquid crystals such as the twisted nematic liquid crystal described in Embodiment 1 can be used without being limited to the polymer dispersed liquid crystal. Third Embodiment FIG. 4 is a cross-sectional view schematically illustrating a configuration of an illumination device and an image display device using the same according to a third embodiment of the present invention. 4, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

As shown in FIG. 4, in the present embodiment, unlike the first embodiment, a first reflective polarizing plate 301a, a polarization modulation element 302, and a first reflection type polarizing plate 301a are provided above the light exit surface 103b of the light guide plate 103. The second reflective polarizing plate 301b is arranged in this order. The first and second reflective polarizers 301a and 301b and the polarization modulator 302 constitute a light quantity modulation structure 305. Also, light guide plate
Scattered dots (not shown) are formed on the lower surface of 103 by printing, and a reflector 105 is arranged so as to be in contact with the lower surface. Fig. 1 (b)
It is as shown in. Other points are described in the first embodiment.
Is the same as

More specifically, the first and second reflective polarizers 301a and 301b are made of chiral liquid crystal, and transmit or reflect incident light depending on the direction of polarization of the liquid crystal depending on the helical pitch of the liquid crystal. Has characteristics. Here, the first reflective polarizing plate 301a transmits only P-polarized light of P-polarized light and S-polarized light included in light emitted from the light guide plate 103,
It is configured to reflect S-polarized light. And the first,
The second reflection type polarizing plates 301a and 301b are arranged such that their polarization axes coincide with each other.

The polarization modulation element 302 has, for example, a configuration in which a twisted nematic liquid crystal is used instead of the polymer dispersed liquid crystal in the dispersion liquid crystal element 104 of the first embodiment. Then, a drive signal for applying a voltage to a predetermined area 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, a 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 the other portion, that is, the peripheral portion 304. A signal is output.

The backlight 100 configured as described above
Then, the light is reflected and scattered on the lower surface of the light guide plate 103,
The light emitted from the upper surface 103b of the light receiving element is modulated in light quantity by the light quantity modulation structure 305. That is, the light amount modulation structure in FIG.
As shown in the enlarged view of 305, the first reflective polarizing plate 301a
Of the light emitted from the upper surface 103b of the light guide plate 103, only the P-polarized light is transmitted and the S-polarized light is reflected. Here, in the polarization modulation element 302, it is assumed that the above-described drive signal is input, a voltage is applied to the central portion 303, and no voltage is applied to the peripheral portion 304. Then, of the transmitted P-polarized light, the one incident on the central portion 303 is transmitted while maintaining its polarization direction, passes through the second reflective polarizing plate 301b, and is incident on 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 modulation element 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.

This recycled light passes through the first reflective polarizing plate 301a as shown in FIG.
When the light enters the portion 303 to which the voltage of 302 is applied, the light sequentially passes through the polarization modulation element 302 and the second reflective polarizing plate 301b,
The light enters the liquid crystal display element 106. That is, the light amount modulation structure 305
Thereby, for light emitted from the upper surface 103b of the light guide plate 103,
It is possible to have a light intensity distribution such that the light amount is large at the center and small at the periphery. as a result,
The backlight 100 has a luminance distribution such that the luminance is high at the center and low at the periphery. 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 little loss of the original light amount. Further, since the polarization directions of the light incident on the liquid crystal display element 106 are uniform, the polarizing plate conventionally disposed on the incident side of the liquid crystal display element 106 can be omitted.

[0200] When a drive signal is applied to the polarization modulation element 302 so that a voltage is applied over the entire area, the light emitted from the light guide plate 103 passes through the polarization modulation 302 as it is and the liquid crystal display element 106 Therefore, the luminance distribution of the backlight 100 corresponds to the scattering dots printed on the lower surface of the light guide plate 103, and the luminance distribution becomes substantially uniform over the entire surface. As described above, two types of luminance distributions can be obtained by switching the drive signal input to the polarization modulation element 302 as in the first embodiment. [Embodiment 4] In this embodiment, similarly to the embodiment of the first embodiment, the light guide plate 103 has a size of 7 inches and a thickness of 10 mm.
A cold cathode tube having an output of about 100 W was used as the luminous body 101. Also, a polarization modulation element
At 302, a voltage was applied to the center and no voltage was applied to the periphery. Then, the second reflective polarizing plate 301b
When the luminance distribution on the emission surface of was measured, it was about 6000 candela at the center and 3000 at the periphery.
It was about a candela. Also, the total amount of light
As a result of comparison with the case where the light quantity modulation structure 305 is not provided, the result is almost the same. From this, it was found that the light quantity loss due to the provision of the light quantity modulation structure 305 hardly occurred.

As described above, according to the present embodiment, by providing the light quantity modulation structure 305 and applying a voltage to the center of the polarization modulation element 302, the brightness is high at the center and the periphery is high. It has been found that a luminance distribution having a low luminance in the portion can be obtained with almost no loss of light amount.

In the above configuration example, the polarization modulator 302
Although a twisted nematic liquid crystal is used as the liquid crystal of the above, a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or the like can be used instead. In addition, the polarization modulator of the polarization modulation element 302 is not limited to liquid crystal, and a material or a configuration other than liquid crystal that can perform polarization modulation can be used. Fourth Embodiment In the first to third embodiments, the liquid crystal display element is configured to shine light from behind. However, the embodiment is also applied to a front light type liquid crystal display device using a reflective liquid crystal display element. The effects described above can be obtained by applying the configurations described in 1 to 3. Embodiment 4 of the present invention
With such a configuration, the same effect as in the first to third embodiments is obtained.

In this embodiment, a reflection type liquid crystal display element having a size of about 5 inches is used. In this liquid crystal display device, a reflection plate is disposed behind (below) a liquid crystal cell, and the reflection type polarization plate and the polarization modulation device described in Embodiment 3 are provided between the liquid crystal cell and the reflection plate. A light quantity modulation structure was arranged. Then, a light source was arranged at the edge of the front surface (upper surface) of the liquid crystal display element. As a result, in the display screen of the liquid crystal display element, the luminance of the peripheral portion is 80% of the luminance of the central portion.
Two types of luminance distribution were obtained: a uniform luminance distribution as described above, and a luminance distribution having a large luminance difference in which the luminance at the peripheral portion falls to about 50% of the luminance at the central portion. Therefore, it has been found that the configuration of the present invention in which the luminance distribution is arbitrarily changed can be applied to the front light type. Embodiment 5 FIG. 5 is a plan view schematically showing a configuration of a lighting device according to Embodiment 5 of the present invention. 5, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

As shown in FIG. 5, in the present embodiment, a plurality of LEDs 401 are used as light emitters instead of cold cathode tubes. Other points are the same as in the embodiment.

More specifically, when a cold-cathode tube is used as the light-emitting body, the brightness of the cold-cathode tube is reduced by the incident surface 103 at the end of the light guide plate 103.
Although it is substantially uniform over the entire length of a, when a plurality of LEDs 401 are used as light emitters, by changing the density of the LEDs 401 in the longitudinal direction of the incident surface 103a,
The luminance of the entire luminous body can be changed. Therefore,
In the present embodiment, for example, the LED 401 is
In the longitudinal direction of 03a, it is arranged so that the density is high at the center and the density is low at both ends.
The luminance of the entire luminous body composed of the ED 401 is set to be large at the center and small at both ends in the longitudinal direction of the incident surface 103a.

With such a configuration, on the incident surface 103 of the light guide plate 103, the amount of incident light increases at the center and decreases at both ends. As a result, the light guide plate 103
In the light emission surface of the above, the luminance increases at the central portion, and conversely, the luminance decreases at the peripheral portion. Therefore, since the configuration and the function of changing the luminance of the luminous body 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 exit surface of the backlight 100 is improved. The degree of freedom in creating a pattern can be further increased. [Embodiment 5] In this embodiment, about ten white LEDs 401 were used as light emitters instead of cold cathode tubes. Then, the white LED 401 is used in the first embodiment.
In accordance with Examples 1 and 2, the density was set to be uniform and to change in the longitudinal direction of the incident surface 103a of the light guide plate 103. Then, when the luminance distribution of the backlight 100 was measured, when the density of the white LED 401 was set to be uniform, the luminance was about 2000 candela over the entire surface, and the density of the white LED 401 was set to change. In the case, the brightness is 50 at the center.
The brightness was about 1000 candela at the periphery at 00 candela.

Thus, by using a plurality of LEDs as light emitters and changing the density of the LEDs in the longitudinal direction of the incident surface 103a of the light guide plate 103, a luminance distribution with a larger luminance difference can be set. There was found. Embodiment 6 In Embodiment 6 of the present invention, an image display device is configured using the lighting devices of Embodiments 1 to 5.

First, the case where the lighting device of Embodiment 1 is used will be described.

As shown in FIGS. 1 and 2, in a liquid crystal display device 1 as an image display device according to the present embodiment, a backlight 100 is arranged below a liquid crystal display element.
The liquid crystal display element 106 is a well-known TFT (Thin Film) here.
Transistor) type, a counter substrate 111 having a common electrode (not shown) formed on the inner surface, and a TFT substrate 112 having pixel electrodes, gate lines, source lines and switching elements (not shown) formed on the inner surface. Are arranged so as to face each other with the liquid crystal 113 interposed therebetween, and further, a polarizing plate (not shown) or the like is attached to both sides of the counter substrate 111 and the TFT substrate 112 which are opposed to each other. In the TFT substrate, gate lines and source lines are arranged in a matrix, and pixel electrodes and switching elements are formed for each pixel partitioned by the gate lines and source lines. The source line and the 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 the 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.

In the liquid crystal display element 1 thus configured, in the drive circuit 36, the controller outputs control signals to the gate driver and the source driver 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 at the same time. Enter sequentially. As a result, the liquid crystal is modulated and the backlight 100
The transmittance of the light emitted from the liquid crystal display device 1 changes.
The image corresponding to the video signal 25 appears in the eyes of the person observing. Hereinafter, the gate signal and the source signal are referred to as drive signals 37.
Collectively.

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 use of the liquid crystal display element 1 as described in Embodiment 1, it is possible to obtain the optimal display screen luminance distribution for the use. Further, 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 a display screen with a desired luminance distribution. .

As shown by the dotted line in FIG. 2, a video synthesizing circuit 901 is provided, and a plurality of video signals 25
May be input, and synthesized so that a plurality of images corresponding to the respective video signals 25 are displayed in a multi-screen in one screen, and the synthesized video signal is input 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 brightness distribution setting circuit 32, it is possible to obtain a preferable brightness distribution for each region constituting the multi-screen of the display screen. The brightness distribution of the display screen can be set as follows.

Next, the case where the lighting devices of Embodiments 2 to 5 are used will be described.

In these cases, in the above configuration, the backlight 100 of Embodiment 1 is replaced with the backlight 100 of FIG. 3 (Embodiment 2) and the backlight 100 of Embodiment 4 (Embodiment 2), respectively. 3) By using the front light (Embodiment 4) and the backlight 100 (Embodiment 5) of FIG. 5, a liquid crystal display device as an image display device can be configured. In any of the liquid crystal display devices, as in the above configuration, by switching the luminance distribution of the lighting device according to the application of the liquid crystal display element, it is possible to obtain an optimal luminance distribution of the display screen for the application. [Embodiment 6] In this embodiment, the first embodiment of the first embodiment,
Similarly to 2, a cold cathode tube of about 100 W was used as a luminous body. 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 a setting in which the uniformity of luminance was increased for monitor use.

On the other hand, for TV use, when the luminance difference between the central part and the peripheral part is increased, the luminance of the central part is 300.
The brightness of the peripheral portion was about 150 candela at about the candela. The total amount of light was almost the same in any luminance distribution setting. In addition, the power consumption of the entire luminous body was almost the same in any luminance distribution setting. Further, when the image in which the luminance difference between the central portion and the peripheral portion was set to be large was observed, it was perceived as brighter in a TV moving image than when the luminance distribution was set to be uniform. This confirmed the effectiveness of the setting for brightening the center of the display screen.

When the difference in luminance between the central portion and the peripheral portion is set to be large, and when the luminance at the center is the same as that when the luminance distribution is set to be uniform, the power consumption of the luminous body is reduced accordingly. be able to.

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 a lighting device and an image display device according to Embodiment 7 of the present invention. 6, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

As shown in FIG. 6, in the present embodiment, a so-called direct-type backlight configuration is adopted, and the liquid crystal display element 106 is directly provided as a backlight 100 behind (below) the liquid crystal display element 106. A plurality of light emitters 501 for irradiation are arranged. A reflector (not shown) is provided behind the plurality of light emitting bodies 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 a light emitting surface of the light source. Note that the luminous body 501 and the liquid crystal display element 106
And a scattering film or the like for making the luminance uniform. In the present embodiment, the luminous bodies 501 are formed of cold cathode tubes, 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 in parallel with a predetermined side. . As in the first embodiment, a luminance distribution setting circuit 32 and operation switches 31 as shown in FIG. 2 are provided. In the present embodiment, the brightness distribution setting circuit 32 can set the output patterns of the plurality of cold cathode tubes 501 in advance, and when the output pattern is selected by the operation switch 31, the plurality of cold cathode tubes 501 A voltage such that the output is in accordance with the selected output pattern is output to each cold cathode tube 501 as a drive signal 35. Here, as in the first embodiment, a uniform luminance distribution and a luminance distribution having 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. As a result, when a uniform luminance distribution is selected, the outputs (luminances) of the plurality of cold cathode tubes 501 are all the same, while a luminance distribution having a large luminance difference between the peripheral part and the central part of the display screen is obtained. When selected, the outputs of the cold cathode tubes 501 are:
The larger one is located at the center, the smaller it is located at the periphery. [Embodiment 7] In this embodiment, a cold cathode tube 501 having a power of about 100 W similar to that of the first embodiment is used. Also,
A liquid crystal display element 106 having a size of about 10 inches was used. When the luminance of the display screen of the liquid crystal display element 106 was measured, when the uniform luminance distribution was selected, the luminance was about 200 candela over the entire area of the display screen. On the other hand, when a luminance distribution having a large luminance difference between the peripheral part and the central part of the display screen is selected, the luminance at the central part is about 300 candela and the luminance at the peripheral part is about 15 candela.
It was about 0 candela. At this time, the cold cathode tube 501
The overall power consumption was almost the same as when a uniform luminance distribution was selected. Further, when the image at this time was observed, it was felt that the moving image of the TV was brighter than when a uniform luminance distribution was selected. By setting the luminance distribution so as to brighten the center, it seems that the sense of brightness is improved in appearance.

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 suppressed.

As described above, according to the present embodiment, in the configuration of the direct type backlight, the luminance distribution of the display screen can be set arbitrarily by changing the luminance of the illuminant according to the arrangement position. It has become possible.

Further, as another configuration example of the present embodiment,
The output of the cold cathode tube 501 may not be changed, and the light amount modulation structure 305 of the third embodiment may be provided between the cold cathode tube 501 and the liquid crystal display element 106. Eighth Embodiment FIG. 7 is a perspective view schematically showing a configuration of a lighting device and an image display device according to an eighth embodiment of the present invention. 7, the same reference numerals as those in FIG. 6 indicate the same or corresponding parts.

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 (peripheral portions) in the arrangement direction. The outputs of all the cold cathode tubes 501 are configured to be constant. Other points are the same as in the seventh embodiment.

With such a structure, the liquid crystal display element 10
In the display screen of 6, the central portion where the cold cathode tubes 501 are densely arranged has a relatively high light output and a high brightness,
Conversely, the peripheral portion where the cold-cathode tubes 501 are sparsely arranged has a relatively low light output and low luminance. In other words, by giving a distribution to the arrangement density of the cold cathode tubes 501, it is possible to give a distribution to the brightness of the liquid crystal display device.

Then, when the luminance was actually measured using the same cold cathode tube and liquid crystal display element as in the seventh embodiment, almost the same results as in the seventh embodiment were obtained. Therefore, it has been found that any luminance distribution can be set in the configuration of FIG.

It is needless to say that the configuration of the present embodiment can be configured to change the output of the illuminant according to the arrangement position as in the seventh embodiment. Ninth Embodiment FIG. 8 is a perspective view schematically showing a configuration of a lighting device and an image display device according to a ninth embodiment of the present invention. 8, the same reference numerals as those in FIG. 6 indicate the same or corresponding parts.

As shown in FIG. 8, in this embodiment, as the direct backlight 100, a surface light source 502 is a liquid crystal display element.
Located behind 106. As in the sixth embodiment, a luminance distribution setting circuit 32 and operation switches 31 as shown in FIG. 2 are provided. The luminance distribution setting circuit 32
The luminance pattern of the surface light source 501 can be set in advance,
When a luminance pattern is selected by the operation switch 31, a control signal such that the luminance distribution of the surface light source 501 is in accordance with the selected luminance pattern is output to the surface light source 501 as a drive signal 35. It is configured as follows. Here, as in the sixth embodiment, a uniform luminance distribution and a luminance distribution having 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 having a large luminance difference between the peripheral portion and the central portion of the display screen is selected, The brightness distribution of the surface light source 501 is such that the brightness is large at the center and small at the periphery. Embodiment 10 Embodiment 10 of the present invention exemplifies an image display device that controls the luminance distribution of a lighting device according to the screen of a video signal input from the outside.

FIG. 9 is a block diagram showing a configuration of a control system of the image display device according to the present embodiment. 9, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts.

As shown in FIG. 9, the liquid crystal display device 1 as the image display device according to the present embodiment is different from the first embodiment in that the video signal input to the drive circuit 36 for driving the liquid crystal display element 106 is provided. A signal processing circuit for judging the brightness of the screen (frame) based on the image signal 25; and a luminance distribution for controlling the luminance distribution by outputting a drive signal 35 to the lighting device 100 in accordance with the determined brightness of the screen. And a setting circuit 32. In addition, as lighting device 100, lighting devices 100 of Embodiments 1 to 5 and 7 to 9 can be used. Other points are the same as the first embodiment.

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 pixel luminance for each screen of the video signal 25, and distributes the histogram. Then, it is determined whether the image is a bright scene (screen) or a dark scene, and the determination result is output to the luminance distribution setting circuit 32. Upon receiving this determination result, the luminance distribution setting circuit 32 operates as follows. That is,
The luminance distribution setting circuit 32 stores in the main memory 33, for example, a luminance distribution for a normal TV and a luminance distribution in which the luminance in the central portion is further increased. Then, a luminance distribution in which the luminance at the center is increased is selected, and a driving signal 35 corresponding to the luminance distribution is output to control the lighting device 100 to have such a luminance distribution. As a result, the display screen of the liquid crystal display element 106 has a luminance distribution in which the luminance at the center is increased. On the other hand, when receiving the result of the determination that the scene is dark, the lighting device 100 outputs a drive signal 35 having a normal luminance distribution to control the drive signal 35. As a result, the display screen of the liquid crystal display element 106 has a luminance distribution for a normal TV. [Embodiment 8] When an image is actually displayed using the liquid crystal display device configured as described above, in a movie screen where a person is displayed at the center, the effect of increasing the brightness at the center is more effective. It felt bright.

As described above, according to the present embodiment, by controlling the luminance distribution of the lighting device according to the image to be displayed, it is possible to perform the optimal setting according to the scene to be displayed. As a result, it was found that visibility could be improved. Embodiment 11 Embodiment 11 of the present invention is configured such that the signal processing circuit 38 and the luminance distribution setting circuit 32 perform the following operations in the liquid crystal display device 1 of FIG. The backlight 100 according to the first embodiment.

That is, the signal processing circuit 38 divides the screen of the input video signal 25 into a plurality of blocks, and obtains a histogram of pixel luminance for each of the blocks. And
The brightness of each block is obtained from the obtained histogram,
Thereby, an approximate luminance distribution of the screen is obtained. Here, the histogram of the pixel brightness for each block is obtained for each screen, but may be obtained for a plurality of continuous screens. In that case, the general luminance distribution is obtained by integrating the plurality of screens. And
A block where the luminance peaks, that is, a position on the screen where the luminance peak exists, is detected from the general luminance distribution, and is output to the luminance distribution setting circuit 32. The luminance distribution setting circuit 32 receives this output, and
The driving signal is output such that the luminance distribution on the light emitting surface becomes high in the vicinity of the position corresponding to the detected peak. Referring also to FIGS. 1 and 2, the lighting device 100 includes the backlight 1 according to the first embodiment.
Since the dot pattern of the dispersed liquid crystal element 104 can be changed to an arbitrary pattern over time according to the drive signal, the dot pattern of the dispersed liquid crystal element 104 is Changes according to the drive signal 35. As a result, the luminance distribution of the liquid crystal display element 1 becomes in accordance with the drive signal 35, and as a result, the luminance distribution of the liquid crystal display device 1 becomes higher near the luminance peak position on the screen of the video signal. Something like [Embodiment 9] When an image is actually displayed using the liquid crystal display device 1 configured as described above, the position where the person's face moves is always displayed on a screen where the person's face is displayed. It was displayed brightly. On a screen where a person is displayed, a human tends to gaze at the face of the person, and in this embodiment, a portion corresponding to the area to be gazed is always displayed brightly. Was recognized as a bright image.

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 of the video signal on the screen, the brightness of the viewer of the liquid crystal display device is reduced. It has been found that an excellent display effect can be obtained. Twelfth Embodiment A twelfth embodiment of the present invention is an example of a configuration of an illuminating device capable of reducing the amount of light passing through the light guide plate.

FIG. 10 is a cross-sectional view schematically showing a configuration of a lighting device according to the present embodiment. In FIG. 10, FIG.
The same reference numerals indicate the same or corresponding parts.

As shown in FIG. 10, in the present embodiment,
On the lower surface 103a of the light guide plate 103, a constant scattering layer (hereinafter, referred to as a semi-transmissive layer) that transmits incident light by scattering it at a predetermined rate.
On the lower surface of the semi-transmissive layer 121, scattering dots (distribution scattering structure) 114 are formed in a predetermined pattern.
The reflecting plate 105 is provided below the semi-transmissive layer 121. Note that the semi-transmissive layer 121 has a substantially uniform transmittance over the entire area. Further, here, the luminous bodies 101 are configured by cold cathode tubes, and are arranged so that two luminous bodies are arranged in the thickness direction of the light guide plate 103. Other points are the same as the first embodiment.

More specifically, the light guide plate 103 is made of, for example, a synthetic resin such as acrylic.

The semi-transmissive layer 121 is made of, for example, S in synthetic resin.
iO2 fine particles are dispersed therein. It is necessary that the synthetic resin of the semi-transmissive layer 121 has a different refractive index from that of SiO 2, and that the material of the light guide plate 103 has a refractive index substantially equal to that of the light guide plate 103.
In order for the SiO2 fine particles to exhibit a 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. Translucent layer
121 is formed by printing on the lower surface 103c of the light guide plate 103 an ink obtained by mixing SiO2 fine particles in a synthetic resin. Further, the transmittance of the semi-transmissive layer 121 is adjusted by controlling its thickness.

The scattering dots 114 are the same as in the conventional example, and are formed by printing a resin containing a pigment, glass, or the like. The pattern of the scattering dots 114 is, for example, such that light emitted from the upper surface 103b of the light guide plate 103 has a uniform intensity distribution. It is formed to be sparse.

Next, the operation of the lighting device configured as described above will be described. The light emitted from the light source 151 is the light guide plate 103
Incident on the inside of. The incident light propagates inside the light guide plate 103. At this time, when the incident 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 through the SiO2 fine particles. . Of the transmitted light, those incident on the scattering dots 114 are scattered there, and the remaining ones are totally reflected on the lower surface of the semi-transmissive layer 121 (interface with air) and return to the light guide plate 103. To be precise, some of the light transmitted through the semi-transmissive layer 121 may not be totally reflected by the lower surface of the semi-transmissive layer 121, but this is reflected by the reflective plate 107 and inside the light guide plate 103. Is returned to.

Then, the light scattered by any of the semi-transmissive layer 121 and 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. The light reaches the opposing light source 151 without performing. Here, paying attention to the light emitted from the light source 151 on one side, the amount of 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 of the light source increases, and the light reaching the light source 151 on the opposite side decreases. Therefore, light loss in the vicinity of the light source 151 on the opposite side decreases, and the light use efficiency increases. As a result, it is possible to obtain an illuminating device having a high light emission surface luminance. In addition, since the semi-transmissive layer 121 can be formed at once by printing or the like, a configuration that increases the light use efficiency can be obtained at a low cost by a simple method.

The semi-transmissive layer 121 is formed on the lower surface 103c of the light guide plate 103.
Is formed over the entire surface of the lower surface 103c, so that the amount of light incident on the scattering dots 114 at any portion of the lower surface 103c is reduced, so that light loss can be further reduced.

In the light propagating in the light guide plate 103, the ratio of light scattered by the scattering dots 114 increases toward the center, and conversely, the light between the upper surface 103 b of the light guide plate 103 and the lower surface of the semi-transmissive layer 121. Since the ratio of total reflection is reduced, 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.

Next, the relationship between the amount of light penetrating the light guide plate (hereinafter referred to as the amount of light penetrating the light guide plate) and the transmittance of the semi-transmissive layer 121 will be described.

FIG. 11 is a graph showing the change in the amount of light penetrating the light guide plate with respect to the transmittance of the semi-transmissive layer. The graph shown in FIG. 11 is obtained by the present inventor by calculating the amount of penetration light when the transmittance of the semi-transmissive layer is changed by simulation. In this simulation, the amount of light penetrating the light guide plate is the amount of light that has leaked (lost) to the outside from the end face 103a of the light guide plate 103 where the two light sources 151 are respectively provided, and is the amount of light that is output from the two light sources 151. Expressed as a percentage. As shown in FIG. 5, the amount of light penetrating through the light guide plate does not exist in the semi-transmissive layer (the transmittance is 100
%) Is about 18%, but the transmittance of the semi-transmissive layer is 5%.
It goes to zero by lowering to 0%. That is, there is no light loss. As described above, since the semi-transmissive layer has a transmittance equal to or less than a certain value, in other words, has a scattering rate equal to or more than a certain value, the light incident on the light guide plate 103 from the two light sources 151 and 151 facing each other has the opposite light source. No light penetration occurs, thereby making it possible to increase the light use efficiency to 100%.

In the above configuration example, the semi-transmissive layer 121 and the scattering dots 114 are arranged on the lower surface of the light guide plate 103 in this order, but they may be arranged in the reverse order.

What is dispersed in the semi-transmissive layer 121 is not limited to SiO2 fine particles, but may be a pigment such as TiO2, or may be composed of a plurality of materials.

The transflective layer 121 only needs to have a function of partially reflecting incident light, and may be composed of a diffraction grating, a hologram film, a scattering anisotropic film, or the like.

The transflective layer 121 may be composed of a plurality of layers, or may be partially provided on the lower surface of the light guide plate 103. Embodiment 13 FIG. 12 is a sectional view schematically showing a configuration of a lighting device according to Embodiment 13 of the present invention. 12, the same reference numerals as those in FIG. 10 indicate the same or corresponding parts.

As shown in FIG. 12, in the present embodiment,
Rather than the transflective layer 121 being provided on the lower surface 103c of the light guide plate 103 as in the tenth embodiment, scatterers 122 are dispersed in the light guide plate 103. Other points are the same as the tenth embodiment.

The light guide plate 103 is made of, for example, an acrylic material, and has a large number of scatterers (scatterers) 122 mixed therein. The scatterer 122 is, for example, air, argon Ar,
Oxygen O2, gas such as nitrogen N2 or vacuum bubbles may be used,
A resin containing a material such as glass or white pigment having a different refractive index from the light guide plate 103 may be used.

According to the above configuration, the light guide plate 1
The light incident on the light guide plate 103 is diffused (scattered) when the light strikes the scatterer 205 in the light guide plate 103, and a part of the scattered light becomes
The light exits to the upper surface 103b of 3. As a result, the amount of light penetrating from one light source 151 to the other light source 151 decreases, and the light guide plate 1
Since light can be efficiently transmitted to the light emission surface 103b of the light emitting device 03, a bright illumination device can be obtained.

The scatterer 1 dispersed in the light guide plate 103
22 only needs to have a diffusion function and does not care about materials. The dispersion of the scatterers 122 may be uniform or non-uniform. Embodiment 14 FIG. 13 is a cross-sectional view schematically showing a configuration of a lighting device according to Embodiment 14 of the present invention. 13, the same reference numerals as those in FIG. 10 indicate the same or corresponding parts.

As shown in FIG. 13, in the present embodiment,
The translucent layer 121 is not provided on the lower surface 103c of the light guide plate 103 as in the tenth embodiment.
The scattering dots 123 formed in 3c are two types of scattering dots 123.
a, 123b. Other points are described in Embodiment 10.
Is the same as

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. And this scattering dot 12
Reference numeral 3 denotes a first scattering dot 123a disposed at the center and a second scattering dot 123b disposed at a peripheral portion, that is, a portion close to the light source 151. The first scattering dots include SiO2 fine particles, and the second scattering dots 123
b is composed of TiO2 fine particles. As a result, the first scattering dots 123a are replaced by the second scattering dots 123b.
The scattering property is higher than that of. Such a configuration is used in order to achieve both uniformity and scattering of light propagating in the light guide plate 103. In other words, in order to make the lighting device 1 brighter, it is advantageous to use scattering dots with enhanced scattering properties. However, if the scattering properties are too high, there is a lower limit to the printable size of the scattering dots. However, even though the low scattering property is required, the scattering property cannot be reduced to a certain level or less, and as a result, the uniformity of the luminance distribution on the light emitting 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 enhanced while maintaining the uniformity of the luminance distribution on the light emitting surface.

The first and second scattering dots 123a and 123b are prepared by preparing an ink obtained by mixing SiO2 fine particles and TiO2 fine particles with a resin, and printing the ink containing the SiO2 fine particles on the lower surface 103b of the light guide plate 103 first. Then, it can be easily formed by printing an 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.

In the lighting 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 incident on the scattering dots 123, and propagates so that light not incident on the scatter dots 123 is totally reflected on the lower surface 103c of the light guide plate 103. I do. At this time, the lower surface 103 of the light guide plate 103
The second scattering dots 123b having relatively low scattering properties are sparsely formed in the portion close to the light source of c, and the first scattering dots 123b having relatively high scattering properties are formed densely in the central portion. Therefore, light propagating in the light guide plate 103 emits light from the light source 151 of the light guide plate.
The scattering rate is higher in the central part than in the part close to. As a result, the brightness distribution of the light exit surface 103b of the light guide plate 103 becomes uniform. In addition, in this case, the scattering properties of the scattering dots formed in the central portion relative to those formed near the light source 151 are higher than those in the case where the scattering dots 123 are composed of one type. Can be set. Therefore, a brighter lighting device 1 can be obtained. Embodiment 15 FIG. 14 is a cross-sectional view schematically showing a configuration of a lighting device according to Embodiment 15 of the present invention. 14, the same reference numerals as those in FIG. 13 indicate the same or corresponding parts.

As shown in FIG. 14, in the present embodiment,
As in the fourteenth embodiment, two types of scattering dots 123a and 123 are used.
Instead of making the scattering property of b different depending on the material, 2
The scattering properties of the scattering dots 1234 and 124b
It varies depending on the dispersion density of the scattering material in 4,124b. That is, the first scattering dots 124a densely contain the SiO2 fine particles, and the second scattering dots 124b loosely contain the SiO2 fine particles, whereby the first scattering dots 124a become the second scattering dots. The scattering property is higher than that of 124b. Other points are the same as in the fourteenth embodiment.

The first and second scattering dots 124a and 124b are made of Si.
It is formed by printing on the lower surface 103c of the light guide plate 103 an ink in which O2 particles are mixed with a resin at different mixing ratios.

According to the above configuration, two types of scattering dots
Using the same material for 124a and 124b, the scattering property is enhanced while maintaining the uniformity of the luminance distribution on the light emitting surface 103c, and as a result,
A brighter lighting device can be obtained. Sixteenth Embodiment FIG. 15 is a sectional view schematically showing a configuration of a lighting device according to a sixteenth embodiment of the present invention. 15, the same reference numerals as those in FIG. 13 indicate the same or corresponding parts.

As shown in FIG. 13, in the present embodiment,
Instead of the 14 scattering dots 123 of the embodiment, the scattering region 1
25 are formed. 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. Then, the first scattering region 125a and the second scattering region 12a
The scattering properties are different from those of 5b by changing the density of the unevenness and the like. The scattering region 125 is the light guide plate 103
Is formed by subjecting a predetermined region on the lower surface of the substrate to mechanical processing and chemical processing to form irregularities. Other points are the same as the tenth embodiment.

In such a configuration, the embodiment 14
The same effect as described above can be obtained.

In Embodiments 12 to 15, it goes without saying that the scattering region of this embodiment may be formed instead of the scattering dots.

In the twelfth to sixteenth embodiments, the light guide plate
Although the lower surface 103 of FIG. 103 is illustrated as being flat, it may have irregularities.

The position of the light emitting body 101 may be anywhere within the reflector 102, and the number of the light emitting body 101 may be any number.

Also, the number of the light sources 151 may be one, and may have a luminance distribution. Seventeenth Embodiment In a seventeenth embodiment of the present invention, an image display device is configured using the lighting 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 arranged above the lighting device 100 shown in 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.

With such a configuration, it is possible to obtain an image display device having the effects described in Embodiments 12 to 16. Eighteenth Embodiment An eighteenth embodiment of the present invention shows a configuration example of an illuminating device capable of reducing penetration light of a light guide plate and controlling a luminance distribution on a light emitting surface.

FIG. 16 is a cross-sectional view schematically showing a configuration of an 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 indicate the same or corresponding parts.

As shown in FIG. 16, in the backlight 100 as the lighting device according to the present embodiment, a large number of scatterers 126 are dispersed in the light guide plate 103, and the lower surface 10 of the light guide plate 103
A scattering dot (distributed scattering structure) 104 having a predetermined pattern is formed in 3b.

The scatterer 126 is made of a material that is present in the material of the light guide plate 103 and that reflects or refracts incident light. The scattering dots 104 have a pattern similar to the pattern shown in FIG. 1B, and are formed such that the area ratio increases from the portion of the light guide plate 103 close to the light source toward the center.

The scattering ratio of the light guide plate 103 and the scattering dot 1
The total scattering rate of 04 is set such that the scattering effect of the scattering dots 104 is greater than the scattering effect of the light guide plate 103 in the degree of contribution to the amount of light emitted from the upper surface 103b of the light guide plate 103. Specifically, the scattering dots 104
Is desirably about twice or more as large as the scattering effect of the light guide plate 103 in the contribution degree. This is because the larger the scattering effect of the light guide plate 103 is, the greater the effect of reducing the penetration light of the light guide plate is. However, the influence of the scattering effect of the scattering dots 104 is relatively reduced, and the luminance at the light exit surface 103b is reduced. This is because the ability to control the distribution is reduced.

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, unlike the conventional example, there is almost no light that passes through the light guide plate and exits from the opposite end face and is lost.

Further, of the light propagating in the light guide plate 103, the light incident on the scattering dots 104 is scattered there,
Light is emitted from the upper surface 103b of the light guide plate 103. On the other hand, those which have not entered 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 light reaching the central portion from the portion close to the light source 151 decreases, so that the intensity of light propagating through the light guide plate 103 is close to the light source 151. It becomes larger at the part and becomes smaller toward the center.

On the other hand, the scattering dots 104 are light sources of the light guide plate 103.
It is formed so that the area ratio is small at a portion near 151, and increases toward the center. Therefore, of the light propagating in the light guide plate 103, the proportion of 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 becomes uniform throughout the light guide plate 103.

Further, by forming the scattering dots 104 such that the area ratio in the vicinity of the light source 151 is smaller than the area ratio in the center, more light is collected in the center and the brightness at the center is improved. Can be made larger. 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.

As described above, according to the present embodiment, by dispersing the scatterers 126 inside the light guide plate 103, the light source
The scattering efficiency of light that has entered the light guide plate 103 from 151 can be improved. As a result, the penetration light of the light guide plate can be reduced. Further, 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 use the light from the light source 151 in the light guide plate 103 without leakage, improve the light utilization rate, and set the luminance distribution of the light exit surface to a desired one. Embodiment 10 In this embodiment, a light guide plate 103 having a size of 7 inches and a thickness of about 10 mm made of acrylic resin was used. The light guide plate 103 was mixed with a scatterer as the scatterer 126 by a method described later, and formed scatter dots 104 on the lower surface thereof. The scatterer mixed into the light guide plate 103 made of an acrylic resin is preferably a scatterer that reflects or refracts incident light and hardly exhibits absorption characteristics. Specifically, for example, metal powder or glass beads can be used. In the present embodiment, since the target is visible light having a wavelength of about 0.5 μm,
In order for the scatterer 126 to cause scattering, the scatterer 126 needs to be larger than the wavelength of this visible light.
In addition, the size of the scatterer 126 cannot exceed the thickness of the light guide plate 103, and is at most about several mm to several tens of mm, and considering the uniformity at the time of mixing, is about several μm to several tens of μm. It is desirable that

Further, when the bubbles are dispersed inside the acrylic plate, a scattering effect is caused by the difference in the refractive index from the acrylic plate. Therefore, the acrylic plate and the bubbles are used as the light guide plate 103 and the scatterer 126, respectively. May be used. Further, an acrylic plate that is commonly used for the light guide plate 103 includes:
Since the scatterer 126 has a refractive index of about 5, the scatterer 126 preferably has a refractive index difference of about 0.1 or more in order to exhibit a scattering characteristic due to the difference in the refractive index with respect to this member. In this embodiment, beads having a size of about 10 μm and a refractive index of about 1.7 are used as the scatterers 126. In addition,
In FIG. 16, the scatterers 126 are randomly dispersed, but they may be dispersed regularly. In addition, the scatterer 12
The shape of 6 is shown in FIG. 16 as a spherical shape,
Any shape may be used, for example, an ellipse, a rectangle, a triangle, and the like having a cross-sectional shape in which these are combined can be used.

The pattern of the scattering dots 104 is
04 were arranged in a lattice pattern, and were formed at a pitch of about 1.5 mm to 3 mm and a diameter of about 0.5 mm to about 2 mm. Then, a cold cathode tube having an output of about 100 W was used as the luminous body 101.

As a comparative example (conventional example), an illuminating device was prepared in which a light guide plate made of an acrylic plate having the same size as that of the present embodiment was used, and scattering dots were formed on the lower surface thereof in the same pattern as that of the present embodiment. .

Then, the intensity of light emitted from the upper surface of the light guide plate was compared for both. 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 the present example, the luminance (outgoing light intensity) increased by about 5 to 10% on average in nine places compared to the comparative example. In addition, the luminance distributions at these nine locations are almost equal between the two, and therefore, it can be said that the present embodiment does not differ from the conventional example in the luminance distribution.

As described above, according to this embodiment, the light guide plate
By dispersing the scatterer in 103 and using it together with the scattering dots, it has been found that it is possible to improve the scattering efficiency, increase the luminance on the light emitting surface of the light guide plate, and obtain a desired luminance distribution. . Nineteenth Embodiment FIG. 17 is a cross-sectional view schematically showing a configuration of an illumination device according to a nineteenth embodiment of the present invention and an image display device using the same. 17, the same reference numerals as those in FIG. 16 indicate the same or corresponding parts.

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 includes the first unit light guide member 204 in which the scatterers 126 are dispersed and the scatterers. And a second light guide member 205 (hereinafter simply referred to as a light guide plate). Other points are the same as those of the eighteenth embodiment.

The first unit light guide member 204 and the second unit light guide member 205 are configured so as to form a rectangular plate-like light guide plate 203 by combining them. That is, the first unit light guide member and the second unit light guide member have a middle point of the upper side and lower left and right sides in a cross section perpendicular to the end surface of the rectangular plate-shaped light guide plate 203 where the light source 151 is provided. First and second regions 204 and 205 formed by dividing the cross section into two by a straight line connecting the side corners.
Are formed respectively. Then, the first unit light guide member 204 and the second unit light guide member 205 are joined to form a light guide plate 203. At the joint between the first unit light guide member 204 and the second unit light guide member 205,
An optical refractive index matching process is performed by a method described later, so that light is not reflected at this joint surface. Accordingly, FIG. 17 shows the interface between the unit light guide members 204 and 205, but this is only shown for convenience of explanation of the structure, and this interface is not actually visible. Also, the first and second unit light guide members 204, 30
5 can be created by cutting a single rectangular light guide plate into a shape as shown in FIG.

The scatterers 126 are dispersed in the first unit light guide member 204 as in the light guide plate of the eighteenth embodiment. On the other hand, no scatterers are dispersed in the second unit light guide member 205.

In the lighting apparatus 100 configured as described above, the light emitted from the light source 151 enters the light guide plate 203 from the end face 203a. This incident light is the first light in which no scatterers are dispersed.
In the unit light guide member 205 of No. 2, while transmitting the light, the scatterer
In the first unit light guide member 204 in which 126 is dispersed, the scatterer
When it hits 126, it is scattered on its surface. Then, while the scattered light is emitted from the upper surface 203b of the light guide plate 203, the light that does 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 reflected. Light plate 20
Propagate in 3 However, since the interface between the second unit light guide member 205 and the first unit light guide member 205 is formed to be inclined with respect to the light propagation direction in the light guide plate 203,
The volume ratio of the unit light guide member 204 to the light guide plate 203 is small near the light source 102 and increases toward the center. Therefore, the light incident on the light guide plate 203 is less scattered by the scatterer 126 in a portion close to the light source, and is more scattered by the scatterer 126 toward the center. On the other hand, the light that has entered the light guide plate 203 has a higher rate of reaching the light source near the light source, and has a smaller rate of reaching the central part. As a result, 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. [Embodiment 11] In this embodiment, 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. Also, the luminous body 10
As 1, a cold cathode tube having an output of about 100 W was used.

[0284] Then, the center of the upper surface 203b of the light guide plate 203 and 4
Luminance was measured at nine points on the line connecting the corners, and the luminance uniformity in the plane was examined. As a result, the upper surface 203 of the light guide plate 203
Assuming that the luminance near the center of b 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 the 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 was found that the light utilization rate could be improved and the luminance uniformity could be increased. Twentieth Embodiment FIG. 18 is a cross-sectional view schematically showing a configuration of an illumination device according to a twentieth embodiment of the present invention and an image display device using the same. 18, the same reference numerals as those in FIG. 17 indicate the same or corresponding parts.

As shown in FIG. 18, in the present embodiment,
Unlike the nineteenth embodiment, the light guide plate 203 includes first, second, and third unit light guide members 206, 207, scatterers 126 having different dispersion densities.
It is composed of a composite light guide plate composed of 208. Other points are the same as in the nineteenth embodiment.

The first, second, and third unit light guide members are formed by dividing a cross section perpendicular to an end face of the rectangular plate-shaped light guide plate 203 where the light source 151 is provided into three parts in the left-right direction. The first, second, and third regions 206, 207, and 208 are formed so as to constitute the respective regions. Then, the first and third light guide plates 206 and 208 are
Are equal to each other. In the second unit light guide member 207, the dispersion density of the scatterers 126 is higher than in the first and third light guide plates 206 and 208. In addition, the scatterer 126
Are uniformly and regularly dispersed in each unit light guide member 206, 207, 208 here.

In the lighting device 100 configured as described above, the light that has entered the light guide plate 203 is scattered when hitting the scatterer 126, exits from the upper surface 203 b of the light guide plate 203, and
When the light does not fall on the light guide plate 203, the light propagates through the light guide plate 203 while being totally reflected by the upper and lower inner surfaces of the light guide plate 203. However, the dispersion density of the scatterer 126 is low at the first and third unit light guide members 206 and 208 close to the light source 151 and is high at the second unit light guide member 208 located at the center. Therefore, the rate at which the light propagating in the light guide plate 203 is scattered is small in the first and third unit light guide members 206 and 208 close to the light source 151 and is high in the second unit light guide member 208 located in the center. On the other hand, the ratio of the light incident on the light guide plate 203 reaching the first and third unit light guide members 206 and 208 close to the light source 151 is large, and the second
The unit light guide member 208 reduces the size. As a result, the light guide plate 203
Of the light emitted from the upper surface 203b of the light guide plate 203 becomes substantially uniform over the entire light guide plate 203.

In the above configuration example, the light guide plate 203 is divided into three parts having different dispersion densities of the scatterers, but the light guide plate 203 may be divided into a number 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 that the luminance distribution on the light emitting surface can be more accurately controlled. can do.

Further, in the above configuration example, the scatterers 126 are dispersed regularly, but they may be dispersed randomly. [Example 12] In this example, as in Example 11 of the nineteenth embodiment, the light guide plate 203 was made of acrylic
An inch-sized one having a thickness of about 10 mm was used. As the scatterer 126, beads having a size of about 10 μm and a refractive index of about 1.7 were used. Then, the addition amount of the beads of the second unit light guide member 207 is changed to the first and third unit light guide members.
Double that of 206,208. In addition, a cold cathode tube having an output of about 100 W was used as the luminous body 101.

Then, the luminance on the upper surface 203b of the light guide plate 203 was measured in three places for each of the unit light guide members 206, 207, and 208.
It was measured at each location, and the degree of uniformity of luminance 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 was set to 100%, the luminance at the unit light guide members 206 and 208 located at both ends was distributed in a range of about 70 to 85%. The total sum of luminance at each measurement point was the same as that of the lighting device according to Example 10 of Embodiment 18. Therefore, it was found that according to the present embodiment, the light utilization rate can be improved and the distribution of luminance can be controlled. Twenty-First Embodiment FIG. 19 is a cross-sectional view schematically showing a configuration of an illumination device and an image display device using the same according to a twenty-first embodiment of the present invention. 19, the same reference numerals as those in FIG. 16 indicate the same or corresponding parts.

As shown in FIG. 19, in this embodiment,
Unlike the eighteenth embodiment, a scatterer 126 is provided in the light guide plate 103,
The density is dispersed such that the density is low near the light source 151 and increases toward the center. Further, no scattering dots are printed on the lower surface of the light guide plate 103. Other points are the same as those of the eighteenth embodiment.

In the lighting device 100 configured as described above, the light that has entered the light guide plate 103 is scattered when hitting the scatterer 126 and exits from the upper surface 103 b of the light guide plate 103, and is scattered.
When the light does not fall on the light guide plate 103, the light propagates through the light guide plate 103 while being totally reflected by the upper and lower inner surfaces of the light guide plate 103. However, the dispersion density of the scatterer 126 is low near the light source 151 and high at the center. Therefore, the rate at which the light propagating in the light guide plate 103 is scattered is small near the light source 151,
While increasing at the center, the ratio of the light incident on the light guide plate 103 reaches the portion near the light source 151 and decreases at the center. As a result, the intensity of light emitted from the upper surface 103b of the light guide plate 103 becomes substantially uniform over the entire light guide plate 103.

Although the scatterers 126 are regularly dispersed in the above configuration example, the scatterers 126 may be irregularly dispersed. [Example 13] In this example, as in Example 10 of the eighteenth embodiment, a light guide plate 103 having a size of about 7 inches and a thickness of about 10 mm made of acrylic was used. The scatterer 126 has a size of about 10 μm and a refractive index of 1.
About 7 beads were used. The scatterers 126 were dispersed by a manufacturing method described later so that the density increased substantially linearly with the distance from the end face of the light guide plate 103 to the center. As the luminous body 101, a cold cathode tube having an output of about 100 W was used.

Then, the center of the upper surface 103b of the light guide plate 103 and the
Luminance was measured at nine points on the line connecting the corners, and the luminance uniformity in the plane was examined. As a result, the upper surface 103 of the light guide plate 103
Assuming that the luminance near the center of b 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 the points was the same as that of the lighting device according to Example 10 of Embodiment 18. Therefore, according to the present example, it was found that the light utilization rate could be improved and the luminance uniformity could be increased. Twenty-Second Embodiment FIG. 20 is a cross-sectional view schematically showing a configuration of a lighting device according to a twenty-second embodiment of the present invention and an image display device using the same. 20, the same reference numerals as those in FIG. 19 indicate the same or corresponding parts.

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 correspond to the light guide plate 10 shown in FIG. 19 (Embodiment 21).
Each part 210,2 formed by dividing 3 in the center in the left-right direction
11, each of which has a joint surface 209 formed as a reflective surface. The reflection surface 209 is formed by attaching a reflection tape to the bonding surface of each unit light guide member 210, 211 or by vapor-depositing a reflection 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.
Other points are the same as in the twenty-first embodiment.

In the lighting device 100 configured as described above, by the action of the scatterer 126 as in the twenty-first embodiment,
The intensity of light emitted from the upper surface 203b of the light guide plate 203 is
It becomes almost uniform throughout.

[0297] Further, two unit light guide members 210,
Since the reflection surface 209 is provided on the bonding surface between the 211, the light incident on the light guide plate 203 from the light source 151 is not sufficiently scattered inside and the loss light which is emitted from the opposite end surface is reduced. Can be. That is, part or all of the incident light is scattered and reflected on the reflection surface 209 provided at the center of the light guide plate 203. Then, the scattered and reflected light is again scattered by the scatterer 126 dispersed in the original unit light guide members 210 and 211. Therefore, the light that is not sufficiently scattered in the light guide plate 203 and penetrates to the opposite end face and becomes a loss is further suppressed. When the reflecting surface 209 is configured to have the function of scattering and transmitting, the light transmitted through the reflecting surface 209 and scattered is dispersed in the other unit light guiding members 210 and 211. It is further scattered by the body 126. Therefore, since the light incident on the light guide plate 203 is sufficiently scattered, the loss of the light that penetrates the end face on the opposite side is further suppressed. [Example 14] In this example, as in Example 10 of the eighteenth embodiment, a light guide plate 203 having a size of 7 inches and a thickness of about 10 mm made of acryl was used. The scatterer 126 has a size of about 10 μm and a refractive index of 1.
About 7 beads were used. The scatterers 126 were dispersed by a manufacturing method described later so that the density increased substantially linearly with 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. Further, the reflection surface 209 is provided for each of the unit light guide members 210 and 211.
A reflective tape was adhered to the joint surface of No. 1 to have a scattering reflection function.

Then, the center of the upper surface 203b of the light guide plate 203 and the
Luminance was measured at nine points on the line connecting the corners, and the luminance uniformity in the plane was examined. As a result, the upper surface 203 of the light guide plate 203
Assuming that the luminance near the center of b is 100%, the luminance at other points is about 80% to 95%, which is the same as in the twenty-first embodiment. The sum of the luminance at each measurement point is
It is increased by about 5% as compared with the twenty-first embodiment. Therefore,
According to this example, it was found that the light utilization rate could be improved and the luminance uniformity could be increased. Twenty-third Embodiment A twenty-third embodiment of the present invention is shown in FIG.
The joint surface between the first unit light guide member 210 and the second unit light guide member 211 is a refractive index matching surface. Other points are the same as those of 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,
These bonding surfaces were bonded using an adhesive having a refractive index substantially equal to that of the bonding surfaces. Since acrylic has a refractive index of about 1.5, an epoxy-based adhesive having a refractive index of about 1.5 was used as the adhesive.

With such a configuration, the joining surface is
It does not act as a light-reflecting boundary surface and functions as if optical matching had been performed.

In the nineteenth or twentieth embodiment,
By applying this refractive index matching process to the bonding surface between the unit light guide members, it is possible to prevent the bonding surface from being seen as a boundary line or the like due to a difference in transmittance or reflectance without using a scattering sheet or the like. Conceivable. Although an adhesive is used in the above configuration example, a similar effect can be obtained by merely applying a liquid having the same refractive index as the unit light guide members 210 and 211 to the joint surfaces and bringing the joint surfaces into close contact with each other.

Actually, in the above configuration, as a result of measuring the luminance on the light emitting surface 203a of the light guide plate 203, a result almost similar to the measurement result in the twenty-second embodiment was obtained. Also, without using the scattering sheet, the light exit surface 203b of the light guide plate 203 is used.
Even when observed, no unnatural boundary such as a line was observed. Therefore, according to the present embodiment, it has been found that the light utilization rate can be improved and the luminance uniformity can be increased. Twenty-Fourth Embodiment FIG. 21 is a plan view schematically showing a configuration of a lighting device according to a twenty-fourth embodiment of the present invention. In FIG.
The same reference numerals indicate the same or corresponding parts.

FIG. 21 is a diagram of the light guide plate viewed from the light emitting surface side. As shown in FIG. 21, in the present embodiment, unlike Embodiment 19, light guide plate 203 is
First and second unit light guide members 20 each composed of a divided part.
4,205, and the luminous bodies 101 are arranged on 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.

The first unit light guide member in which the scatterers 126 are dispersed is composed of a rhombic part 204 formed by connecting the midpoints of the sides of the rectangular light guide plate 203 with straight lines, and the scatterers are not dispersed. The second unit light guide member includes the remaining part 205 of the rectangular light guide plate 203. As a result, the occupation ratio of the first unit light guide member 204 in which the scatterers 126 are dispersed to the light guide plate 203 increases from the portion of the light guide plate 203 closer to the light emitter 101 toward the center. . In addition, the first and second
Are bonded to each other by performing the refractive index matching processing described in the twenty-third embodiment.
The mode of the scatterer 126 is the same as that of the nineteenth embodiment.

The shape of the first unit light guide member 204 is as follows.
It is sufficient that the occupation ratio of the first unit light guide member 204 to the light guide plate 203 increases from a portion close to the light emitting body 101 toward the center, and is not limited to a rhombus. The configuration of the luminous body 101 includes two L-shaped luminous bodies 1.
01 may be arranged on the four end faces of the light guide plate 203, or 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. Good. [Embodiment 15] In the present embodiment, the material and shape of the light guide plate, the luminous body, and the like were formed in the same manner as in Embodiment 10 of the eighteenth embodiment. Also, a diamond-shaped portion as shown in FIG. 21 is cut out from a rectangular acrylic plate in which the scatterers 126 are dispersed in advance,
This was designated as a 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, and this is cut into a second rectangular plate. The unit light guide member 205 was used. Then, the bonding surfaces of the first and second unit light guide members 204 and 205 were bonded together using an epoxy adhesive.

Then, the luminance at the light exit surface 203b of the light guide plate 203 was measured in the same manner as in Example 10 of Embodiment 18, and as a result, the luminance near the center of the light exit surface 203b was 10%.
When it is set to 0%, the luminance at other places is 80% to 95%.
%. Therefore, it was found that the present embodiment can control the luminance distribution on the light emitting surface. Twenty-Fifth Embodiment In a twenty-fifth embodiment of the present invention, an image display device is configured using the lighting 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 (eighteenth embodiment) and the backlight in FIG. Light 100 (Embodiment 19),
The backlight 100 (Embodiment 20) in FIG. 18, FIG.
By using the backlight 100 (Embodiment 21) of FIG. 20, the backlight 100 (Embodiments 22 and 23) of FIG. 20, and the backlight 100 (Embodiment 24) of FIG.
The liquid crystal display device 1 as an image display device can be configured. As the liquid crystal element 106, a twisted nematic type having a size of about 7 inches was used. Further, polarizing plates (not shown) are arranged in a crossed Nicols on both sides of the liquid crystal element 106.

Then, when the luminance distribution of the display screen was measured via the liquid crystal element 106, the result obtained by multiplying the luminance measured by the illumination device 100 alone by about 5 to 7% of the transmittance of the liquid crystal element 106 was obtained. became. Therefore, it has been found that even when the image display device is configured using the lighting devices according to Embodiments 18 to 24, it is possible to improve the light utilization rate and control the luminance distribution. Twenty-Sixth Embodiment A twenty-sixth embodiment of the present invention exemplifies a method for manufacturing a light guide plate in which scatterers are dispersed.

FIG. 22 is a sectional view showing a method of manufacturing the light guide plate according to the present embodiment. In FIG.
Shows a mold for forming a light guide plate by heating and melting. On the surface of the mold 702, a concave portion 702 having substantially the same planar shape as a desired light guide plate and having a predetermined depth is formed. The mold 702 is made of a metal such as aluminum Al.

In the present embodiment, the product is a light guide plate in which a scatterer is dispersed in an acrylic resin. As a scatterer,
It is preferable that the material has a function of reflecting and refracting incident light and hardly exhibits absorption characteristics. Specifically, metal powder, glass beads, or the like can be used as a scatterer. Since the object to be scattered 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. In addition, the size of the scatterer cannot exceed the thickness of the light guide plate, and is at most about several mm to about several tens of mm. Therefore, considering the uniformity at the time of mixing, it is desirable that the size of the scatterer is about several μm to several tens μm.

To manufacture a 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 the acrylic resin is placed in the concave portion 70 of the mold 702.
Inject into 2a. Next, the temperature of both ends a and c of the mold 702 is set to be higher by about 50 to 100 ° C. than the temperature of the central part 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 as the additive becomes large. For this reason, at both ends a and c where the temperature is high, the dispersion density of the beads decreases, and the dispersion density increases 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 the beads is low at both ends and the dispersion density of the beads increases toward the center.

[0310] A light curing agent may be added to the mixture 701 in advance, and the mixture 701 may be cured by light irradiation.

Further, if the heating temperature of the mold 702 is made uniform, it is possible to obtain a light guide plate in which the scattering density of the scatterers is uniform.

The light guide plate prepared as described above and having different dispersion densities depending on locations was used as the light guide plate 103 in the twenty-first embodiment. Regarding the optical characteristics of the illumination device 100 using the light guide plate 103, as described in the twenty-first embodiment, it is possible to improve the light utilization rate and control the luminance distribution. Light guide plate 10
The effectiveness of 3 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.

In the present embodiment, the product is a light guide plate in which bubbles are dispersed as a scatterer 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 the acrylic resin is about 1.5. Therefore, the air bubbles dispersed in the base made of the acrylic resin scatter the incident light due to the difference in refractive index between the air bubbles, thereby functioning as a scatterer.

To manufacture a light guide plate, first, an 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 has been added is injected into the concave portion 702a of the mold 702. Next, in this state, the molten acrylic resin 703 is irradiated with light 704.

Here, the foaming agent has a property of generating bubbles according to the intensity of the irradiated light. Therefore, by setting the intensity of the irradiated light 704 to be distributed on the irradiation surface, the dispersion density of the bubbles in the molten acrylic resin 703 can be changed depending on the location. Therefore, in the present embodiment, for example, the intensity of irradiation light 704 is set to be small at both ends of the surface of molten acrylic resin 703, and to be increased toward the center.

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.

Next, in this state, the molten acrylic resin 703 was used.
Quench. Then, the dispersion density of the bubbles is low at both ends,
A light guide plate is obtained in which the dispersion density of the bubbles increases toward the center.

In addition, a curing agent which reacts to ultraviolet rays is added to the molten acrylic resin 703 in advance, and
By irradiating 703 with ultraviolet light, it may be cured.

Further, if the intensity distribution of the irradiation light 704 on the irradiation surface is made uniform, it is possible to obtain a light guide plate having a uniform dispersion density of bubbles. Further, by selecting the intensity distribution of the irradiation light 704 in the irradiation surface, the dispersion density of bubbles in the light guide plate can be arbitrarily controlled.

The light guide plate prepared as described above was used as the light guide plate 103 in the twenty-first embodiment. Regarding the optical characteristics of the illumination device 100 using the light guide plate 103, as described in the twenty-first embodiment, it is possible to improve the light utilization rate and control the luminance distribution. The effectiveness of the light guide plate 103 thus obtained was confirmed. Twenty-Eighth Embodiment A twenty-eighth embodiment of the present invention exemplifies an illumination device and an image display device in which the light utilization is improved and the luminance is increased by using a reflective polarizing plate.

FIG. 24 is an exploded perspective view schematically showing the structures 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. 24;
(a) is a cross-sectional view showing a case where the reflection type polarizing plate has a multilayer film structure, (b) is a diagram showing a case where the reflection type polarizing plate is made of cholesteric liquid crystal, and FIG. 26 is a view with respect to the viewing angle of the prism sheet of FIG. It is a graph showing the change in transmittance, (a)
FIG. 6 is a diagram illustrating a change in a direction perpendicular to the ridge direction of the prism sheet, and FIG. 7B is a diagram illustrating a change in the ridge direction of the prism sheet. 24, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts. In FIG. 24,
For convenience, the Y direction is defined as a forward direction. (Illumination Device) As shown in FIG. 24, in illumination device 100 according to the present embodiment, light sources 102 and 102 are disposed on the upper end surface and the lower end surface of rectangular light guide plate 103, respectively. Further, a reflection sheet 105 is provided behind the light guide plate 103, and further, a diffusion sheet 131, a reflection type polarizing plate 132,
And the prism sheet 133 are arranged in this order. The prism sheet 133 is arranged so that its ridgeline direction 145 is horizontal.

As shown in FIG. 25A, the reflective polarizing plate 132
In the cross section, an interface is formed so as to extend in a triangular wave shape in the left-right direction in the cross section, and a multi-layer film composed of a number of films having different refractive indexes is formed on the interface. Since such an interface has a function similar to that of the polarization beam splitter, at this interface, of the incident light 137, P-polarized light is transmitted and S-polarized light is reflected. The reflected S-polarized light is returned to the incident side, that is, to the light guide plate 103. The reflective polarizer 132 is arranged so that the emitted polarized light (here, “P-polarized light in the reflective polarizer 132”) is incident on the prism sheet 133 as “P-polarized light in the prism sheet 133”. I have. That is, the polarization axis (polarization plane) of the P-polarized light in the prism sheet 133 is a direction perpendicular to the ridgeline direction 145, that is, a vertical direction. Therefore, the reflective polarizing plate 132 is configured so that the polarization axis of the emitted P-polarized light is in the vertical direction. Specifically, the interface is formed vertically.

Next, the lighting apparatus 10 configured as described above
The operation of 0 will be described. Light emitted from the light source 102 is incident on the light guide plate 103 and repeats internal reflection.
Are scattered by scattering dots (not shown) formed on the back surface of the light guide plate 103 and exit from the front surface of the light guide plate 103. At this time, the light guide plate 1
Light leaking from the back of 03 is reflected by the reflective sheet 105 to the light guide plate 1
Returned inside 03. 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, of the incident light, P-polarized light is transmitted through the reflective polarizer 132, and S-polarized light is transmitted through the reflective polarizer 132.
Reflected at 32. The reflected S-polarized light is applied to the light guide plate 103.
Are reflected by the scattering dots or the reflection sheet 105, and then enter the reflection type polarizing plate 132 again. At this time, the polarization direction is also modulated in the reflection process. Therefore, a part of the re-entered 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 polarized by the reflective polarizing plate 132 so as to have the same polarization direction as P-polarized light.

The P-polarized light enters the prism sheet 133 as P-polarized light on the prism sheet 133, and is condensed in the central direction at the viewing angle.

Here, as shown in FIGS. 26A and 26B, in the prism sheet 133, the transmittance 141 of the P-polarized light is smaller than that of the S-polarized light for the light emitted at an angle close to the vertical. 142
It is higher than. Specifically, the transmittance 141 of the P-polarized light is approximately 6.5% higher than the transmittance 142 of the S-polarized light within a range of the viewing angle from −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 where the S-polarized light is also transmitted as in the conventional example. As a result, effective use of light can be achieved.

Next, as a modification of the present embodiment, FIG.
In 4, a phase plate such as a 波長 wavelength plate may be provided on the light incident side of the reflective polarizing plate 132, and the S-polarized light reflected by the reflective polarizing plate 132 may pass twice back and forth. . As a result, the polarization direction of the reflected S-polarized light is rotated by 90 °, and the reflected S-polarized light can be transmitted through the reflective polarizer 132. Therefore, the polarization directions can be more easily aligned than in the above configuration example.

Further, as shown in FIG. 25B, the reflective polarizing plate 132 may be configured to have a film structure including a cholesteric liquid crystal. In such a reflective polarizing plate 132, the clockwise polarized light of the incident light 137 is transmitted and the counterclockwise 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 together. (Image Display Device) FIGS. 27A and 27B are cross-sectional views showing the configuration of the liquid crystal cell of FIG. 24, wherein FIG. 27A shows a state where no voltage is applied, and FIG. 27B shows a state where a voltage is applied. FIG. 27, the same symbols as those in FIG. 1 indicate the same or corresponding parts. FIGS. 27A and 27B show one pixel.

As shown in FIG. 24, an image display device 1 according to the present embodiment has a liquid crystal display
06, and a drive circuit (not shown) for driving the liquid crystal display element 106 is further provided. Since the configuration and operation of the drive circuit are the same as those in Embodiment 1,
The description is omitted.

The liquid crystal display element 106 includes a liquid crystal cell 135, an incident side polarizing plate 134 disposed on the back side of the liquid crystal cell 135, and an output side polarizing plate 136 disposed on the front side of the liquid crystal cell 135. It is configured. The incident-side polarizing plate 134 is disposed 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.
Are arranged such that the polarization axis 147 thereof is perpendicular to the polarization axis 146 of the incident-side polarizing plate 134.

As shown in FIG. 27A, the liquid crystal cell 135
Each pixel 139 has a liquid crystal mode in which the orientation direction of the liquid crystal molecules 113a has a different pretilt angle from the center plane 139a of the pixel in a state where no voltage is applied. 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 supply 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, the substrates 111, 112
When the liquid crystal cell 135 is viewed from two directions (indicated by arrows A and B in FIG. 27A) opposite to the normal to FIG.
As apparent from (a), the apparent refractive index becomes substantially the same in any direction. Therefore, the contrast is the same in both directions, and a wide viewing angle characteristic can be obtained.

[0331] Such a liquid crystal mode is applied to the substrates 111 and 112.
Can be realized by performing a rubbing process on each of the two regions on the center plane 139a of the pixel 139 shown in FIG. 27A in opposite directions while masking the other side. Further, the substrates 111 and 11 on which the liquid crystal layer is disposed
In the space between the two, a partition made of a polymer material is formed so as to partition the pixel 139 into a plurality of regions, and liquid crystal molecules move along the partition when a voltage is turned on / off. You may. This partition can be formed by irradiating a mixture of liquid crystal and a photocurable polymer material with light using a photomask having a predetermined pattern.
With such a configuration, the liquid crystal mode can be realized. In addition, the liquid crystal mode can be realized by the following configuration. That is, unevenness may be formed on the inner surface of one of the opposing substrates 111 and 112 by, for example, a comb-shaped pattern, and the liquid crystal molecules may be oriented in different directions along the unevenness. Instead of switching the orientation of the liquid crystal by applying a voltage between the opposing substrates, the switching electrode is formed on one substrate and the orientation of the liquid crystal is switched in a direction parallel to the substrate. May be. In this case, the pattern of the switching electrode may be formed in a comb shape.

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 is not inclined by 45 degrees with respect to the longitudinal direction of the panel as in the conventional example. However, good viewing angle characteristics can be obtained.
Therefore, in the present embodiment, the polarization axis 1
46 is the same vertical direction as the polarization axis of the P-wave transmitted by the reflective polarizer 132, and accordingly, the polarization axis 1 of the output-side polarizer 136
47 is horizontal.

In the image display device 1 configured as described above, the light emitted from the prism sheet 133 of the illuminating device 100 is incident on the incident side polarizing plate 134, the liquid crystal cell 106, and the emitting side polarizing plate 13
6 sequentially, whereby an image corresponding to the video signal input to the drive circuit is displayed on the display screen. On this occasion,
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 in 4 is prevented, and heat generation in the prism sheet 133 is reduced as described above, so that deterioration such as heat shrinkage of the incident side polarizing plate 134 and the prism sheet 133 and non-uniform optical characteristics are prevented. Is prevented. Therefore, according to the present embodiment, it is possible to obtain an image display device in which the light utilization rate is improved and the luminance can be increased.

[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, picture elements (dots) of each color constituting a pixel are displayed. , The pixel may be configured in the same manner.

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 condenses incident light in a predetermined direction using refraction or reflection at the interface. A plurality of ridges may be formed on the main surface of a flat member such as a prism sheet, and the ridges may have a cross section other than a triangle. Twenty-Eighth Embodiment FIG. 28 is an exploded perspective view schematically showing a configuration of a lighting device according to a twenty-ninth embodiment of the present invention, in which (a) shows a case where a point light emitter is used as a light source. (B) is a diagram showing a case where a linear illuminant is used as a direct light source, and (c) is a diagram showing a case where a planar illuminant is used as a light source. FIG.
27, the same reference numerals as those in FIG. 27 denote the same or corresponding parts.

This embodiment shows a specific configuration example of the light source 102 in the twenty-eighth embodiment.

In the first configuration example, as shown in FIG. 28 (a), 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. I have.

In the second configuration example, as shown in FIG. 28B, for example, a linear light-emitting body 101 such as a cold cathode tube is
Behind each other. That is, it is configured as a direct-type lighting device.

In the third configuration example, as shown in FIG. 28C, a planar light-emitting body 10 is provided instead of the light guide plate.

It is also possible to obtain a new configuration by combining the above configurations. For example, a plurality of cold-cathode tubes are disposed behind the light guide plate 103 to form a direct type, and L and L emit light of several colors on upper and lower end surfaces of the light guide plate 103.
By arranging a plurality of EDs, the luminance can be further increased. In addition, for example, by configuring a portion of a color having a low luminous intensity in an emission spectrum of a cold cathode tube by using an LED, it is possible to improve a color balance. [Embodiment 16] In this embodiment, a direct-type lighting device is used as in the second configuration example. A cold cathode tube having an output of about 100 W was used. The light guide plate used had a size of about 10 inches.

When the luminance at the exit surface of the prism sheet 133 was measured, a high luminance output of about 10000 cd / mm ² was obtained. In that state, 10
Even if illumination was continuously performed for 0 hours or more, unevenness of the luminance distribution due to thermal deformation of the prism sheet 132 did not occur. From this, it was found that the lighting device according to the present embodiment can obtain stable performance even when operated at high luminance.

It is needless to say that an image display device can be obtained by combining the illumination device according to the present embodiment with a liquid crystal display element and a driving circuit in the same manner as in the twenty-eighth embodiment. Embodiment 30 FIG. 29 is an exploded perspective view schematically showing a configuration of a lighting device and an 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.

As shown in FIG. 29, in this embodiment,
The polarizing sheet is set so that the polarizing axis 146 of the incident-side polarizing plate 134 is inclined at 45 degrees to the horizontal direction, and the polarizing axis 147 of the emitting-side polarizing plate 136 is perpendicular to the polarizing axis 146 of the incident-side polarizing plate 134. The ridge directions 145A and 145B of the 133A and 133B and the polarization axis of the P wave are set in the directions corresponding thereto. The liquid crystal cell 135 is of a TN type liquid crystal mode.
Other points are the same as those of the twenty-eighth embodiment. [Embodiment 17] In this embodiment, only the prism sheet 133A is arranged in FIG.
However, they are arranged obliquely such that the ridge 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 thereof, matches the polarization axis 146 of the incident-side polarizing plate 134.
Then, cold cathode tubes of about 100 W were arranged on the upper and lower end faces of the light guide plate 103 as light emitters. Comparative example (conventional example)
In the configuration of the present embodiment, the prism sheet 133A
The ridgeline direction 133A is horizontal, and the reflective polarizing plate 13
2 was made to remove.

Then, 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.

From the above results, it can be seen that T which is currently widely used
It has been found that even when a polarizing plate is arranged so as to be applicable to N-mode liquid crystal, front luminance can be improved by arranging a prism sheet and a reflective polarizing plate so as to conform to the structure. [Embodiment 18] In Embodiment 17, although the front luminance improving effect was obtained as described above, since the prism sheet 133A was arranged obliquely, non-uniformity occurred in the viewing angle characteristics (contrast viewing angle characteristics) in the horizontal direction. Was. Therefore, in the present embodiment, in order to solve this, a prism sheet 133B is further added in front of the prism sheet 133A, and this is added to the ridge direction 145B.
Are arranged so as to coincide with the polarization axis 146 of the incident side polarizing plate.

Then, as a result of measuring the luminance of the display screen, the left and right viewing angle characteristics were almost symmetric. Regarding the front luminance, of the two prism sheets, the liquid crystal cell
Making the ridge direction 145B of the object 133B close to 135 perpendicular to the polarization axis 146 of the incident-side polarizing plate 134 may increase the brightness by several percent compared to the opposite case (the configuration shown in FIG. 29). confirmed. If two prism sheets are used and arranged so that the ridge directions are perpendicular to each other, the transmittance due to polarized light should be equal. However, in fact, since the medium of the prism sheet itself has some refractive index anisotropy, it is considered that the combination of the arrangement and the incident side polarizing plate 134 affects the transmittance of the liquid crystal cell 135.

As described above, according to this embodiment, two prism sheets 133A and 133B are used, and both ridge directions are perpendicular to each other and one ridge direction is the direction of the polarization axis 146 of the incident side polarizing plate 134. It was confirmed that by configuring the display device to be parallel to the direction, the left-right viewing angle characteristics can be made symmetrical while improving the front luminance. Embodiment 31 In the invention according to Embodiments 28 and 30, the reflection type polarizing plate is inserted on the optical path of the illumination device, and the ridge direction of the prism sheet and the polarization axis of the P-wave, which is the transmission axis thereof, and the liquid crystal display element. The essential configuration is to make the polarization axes of the polarizing plates correspond. Therefore, the present invention can be applied to various types of lighting devices by adding this essential configuration. Therefore, this embodiment is directed to Embodiments 28 and 3
0, the configuration of the illuminating device 100 except for the reflective polarizer 132 and the prism sheet 133 is replaced with the illuminating devices of the first to twenty-seventh embodiments. With such a configuration, the effects of Embodiments 1 to 27 can be obtained in addition to the effects of Embodiments 28 and 30.

It is needless to say that an image display device can be obtained by combining a liquid crystal display element and a driving circuit with the lighting device according to the present embodiment in the same manner as in the twenty-eighth embodiment. Embodiment 32 Embodiment 32 of the present invention relates to Embodiments 6 to 11, 1
7 illustrates a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal device using the image display devices (liquid crystal display devices) 7, 25, 28 to 31 as display units.

FIG. 30 is an external view showing the structure 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 (for processing a monitor signal input from the outside). Not shown), and
The monitor video signal output from the signal processing unit is configured to be 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 whose luminance distribution can be controlled can be obtained.

Here, as the liquid crystal display device, another liquid crystal display device of Embodiment 6 and Embodiments 7 to 11, 17,
Twenty-five liquid crystal display devices may be used, and a liquid crystal monitor exhibiting effects corresponding to the respective embodiments can be obtained.

FIG. 31 is an external view showing a configuration of a liquid crystal television according to the present embodiment. Referring also to FIG. 2, liquid crystal television 602 includes a display unit including liquid crystal display device 1 using lighting device 100 of Embodiment 1, and a tuner for selecting a channel of a television broadcast signal input from the outside. And a television signal of the channel selected by the tuner unit 603 is inputted to the drive circuit 36 of the liquid crystal display device 1 as the video signal 25. In addition. In FIG. 31, the wiring between the liquid crystal display device 1 and the tuner unit 603 is omitted. With such a configuration, a liquid crystal television whose luminance distribution can be controlled can be obtained.

Here, as the liquid crystal display device, another liquid crystal display device of Embodiment 6 and Embodiments 7 to 11, 17, 17,
25 liquid crystal display devices may be used, and a liquid crystal television having effects corresponding to the respective embodiments can be obtained.

The liquid crystal information terminal device according to the present embodiment
The liquid crystal television 602 includes a transmission / reception unit for transmitting / receiving communication information instead of the tuner unit 603, and an image signal including required information output from the transmission / reception unit is transmitted to the drive circuit 36 of the liquid crystal display device 1 as a video signal 25. It is configured to be input. With such a configuration, an information terminal device whose luminance distribution can be controlled can be obtained.

Here, as the liquid crystal display device, another liquid crystal display device of Embodiment 6 and Embodiments 7 to 11, 17,
Twenty-five liquid crystal display devices may be used, and an information terminal device having effects corresponding to the respective embodiments can be obtained.

It should be noted that the embodiments of the present invention are not limited to Embodiments 1 to 32 described above, and it goes without saying that a configuration for improving or modifying them can be used.
Further, an example of a configuration using a liquid crystal display element as an image display device has been described. However, the present invention is not limited to the liquid crystal display element, and may be any element that performs display using a backlight or a front light.

[0356]

The present invention is embodied in the form described above, and has the following effects. (1) An illumination 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 used in these devices, which can achieve high luminance, can be provided. (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 a light guide plate used for these devices, which can reduce the penetration light of the light guide plate and control the luminance distribution. . (3) It is possible to provide a lighting device, an image display device, a liquid crystal monitor, a liquid crystal television, and a liquid crystal information terminal that can change the luminance distribution. (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 capable of reducing the loss of light 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 showing a configuration of an illumination device according to Embodiment 1 of the present invention and an image display device using the same, wherein FIG. 1A is a cross-sectional view, and FIG. FIG. 4 is a plan view showing a dot pattern of the dispersion liquid crystal element.

FIG. 2 is a block diagram showing a configuration of a control system of the image display device of FIG.

FIG. 3 is a cross-sectional view schematically illustrating a configuration of a lighting device according to Embodiment 2 of the present invention and an image display device using the same.

FIG. 4 is a cross-sectional view schematically showing a configuration of a lighting device according to Embodiment 3 of the present invention and an image display device using the same.

FIG. 5 is a plan view schematically showing a configuration of a lighting device according to Embodiment 5 of the present invention.

FIG. 6 is a perspective view schematically showing a configuration of a lighting device and an image display device according to a seventh embodiment of the present invention.

FIG. 7 is a perspective view schematically showing a configuration of a lighting 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 a lighting 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 device according to Embodiment 10 of the present invention.

FIG. 10 is a cross-sectional view schematically showing a configuration of a lighting device according to Embodiment 12 of the present invention.

11 is a graph showing a change in the amount of light penetrating 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 device according to Embodiment 13 of the present invention.

FIG. 13 is a cross-sectional view schematically showing a configuration of a lighting device according to Embodiment 14 of the present invention.

FIG. 14 is a cross-sectional view schematically showing a configuration of a lighting device according to Embodiment 15 of the present invention.

FIG. 15 is a cross-sectional view schematically showing a configuration of a lighting device 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 Embodiment 18 of the present invention.

FIG. 17 is a cross-sectional view schematically showing a configuration of an illumination device according to a nineteenth embodiment of the present invention and an image display device using the same.

FIG. 18 is a cross-sectional view schematically showing a configuration of a lighting device according to Embodiment 20 of the present invention and an image display device using the same.

FIG. 19 is a sectional view schematically showing a configuration of an illumination device according to a twenty-first embodiment of the present invention and an image display device using the same.

FIG. 20 is a sectional view schematically showing a configuration of an illumination device according to a twenty-second embodiment of the present invention and an image display device using the same.

FIG. 21 is a cross-sectional view schematically showing a configuration of a lighting device according to Embodiment 24 of the present invention.

FIG. 22 is a cross-sectional view showing the method of manufacturing the light guide plate according to Embodiment 26 of the present invention.

FIG. 23 is a cross-sectional view showing the method of 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 a lighting device and an image display device according to Embodiment 28 of the present invention.

25A and 25B are schematic diagrams illustrating the operation of the reflective polarizing plate of FIG. 24, wherein FIG. 25A is a cross-sectional view illustrating a case where the reflective polarizer has a multilayer structure, and FIG. It is a figure showing the case where it consists of cholesteric liquid crystal.

26 is a graph showing a change in transmittance with respect to a viewing angle of the prism sheet of FIG. 24, where (a) shows a change in a direction perpendicular to the ridge direction of the prism sheet, and (b)
FIG. 4 is a diagram showing a change in a ridge direction of a prism sheet.

27A and 27B are cross-sectional views illustrating the configuration of the liquid crystal cell of FIG. 24, where FIG. 27A is a diagram illustrating a state where no voltage is applied, and FIG. 27B is a diagram illustrating a state where a voltage is applied.

FIG. 28 is an exploded perspective view schematically showing a configuration of a lighting device according to Embodiment 29 of the present invention.
Is a diagram showing a case where a point light emitter is used as a light source, (b) is a diagram showing a case where a linear light emitter is used as a direct type light source,
(c) is a diagram showing a case where a planar light emitter is used as a light source.

FIG. 29 is an exploded perspective view schematically showing a configuration of a lighting device and an image display device according to Embodiment 30 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 illustrating a configuration of a conventional lighting device and an image display device using the same, wherein FIG. 32A is a cross-sectional view, and FIG.
FIG. 3 is a plan view showing a dot pattern of the dispersed liquid crystal element of 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 device.

[Explanation of symbols]

 Reference Signs List 1 liquid crystal display device 25 video signal 31 operation switch 32 brightness distribution setting circuit 33 main memory 34 CPU 35,37 drive signal 36 drive circuit 38 signal processing circuit 41 dot 42 area other than dot 100 lighting device (backlight) 101 illuminant ( (Cold cathode tube) 102 Reflector 103 Light guide plate 103a End face 103b Upper surface 103c Lower surface 104 Dispersed liquid crystal element 105 Reflector (reflective sheet) 106 Liquid crystal display element 107 Scattering control plate 111 Opposite substrate 112 TFT substrate 113 Liquid crystal 114 Scattered dots 121 Semi-transmissive layer 122 Scatterers 123,124 Scattering dots 123a, 124a First scattering dots 123b, 124b Second scattering dots 125 Scattering regions 125a First scattering regions 125b Second scattering regions 126 Scatterers 131 Diffusion sheets 132 Reflective polarizing plates 133,133A, 133B Prism sheet 134 Incident side polarizing plate 135 Liquid crystal display element 136 Outgoing side polarizing plate 137 Incident light 139 Pixel 139a Pixel center plane 141 P polarized light transmittance 142 S polarized light transmittance 145,145A, 145B Edge direction of sheet 146 Polarization axis of entrance-side polarizer 147 Polarization axis of exit-side polarizer 151 Light source 201 Scattering reflector 203 Light guide plate 204 to 208, 210, 211 Unit light guide member 209 Reflective surface 301 Reflective polarizer 302 Polarization modulator 305 Light intensity Modulation structure 401 LED 501 Light emitter 502 Planar light emitter 601 LCD monitor 602 LCD TV 603 Tuner 701 Mixture 702 Mold 702a Concave part 703 Fused acrylic resin 901 Video signal synthesis circuit 1000 Backlight 1001 Light emitter 1002 Reflector 1003 Light guide plate 1004 Scattering Dot 1005 Reflector 1006 Liquid crystal display

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G02F 1/13 505 G02F 1/13 505 2H093 1/133 505 1/133 505 5C006 535 535 5C080 1/1334 1/1334 5G435 1/1335 510 1/1335 510 520 520 1/13357 1/13357 1/13363 1/13363 G09F 9/00 336 G09F 9/00 336H 336J G09G 3/20 612 G09G 3/20 612U 642 642A 642P 680 680T 680V 380V 380V / 34 3/34 J 3/36 3/36 // F21Y 101: 02 F21Y 101: 02 (31) Priority claim number Japanese Patent Application No. 2000-343267 (P2000-343267) (32) Priority date November 10, 2000 (2000.11.10) (33) Priority Country Japan (JP) (72) Inventor Junko Asayama 1006 Oazadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Kazunori Komori Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 2H038 AA55 BA06 2H042 BA02 BA03 BA12 BA15 BA20 2H088 EA22 EA33 GA06 GA10 HA06 HA15 HA23 HA28 HA30 MA06 2H089 HA04 QA16 TA07 TA15 TA17 TA18 2H091 FA08Z FA12Z FA16Z FA23Z FA41Z09 NC11 NC12 NC11 5C006 AF45 AF51 AF52 AF54 BF02 BF15 EA01 FA22 5C080 AA10 DD05 EE28 JJ02 JJ06 KK07 5G435 AA03 BB12 BB15 FF05 FF07 FF08 FF11 GG23 GG24 GG25 GG26 KK07 LL04 LL06

Claims (78)

[Claims] 1. An illumination device comprising: a light source; a light guide plate arranged so that light from the light source is incident from an end face; and a reflection surface formed to face one main surface of the light guide plate. In the above, a constant scattering layer is formed on one main surface of the light guide plate so as to transmit incident light so as to be scattered at a predetermined rate, and the surface of the constant scattering layer changes the incident light according to a distance from the light source. An illumination device, wherein a distributed scattering structure that transmits light so as to be scattered at a constant rate is formed. 2. The lighting device according to claim 1, wherein the constant scattering layer is formed on an entire surface of one main surface of the light guide plate. 3. The lighting device according to claim 1, wherein the distributed scattering structure is a scattering region formed on a surface of the constant scattering layer so that an area ratio changes according to a distance from the light source. 4. The lighting device according to claim 3, wherein the scattering area is a scattering dot formed on a surface of the constant scattering layer. 5. The lighting device according to claim 3, wherein the scattering region is a region in which irregularities on the surface of the constant scattering layer are formed. 6. An illuminating device comprising: a light source; a light guide plate arranged so that light from the light source is incident from an end face; and a reflecting surface formed to face one main surface of the light guide plate. In the above, the light guide plate scatters light propagating inside at a certain rate, and scatters incident light on one main surface of the light guide plate at a rate that varies according to the distance from the light source. An illuminating device comprising a transmission scattering structure formed therein. 7. The lighting device according to claim 6, wherein the scattering effect of the distributed scattering structure is larger than the scattering effect of the light guide plate in the contribution to the amount of light emitted from the other main surface of the light guide plate. 8. The lighting device according to claim 7, wherein the scattering effect of the distributed scattering structure is substantially twice or more the scattering effect of the light guide plate. 9. The lighting device according to claim 6, wherein the distributed scattering structure is a scattering region formed on one main surface of the light guide plate such that an area ratio changes according to a distance from the light source. . 10. The lighting device according to claim 9, wherein the scattering area is a scattering dot. 11. The lighting device according to claim 6, wherein the light guide plate scatters light by a scatterer dispersed in the light guide plate. 12. The distributed scattering structure according to claim 6, wherein the incident light is scattered at a smaller rate as the light is closer to the light source.
The lighting device according to the above. 13. A lighting device comprising: a light source; a light guide plate arranged so that light from the light source is incident from an end face; and a reflecting surface formed to face one main surface of the light guide plate. The lighting device according to claim 1, wherein the light guide plate scatters light propagating inside at a rate that changes according to a distance from the light source. 14. The light guide plate is composed of a plurality of unit light guide members having different scattering ratios, and the plurality of unit light guide members change the scattering ratio of the entire light guide plate according to the distance from the light source. 14. An arrangement according to claim 13, wherein
The lighting device according to the above. 15. The lighting device according to claim 14, wherein the plurality of unit light guide members include members that do not have a scattering function. 16. The lighting device according to claim 14, wherein a joint between the unit light guide members is configured to reflect or scatter incident light. 17. The method according to claim 1, wherein the reflection or scattering is at least one of total reflection, scattering reflection, and scattering transmission.
7. The lighting device according to 6. 18. The lighting device according to claim 14, wherein the plurality of unit light guide members are joined so as to be in a refractive index matching state. 19. The lighting device according to claim 18, wherein the plurality of unit light guide members are joined to each other via a member having a refractive index of about 1.5 so as to be in a refractive index matching state. . 20. The light guide plate, wherein the light is scattered by a scatterer dispersed in the light guide plate, and the scatterer is dispersed at a density that varies according to a distance from the light source. The lighting device according to claim 13. 21. The lighting device according to claim 13, wherein the light guide plate scatters light propagating inside the light guide at a smaller rate as the light is closer to the light source. 22. The lighting device according to claim 6, wherein the plurality of light sources are arranged so as to make each of the outgoing lights enter each of the plurality of end faces of the light guide plate. 23. The lighting device according to claim 11, wherein the scatterer reflects or refracts incident light. 24. The lighting device according to claim 11, wherein the size of the scatterer is substantially larger than the wavelength of visible light. 25. The size of the scatterer is approximately sub-μm or less.
21. The lighting device according to claim 11, which is several mm. 26. The lighting device according to claim 11, wherein the scatterer is made of beads, SiO 2, or bubbles. 27. A lighting device comprising: a light source; a light guide plate arranged so that light from the light source enters from an end face; and a reflecting surface formed to face one main surface of the light guide plate. In the above, a plurality of scattering regions that scatter incident light on one main surface of the light guide plate are formed so that an area ratio changes according to a distance from the light source, and the plurality of scattering regions have different scattering properties from each other. A lighting device comprising a plurality of types. 28. The lighting device according to claim 27, wherein the plurality of types of scattering regions have different scattering properties due to a difference in a material constituting the scattering regions. 29. The plurality of types of scattering regions are formed by dispersing a scatterer having a different refractive index from the substrate in a substrate that transmits incident light, and the scattering properties are different due to the difference in the dispersion density of the scatterers. 28. The lighting device according to claim 27, which is different. 30. An image display device comprising the lighting device according to claim 1, wherein light emitted from the lighting device is used as light for image display. 31. A method of manufacturing a light guide plate in which scatterers that scatter incident light are dispersed in a transparent substrate, wherein the scatterers are dispersed in the substrate so that the density varies depending on a portion. A method of manufacturing a light guide plate. 32. A step of heating and melting the base material, mixing the scatterer into the melted base material, and holding the molten base material in a plate-like shape. The method of manufacturing a light guide plate according to claim 31, further comprising the steps of: 33. The method for manufacturing a light guide plate according to claim 31, wherein the air bubbles as the scatterers are generated in the base so that the density varies depending on the site. 34. The method for manufacturing a light guide plate according to claim 33, wherein the bubbles are generated using a foaming agent. 35. An illumination device comprising a light source and a light exit surface from which light from the light source exits, comprising: a luminance distribution changing unit for changing a luminance distribution of the light exit surface. apparatus. 36. A light guide plate for guiding light from the light source to the light exit surface, wherein the luminance distribution changing means changes a distribution of a scattering ratio of light guided by the light guide plate as viewed from the light exit surface. 36. The lighting device according to claim 35, comprising a scattering ratio distribution changing means for changing. 37. The light guide plate is arranged so that light from the light source is incident from an end surface, and a reflection surface is formed so that light emitted from one main surface of the light guide plate returns to the one main surface. By doing so, the other main surface of the light guide plate constitutes the light exit surface, and between the one main surface of the light guide plate and the reflection surface, is parallel to the light exit surface of incident light. 37. The lighting device according to claim 36, wherein a light dispersion structure for changing the distribution of the scattering ratio in the plane is provided as the scattering ratio distribution changing means. 38. The light dispersion structure is disposed between one main surface of the light guide plate and the reflection surface so as to transmit or scatter incident light depending on a position in a plane where the liquid crystal extends. 38. The lighting device according to claim 37, further comprising: a liquid crystal element capable of switching the orientation of the liquid crystal; and control means for switching the orientation of the liquid crystal of the liquid crystal element according to the position. 39. The light dispersion structure comprises:
39. The lighting device according to claim 38, wherein the region that scatters the incident light is generated such that the area ratio of the region changes according to the distance from the light source. 40. The lighting device according to claim 38, wherein the liquid crystal of the liquid crystal element includes a polymer dispersed liquid crystal. 41. The light guide plate is arranged so that light from the light source enters from an end face, and a reflection surface is formed so that light emitted from one main face of the light guide plate returns to the one main face. As a result, the other main surface of the light guide plate constitutes the light emission surface, and the scattering ratio distribution changing means is formed so as to be distributed on the one main surface of the light guide plate by the first scattering. A region, a scattering control structure that scatters or transmits light passing between one main surface of the light guide plate and the reflection surface by switching, and a second scattering region formed so as to be distributed on the reflection surface. 37. The lighting device according to claim 36, comprising: 42. The brightness distribution changing means comprises a light intensity distribution changing means for changing a light intensity distribution of light traveling toward the light emission surface in the light emission surface.
The lighting device according to the above. 43. The light intensity distribution changing means according to claim 42, wherein the light intensity distribution changing means changes the light intensity distribution by transmitting or reflecting the light according to a position in a plane parallel to the light emitting surface. Lighting equipment. 44. The brightness distribution changing means for changing a brightness distribution on a light emitting surface of a light source.
The lighting device according to claim 5. 45. The light source comprises a plurality of light emitters,
5. The brightness distribution changing means changes the amount of light emitted from each light emitter according to the arrangement position of each light emitter.
5. The lighting device according to 4. 46. The lighting device according to claim 45, wherein the brightness distribution changing means changes the amount of light emitted from each of the light emitters by changing power supplied to each of the light emitters. 47. The lighting device according to claim 45, wherein the luminous body is constituted by an LED. 48. The lighting device according to claim 44, wherein the light source is formed of a surface light emitter, and the luminance distribution changing means changes a luminance distribution on a light emitting surface of the surface light emitter. 49. An illuminating device including a light source and a light exit surface from which light from the light source exits, wherein the light source is composed of a plurality of luminous bodies, and the plurality of luminous bodies change in density. A lighting device characterized by being disposed in a lighting device. 50. The lighting device according to claim 49, wherein said illuminant is constituted by an LED. 51. A lighting device, a liquid crystal display element for displaying an image by transmitting light emitted from the lighting device to a liquid crystal layer forming a display screen while changing transmittance, and a transmission of the liquid crystal display device An image display device comprising: a driving unit that changes a rate so as to display an image according to a video signal. The lighting device includes: a light source; a light exit surface from which light from the light source exits; and the light exit surface. And a luminance distribution changing means for changing the luminance distribution of the image display. 52. The luminance distribution changing means, comprising: a luminance distribution setting means capable of setting a luminance distribution of the plurality of light exit surfaces;
52. The image display device according to claim 51, further comprising: selection means for selecting the luminance distribution of the set plurality of light exit surfaces. 53. The image display device according to claim 52, wherein said brightness distribution changing means changes the brightness distribution of said light exit surface in accordance with said video signal. 54. The brightness distribution changing means obtains an overview brightness distribution of a screen of the video signal, and changes the brightness distribution of the light emitting surface according to the obtained overview brightness distribution. 52. The image display device according to 52. 55. The brightness distribution changing means for obtaining a brightness histogram of pixels of the video signal, and changing the brightness distribution of the light emitting surface based on the obtained histogram. Image display device. 56. A lighting device, a liquid crystal display element for displaying an image by transmitting light emitted from the lighting device to a liquid crystal layer forming a display screen while changing transmittance, and a transmission of the liquid crystal display device An image display device comprising: a driving unit that changes a rate so as to display an image according to a video signal. The lighting device includes: a light source; a light exit surface from which light from the light source exits; and the light exit surface. And a luminance distribution changing means for changing a luminance distribution of the input image signal so as to display an image corresponding to the plurality of image signals in a plurality of regions in one screen. An image display device comprising a video signal synthesizing means for synthesizing and inputting the synthesized signal as the video signal to the driving means. 57. A lighting device, a liquid crystal display element for displaying an image by transmitting light emitted from the lighting device to a liquid crystal layer forming a display screen while changing transmittance, and a transmission of the liquid crystal display device An image display device comprising: a driving unit that changes a rate so as to display an image according to a video signal, wherein the illumination device has a light source and a light exit surface from which light from the light source exits. An image display device, wherein a light source is constituted by a plurality of light emitters, and the plurality of light emitters are arranged so as to change in density. 58. An illumination device comprising a light source and a light condensing means for condensing light emitted from the light source, wherein the light emitted from the light source is polarized so as to be P-polarized light, and the light is condensed. An illuminating device comprising a polarizing means for entering the light. 59. The illuminating device according to claim 58, wherein said condensing means comprises a prism sheet. 60. The lighting device according to claim 58, wherein said polarizing means comprises a reflective polarizing plate. 61. The reflection type polarizing plate has a multilayer structure including a plurality of films having different refractive indexes from each other.
0. The lighting device according to 0. 62. The lighting device according to claim 60, wherein the reflective polarizing plate comprises a cholesteric liquid crystal. 63. The lighting device according to claim 60, wherein a phase plate is provided in front of said reflective polarizing plate. 64. The lighting device according to claim 58, wherein the light source includes a plurality of point light emitters. 65. The lighting device according to claim 58, wherein the light source comprises a linear illuminant. 66. The lighting device according to claim 58, wherein the light source comprises a planar light emitter. 67. The lighting device according to claim 58, wherein the light source includes a combination of a plurality of point light emitters, linear light emitters, and planar light emitters. 68. An image display device using light emitted from a lighting device as light for image display, wherein the lighting device emits light from a light source, light collecting means for collecting incident light, and light emitted from the light source. An image display device comprising: a polarizing means for polarizing light to P-polarized light so as to be incident on the light collecting means. 69. A polarization axis of the incident-side polarizing plate and an exit-side polarizing plate, comprising: an incident-side polarizing plate, a liquid crystal cell, and an exit-side polarizing plate which are sequentially arranged on an optical path of light emitted from the condensing unit. 70. The image display device according to claim 68, wherein the polarization axes are substantially parallel and substantially perpendicular to the polarization axis of the P polarized light, respectively. 70. The image display device according to claim 69, wherein the polarization axis of the P-polarized light is set to be inclined at approximately 45 degrees with respect to the longitudinal direction of the display screen of the liquid crystal cell. 71. A pair of the light condensing means are provided so that directions perpendicular to surfaces including the respective light condensing directions are perpendicular to each other, and one of the light condensing means is perpendicular to a surface including the light condensing direction. 71. The image display device according to claim 70, wherein a direction is substantially parallel to a polarization axis of the incident side polarizing plate. 72. The image display according to claim 71, wherein a direction perpendicular to a plane including the light collecting direction of the light collecting means closer to the incident side polarizing plate is substantially parallel to a polarization axis of the incident side polarizing plate. apparatus. 73. The image according to claim 69, wherein the liquid crystal in a region constituting each pixel or picture element of the liquid crystal cell is oriented in different directions from each other on a plane substantially perpendicular to the substrate of the liquid crystal cell. Display device. 74. The image display device according to claim 72, wherein the liquid crystal is oriented substantially symmetrically with respect to the plane. 75. A polarization axis of the P-polarized light is set substantially perpendicular to a longitudinal direction of a display screen of the liquid crystal cell.
3. The image display device according to 3. A liquid crystal monitor using the image display device according to any one of claims 51, 56, and 57 as a display unit. A liquid crystal television using the image display device according to any one of claims 51, 56, and 57 as a display unit. A liquid crystal information terminal using the image display device according to any one of claims 51, 56, and 57 as a display unit.