JP2005228535A - Planar light source device and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar light source device and a liquid crystal display that suppress unevenness in luminance and in color in the vicinity of the sidelight of an opening, while enhancing the luminance at the center of the opening, in a direction along the sidelight without a light guide plate higher than the luminance at ends. <P>SOLUTION: The devices comprises a diffuser sheet 2 provided in the opening 11 of a case 1, a reflector 5 provided by sandwiching a hollow region B1 in the case 1 between the diffuser sheet 2 and the reflector 5, a sidelight section 13 consisting of a plurality of point sources of light 3 arranged in the case 1 along the hollow region B1, and an deflection angle element 6 for deflecting the light from the point sources of light 3 to the reflector 5 to emit the light to the hollow region B1. It is configured so that the arrangement density of the point sources of light 3 at the center of the sidelight 13 becomes higher than those at the ends. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a planar light source device and a liquid crystal display device, and more specifically, diffuses light from a point light source disposed along a hollow region in the hollow region, and diffuses the diffused light to the back surface of the liquid crystal panel. The present invention relates to an improvement in a side light type planar light source device for irradiation.

  A planar light source device that illuminates the display screen from the back side by irradiating light on the back of the liquid crystal panel includes a side light type (also called an edge light type) in which the light source is arranged on the side of the housing, and a light source. There is a direct type that is disposed on the back of the casing so as to face the liquid crystal panel. Further, some side light type planar light source devices use a light guide plate to guide light from the light source to the opening of the housing. The planar light source device using this light guide plate is a light emitted from a sidelight unit composed of a linear light source such as a cold cathode fluorescent lamp (CCFL) or a point light source such as a light emitting diode (LED). Is reflected in the light guide plate and diffused by a diffusion pattern provided in the light guide plate, thereby extracting light in a planar shape from the opening.

  In general, in a display device such as a television monitor or a personal computer monitor, it is preferable that the brightness at the central portion of the display screen is brighter than the peripheral portion with respect to the screen display because it gives a natural impression to the user. For this reason, in the planar light source device used for these monitors, many products have a configuration in which the luminance at the central portion of the opening is higher than the luminance at the peripheral portion.

  In the planar light source device using the light guide plate described above, a desired luminance distribution is obtained by adjusting the diffusion pattern to be applied to the light guide plate. In particular, in a planar light source device in which the sidelight part is composed of a large number of point light sources, by adjusting the spacing in the arrangement direction of these point light sources, the luminance of the central part in the arrangement direction of the openings is set to be higher than the luminance at the end part. Increasing the height is performed (for example, Patent Document 1). However, in such a conventional planar light source device, since a heavy light guide plate is used, it is difficult to reduce the weight of the device, and if the device is to be enlarged, the molding machine for forming the light guide plate must be enlarged. Therefore, there is a problem that it is not easy to increase the size of the apparatus in terms of manufacturing cost.

  Thus, a sidelight type planar light source device that does not use a light guide plate has been proposed. This planar light source device can extract light in a planar shape from the opening by reflecting the light emitted from the sidelight part with a reflector arranged on the back surface of the hollow region in the housing. However, in such a conventional planar light source device, the intensity of the light emitted from the sidelight part with respect to the hollow region is the same at the center part and the end part of the sidelight part. It was not easy to make the luminance at the center of the opening portion higher than the luminance at the end with respect to the direction.

In the case of a planar light source device in which the sidelight part is composed of a large number of point light sources, it is considered that the luminance distribution in the arrangement direction of the apertures becomes a desired one by adjusting the spacing in the arrangement direction of the point light sources It is done. However, if the interval between the point light sources is adjusted, the arrangement of the point light sources will become coarse and dense, and the light intensity in the rough portion will be reduced. There was a problem. That is, since the interval in the arrangement direction of the point light sources is large in the rough portion, there is a problem that local luminance unevenness in the vicinity of the side light portion of the opening is likely to occur, and the display quality is deteriorated. Further, when three color point light sources are arranged, there is a problem that color unevenness easily occurs in a portion where the arrangement density of the point light sources is coarse.
JP 2002-75038 A

  As described above, in a conventional side light type planar light source device that does not use a light guide plate, it is not easy to make the luminance at the center of the opening portion higher than the luminance at the end in the direction along the side light portion. There was a problem. In particular, if an attempt is made to achieve a desired luminance distribution of the apertures in the arrangement direction of the point light sources by adjusting the interval between the point light sources, luminance unevenness and color unevenness in the arrangement direction with respect to the rough portion of the sidelight portion. There was a problem that would stand out.

  The present invention has been made in view of the above circumstances, and a sidelight type planar light source device capable of making the luminance at the center of the opening higher than the luminance at the periphery without using a light guide plate, and An object is to provide a liquid crystal display device. In particular, with respect to the direction along the sidelight portion, the luminance at the center portion of the opening can be made higher than the luminance at the end portion, and luminance unevenness and color unevenness in the vicinity of the sidelight portion of the opening can be suppressed. It aims at providing the planar light source device which can be performed.

  The planar light source device according to the present invention is disposed in the casing along the hollow region, the diffusion plate provided in the opening of the casing, the reflection plate provided across the hollow region in the casing with respect to the diffusion plate. A sidelight unit composed of a plurality of point light sources, and a declination element that refracts light from the point light source toward the reflector and emits the light to the hollow region. It is comprised so that it may mutually differ in the center part and edge part of a part.

  Since the arrangement density of point light sources, for example, the intervals in the arrangement direction are different from each other at the central part and the end part of the sidelight part, the intensity of light emitted from the sidelight part is different between the central part and the end part of the sidelight part. The brightness at the opening can be made different at the center and at the end with respect to the direction along the sidelight part. At that time, the light from the point light source is refracted to the reflecting plate side by the declination element and emitted to the hollow region, thereby increasing the amount of light reflected by the reflecting plate and propagating in the hollow region. The propagation path of light to be transmitted is lengthened. Accordingly, it is possible to obtain a desired luminance distribution in the opening with respect to the direction along the sidelight part, and it is possible to sufficiently reflect and diffuse the light from the sidelight part in the hollow region and take it out from the opening. It is possible to suppress occurrence of luminance unevenness and color unevenness in the direction along the sidelight portion in the vicinity of the sidelight portion of the opening.

  In particular, if the arrangement density of the point light sources in the central part of the sidelight part is higher than the arrangement density in the end part, the luminance at the central part of the opening in the direction along the sidelight part is higher than the luminance at the end part. Since it can be made high, it is preferable. Further, the declination element refracts light of an incident angle having the maximum intensity out of light incident on the incident surface of the declination element, and more preferably emits the light toward the reflection plate. In this case, incident light from the point light source can be effectively directed to the reflecting plate, which is preferable for eliminating luminance unevenness and color unevenness in the vicinity of the side light portion of the opening.

  In addition to the above configuration, the planar light source device according to the present invention is configured such that the surface of the deflection element facing the reflection plate is inclined so as to move away from the opening as it moves away from the incident surface. According to such a configuration, the surface facing the reflecting plate moves away from the opening as it moves away from the incident surface, that is, is inclined to the back side, so that the light incident on the incident surface faces the reflecting plate. The light reflected by the surface to be directed can be directed to the back side rather than the one having no inclination. For this reason, since it can suppress effectively that the brightness | luminance of the side light part vicinity in an opening part becomes high too much, a desired luminance distribution can be obtained regarding the direction perpendicular | vertical to a side light part.

  In addition to the above configuration, the planar light source device according to the present invention includes a light diffusing unit that is provided on a surface of the declination element facing the reflector and diffuses incident light from the point light source in the arrangement direction. Composed. According to such a configuration, the light reflected from the surface facing the reflector out of the light incident from the incident surface is diffused in the point light source arrangement direction by the light diffusing means. In addition, color unevenness can be effectively suppressed. As the light diffusing means, there can be considered one comprising a plurality of grooves formed in a direction away from the incident surface of the deflection element.

  A liquid crystal display device according to the present invention is a liquid crystal display device including a liquid crystal panel and a planar light source device that irradiates light on the back surface of the liquid crystal panel, and the planar light source device is provided in an opening of a housing. A diffusion plate provided; a reflector provided across the diffusion plate with a hollow region in the housing interposed therebetween; a sidelight unit including a plurality of point light sources disposed in the housing along the hollow region; It consists of a declination element that refracts light from the light source toward the reflector and emits it to the hollow region, and is configured such that the arrangement density of the point light sources is different from each other at the center part and the end part of the sidelight part. .

  According to the planar light source device and the liquid crystal display device according to the present invention, the arrangement density of the point light sources is different from each other at the central portion and the end portion of the sidelight portion. The center part and the end part can be made different from each other, and the light from the point light source is refracted and emitted to the reflector side by the declination element, so that the light from the side light part is sufficiently propagated in the hollow region, It can be diffused and taken out from the opening. Accordingly, it is possible to suppress the occurrence of luminance unevenness in the direction along the sidelight portion in the vicinity of the sidelight portion of the opening portion, and the luminance at the central portion of the opening portion can be reduced without using the light guide plate. The display quality can be improved. In particular, the luminance at the center can be made higher than the luminance at the end with respect to the direction along the sidelight portion, so that a desired luminance distribution can be obtained at the opening. Further, when three color point light sources are arranged, the occurrence of color unevenness can be suppressed.

Embodiment 1 FIG.
1 and 2 are diagrams showing an example of a schematic configuration of a planar light source device according to Embodiment 1 of the present invention. FIG. 1 is a plan view, and FIG. A cross-sectional view along the line AA is shown. The planar light source device 10 according to the present embodiment is a light source device that can extract planar illumination light having a desired luminance distribution from the opening 11 on the front surface of the housing 1, and in the central portion of the sidelight unit 13. The arrangement density of the point light sources 3 is set higher than the arrangement density at the end. The surface light source device 10 is not particularly limited in use, but is suitable for illuminating the display screen from the back surface by irradiating the back surface of a liquid crystal panel (not shown). That is, if a transmissive liquid crystal panel is attached to the front surface of the planar light source device 10, a liquid crystal display device can be configured.

  The planar light source device 10 includes a housing 1, a diffusion plate 2, a point light source 3, a substrate 4, a reflection plate 5, a deflection element 6, and a reflector 12. An opening 11 is provided on the front surface of the housing 1, and a hollow region B <b> 1 is formed in the housing 1. The housing 1 prevents light from leaking from other than the opening 11.

  The diffusing plate 2 is a diffusing unit provided in the opening 11 and suppresses luminance unevenness and color unevenness in the opening surface of the opening 11. The diffusing plate 2 is made of a translucent member such as transparent resin or glass, and is formed by mixing a reflective material in the translucent member or roughening the surface of the member.

  The point light source 3 includes a light emitting diode (LED) that generates light of a single color such as red, green, or blue. For example, the point light source 3 is formed by sealing an LED element that is a light emitting unit with a lens-shaped transparent resin. . A plurality of point light sources 3 are mounted on the substrate 4 and driven by a drive circuit (not shown). Here, each point light source 3 on the board | substrate 4 shall be arrange | positioned in a line along the board | substrate 4, and the linear point light source row | line | column is formed. The point light sources 3 of each color are arranged in the number and arrangement order according to the target luminance and chromaticity. For example, when obtaining white light as irradiation light, the adjacent point light sources 3 have different colors. Arranged to generate light. The planar light source device 10 may use an LED that generates white light as the point light source 3 instead of using red, green, and blue LEDs.

  The arrangement density of the point light source arrays is different between the central portion and the end portion of the substrate 4. Here, in order to make the brightness in the central portion of the display screen brighter than the peripheral portion, the arrangement density in the central portion of the substrate 4. Is higher than the arrangement density at the end. That is, the intervals in the arrangement direction of the point light sources 3 are dense at the center of the point light source array. It is assumed that the arrangement density of the point light sources 3, that is, the interval in the arrangement direction, gradually changes from the end to the center of the point light source array.

  The substrate 4 (light source unit) on which such a point light source array is formed is attached to both sides of the housing 1, for example. Each light source unit is attached to the bottom surface 1a of the housing 1 along the side surface 1b of the housing 1, and the point light source 3 mounting surface of the substrate 4 faces the front surface side (positive direction in the Z-axis direction). That is, each point light source 3 is arrange | positioned in the housing | casing along hollow area | region B1. Here, the arrangement direction of the point light sources 3 is the X-axis direction, and the direction perpendicular to the X-axis direction is the Y-axis direction. In addition, the front side of the housing 1, that is, the liquid crystal panel mounting surface side is set to a positive direction in the Z-axis direction. In addition, the planar light source device 10 may be attached to the side surface 1b of the housing 1 instead of attaching each light source unit to the bottom surface of the housing.

  The reflecting plate 5 is a reflecting means that reflects light, and is made of a metal plate such as aluminum or silver. The reflecting plate 5 is provided on the bottom surface 1 a of the housing 1 so as to face the opening 11. That is, the reflection plate 5 is attached to the diffusion plate 2 with the hollow region B1 in the housing interposed therebetween. Further, the reflecting plate 5 protrudes toward the front side in the central portion of the housing 1 in order to make the luminance of the central portion in the opening portion 11 higher than the luminance in the end portion with respect to the Y-axis direction. As a result, the light from the sidelight part 13 is reflected more at the central part of the housing 1 than at the end part, so that the luminance at the central part in the opening 11 in the Y-axis direction is made higher than the luminance at the end part. And a desired luminance distribution is obtained. In addition, the reflecting plate 5 is arrange | positioned also at the side surface of the housing | casing 1 in which the light source unit is not arrange | positioned. Further, the planar light source device 10 may use a member obtained by vapor-depositing a metal such as aluminum or silver on a resin sheet as the reflection plate 5 instead of using a metal plate. Furthermore, a member having a diffuse reflection function such as a white resin sheet may be used as the reflection plate 5, or the reflection plate 5 may be configured from a plurality of members having different reflection characteristics.

  The reflector 12 is a reflecting means for reflecting light from the point light source 3 toward the hollow region B1, and is a metal plate on which a reflective layer made of metal such as silver or aluminum is formed, or a member made of a white resin sheet. Is used. The reflector 12 is disposed so as to wrap around the light emitting part of the point light source array. Here, the side light part 13 shall be formed from the light source unit and the reflector 12. That is, the light from the side light portions 13 disposed on both sides of the housing 1 is emitted to the hollow region B1, and a part of the light is reflected by the reflecting plate 5 and propagates in the hollow region B1. The light propagated in the hollow region B1 is diffused by the diffusion plate 2 and emitted to the front side.

  The planar light source device 10 may be integrally formed using the same member instead of forming the reflector 5 and the reflector 12 with different members. If comprised in this way, since a number of parts (number of members) can be decreased, a manufacturing cost can be reduced and an assembly operation can be simplified. In addition, if the inner surface of the housing is configured to also serve as the reflecting plate 5 and the reflector 12, the number of parts can be further reduced.

  The deflection element 6 is an optical element that refracts the light from the point light source 3 toward the reflection plate 5 and emits the light to the hollow region B1, and is made of a transparent resin such as acrylic or a member such as glass. For example, a prism-shaped column having a pentagonal cross section can be used as the deflection element 6. The deflection element 6 is disposed between the point light source 3 and the hollow region B1 along the arrangement direction of the point light sources 3. By using such a declination element 6, the amount of light reflected by the reflector 5 increases, and the propagation path of light propagating in the hollow region B1 becomes long, so that a good diffusion effect can be obtained. In the opening 11, it is possible to prevent the vicinity of the sidelight part 13 from becoming too bright, and to suppress luminance unevenness in the vicinity of the end of the sidelight part 13 in the opening 11 in the arrangement direction of the point light sources 3. . That is, the decrease in the light intensity in the rough portion in the array of the point light sources 3 can be mitigated by the diffusion effect in the array direction by the deflection element 6, so that uneven brightness in the array direction can be prevented. .

  The planar light source device 10 may have various optical sheets on the diffusion plate 2. For example, a combination of a lens sheet, a diffusion sheet, a protective sheet, and a polarizing sheet can be used as the optical sheet.

  FIG. 3 is a perspective view showing an example of the details of the main part of the planar light source device of FIGS. 1 and 2, and shows a light source unit 21 including a large number of point light sources 3. The point light sources 3 mounted on the substrate 4 have a denser interval at the center than in the ends in the arrangement direction, that is, the longitudinal direction of the substrate 4. That is, the distance between the point light sources 3 in the arrangement direction is rough at the end. By arranging such a light source unit 21 along the side surface of the housing 1, a desired luminance distribution can be obtained with respect to the arrangement direction.

  FIG. 4 is a diagram illustrating an example of an LED array of each color in the light source unit of FIG. On the substrate 4, a point light source 3 composed of LEDs of each color is arranged in a predetermined arrangement order. For example, when 13 point light sources 3 are arranged, the red point light source 3r is R, the green point light source 3g is G, the blue point light source 3b is B, and G, B, G, R, G, B, G, B, G, R, G, B, G are arranged in this order. In this way, when the interval between the central portions in the arrangement direction of the point light sources 3 is made smaller than the interval between the end portions, the interval for each color also becomes dense in the central portion, so that a desired chromaticity distribution in the arrangement direction is obtained. Can be obtained.

  FIG. 5 is a side view showing an example of the details of the main part of the planar light source device of FIGS. 1 and 2, and light having an incident angle θ having the maximum intensity is incident on the incident surface 22 of the deflection element 6. The state is shown. The deflection element 6 has an incident surface 22 on which light from the point light source 3 is incident, a bottom surface 24 facing the bottom surface 1a of the housing 1, and an exit surface 23 from which refracted light is emitted.

  The incident surface 22 is inclined toward the hollow region B1 as it moves away from the bottom surface 24. The exit surface 23 is inclined toward the point light source 3 as it is farther from the bottom surface 24. Incident light from the point light source 3 is refracted toward the reflecting plate 5 disposed on the bottom surface 1 a of the housing 1, that is, toward the bottom surface 24, and is emitted from the emission surface 23. Further, since the incident surface 22 is inclined toward the hollow region B1 as the distance from the bottom surface 24 increases, the ratio of the light from the point light source 3 reflected on the surface of the incident surface 22 increases, and the vicinity of the side light portion 13 of the opening 11 is increased. The light emitted to the light can be suppressed, and the luminance unevenness and color unevenness can be effectively eliminated. In particular, the deflection element 6 refracts light having an incident angle θ that maximizes the intensity of light incident on the incident surface 22 toward the bottom surface 24, and more preferably emits the light toward the bottom surface 24. By configuring in this way, the incident light from the point light source 3 can be effectively directed to the reflecting plate 5, so that luminance unevenness and color unevenness in the vicinity of the sidelight portion 13 of the opening 11 can be more effectively prevented. Can be resolved.

  6A and 6B are diagrams showing the luminance distribution in the planar light source device of FIGS. 1 and 2, and FIG. 6A shows the central portion of the opening 11 in the X-axis direction. FIG. 6B shows a state in which the luminance is higher than the luminance at the end, and FIG. 6B shows a state in which the luminance at the center of the opening 11 is higher than the luminance at the end in the Y-axis direction. It is shown. By adjusting the interval in the arrangement direction of the point light sources 3, a desired luminance distribution can be obtained in the arrangement direction of the openings 11, that is, the X-axis direction. In particular, the luminance at the central portion can be made higher than the luminance at the end portions by arranging the central portion densely. Further, by adjusting the shape of the reflecting plate 5 in the Y-axis direction, a desired luminance distribution in the Y-axis direction can be obtained. In particular, by projecting the central portion of the reflecting plate 5 in the Y-axis direction, the luminance at the central portion of the opening 11 can be made higher than the luminance at the end portion.

  According to the present embodiment, the luminance of the central portion of the opening 11 in the direction along the sidelight portion 13 can be made higher than the luminance at the end portion, and the light is emitted from the sidelight portion 13 to the hollow region B1. Since a part of the light to be refracted by the deflection element 6 toward the reflecting plate 5, the light from the side light part 13 can be sufficiently reflected and diffused in the hollow region B 1 and taken out from the opening part 11. Therefore, it is possible to obtain a desired luminance distribution with respect to the arrangement direction of the point light sources 3 and to suppress occurrence of luminance unevenness and color unevenness in the vicinity of the side light portion 13 of the opening 11.

  In the present embodiment, an example in which the deflection element 6 with nothing formed on the bottom surface is used has been described, but the present invention is not limited to this. For example, in order to more effectively diffuse the light from the point light source 3 in the arrangement direction, a light diffusion means for diffusing the light in the arrangement direction of the point light source 3 may be provided on the bottom surface.

  FIG. 7 is a diagram showing another example of the planar light source device according to the first embodiment of the present invention, and is a planar light source having a deflection element 6 in which a plurality of grooves 31 in the Y-axis direction are provided on the bottom surface. A cross section of the device is shown. A plurality of grooves 31 are formed on the bottom surface of the deflection element 6 as light diffusing means in the Y-axis direction, that is, in the direction from the point light source 3 toward the hollow region.

  FIGS. 8A and 8B are diagrams showing an example of a deflection element in the planar light source device of FIG. 7, and FIG. 8A shows a side shape of the deflection element 6. FIG. 8B shows a state where the deflection element 6 is viewed from the exit surface side. The grooves 31 are uniformly provided in the arrangement direction. By providing such a groove 31, light reflected from the bottom surface among the light incident from the incident surface of the deflection element 6 is diffused by the groove 31 in the arrangement direction of the point light sources 3. Brightness unevenness and color unevenness can be effectively suppressed. Therefore, it is possible to effectively prevent the luminance unevenness and the color unevenness from being conspicuous in the vicinity of the opening 11 in the portion where the arrangement density of the point light sources 3 is coarse.

  FIG. 9 is a diagram showing another example of the deflection element in the planar light source device of FIG. 7, and shows the deflection element 6 provided with grooves 31 a so as to face each point light source 3. In this declination element 6, each groove 31 a on the bottom surface is formed at a position facing the point light source 3. That is, the interval of the grooves 31a at the central portion in the longitudinal direction of the deflection element 6 is closer than at the end portion. This is preferable because only the light propagating from the point light source 3 toward the hollow region can be diffused in the arrangement direction by the grooves 31a.

  As the light diffusing means, in addition to the above, a white diffuse reflector may be attached to the bottom surface of the deflection element 6 or the bottom surface of the deflection element 6 may be roughened.

Embodiment 2. FIG.
In the first embodiment, an example in which the bottom surface of the deflection element 6 faces the bottom surface of the housing has been described. On the other hand, in this embodiment, a case will be described in which the bottom surface is inclined so as to move away from the opening 11 as it moves away from the incident surface.

  FIG. 10 is a cross-sectional view showing an example of a planar light source device according to Embodiment 2 of the present invention. In the planar light source device according to the present embodiment, the bottom surface (surface facing the reflection plate 5) 32 of the deflection element 6 is provided so as to be inclined toward the back surface side (negative direction in the Z-axis direction). That is, the bottom surface 32 of the deflection element 6 is inclined so as to move away from the opening 11 as it moves away from the incident surface.

  FIGS. 11A and 11B are diagrams showing a state in which light from a point light source is emitted to a hollow region in the planar light source device of FIG. 10 in comparison with the planar light source device of FIG. FIG. 11A shows a planar light source device (this embodiment) in which the light 33 reflected by the bottom surface 32 is refracted to the reflecting plate 5 side, and FIG. 11B shows the bottom surface. 1 shows a planar light source device (Embodiment 1) in which the light 34 reflected by the light is refracted toward the opening 11 side.

  In the present embodiment, since the bottom surface 32 is inclined, out of the light incident on the incident surface of the deflection element 6 from the point light source 3, the light 33 reflected by the bottom surface 32 can be refracted to the reflecting plate 5 side. it can. For this reason, it is possible to prevent the light 33 reflected by the bottom surface 32 from being emitted toward the vicinity of the sidelight part 13 of the opening 11. On the other hand, in Embodiment 1, since the bottom surface of the deflection element 6 is parallel to the bottom surface of the housing, the light 34 reflected by the bottom surface of the deflection element 6 is directed to the opening 11 side, that is, the front surface side. The light is refracted and emitted toward the opening 11. For this reason, the side light part 13 vicinity of the opening part 11 will become too bright.

  According to the present embodiment, the light 33 reflected from the bottom surface 32 of the deflection element 6 out of the incident light from the point light source 3 can be appropriately emitted to the hollow region, and thus the sidelight part 13 of the opening 11. It is possible to prevent the vicinity from becoming too bright. Further, since the luminance in the vicinity of the side light portion 13 of the opening 11 is reduced, it is effective for eliminating luminance unevenness and color unevenness related to the arrangement direction of the point light sources 3.

It is the figure which showed an example of schematic structure in the planar light source device by Embodiment 1 of this invention. It is the figure which showed an example of schematic structure in the planar light source device by Embodiment 1 of this invention. It is the perspective view which showed an example of the principal part detail in the planar light source device of FIG.1 and FIG.2. It is the figure which showed an example of the LED arrangement | sequence of each color in the light source unit of FIG. It is the side view which showed an example of the principal part detail in the planar light source device of FIG.1 and FIG.2. It is the figure which showed the luminance distribution in the planar light source device of FIG.1 and FIG.2. It is the figure which showed the other example of the planar light source device by Embodiment 1 of this invention. It is the figure which showed an example of the deflection | deviation element in the planar light source device of FIG. It is the figure which showed the other example of the deflection | deviation element in the planar light source device of FIG. It is sectional drawing which showed an example of the planar light source device by Embodiment 2 of this invention. It is the figure which showed a mode that the light from a point light source was radiate | emitted to a hollow area | region in the planar light source device of FIG. 10 compared with the case of the planar light source device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case 1a Bottom face 1b Side surface 2 Case 2 Diffuser 3 Point light source 4 Substrate 5 Reflector 6 Deflector 10 Planar light source device 11 Opening 12 Reflector 13 Sidelight 21 Light source unit 31, 31a Groove 32 Bottom surface B1 hollow area of deflection element

Claims (10)

A diffusion plate provided in an opening of the housing;
A reflector provided across the hollow region in the housing with respect to the diffusion plate;
A sidelight part composed of a plurality of point light sources arranged in the housing along the hollow region;
A deflection element that refracts light from the point light source toward the reflector and emits the light to the hollow region;
The planar light source device, wherein the arrangement density of the point light sources is different from each other at the central portion and the end portion of the sidelight portion.   The planar light source device according to claim 1, wherein the arrangement density in the central portion is higher than the arrangement density in the end portion.   The planar light source device according to claim 1, wherein the deflection element refracts light having an incident angle having the maximum intensity among light incident on the incident surface toward the reflector.   2. The planar light source device according to claim 1, wherein the deflection element emits light of an incident angle having a maximum intensity among light incident on an incident surface toward a reflecting plate.   2. The planar light source device according to claim 1, wherein a surface of the deflection element facing the reflection plate is inclined so as to move away from the opening as it moves away from the incident surface.   2. The planar light source device according to claim 1, further comprising: a light diffusing unit that is provided on a surface of the deflection element facing the reflector and diffuses incident light from the point light source in an arrangement direction.   7. The planar light source device according to claim 6, wherein the light diffusing means comprises a plurality of grooves formed in a direction away from the incident surface of the deflection element.   2. The planar light source device according to claim 1, wherein each of the point light sources includes a light emitting diode that generates red, green, or blue light.   2. The planar light source device according to claim 1, wherein each of the point light sources includes a light emitting diode that generates white light. In a liquid crystal display device comprising a liquid crystal panel and a planar light source device for irradiating light on the back of the liquid crystal panel,
The planar light source device includes a diffusion plate provided at an opening of a housing;
A reflector provided across the hollow region in the housing with respect to the diffusion plate;
A sidelight part composed of a plurality of point light sources arranged in the housing along the hollow region;
It consists of a deflection element that refracts light from the point light source toward the reflector and emits it to the hollow region,
2. A liquid crystal display device according to claim 1, wherein the arrangement density of the point light sources is different between the central portion and the end portion of the sidelight portion.

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