SURFACE LIGHT SOURCE DEVICE AND DISPLAY DEVICE USING SAME

Abstract

The present invention provides a surface light source device capable of reducing luminance non-uniformity near point light sources and near between the point light sources adjacent to each other, and a display device of high display quality. The surface light source device includes: a plurality of LEDs arranged at a predetermined spacing; a light guide plate that emits, as a surface light, light emitted from the point light sources and entered into at least one side surface, through a light emission surface perpendicular to a light incident surface; reflecting sheets disposed respectively on a light anti-emission surface and near the LEDs in the light guide plate; and a casing having an opening part at a location corresponding to the light emission surface of the light guide plate, and holding the LEDs and the light guide plate and the reflecting sheets. The surface light source device further includes, near between the LEDs adjacent to each other, light introducing means for introducing the light emitted from the LEDs into the light emission surface or the light anti-emission surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a surface light source device according to a first preferred embodiment of the present invention;

FIG. 2 is a plan view of the surface light source device of the first preferred embodiment;

FIG. 3 is a cross section of a region near LEDs in the surface light source device of the first preferred embodiment;

FIG. 4 is a cross section of a region near between adjacent LEDs of the surface light source device of the first preferred embodiment;

FIG. 5 is a cross section of a region near between adjacent LEDs in a surface light source device according to a second preferred embodiment of the present invention;

FIG. 6 is a cross section of a region near between adjacent LEDs of a surface light source device according to a third preferred embodiment of the present invention;

FIG. 7 is a cross section of a region near between adjacent LEDs of a surface light source device according to a fourth preferred embodiment of the present invention;

FIG. 8 is a cross section of a region near between adjacent LEDs of a surface light source device according to a fifth preferred embodiment of the present invention;

FIG. 9 shows a front view and a side view of a light guide plate of the surface light source device in the fifth preferred embodiment;

FIG. 10 is a cross section of a region near between adjacent LEDs of a surface light source device according to a modification 1 of the fifth preferred embodiment;

FIG. 11 shows a front view and a side view of a light guide plate of the surface light source device in the modification 1 of the fifth preferred embodiment;

FIG. 12 is a cross section of a region near between adjacent LEDs of a surface light source device according to a modification 2 of the fifth preferred embodiment; and

FIG. 13 shows a front view and a side view of a light guide plate of the surface light source device in the modification 2 of the fifth preferred embodiment.

Claims

1. A surface light source device comprising: a plurality of point light sources arranged at a predetermined spacing;a light guide plate that emits, as a surface light, light emitted from the point light sources and entered into at least one side surface, through a light emission surface located perpendicularly to the side surface;reflecting parts disposed respectively at a light anti-emission surface of the light guide plate and at near the point light sources; anda casing that has an opening part at a position corresponding to the light emission surface of the light guide plate, and that holds the point light sources and the light guide plate and the reflecting parts,the surface light source device further comprising:light introducing means for introducing the light emitted from the point light sources into the light emission surface or the light anti-emission surface of the light guide plate, the light introducing means being disposed near between the point light sources adjacent to each other.

2. The surface light source device according to claim 1 wherein, the light introducing means has a hole of the reflecting part extending from the point light sources side to part of the light anti-emission surface of the light guide plate, and a second reflecting part arranged in parallel with the hole.

3. The surface light source device according to claim 2 wherein, the hole of the reflecting part is present a plurality of numbers each for between the point light sources adjacent to each other.

4. The surface light source device according to claim 2 wherein, the hole of the reflecting part is maximized at a mid-point between the point light sources adjacent to each other, in cross-sectional length in a direction from the point right sources side to the light guide plate side.

5. The surface light source device according to claim 3 wherein, the hole of the reflecting part is maximized at a mid-point between the point light sources adjacent to each other, in cross-sectional length in a direction from the point right sources side to the light guide plate side.

6. The surface light source device according to claim 2 wherein, the hole of the reflecting parts is maximized at a position of one third and at a position of two third in between the point light sources adjacent to each other, in cross-sectional length in a direction from the point right sources side to the light guide plate side.

7. The surface light source device according to claim 3 wherein, the hole of the reflecting part is maximized at a position of one third and at a position of two third in between the point light sources adjacent to each other, in cross-sectional length in a direction from the point right source side to the light guide plate side.

8. The surface light source device according to claim 1 wherein, the light introducing means has an exposed part of the light emission surface in between the casing holding the light guide plate and the point light sources.

9. A surface light source device comprising: a plurality of point light sources arranged at a predetermined spacing;a light guide plate that emits, as a surface light, light emitted from the point light sources and entered into at least one side surface, through a light emission surface located perpendicularly to the side surface;reflecting parts disposed respectively at a light anti-emission surface of the light guide plate and at near the point light sources; anda casing that has an opening part at a position corresponding to the light emission surface of the light guide plate, and that holds the point light sources and the light guide plate and the reflecting parts,the surface light source device further comprising:light introducing means for forming an incident angle different from an incident angle of light directly entering into the side surface, disposed on the side surface of the light guide plate located near between the point light sources adjacent to each other.

10. The surface light source device according to claim 9 wherein, the light introducing means is a portion obtained by shaping, in the form of a circular arc having a predetermined radius, at least one of a corner formed by the light emission surface and the side surface of the light guide plate, and a corner formed by the light anti-emission surface and the side surface of the light guide plate.

11. The surface light source device according to claim 9 wherein, the light introducing means has a projection on at least one of a side formed by the light emission surface and the side surface of the light guide plate, and a side formed by the light anti-emission surface and the side surface of the light guide plate.

12. The surface light source device according to claim 9 wherein, the light introducing means has a V-shaped groove in the side surface of the light guide plate located near between the point light sources adjacent to each other.

13. The surface light source device according to claim 9 wherein, the light introducing means has a V-shaped convex portion on the side surface of the light guide plate located near between the point light sources adjacent to each other.

14. The surface light source device according to claim 9 wherein, the light introducing means has convexes and concaves each having a predetermined shape, on the side surface of the light guide plate located near between the point light sources adjacent to each other.

15. The surface light source device according to claim 1 wherein the point light sources are light emitting diodes.

16. The surface light source device according to claim 9 wherein the point light sources are light emitting diodes.

17. A display device comprising: (i) a surface light source device comprising: (a) a plurality of point light sources arranged at a predetermined spacing;(b) a light guide plate that emits, as a surface light, light emitted from the point light sources and entered into at least one side surface, through a light emission surface located perpendicularly to the side surface;(c) reflecting parts disposed respectively at a light anti-emission surface of the light guide plate and at near the point light sources;(d) a casing that has an opening part at a position corresponding to the light emission surface of the light guide plate, and that holds the point light sources and the light guide plate and the reflecting parts; and(e) light introducing means for introducing light emitted from the point light source into the light emission surface or the light anti-emission surface of the light guide plate, the light introducing means being disposed near between the point light sources adjacent to each other; and(ii) a display part displaying image with light emitted from the opening part, disposed on the opening part of the surface light source device.

18. A display device comprising: (i) surface light source device comprising: (a) a plurality of point light sources arranged at a predetermined spacing;(b) a light guide plate that emits, as a surface light, light emitted from the point light sources and entered into at least one side surface, through a light emission surface located perpendicularly to the side surface;(c) reflecting parts disposed respectively at a light anti-emission surface of the light guide plate and at near the point light sources;(d) a casing that has an opening part at a position corresponding to the light emission surface of the light guide plate, and that holds the point light sources and the light guide plate and the reflecting parts; and(e) light introducing means for forming an incident angle different from an incident angle of light directly entering into the side surface, disposed on the side surface of the light guide plate located near between the point light sources adjacent to each other; and(ii) a display part displaying image with light emitted from the opening part, disposed on the opening part of the surface light source device.