JP2006185653A - Surface lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface lighting system wherein uneven luminance is lowered as much as possible. <P>SOLUTION: In this surface lighting system, a light source 2 such as a light emitting diode emitting light inward is disposed on both sides of an almost semicylindrical light guide plate 1, the projecting surface side of the light guide plate 1 is used as a light reflecting surface 3, and the flat surface side is used as a light emitting surface 4. Since light from the light source 2 is reflected more on the side remote from the center 5 of the light guide plate 1 by this structure, uneven luminance can be reduced. Since 60-70% of total light flux of the light source 2 can be reflected by the light reflecting surface 3 on the side remote from the center 5 of the light guide plate 1, although it depends on the curvature of the projecting side of the light guide plate 1, the uneven luminance can be substantially lowered. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface illumination device that reduces luminance unevenness as much as possible.

Patent Document 1 discloses a surface illumination device in which a light source that emits light inwardly is disposed on a wide side surface of a tapered light guide plate, the tapered side of the light guide plate is a light reflecting surface, and the flat side is a light emitting surface. It has been.
Japanese Patent Laid-Open No. 9-159831

  However, it should be noted that on the far side from the light source, there is a problem to be solved that the light is difficult to reach the reflecting surface and the emitted light is weakened to easily cause luminance unevenness. In view of such a problem to be solved, an object of the present invention is to provide a surface illumination device in which luminance unevenness is reduced as much as possible.

  In summary, the present invention provides a surface illumination device in which light sources that emit light inwardly are arranged on both side surfaces of a substantially semi-cylindrical light guide plate, the convex side of the light guide plate is a light reflecting surface, and the plane side is a light emitting surface. is there. Further, the light source is a surface illumination device in which light sources that emit light inward are disposed near both side edges of a substantially arc-shaped reflector, and a light-diffusing translucent plate is disposed on the opposite side of the reflector.

  According to the present invention, a large amount of light from the light source is reflected farther from the center of the light guide plate or the reflection plate, so that the luminance unevenness can be reduced.

  Next, an embodiment of the present invention will be described. However, this is merely an exemplary embodiment adopted based on the present invention, and the present invention should not be limitedly interpreted based on matters specific to the embodiment. The technical scope of the present invention should be determined based on the matters shown in the claims of the claims and matters substantially equivalent to the matters.

  In the first embodiment of FIGS. 1 and 2, light sources 2 such as light emitting diodes that emit light inwardly are arranged on both side surfaces of a substantially semi-cylindrical light guide plate 1, and the convex side of the light guide plate 1 is a light reflecting surface 3. This is a surface illumination device having the light exit surface 4 on the plane side. According to this configuration, a large amount of light from the light source 2 is reflected on the far side from the center 5 of the light guide plate 1, so that luminance unevenness can be reduced. Although depending on the curvature on the convex surface side of the light guide plate 1, 60% to 70% of the total luminous flux of the light source 2 can be reflected by the light reflecting surface 3 farther from the center 5 of the light guide plate 1. Unevenness can be significantly reduced.

  More specifically, for example, a large number of quadrangular pyramidal projections 6 are recessed in the light reflecting surface 3, and the light from the light source 2 is diffusely reflected on the surface of the projections 6. Then, the diffusely reflected light is emitted to the outside from the light emitting surface 4, but the light unevenness may be further eliminated by transmitting it through the light diffusing translucent plate 7. Further, if a substantially arc-shaped reflecting plate 8 such as white is provided outside the light reflecting surface 3 and light leaking from the light reflecting surface 3 to the outside is returned into the light guide plate 1, the light utilization efficiency is improved.

  In the second embodiment of FIG. 3, light sources 12 such as light emitting diodes that emit light inward are arranged near both side edges of a substantially arc-shaped reflecting plate 11 such as white, and light diffusive properties are provided on the opposite side of the reflecting plate 11. This is a surface illumination device in which a translucent plate 13 is arranged. According to this configuration, a large amount of light from the light source 12 is reflected on the far side from the center 14 of the reflecting plate 11, so that luminance unevenness can be reduced. Although depending on the curvature of the reflecting plate 11, 60 to 70% of the total luminous flux of the light source 12 can be reflected farther from the center 14 of the reflecting plate 11, so that luminance unevenness can be significantly reduced.

  More specifically, for example, a large number of quadrangular pyramid-shaped protrusions 15 are formed on the inner surface of the reflecting plate 11, and light from the light source 12 is diffusely reflected by the surface of the protrusion 15 and diffused by the translucent plate 13. Luminance unevenness is further reduced by radiating to the outside with good properties.

1 is a longitudinal sectional view showing a first embodiment of the present invention. Cross section A longitudinal sectional view showing a second embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light guide plate 2 Light source 3 Light reflection surface 4 Light emission surface 5 Center of light guide plate 1 11 Reflection plate 12 Light source 13 Translucent plate 14 Center of reflection plate 11

Claims (4)

  A surface illumination device in which light sources that emit light inwardly are arranged on both side surfaces of a substantially semi-cylindrical light guide plate, the convex side of the light guide plate is a light reflecting surface, and the flat side is a light emitting surface.   2. The surface illumination device according to claim 1, wherein 60 to 70% of the total luminous flux of the light source is reflected by the light reflecting surface farther from the center of the light guide plate.   A surface illumination device in which a light source that emits light inward is disposed in the vicinity of both side edges of a substantially arc-shaped reflecting plate, and a light-diffusing translucent plate is disposed on the opposite side of the reflecting plate.   4. The surface illumination device according to claim 3, wherein 60% to 70% of the total luminous flux of the light source is reflected farther from the center of the reflector.

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