A surface light source device using a light conducting member, in which a multiplicity of concave portions are formed on an opposite surface of a light emitting surface of the light conducting member and the concave portions are arranged to have specific shapes to obtain a bright surface light source with a uniform brightness. A light diffusing material is fulfilled within the concave portions of the light conducting member so that a more uniform brightness can be obtained in an easy manner.
This is a division of application Ser. No. 08/709,118, filed Sep. 6, 1996, now U.S. Pat. No. 5,779,338, which is a division of application Ser. No. 08/290,087, filed Aug. 12, 1994, which issued as U.S. Pat. No. 5,575,549. The contents of these applications being relied upon and incorporated by reference herein.
The transreflectors may comprise a transparent substrate having reflective surfaces and other light transmissive surfaces for respectively reflecting and transmitting a greater portion of the light striking opposite sides of the substrate. Alternatively, the transreflectors may comprise two or more transparent substrates of different indices of refraction bonded together, with a pattern of optical deformities in the mating side of one of the substrates and an inverse pattern of optical deformities in the mating side of an other substrate in mating engagement with each other. The transreflectors are used in a transreflector system or display to transmit more of the light emitted by a backlight or other light source incident on one side of the transreflectors and reflect more of the light incident on the opposite side of the transreflectors. The transreflectors and backlight may be tuned to each other to enable the transreflectors to better transmit more of the light emitted by the backlight.
A light-guide board includes a light guide plate made out of an optically transmissive material and having a transparent layer and a back reflecting layer formed integral with the back side of the transparent layer, and a plurality of reflecting baffles respectively extending from the back reflecting layer and embedded in the transparent layer for reflecting light to enhance the intensity of light and the uniformity in light intensity.
A light guide plate (32) used in a surface light source (30) for a liquid crystal display includes a light incidence surface (321) for receiving light beams, an emission surface (325) perpendicular to the light incidence surface for emitting the light, a bottom surface (323) opposite to the emission surface, and a plurality of grooves (327) and light reflection dots (329) formed on the bottom surface. The grooves are formed in a continuous band adjacent to the light incidence surface and extend perpendicular to the light incidence surface for scattering the light beams. The light guide plate provides highly uniform illumination for a liquid crystal display panel.
A backlight system comprises at least two light-emitting panels (1; 11) having a front wall (2; 12), an opposing rear wall (3; 13) and opposite edge surfaces (4, 14; 5, 15). At least one of the edge surfaces (4; 14) is light-transmitting and associated with a plurality of light sources (6, 16). Light originating from the light sources (6; 16) is diffused in the panel (1; 11). Sub-surfaces (8, 18) of the rear walls (3, 13) are provided with means for extracting light from the panel (1, 11). In operation, said sub-surfaces (8, 18) project light on areas (9, 19) of an (imaginary) plane (40) which is positioned parallel to the light-emitting panels (1, 11). Said projected areas (9, 19) in the plane (40) are substantially contiguous. Preferably, said sub-surfaces (8, 18) are remote from the light-transmitting edge surfaces (4; 14). Preferably, each of said sub-surfaces (8, 18) forms a single surface covering half the front wall (2, 12) of the light-emitting panel (1, 11). Alternatively, the sub-surfaces encompass a substantial area of the rear walls, the distribution of the means for extracting light from the panel being such that the amount of extracted light changes as a function of the distance to the light-transmitting edge surfaces. Preferably, the light source comprises a plurality of red, green, blue (and amber) LEDs, each preferably having a luminous flux of at least 5 lumen.
A backlight assembly has a light diffusion member including a diffusion layer for diffusing first light emitted from at least one lamp and a light path modulation layer formed on the diffusion layer to modulate the path of the first light, Therefore, the light diffusion member emits second light having uniform distribution of the brightness. The light path modulation layer may be disposed on one surface of the diffusion layer where the first light is input, or another surface of the diffusion layer where the second light is emitted.
