Kabushiki Kaisha Toshiba

Konica Corporation

Toshiba Corporation

Yasuo Shono

Yoshinori Higuchi

Yasoji Suzuki

Shinichiro Saito

Norio Nakamura

Atsunori Ohyama

Naoto Ide

A plane light source unit includes a tubular light source, and a light guide. The light guide has a light emitting surface and a reflecting surface in addition to a light incident face placed near the tubular light source to receive light emitted from the tubular light source. The light guide has a plurality of projections or grooves arrayed on the light emitting surface to extend parallel to each other along a longitudinal direction of the tubular light source so as to cause the light incident from the light incident face to emerge from the light emitting surface. The height or depth of each of the projections or grooves increases from the central portion to the two end portions in the longitudinal direction of the tubular light source.

Plane light source unit and light guide used therein

On a light exit surface which is the first principal plane of a light guide, multiple projections are fabricated in specific rows. These projections have light exit surfaces and continuous multiple slopes, and are fabricated from optically identical materials having the same refractive index as the substrate of the light guide. The slope farthest from the light entry edge surface is formed as a light exit surface, i.e., a surface which breaks the conditions for the total reflection of the incident light. On the other hand, the slope nearest the light entry edge surface which is the total reflection surface is formed such that the incident light is totally reflected.

Light guide and liquid crystal display device using it

Growing community of inventors

Tokyo, Japan

Yasuo Shono