Surface light source device of side light type with belt-like diffusible area
US6024463A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 7, 1997 |
| Grant date | Feb 15, 2000 |
| Priority date | — |
| Expiry date | Nov 7, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/0053
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a surface light source device of side light type applied to a liquid crystal display device, etc., more specifically a surface light source device of side light type having a directivity emitting characteristic, a bright-and-dark-band contrast which is generated in a vicinity of an incidence surface is prevented. In a surface light source device of side light type, light diffusible areas composed on main-and-supplementary diffusible areas are formed on a slanted surface and an emitting surface of a light guide plate having a directivity emitting characteristic. A silver sheet is fixed to a projected portion of a prism sheet along an upper edge, and an illumination light which arrives at the upper edge from a fluorescent lamp is blocked so that the strong brightening of the upper edge is prevented. An illumination light form a lower edge is blocked by a reflector or a frame and reflected diffusively. The light diffusible area may be formed on one of the slanted surface and the emitting surface. Moreover, the light diffusible area may be formed on an additional element such as a reflection sheet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.