Surface illuminant device emitting light in multiple directions in concentrative manner
US6357888B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1999 |
| Grant date | Mar 19, 2002 |
| Priority date | — |
| Expiry date | Sep 22, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/0053
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A surface illuminant device includes a surface illuminant having a light distribution characteristic with no directivity relative to specific directions, and a prism sheet having a plurality of prisms each having a predetermined apical angle. The prism sheet is placed on the light emission side of the surface illuminant. One side of the prism sheet on which a plurality of prisms are placed is opposite to the light emission side of the surface illuminant. Accordingly, light can be emitted in a plurality of specific directions in concentrative manner to enhance luminance in that plurality of directions. Further, the surface illuminant device includes an optical sheet which condenses the incident light. In the luminance distribution (light distribution characteristic) thus obtained, the luminance gently decreases in the vicinity of the directions in which light is emitted in concentrative manner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.