Spread illumination apparatus having trapezoidally-shaped grooves
US6644823B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 2001 |
| Grant date | Nov 11, 2003 |
| Priority date | — |
| Expiry date | Jun 26, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/0031
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides a spread illuminating apparatus for improving the machinability and durability of a molding die for a transparent substrate and obtaining an excellent light reflection. In a light reflection pattern comprising grooves and substantially flat portions adjacent to the grooves and formed on an upper surface of the transparent substrate in parallel to the optical axis of a bar-like light conductive member located close to an end surface of the transparent substrate, the grooves are each formed substantially trapezoidal in section with their bottom surface defining a shorter side of trapezoid. The inclination angle of an inclined surface positioned closer to a light source is set to range between 35° and 55°, the inclination angles of both the substantially flat portions and the bottom surfaces are set to range between −5° and +5°, the width of the substantially flat portions is set to be constant, and the width and depth of the grooves gradually increase in proportion to the increase in distance from the light source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.