Large-area light source
US4277817A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 13, 1979 |
| Grant date | Jul 7, 1981 |
| Priority date | — |
| Expiry date | Jun 13, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/0038
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
To provide for uniform output throughout the area of the light source, particularly to provide a background illuminating surface for liquid crystal display, an especially adapted for automotive application, the light-emitting surface is formed as a wedge-shaped body of transparent material, such as Plexiglas, with light being coupled thereinto at the wider side surface, the bottom surface of the wedge-shaped body having, preferably, a reflective, light dispersing layer or coating applied thereto, for example in form of a white pigmented lacquer, white paper, a ceramic plate, or the like; an intermediate layer of light-transmissive material having an index of refraction less than the index of refraction of the body may be interposed between the surface of the body and the reflective coating of layer. The top surface of the body can be matte, for example formed by microgrooves extending transversely to the plane of the side surface through which light is coupled into the wedge-shaped body. The light can be coupled thereinto derived, for example, from an incandescent bulb.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.