Light scattering and guiding light source device and liquid crystal display
US5993020A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 16, 1997 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | May 16, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133615
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A light scattering and guiding light source device which is capable of providing a uniform illumination light, simple structure and low cost. A wedge-shaped light scattering guide has an incident surface for introducing light rays from a fluorescent lamp. The directions of the rays are changed by scattering. The rays propagate through the body while reflected repeatedly. Parts of the rays go outwards at plural reflective points. The angle of reflection increases successively, thus increasing the possibility that the light exits from the exit surface. This effect cancels another effect that portions close to the light source shines strongly. Both effects are balanced to make uniform the brightness over the exit surface. Reflective sheets are disposed along the inclined surface and around the fluorescent lamp to keep the brightness high. A prismatic exit direction modifier giving on the light exit surface is employed to modify the light exit direction characteristic. The light source device is mounted on a liquid crystal display as a backlight source to provide an improved display quality.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.