Surface light source device of side light type and mold for light guide plate employed in the device
US6027221A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 31, 1997 |
| Grant date | Feb 22, 2000 |
| Priority date | — |
| Expiry date | Jul 31, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/0046
- 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 or the like, a light control member is prevented from clinging to a light guide plate. The light guide plate is formed by means of injection molding with molds 16A and 16B. The molds 16A and 16B have an additional cavity 13 in a portion corresponding to a position close to an incidence surface of the light guide plate 11, with a gate G being arranged in the cavity. In the mold 16B, its inside surface corresponding to an emitting surface 12 is roughened. According to gradient in roughness, the emitting surface of a light guide plate to be manufactured is roughened so as to have uniform or graded roughness. On a center line C--C, the inside surface is much roughened in a portion distant from the cavity 13. Further, on a crossing line D--D, the inside surface is roughened so as to reduce the roughness according to distance from the center. If the gradient in roughness on the inside surface of the mold 16B is intensified, the emitting surface of the light guide plate may be roughened so as to have graded roughness. It is thereby possible to prevent clinging of the control member from occurring even …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.