Film lens and a surface light source using the same
US5598280A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 1994 |
| Grant date | Jan 28, 1997 |
| Priority date | — |
| Expiry date | Mar 22, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/045
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A film lens comprises a light transmitting base having one side and an opposite side, a plurality of concave or convex unit lenses formed on the one side of the light transmitting base, and a plurality of projections formed on the opposite side of the light transmitting base and having a profile height not smaller than the wavelength of a source light and not greater than 100 .mu.m. In this arrangement, when the film lens is placed on a smooth surface of a light guide plate of a surface light source of the edge-light type, the projections on the reverse side of the light transmitting base can secure a gap with a width not smaller than the wavelength of the source light between the film lens and the light guide plate. Thus, the source light can be uniformly distributed without hindrance throughout the light guide plate as it is totally reflected by the surface of the guide plate. In the surface light source using the film lens, moreover, the lens can provide a uniform luminance in a desired angular range, and a uniform luminance distribution can be obtained for the whole surface without concentration in the vicinity of the light source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.