Planar lighting device and method of making light guides used therein
US6206535A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1999 |
| Grant date | Mar 27, 2001 |
| Priority date | — |
| Expiry date | Nov 30, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/0065
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A light guide member (2) includes a first light guide section (2A), which is a non-scattering light guide region, and a second light guide section (2B) which is a scattering light guide section and is made of material of the same composition as that of the first light guide section (2A), but mixed with scattering particles. Therefore, while the concentration of the scattering particles in the second light guide section (2A) is retained as high as possible, the gradient of the light scattering power can be increased to thereby allow a light exit surface to exhibit a high brightness and uniformity in luminance over the entire surface thereof. Also, the first light guide section (2A) and the second light guide section (2B) are formed by bonding them in the thicknesswise direction by the effect of a cohesive strength exhibited by material themselves therefore. Accordingly, there is no need to separately mold and then bond the first and second light guide sections (2A, 2B), the light guide member (2) can be molded at a time, accompanied by increase in productivity. In addition, since no bonding agent is used at the interface, the flatness can be secured with high precision.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.