Light-scattering light-guiding device
US5548670A · kind A · utility
Inventor
Key dates
| Filing date | Jul 25, 1994 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Jul 25, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133615
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A light-scattering light-guiding device includes a light-scattering light guide having an incident surface, an exit surface from which scattered light is emitted, and a volume region having uniform scattering power. The volume region has an effective scattering illumination parameter E (cm.sup.-1) whose value satisfies the relation 0.45.ltoreq.E.ltoreq.100. The light guide has a nonuniform refractive index structure having a correlation function .gamma. (r), which is approximated by exp {-R/A}, where r is the distance between two points in the light guide. This distance a satisfies the relation 0.01 .mu.m.ltoreq.a.ltoreq.50 .mu.m. It is not necessary to form a scattering layer of diffusive ink or the like on the rear surface of the light guide. If an exit direction-modifying device having a prismatic cross section is disposed on the side of the exit surface, the flux of the outgoing light directed in a specified direction can be increased. The nonuniform refractive index structure is obtained by kneading together a polymer matrix and a particulate material of a different refractive index, by kneading together two or more kinds of polymers of different refractive indices, or by disp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.