Holographic diffuser for back-lit display
US5471327A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 1993 |
| Grant date | Nov 28, 1995 |
| Priority date | — |
| Expiry date | May 14, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133605
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A holographic diffuser for use in conjunction with a back-lit flat-panel display and a source of illumination in the form of one or more tubular lamp segments is recorded so as to receive light from the lamp segments and scatter it preferentially along a plane perpendicular to the axis of the bulbs. In a back-lit display having vertically oriented tubular lamps, the diffuser scatters substantially more in the horizontal dimension, thus filling in the gaps of light intensity between the bulbs, which would otherwise be viewed by an observer, as with conventional diffusers. The high aspect ratio diffusers of the present invention are preferably formed by projecting coherent radiation through a mask having dimensions functionally related to the desired final aspect ratio, with an optional collimating lens being used to project that mask to infinity. A contact exposure process is also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.