Holographic filter construction for protective eyewear
US4830441A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 25, 1987 |
| Grant date | May 16, 1989 |
| Priority date | — |
| Expiry date | Mar 25, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S359/90
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The present invention is a manner of constructing holographic optical elements for use in laser eye protection. A photosensitive layer, preferably formed of dichromated gelatin, is disposed on a transparent supporting substrate with a reflecting surface conformal to the outer surface of the photosensitive layer. The photosensitive layer is exposed with light from a laser point source. The photosensitive layer records the interference patterns between light incident directly from the laser point source and light reflected from the reflecting surface. The photosensitive layer is developed to form a holographic optical element. When this holographic optical element is disposed before the eye, with the center of the eye located at a point equivalent to the location of the laser point source, laser light directed toward the center of the eye is diffracted by the holographic optical element and effectively reflected away from the eye. Construction of the holographic optical element in this manner enables the use of a flatter spectacle lens while minimizing flare. The blocking angles at any particular portion of the holographic optical element can be reduced, thus increasing the transmiss…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.