Eye protection device against broadband high intensity light
US4986639A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 13, 1989 |
| Grant date | Jan 22, 1991 |
| Priority date | — |
| Expiry date | Jan 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/015
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An eye protection device against broadband high intensity light sources, including a fast response component (picosecond to microsecond) and a slow response component (microsecond and longer). The fast response component consists of two thin semiconductor layers "sandwiched" between two transparent electrodes. The natures and dimensions of the semiconductor layers and the voltage bias applied to them are determined such that enough photo-excited electrons are generated in the first small bandgap layer so that the second large bandgap layer undergoes a rapid insulator-to-metal transition at the light-intensity threshold for eye damage. Upon becoming metal-like, this layer blocks the incident light. Below the damage threshold, the fast response component is transparent. The slow response component includes a PLZT (lanthanum-modified lead zirconium titanate) or similar electro-optic shutter. This component is transparent below the damage threshold. Finally, ballistic and chemical protection are obtained by embedding these slow and fast response components in a suitable plastic goggle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.