Fluorescent optical switch and keyboard apparatus
US4617461A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1984 |
| Grant date | Oct 14, 1986 |
| Priority date | — |
| Expiry date | Apr 25, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/969
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Fluorescent optical switch and keyboard apparatus wherein a plurality of fluorescent optical key switches are arranged in a matrix array of rows and columns with a key disposed at each column-row intersection and wherein each key carries a fluorescent optically reflective element thereon. A single optical photo-diode disposed at each key location is caused to operate in three discrete modes with respect to the fluorescent element. In one mode the diode emits light which is caused to be reflected upon key when the key is depressed. In another mode the reflected light striking the diode causes the diode to act as a photo-receptor effectively indicating key actuation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.