Radiation interruption keyboard
US4860008A · kind A · utility
Inventor
Key dates
| Filing date | Apr 20, 1987 |
| Grant date | Aug 22, 1989 |
| Priority date | — |
| Expiry date | Apr 20, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/969
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A radiation interruption keyboard is provided including a key matrix, a series of light emitting diodes and a series of photodiodes. With each diode is associated a column along which the light radiation propagates in a hollow channel. With each photodiode is associated a line along which the light radiation propagates in a strip made from a transparent material. Each strip has a deflecting area for deflecting the radiation from the light emitting diodes towards the corresponding photodiode. Upstream of each deflection area, in the path of the light beam, and in direct view of the corresponding light emitting diode is a flap for interrupting the radiation controlled by a key. The light emitting diodes are controlled sequentially and cyclically.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.