Thermally-sensitive, photo-controlled semiconductor switching systems
US4119845A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 21, 1977 |
| Grant date | Oct 10, 1978 |
| Priority date | — |
| Expiry date | Mar 21, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/0824
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A switching system having a photo-sensitive power switching or control element such as a photo SCR, photo triac, photo transistor or the like that is normally turned on or off by coupled light from a controlled light source such as an LED (light emitting diode), neon lamp, incandescent lamp or the like. A thermally-sensitive light-gating element such as an LC (liquid crystal) element controls the light impinging on the photo-sensitive element. The gating element may sense the temperature of the photo-sensitive power switching or control element directly if the two are integral in which case the combined device would be self-protecting. On the other hand, the gating element may be separate and may be arranged to sense the temperature of an external source that may or may not be controlled by the photo-sensitive power switching or control element in which case the latter would be controlled by the temperature. Different types of temperature-sensitive gating elements or combinations thereof may be used in the systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.