Opto sensor signal current detector
US6392612B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 30, 1999 |
| Grant date | May 21, 2002 |
| Priority date | — |
| Expiry date | Jun 30, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/28
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A projection display apparatus comprises a display device forming an image for projection to illuminate a display screen. A current source generates a current. A current sink is adjacent to the display screen and is coupled to the current source for receiving the current. A detector is coupled to the current source and the current sink for receiving the current and detecting a presence of the received current. Wherein a first condition, absent illumination by the projected image on the current sink, the current from the source divides and is coupled to the detector in accordance with a first ratio, the detector assuming a first state indicative of the absence of illumination, and in a second condition in accordance with an intensity of illumination by the projected image on the current sink, the current from the current source is received by the current sink in accordance with a second ratio and the detector, absent the received current, assumes a second state indicative of illumination on the current sink.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.