Optical sensor and sensing method with stray illumination compensation
US8283620B2 · kind B2 · utility
6Cited by
7References
25Claims
0Family size
Assignee
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Key dates
| Filing date | Sep 8, 2009 |
| Grant date | Oct 9, 2012 |
| Priority date | — |
| Expiry date | Mar 5, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/087
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An optical sensor includes an infra red LED, a photodetector and a lock in charge amplifier. The photodetector passes charge to a feedback capacitor of the charge amplifier following an illumination cycle during which the LED is emitting and also following an illumination cycle during which the LED does not emit. An amplifier presents an output indicative of the difference between the charge generated at the photodetector during the illuminated and non-illuminated cycles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.