Optical reflectance proximity sensor
US7486386B1 · kind B1 · utility
104Cited by
29References
23Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 21, 2007 |
| Grant date | Feb 3, 2009 |
| Priority date | — |
| Expiry date | Oct 24, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/94026
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for calibrating an optical reflectance proximity sensor and then measuring proximity in a repeating cycle or on demand, the sensor including one or more wavelength transmitting diodes, one or more wavelength receiving diodes, an ambient correction circuit, and a comparator circuit, and further teaching steps for powering on the sensor, canceling the ambient signal during a calibration period, transmitting wavelengths to and receiving reflectance from an object in the path of the transmitted wavelengths, and measuring a reflectance pulse width and comparing the value to a preset value to determine proximity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.