Optical position sensor employing encoder delay
US5030824A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 22, 1990 |
| Grant date | Jul 9, 1991 |
| Priority date | — |
| Expiry date | Feb 22, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/2497
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical sensor that uses laser radar techniques to determine the value of a mesaurand. The sensor comprises an encoder, an optical source, sensing means and detection means. The encoder has a plurality of tracks, each track including means for receiving an optical signal and for delaying the optical signal by an encoder delay that is a function of the measurand value. The optical source produces a chirped optical interrogation signal that is received by the sensing means and divided into N channel signals, such that each channel signal strikes one of the tracks. The sensing means delays each channel signal by a unique channel delay. The detection means receives the channel signals after they have struck the tracks, and mixes the channel signals with a facsimile of the interrogation signal, to produce a demodulated signal. The detection means analyzes the frequency components of the demodulated signal, to determine the encoder delays and thereby the value of the measured. The encoder preferably comprises a transparent moveable substrate having a variable pattern of reflecting elements on one side, and a uniform reflective coating on the opposite side.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.