Optical encoder
US6054938A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1998 |
| Grant date | Apr 25, 2000 |
| Priority date | — |
| Expiry date | Feb 10, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/34723
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A detecting unit provided with an optical system is disposed away from a control unit formed by an electric circuit and an optical transmission/receiving means, and the detecting unit and the control unit are coupled through a transmission optical fiber. The control unit transmits to the detecting unit through the optical fiber a light wave which was subjected to the intensity modulation by a sinusoidal wave of a predetermined frequency. The transmitted light wave is branched into at least two branched optical paths within the detecting unit thereby to perform the phase modulation as to the respective light waves. The light waves passed through the respective branched optical paths are subjected to the phase modulation by the sinusoidal waves which differ in phase 1/4 period by 1/4 period from one another according to a position on a straight line or a rotation angle of a subject to be detected. Then, the light waves thus subjected to the intensity modulation are coupled to a single transmission optical fiber through the branched optical paths and transmitted to the control unit through the transmission optical fiber. In the control unit, the modulated light wave is received and su…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.