Optical displacement sensor
US5619318A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 1995 |
| Grant date | Apr 8, 1997 |
| Priority date | — |
| Expiry date | Jun 13, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/266
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention comprises a compound cavity in which a vertical-cavity surface-emitting laser and external mirror are combined, and the change in intensity of a laser beam or in mirror loss is detected by the detection unit. The detection unit includes a photodetector for directly detecting a variation in intensity of a laser beam, and PN junction potential difference detecting device for detecting a variation in mirror loss created due to a relative displacement between the external mirror and the vertical-cavity surface-emitting laser, based on a change in carrier density within the surface-emitting laser. The phase of the laser beam returning from the external mirror is determined by a relative displacement between the external mirror and the vertical-cavity surface-emitting laser, and the laser beam output varies at a period of a displacement amount corresponding to 1/2 of the wavelength of the laser beam. Such a displacement amount is calculated by the counting device and the operation device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.