Electro-optical measuring device for absolute distances
US5764360A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 28, 1997 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | May 28, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Electro-optical measuring device for absolute distances to a target point. In addition to the beam polarization being modulated as is required for the Fizeau method, the invention provides that the modulation means contain a modulator crystal (8; 7) having electrodes which are connected to a variable DC source (11; 10), and that a control apparatus (19) is provided which initiates the determination of the value of the modulation phase in the region of minimum brightness at the associated modulation frequency, successively for different DC voltage values, over a full cycle of the basic polarization of the modulator crystal, stores and averages the measured values, repeats the measurement at a slightly changed modulation frequency if the mean value is not zero, and uses interpolation to determine the modulation frequency which is associated with the mean modulation phase value of zero. The measuring device is particularly suitable for coupling to a tracking system based on interferometry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.