Method and apparatus for generating a straight reference line
US4963022A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 24, 1988 |
| Grant date | Oct 16, 1990 |
| Priority date | — |
| Expiry date | Oct 24, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/272
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for generating a spatially stable, small diameter light beam (18) which serves as a straight reference line over long distances may use the direction of propagation of light and one fixed point (11, 12) or may be between two fixed points (12, 21). In either instance, a light source (1) emits a beam (2) which is expanded, collimated and spatially filtered (3, 4). In the first instance, the collimated light wave (11) produced is diffracted by a sphere (12) to produce the small diameter light beam (18) which is constituted by a continuum of spots (16) which, in turn, produces a Poisson's spot (16) on a detector (21) which spatially samples the intensity of the spot (16). The resultant voltage (22) from each active detection are sent to a center locating electronics/computer (24) which processes the voltages (22) to give the position of the detector (21) relative to the straight reference line (18). In the second instance, the collimated light wave (11) is produced by reflecting the beam (5) passing through the pinhole (4) from a steering mirror (6) which can be tilted about two axes by applying error signal voltages (27, 28) to tilt adjusters (7, 8) which are related to the d…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.