Multiple reference laser beam apparatus
US4676598A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 1985 |
| Grant date | Jun 30, 1987 |
| Priority date | — |
| Expiry date | May 15, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C15/004
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus for projecting a laser beam to provide simultaneously a stationary reference beam and a moving reference beam, which rotates in a plane normal to the stationary reference beam, includes a beam diverting arrangement for intercepting a primary beam and for splitting the beam into the two reference beams. The beam diverting arrangement includes first and second deflecting elements which deflect the beam by 90.degree. with respect to the primary beam. A portion of the primary beam, striking the first deflecting element, passes through the element and is shifted slightly by refraction. This shift is compensated by a third beam deflecting element which is fully transmissive, and which refracts the stationary reference beam into alignment with the primary beam. By cutting the first and third deflection elements from the same sheet of material and reorienting the elements appropriately, slight deviation from parallelism in the opposing surfaces of the sheet of material are compensated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.