Optical measuring apparatus
US4611916A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 11, 1984 |
| Grant date | Sep 16, 1986 |
| Priority date | — |
| Expiry date | May 11, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an optical measuring apparatus, measuring light having a frequency f.sub.1 is focused and its beam spot irradiates a surface of an object fixed on a carrier. The carrier is shifted in a direction perpendicular to the optical axis of an objective lens to obtain measuring light reflected by the surface of the object. At the same time, reference light having a frequency f.sub.2 irradiates a mirror mounted on the carrier to be substantially perpendicular to the optical axis of the lens to obtain reflected reference light. The reflected reference light is interfered with the reflected measuring light to detect a beat frequency to optically, precisely measure a shape of the surface of the object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.