System for eliminating scattered light in autocollimator for magnetic-head suspension measuring instrument
US5929987A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 23, 1998 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Jul 23, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B33/10
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An autocollimator/point-range sensor system produces a linearly polarized light beam that is split into a point-range sensor beam and an autocollimator beam. The linearly polarized point-range sensor beam is utilized to carry out z-position measurements according to prior-art techniques. The autocollimator beam is passed through a quarter-wave plate to introduce a 90-degree phase shift and convert it to circularly polarized light. An analyzer placed in front of the autocollimator detector is positioned such that its transmission axis is offset with respect to the plane of polarization of the linearly polarized point-range sensor beam, thereby blocking any scattered light from the sensor beam while passing a component of the circularly-polarized autocollimator light to reach the detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.