System and method of astigmatism correction in an optical head apparatus
US4789978A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 24, 1986 |
| Grant date | Dec 6, 1988 |
| Priority date | — |
| Expiry date | Nov 24, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1374
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical head apparatus comprises a laser light source device emitting linearly polarized light, a converging lens for converging the light pencil emitted from the laser light source onto information recording tracks on a recording medium, and an optical system including a beam splitter for separating the light pencil reflected from the recording medium from the light pencil emitted from the laser light source. The converging lens is one formed by molding. The rotary position of the converging lens about the optical axis of the converging lens is so adjusted that the astigmatism of the optical system from the laser light source to the recording medium is minimum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.