Optical pick-up head and integrated type optical unit for use in optical pick-up head
US5804814A · kind A · utility
Inventors
Key dates
| Filing date | May 22, 1995 |
| Grant date | Sep 8, 1998 |
| Priority date | — |
| Expiry date | May 22, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10543
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pick-up head for reading writing information from on a magneto-optical record medium including a semiconductor laser, a multi-image plane parallel plate for separating an incident light beam emitted by the semiconductor laser from a return light beam reflected by the optical record medium and dividing the return beam transmitted through and refracted by the multi-image plane parallel plate into a plurality of return light beams, and a signal detecting photodetector receiving a plurality of return light beams, wherein the multi-image plane parallel plate is formed by first and second prisms made of birefringent material and is arranged such that major and minor axes of astigmatism introduced by the plane parallel plate are inclined by 45.degree. with respect to an information track. An optic axis of the first prism is set such that the return beam is separated into ordinary and extraordinary light beams having identical intensities and an optic axis of the second prism is rotated with respect to the optic axis of the first prism. The optical elements are positioned and mounted on a mounting substrate having guide walls formed by a photolithography.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.