Optical head devices for use in recording and/or reproduction of information
US5060217A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 30, 1989 |
| Grant date | Oct 22, 1991 |
| Priority date | — |
| Expiry date | May 30, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/123
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical head device for use in recording and/or reproduction of information comprises a light beam generating portion, a lens element for causing a light beam obtained from the light beam generating portion to impinge upon a record medium and receiving the light beam from the recording medium, and a photodetecting portion to which the light beam from the record medium received by the lens element is guided and which has three photosensitive elements separated from each other by a couple of parallel dividing portions and disposed to form a common light receiving plane on which a beam spot is formed by the light beam guided to the photodetecting portion for detecting the light beam guided to the photodetecting portion to produce respective detection output signals from which a tracking error signal is produced, wherein each of the parallel dividing portions extends along a direction selected to be at an angle within an angle rqnge of 0 to 90 degrees to a direction of movement of a diffraction pattern appearing in the beam spot formed on the common light receiving plane in accordance with a record track in the record medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.