Optical disc apparatus with sensing circuitry to judge a movement direction of a beam spot
US5901120A · kind A · utility
5Cited by
4References
4Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 18, 1997 |
| Grant date | May 4, 1999 |
| Priority date | — |
| Expiry date | Apr 18, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/133
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disc apparatus which records and reproduces an information signal from an optical disc having land and groove tracks, whose width ratio being set to be 1 or to be a value close thereto, is capable of detecting a moving direction of a beam spot in a random access mode, by applying a four-division or six-division optical sensor, segmented by division lines tilted by 45.degree..+-.25.degree. from the track tangential direction, wherein two output signals having a phase difference of about 90.degree. are produced and the moving direction is detected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.