Optical information recording medium
US5638354A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1994 |
| Grant date | Jun 10, 1997 |
| Priority date | — |
| Expiry date | Jul 15, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0943
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a control method of an optical disk unit, it is judged by performing a tentative tracking operation of an optical pickup in a constant region of an optical disk whether a tracking position of the optical pickup is located in a land or groove portion. After a correct tracking control condition is judged, an access operation according to command information is executed. The optical disk unit has a two-divisional light receiving element for receiving diffracted light caused by a pregroove and a prepit of the optical disk, and a differentiator for generating a difference signal between signals of this light receiving element. The optical disk unit further has an adder for generating a sum signal of the signals of the light receiving element, and a tracking signal selector for selecting the difference or sum signal when the tracking operation is performed in a pregroove or prepit region, respectively. An optical information recording medium and a method for recording and regenerating information by using this optical information recording medium are also shown.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.