Method of and device for recording and playing back an optical disk having a test playback region utilizing pits of minimum size for controlling the power of the laser
US5699342A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 7, 1995 |
| Grant date | Dec 16, 1997 |
| Priority date | — |
| Expiry date | Feb 7, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10595
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a method of reproducing information from an optical disk, the disk is scanned with a laser beam forming a light spot on the disk, at least some of the recording pits being smaller in size than the light spot, the laser beam heating the disk so that effective detection area being formed at only part of the light spot, a sequence of preformatted pits of a minimum size are formed, playback signals are produced in accordance with a reflected light from the disk, and a power of the laser beam is so controlled so as to maximize the level of the playback signals produced from the reflected light from the sequence of pits of the minimum size. In another method using a magneto-optical disk, information is recorded by scanning the disk with a laser beam, each of the recording pits being substantially crescent-shaped, the direction of rotation during playback is opposite to the direction of rotation during playback, and the order of bits forming the information is reversed either during the playback or recording.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.