Light modulation method for forming a mark in magneto-optical recording system
US5457666A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1993 |
| Grant date | Oct 10, 1995 |
| Priority date | — |
| Expiry date | Aug 31, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/1053
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magneto-optical disk recording control method using the mark length recording method wherein the marks and gap regions between marks are recorded on the surface of the disk by maintaining a constant temperature distribution during the recording. The laser is driven to a non-recording level in gap regions between marks that exceed a base recording level used for reproduction of the marks. When a mark is recorded, the laser power is increased to a recording power level and after the mark has been recorded, the laser power level is reduced to the base power level, followed by being raised to the gap recording level. Control of the laser is performed by superposing a plurality of pulse trains that are synchronized with respect to a clock having a cycle T. The pulse trains are derived from the code train to be recorded and have pulses with a duration that is an integral multiple of (1/2)T. If the pulse width of the recording code train exceeds 2T, then the laser is controlled to reach a first power level in accordance with pulses of a first pulse train, be reduced to the gap recording level and then raised to a second power level in accordance with a second recording pulse train to ma…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.