Micro optical head with an optically switched laser diode
US4860276A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1987 |
| Grant date | Aug 22, 1989 |
| Priority date | — |
| Expiry date | Sep 16, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/4031
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A micro optical head, for optically reading and/or writing digital data on a recording medium in which digital data 1 and 0, corresponding to a high reflection factor and a low reflection factor, is composed of a self-coupled semiconductor laser located close to the recording medium. A bias current of the laser is determined so that it is smaller than a first threshold current, in which the medium has a low reflection factor, and is higher than a second threshold current, in which the medium has a high reflection factor. Output light of the laser is either strong stimulated emission light, corresponding to the high reflection factor, or weak spontaneous emission light, corresponding to the low reflection factor. The present head is carried on a flying slider with a spacing length less than several .mu.m which provides a small beam spot of about 1 .mu.m, and has an excellent signal to noise ratio. A photodetector for sensing the output of the laser may be carried on the same semiconductor substrate as that of the laser.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.