Laser emission unit, optical head and optical memory device
US5680384A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 13, 1995 |
| Grant date | Oct 21, 1997 |
| Priority date | — |
| Expiry date | Oct 13, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/0683
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A laser emission unit for use in an optical head performs a plurality of functions which are integrated. A laser beam from the laser emission unit mounted in a lens holder is emitted through an objective lens and is focused on an optical medium. A reflected beam from the optical medium returns through the objective lens and a diffraction grating to a signal detection circuit in the laser emission unit. Since the laser emission unit performs a plurality of functions, the space for various elements otherwise required in the optical head can be eliminated. The space for an additional light path for the reflected beam is also eliminated. Therefore, the size of the optical head is very small. Since the optical head can be assembled by using a small number of parts, the production costs can be reduced. Furthermore, the optical head can shield the noises by using the housing and/or the lens holder itself.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.