Data storage apparatus using optical servo tracks
US4843494A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 15, 1987 |
| Grant date | Jun 27, 1989 |
| Priority date | — |
| Expiry date | Oct 15, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B21/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic data storage system for use with a double sided disk in which a prerecorded pattern of opaque optical lines is used to define the tracks in which magnetic data is to be stored. A separate optical system including an illumination source and a photosensitive detector is provided on a read/write assembly for each side of the disk. Each detector is designed also to serve as a reference grating. The illumination source is designed to image the prerecorded pattern of optical lines on the reference grating as an indication of the alignment of the read/write head of the assembly and a desired data rack and any misalignment of the head and track generates a servo signal. The detector uses four separate photocells interleaved in a prescribed fashion to form a quadrature detector that is adjustable to compensate for various non-uniformities. One form of illumination source uses a surface-emitting light emitting diode and optics for forming a multiple beam source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.