Track pitch calibration system for use in optical storage devices
US4578786A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1984 |
| Grant date | Mar 25, 1986 |
| Priority date | — |
| Expiry date | Jul 6, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/08505
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system and method for maintaining a prescribed track pitch in an optical storage system wherein a second radiation beam is aligned a desired distance from a first radiation beam, the first radiation beam being controllably steered to follow a previously written data track on a record carrier used within the optical storage system. A write alignment servo aligns the second radiation beam the prescribed distance from the first radiation beam in response to an offset signal. The offset signal is generated by optically measuring the distance between a pair of calibration tracks that have previously been placed on the disk so as to have the desired track pitch therebetween. The effect of variations or drift occurring in the optical or electrical components of either the write alignment servo or the optical track pitch measurement system is significantly reduced by regularly calibrating against the fixed track pitch of the calibration tracks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.