Optical memory system which uses a different illumination mode when scanning reserved areas
US4868804A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1986 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Jun 27, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/02
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to optical memories for storing data on the surface of an information-supporting medium including pre-formatted patterns. Such a memory may constitute a random access mass memory, and it may be read/write memory or it may be a write-once memory. The operations of writing to the memory and reading from the memory are based on the optical interaction which occurs at the point of impact of an incident optical beam which causes local changes in optical characteristics which are representative of the data when data is being written, and which produce optical modulation detectable by photoelectric means during data reading. The invention provides an optical memory in which the illumination mode common to reading data and to detecting pre-formatting patterns is modified in order to allow for operation in a standby mode or in order to delete areas reserved for storing data, for example.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.