Optical recording medium and information record with tracking aid
US4387381A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 12, 1981 |
| Grant date | Jun 7, 1983 |
| Priority date | — |
| Expiry date | Jun 12, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0938
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording medium comprising a substrate, a light absorptive layer overlying the substrate, a buffer layer overlying the absorptive layer and a masking layer having slots therethrough overlying the buffer layer. The invention also includes an information record having information recorded in the absorptive layer as a series of regions of the absorptive layer, underlying the slots in the masking layer, whose optical properties differ from those of the remainder of the absorptive layer. The presence of the slots in this medium can provide a spatially varying recording sensitivity, track identification and a means for obtaining a radial tracking error signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.