Optical recording method having two degrees of reflectivity and a diffraction grating or hologram formed integrally thereon and process for making it
US5138604A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 1989 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Dec 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2270/54
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical recording medium of the present invention has on a substrate information recording patterns (2) and (3) distinguishable by a difference in light reflectivity, and is characterized in that said information recording pattern (2) is comprised of a portion (2a) of high reflectivity and a portion (2b) of low reflectivity and at least a part of said information recording patterns is formed by a diffraction grating or hologram (3). Since such plural types of information can be formed at the same time and at high density, the present invention has a merit of its having excellent fake-proofness and its manufacturing process being simplified.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.