Optical recording medium
US4245229A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 26, 1979 |
| Grant date | Jan 13, 1981 |
| Priority date | — |
| Expiry date | Jan 26, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/258
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording medium is disclosed which comprises a reflecting material, the surface of which is characterized by cavities of average depth D and of average spacing S such that for incident radiation of wavelength .lambda., S is less than about .lambda./20 and D is either greater than .lambda./6 or less than .lambda./6 and is capable of being altered to either less than or greater than .lambda./6, respectively. In the practice of the invention, the heat from a high intensity energy source, such as a laser operating in the ultraviolet, optical or near-infrared region or a beam of electrons, softens the reflective material at the surface and, depending on the sign of the surface energy, either increases or decreases D, thus lowering or raising the reflectivity of the surface, respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.