Optical disc and optical system for reproducing the optical disc
US5436885A · kind A · utility
24Cited by
5References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 8, 1994 |
| Grant date | Jul 25, 1995 |
| Priority date | — |
| Expiry date | Mar 8, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/2572
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disc has a recording film with information recorded thereon, and a photochromic material film provided adjacent the recording film. The photochromic material film is made of a photochromic material. The photochromic material has a first state irradiated with reading light having a first wavelength. In the first state, the transmittance of the material is increased so as to enable reading of the recorded information. The photochromic material further has a second state irradiated with auxiliary light having a second wavelength, where the transmittance becomes low so as to disable the reading of the recorded information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.