Optical recording medium and optical recording/reproducing apparatus
US5097464A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1990 |
| Grant date | Mar 17, 1992 |
| Priority date | — |
| Expiry date | Jul 24, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A data playback apparatus for reproduction of data from an optical recording medium which has a data layer disposed on a substrate thereof having a specific thickness is provided with an optical length corrector interposed between the recording medium and an objective lens for converging a light beam. The optical length corrector is selected so that the sum of the optical length of the substrate of the recording medium and the optical length of the optical length corrector equals a predetermined length for the objective lens. Accordingly, the light passing the objective lens can converge on the data layer developing a light spot close to the limit of refraction, regardless of the thickness of the substrate of the recording medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.