Optical pickup for reading or recording information on a recording surface
US5892748A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 6, 1996 |
| Grant date | Apr 6, 1999 |
| Priority date | — |
| Expiry date | Mar 6, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup reads or records information on a recording surface of a first optical record medium or a second optical record medium, each of which has a protection film different in thickness from each other. The optical pickup includes: a light beam source for emitting a light beam; a dividing unit for dividing the light beam into a non-diffracted light, which is a portion of the light beam other than diffracted lights, and a first order diffracted light; and a converging unit for converging the non-diffracted light and the first order diffracted light. Further, an optical path length between the light beam source and the converging unit is determined so that the non-diffracted light is converged onto the recording surface of the first optical record medium and a spherical aberration of the non-diffracted light converged onto the recording surface of the first optical record medium is minimized. And the dividing unit is constructed so that the first order diffracted light is converged onto the recording surface of the second optical record medium and a spherical aberration of the first order diffracted light converged onto the recording surface of the second optical record me…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.