Optical pickup device
US5392274A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 15, 1992 |
| Grant date | Feb 21, 1995 |
| Priority date | — |
| Expiry date | Dec 15, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10545
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an optical pickup device, signal light is reflected on an optical disk and is converged by a condenser lens. A polarizing plane of the signal light is rotated 45.degree. by a 1/2 wave plate. The signal light is then incident to a polarizing beam splitter at an incident angle .theta.. The polarizing beam splitter is constructed by a plane parallel plate having a polarizing coating film. An s-polarized component of light reflected on the polarizing beam splitter is received by first divisional light-receiving elements and a difference signal between outputs of the first divisional light-receiving elements is set to a tracking control signal. A p-polarized component of light transmitted through the polarizing beam splitter is received by second divisional light-receiving elements and a difference signal between outputs of the second divisional light-receiving elements is set to a focusing control signal. Sum signals of the first and second divisional light-receiving elements are respectively inputted to a reproducing signal detector. The reproducing signal detector obtains a reproducing signal of recorded information by calculating a difference between these sum signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.