Optical head for optical recording having a hologram element that generates multiple diffracted light beams of different orders
US7120107B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 28, 2000 |
| Grant date | Oct 10, 2006 |
| Priority date | — |
| Expiry date | Jul 6, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0912
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical head is provided, which suppresses the offset in the tracking error signal. This head comprises (a) a light source for emitting a light beam to be irradiated to an optical recording medium as an incident light beam; (b) a hologram element for receiving a reflected light beam generated by reflection of the incident light beam on the medium to generate at least two diffracted light beams for focusing error detection and at least two diffracted light beams for tracking error detection; and (c) an optical detector for detecting the at lease two diffracted light beams for focusing error detection and the at least two diffracted light beams for tracking error detection; the detector including a first receiving surface for receiving the at least two diffracted light beams for focusing error detection and a second detection surface for receiving the at least two diffracted light beams for tracking error detection; each of the first and second receiving surfaces being divided into receiving regions; the at least two diffracted light beams for focusing error detection being received at the receiving regions of the first receiving surface; the at least two diffracted light beams fo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.