Optical head, and information recording-and-regeneration apparatus
US7656775B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 2005 |
| Grant date | Feb 2, 2010 |
| Priority date | — |
| Expiry date | Jun 29, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical head that is restrained from becoming larger, even if it is used for an optical-information recording medium that includes a plurality of information recording layers. In this optical head, a collimating lens is formed by a concave lens disposed on the side of a light source and a convex lens disposed on the side of an objective lens. A collimating-lens actuator moves the convex lens in a direction where a spherical aberration is cancelled which is generated according to the thickness of a light transmission layer up to an information recording layer of the optical-information recording medium. An aperture stop is provided on the side of the collimating lens with respect to the objective lens, and the aperture stop is located near the focal position of the convex lens on the side of the objective lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.