Optical head apparatus and optical information recording and reproduction apparatus
US7177101B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 2002 |
| Grant date | Feb 13, 2007 |
| Priority date | — |
| Expiry date | Feb 24, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is an optical head apparatus comprising: a light source; a collimating means of converting a beam of light emitted from the light source into a substantially parallel beam of light; a focusing means of focusing the light onto an information medium surface; a beam splitting means of splitting the beam of light modulated by the information medium; and a light receiving means of receiving the light modulated by the information medium, wherein a lens having a negative power and a lens having a positive power are arranged in this order as viewed from the collimating means side between the collimating means and the focusing means, and at least either one of the lenses is moved along an optical axis to correct spherical aberration occurring on the information medium surface, and wherein the distance from the lens having the positive power to the focusing means is set substantially equal to the focal length of the lens having the positive power.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.