Optical pickup
US7075865B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2003 |
| Grant date | Jul 11, 2006 |
| Priority date | — |
| Expiry date | Jul 28, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup includes a semiconductor laser for emitting light at a wavelength λ1 and a semiconductor laser for emitting light at a different wavelength λ2 from the wavelength λ1. The light at the wavelength λ1 transmitted through an objective lens forms a light-collecting spot on an optical disk to record/reproduce information thereon. The light at the wavelength λ2 transmitted through the objective lens forms a light-collecting spot on an optical disk to record/reproduce information thereon, the two optical disks having different substrate thicknesses. Between the semiconductor laser and the objective lens is there provided a combination-type diffractive element fabricated by combining two raw materials having different refractive index behaviors in relation to wavelength at a combining plane shaped as a grating. The structure facilitates good recording/reproduction on the two types of recording media irrespective of the reproduction wavelengths or substrate thicknesses of the recording media.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.