Wavelength-selective diffraction element and an optical head device
US6891147B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 2003 |
| Grant date | May 10, 2005 |
| Priority date | — |
| Expiry date | Dec 4, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical head device having an optical element capable of transmitting without diffracting light having a wavelength emitted from a two-wavelength semiconductor laser and capable of diffracting light having another wavelength, to provide high utilization efficiency of light in a stable manner.For this purpose, a wavelength-selective diffraction element 1A comprising a transparent substrate having a front surface on which a grating having a periodically recessed and projected shape in cross section is formed and a filling member 13A filled in the concavo-convex portion 12A of the grating wherein the concavo-convex portion of the grating is provided with an organic pigment having the absorption edge of light in a region having a shorter wavelength than the wavelength λ1, and the concavo-convex member and the filling member have the same refractive index with respect to either one of light having a wavelength λ1 and light having a wavelength λ2, and they have different refractive indices with respect to the other light having a wavelength, is disposed between the light source and the objective lens of the optical head device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.