Optical head device
US6510119B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 2000 |
| Grant date | Jan 21, 2003 |
| Priority date | — |
| Expiry date | Dec 4, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A light source (1) is composed of a single element having a light emitting point (2S) emitting a light (3S) and a light emitting point (2L) emitting a light (3L) at a longer wavelength than the light (3S), the light emitting point (2S) and the light emitting point (2L) being formed monolithically. In the direction parallel to the optical axis of a collimator lens (6), the light emitting point (2S) is placed closer, than the light emitting point (2L), to the collimator lens (6) and is placed on the side of the inclined plane (7a) of the beam shaping prism (7). The incidence angles of the light (3S) and the light (3L) to the inclined plane (7a) are set so that the incidence angle of the light (3S) is larger than that of the light (3L) and so that the lights (3S) and (3L) exit from the inclined plane (7a) at equal exit angles. The collimator lens (6), the beam shaping prism (7), etc. have refractive indexes which become larger as the wavelength of incident light becomes shorter. It is then possible to simplify the structure and reduce the unstableness of operation caused by a difference in light wavelength.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.