Optical pickup device
US7355933B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 7, 2003 |
| Grant date | Apr 8, 2008 |
| Priority date | — |
| Expiry date | Nov 29, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0903
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Substantially all of the laser light emitted from laser chip(s) 11 toward optical disk(s) 17 may be transmitted through polarizing hologram(s) 13 and may thereafter be transmitted through quarter-wave plate(s) 15, and after being reflected at optical disk(s) 17, may again be transmitted through quarter-wave plate(s) 15 and be incident on polarizing hologram(s) 13. Accordingly, where laser light is transmitted twice through quarter-wave plate(s) 15, the direction(s) of polarization thereof may be rotated by 90 degrees before it is incident on polarizing hologram(s) 13. For this reason, even if laser light is p-polarized when it is transmitted through polarizing hologram(s) 13 from laser chip(s) 11, it may be s-polarized when it is again transmitted through polarizing hologram(s) 13 after being reflected from optical disk(s) 17. Laser light, after being made s-polarized, may be diffracted by polarizing hologram(s) 13, which diffracts only s-polarized light. Light of order ±1 produced as a result of diffraction of laser light by polarizing hologram(s) 13 may be incident on photodiode(s) 18.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.