Diffraction grating, method of fabricating diffraction optical element, optical pickup device, and optical disk drive
US7511887B2 · kind B2 · utility
1Cited by
22References
17Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 8, 2006 |
| Grant date | Mar 31, 2009 |
| Priority date | — |
| Expiry date | Aug 8, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A diffraction grating with periodically arranged protrusions and grooves at a relatively narrow pitch and improved diffraction efficiency is disclosed. The protrusions of the grating are made of a material whose index of refraction is greater than that of the grooves, and the ratio of the width D of the protrusion to the pitch Λ of the protrusion is set equal to or less than 0.4 (D/Λ≦0.4).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.