Diffraction element and optical pick-up apparatus having the same
US7593306B2 · kind B2 · utility
2Cited by
3References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 24, 2006 |
| Grant date | Sep 22, 2009 |
| Priority date | — |
| Expiry date | Sep 22, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1381
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A diffraction element for an optical pick-up apparatus is provided that enables more accurate focusing control. The diffraction element for an optical pick-up apparatus is divided into first and second regions, each being formed with a grid pattern in which grids are repeated with a predetermined pitch P. The grid pattern in at least one of the first and second regions is tilted by a predetermined angle with respect to a virtual line VL substantially perpendicular to a division line DL that divides the first and second regions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.