Polarization hologram lens, optical pickup, information reproduction apparatus and information recording apparatus
US6518555B1 · kind B1 · utility
8Cited by
5References
17Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 17, 1999 |
| Grant date | Feb 11, 2003 |
| Priority date | — |
| Expiry date | Mar 17, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A polarization hologram lens includes: a first portion, positioned at a center of the hologram lens, on which no grating pattern is formed; and a second portion, positioned at an outer circumferential area of the first portion, on which grating patterns are formed, wherein the grating patterns do not diffract a light beam of a first polarization direction, and wherein the grating patterns diffract a light beam of a second polarization direction perpendicular to the first polarization direction to produce a diverging diffracted light or a converging diffracted light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.