Movable optical head integrally incorporated with objective lens and hologram element
US5648951A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1995 |
| Grant date | Jul 15, 1997 |
| Priority date | — |
| Expiry date | Apr 3, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0912
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is a compact optical pick-up head apparatus suitable for mass-production, which comprises a light radiation source, an element composed of photodetector split into a plurality of regions and integrated on the same base, an objective lens for focusing a beam from the above source on an optical disk, a blazed hologram integrated to the support member of the lens, a means for driving the support member to which the objective lens and blazed hologram are integrated in response to an output as servo signal output from the photodetector which receives a diffracted beam produced in such a manner that a return beam reflected or diffracted by the optical disk is incident on the objective lens integrated with the above hologram. The optical pickup apparatus according to the present invention employs a region-split-type phase hologram in which a pair of Flesnel zone plate-like patterns, by which a plurality of diffraction wavefronts having a different focus and the same diffraction order are produced outside an optical-axis, are non-superimposedly formed. The above hologram can be blazed with a pinpoint accuracy by lithography using a few mask patterns synthesized by a computer, and…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.