Hologram media reading apparatus
US7957045B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 2008 |
| Grant date | Jun 7, 2011 |
| Priority date | — |
| Expiry date | Dec 17, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0065
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A hologram media reading apparatus including a reference light source, a stop with gray level aperture, and an optical sensor is provided. The reference light source is disposed on one side of a hologram medium, and capable of emitting a reference light beam. The reference light beam is transmitted to the hologram medium. The stop with gray level aperture and the reference light source are disposed on the same side or opposite sides of the hologram medium. The stop with gray level aperture has a light transmissive region, an opaque region, and a transmittance gradually varying region. The opaque region surrounds the light transmissive region. The transmittance gradually varying region surrounds the light transmissive region. A part of the reference beam from the hologram medium passes through the stop with gray level aperture and is transmitted to the optical sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.