Information reading apparatus and information recording medium
US6729541B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1999 |
| Grant date | May 4, 2004 |
| Priority date | — |
| Expiry date | Jun 29, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C13/042
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An information reading apparatus can detect the coupling state of the input light to a waveguide of a laminated recording medium in a simple manner, so as to enable to focus the input light on a target recording layer to access the information recorded in the target recording layer quickly. The apparatus is compact and is economical to produce. The apparatus has a light source for injecting a light on an input edge of a lamination recording section, assembled into the recording medium containing a lamination of recording layers. Each recording layer has data represented by scattering centers which diffract an input light generated by a converging lens. An input light directing device directs the light source and the converging lens as a unit to focus the input light on a desired location. An image recording device records an informational image generated by guided waves produced within a laminated waveguide. An optical power detector detects output light emitted from an output edge of a specific recording layer as well as scattered light generated from recording layers other than the specific recording layer. An optical power discrimination circuit determines whether an optical pow…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.