Device for detecting light transmissivity of detected object and record and/or reproducing apparatus using same
US4905106A · kind A · utility
1Cited by
2References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 22, 1989 |
| Grant date | Feb 27, 1990 |
| Priority date | — |
| Expiry date | May 22, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B15/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A device for detecting the light transmissivity of an object to be detected comprises a light emitting element and a light receiving element which are opposed to each other across the detected object. The device is arranged to cause the light emitting element to intermittently emit a light and to detect the light transmissivity of said detected object on the basis of a detection signal obtained from the light receiving element when the light is emitted by the light emitting element and another detection signal obtained from the light receiving element when no light is emitted by the light emitting element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.