Optical signal detecting circuit and information reproducing device using the same
US8576677B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 2009 |
| Grant date | Nov 5, 2013 |
| Priority date | — |
| Expiry date | Jan 12, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/10009
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An object of the present invention is to achieve both low noise and fast response in an optical signal detecting circuit capable of providing all of three signals—a focus error signal, a tracking error signal, and an RF signal—with only a single detection system. A single current-to-voltage converter converts a current signal obtained by adding currents flowing through two photodiodes, into a voltage signal. Not only currents flowing into the photodiodes, but also currents flowing out from the photodiodes are taken out as the voltage signals. Moreover, by applying two different reference voltages to the current-to-voltage converters, a reverse bias voltage is applied between the terminals of each photodiode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.