发明名称 DEVICE AND METHOD FOR DETECTING FOCUS ERROR SIGNAL
摘要 PROBLEM TO BE SOLVED: To provide a focus error signal detector which has less fluctuation of focus zero cross on change of temperature and which reduces noise to be generated in the case of RF signal detection. SOLUTION: Light reflected on an optical disk 6 returns on the same route as the incident route and, after passing a collimator lens 2, deflects by 90 degrees by a polarizing beam splitter 7. After the 90 degree deflection, the light goes through a linearly arranged double Foucault prism 8, concave lens 9 and diffraction grating 11, and reaches a focus error signal/RF signal detecting sensor 12. The light diffuses at the diffraction grating 11. The focus error signal/RF signal detecting sensor 12 is a five-division sensor, in which one sensor element receives 0-order light while four other sensor elements receive +1 order light of -1 order light. The focus error signal/RF signal detecting sensor 12 detects an RF signal by the 0-order light and a focus error signal by the +1 order light or -1 order light.
申请公布号 JP2001134959(A) 申请公布日期 2001.05.18
申请号 JP19990314448 申请日期 1999.11.04
申请人 NEC CORP 发明人 MATSUI TSUTOMU
分类号 G11B7/09;G11B7/135 主分类号 G11B7/09
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