| 摘要 |
PROBLEM TO BE SOLVED: To reduce the resistant noise voltage by equipping one or two photosensor element(s) used for an RF signal for the purpose of receiving two beams split by a prism piece and outputting a signal for generating the RF signal. SOLUTION: Return light from an optical disk 150 is distributed by the optical head device with a quadripartite prism 20 to a photosensor element 31 used for a focus error signal and the photosensor elements 32 and 33 used for the RF signal. Consequently, a circuit for generating the focus error signal (A+C)-(B+D) and a circuit for generating the RF signal are individually arranged, and hence the number of resistors to be connected to the circuit for generating the RF signal can be reduced. |
