| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical head in which assembling performance is enhanced by relaxing relative positional accuracy between a hologram element and a photodetector, a high quality noise suppressed signal is obtained by simplifying a signal processing circuit and a focus error is detected accurately even in the case of a recording medium having multilayer recording/reproducing layer. SOLUTION: A polarizing hologram element 4 including the optical axis of laser light emitted from a laser light source 1 is divided into four regions by a first dividing line corresponding to the radial direction of a recording medium 7 and a second dividing line corresponding to the tangential direction of the recording medium 7. A focus error signal is detected at a light receiving section 9 for detecting focus error signal divided into four by a dividing line substantially parallel with the first dividing line of the polarizing hologram element 4 and a track error signal is detected at a light receiving section 10 for detecting track error signal divided into four by a dividing line substantially parallel with the second dividing line of the hologram element. |
