DIFFRACTION ELEMENT AND OPTICAL PICKUP DEVICE

摘要

PURPOSE:To obtain a diffraction element without the deviation of the optical axis of optical parts even when the adjustment of a tracking error signal is carried out without complicating the assembling and to obtain an optical pickup device using this diffraction element. CONSTITUTION:A sliding part 106C with a cylindrical surface making the optical axis 107 of a diffraction element 106 a central axis is provided on at least a part of the diffraction element 106 manufactured by integrally forming a diffraction grating 106B together with a hologram 106A and assembling is completed only by positioning the diffraction element 106 at the position where a photodetector 104 is aligned on the position of emitted light from a light source 103 (the assembled object is called an optical unit 108). A hole is provided on a holding member 111 holding an objective lens 112, the sliding part 106C of the diffraction element 106 is engaged with the hole and the adjustment of a tracking error signal is performed by rotating the optical unit 108 on the engaged part.