| 摘要 |
PROBLEM TO BE SOLVED: To lower the price and improve the reliability by making a photodetection part and an optical detector small-sized and making it hard for diffracted light generated in a hologram grating area to enter the aperture of a lens and a diffraction grating area. SOLUTION: This optical pickup head device makes it harder to make primary diffracted light enters the aperture of a lens 8 than a conventional optical pickup head device which is given lens operation in an X direction. Therefore, the angles of diffraction of primary diffracted lights 73 and 74 generated in the holographic grating area 7B can be made less than those of the conventional optical pickup head device, so photodetection parts 3A-3J of the optical detector 3 can be formed at the center part of the optical detector 3. Consequently, the optical detector 3 can be made small-sized. |
