| 摘要 |
PURPOSE: An optical pick-up device is provided to form a diffraction pattern of an uneven shape in a polarization hologram device, thereby preventing inter-layer interference in a signal processing process for recording and reproduction. CONSTITUTION: A diffraction pattern(21) of an uneven shape is formed in a polarization hologram device(20). The diffraction pattern is composed of three block areas(21a-21c). The center of a block area is narrower than an upper part and a lower part of the block area. The polarization hologram device diffracts a beam, which is reflected in each layer of a blue-ray disk, and passes a main beam of a target layer.
|
