OPTICAL HEAD AND OPTICAL DISC DEVICE

摘要

The present invention aims to provide an optical head and an optical disk device capable of suitably detecting tracking error signals for different types of optical discs. A polarizing hologram element includes a first area and a second area adjacent to the first area in an area where a beam reflected and diffracted by a BD passes. The first area includes a first transmission area for transmitting many 1^st-order diffracted lights from the BD, a second transmission area adjacent to the first transmission area and closer to an optical axis than the first transmission area, and a third transmission area adjacent to the first and second transmission areas. The second area includes a fourth transmission area for transmitting many 1^st-order diffracted lights from the BD, a fifth transmission area adjacent to the fourth transmission area and closer to the optical axis than the fourth transmission area, and a sixth transmission area adjacent to the fourth and fifth transmission areas.