| 摘要 |
PROBLEM TO BE SOLVED: To properly detect a focus error signal caused by astigmatism, and to miniaturize an entire head in an optical head dealing with plural optical recording media different in kind. SOLUTION: This device is provided with a light emission means having a relative positional relation between first and second light sources set such that a straight line connecting the spot position of a first laser light projected to an optical recording medium with the spot position of a second laser light projected to the optical recording medium is set at 45 deg.±15 deg. with respect to the recording track of the optical recording medium, plural light receiving parts disposed roughly in parallel with the straight line projected on a light receiving means, when the straight line connecting the spot position of the first laser light projected to the optical recording medium with the spot position of the second laser position projected to the optical recording medium, and the light receiving means having the plural light receiving parts divided into four parts in the shape of a cross surrounded by a square by dividing lines roughly parallel and vertical to a recording track on the signal recording surface of the optical recording medium. |
