| 摘要 |
PROBLEM TO BE SOLVED: To finely detect a servo signal and to miniaturize a whole optical head by forming a diffraction grating at a sticking plane side of a member contacting with an end plane of a prism and the prism or a back side of it. SOLUTION: A reflected light from a disk 106 is returned to a rectangular prism 102 through an object lens 105, a collimator lens 104, and a 174 wavelength plate 104, it is passed through a flat plate 107, a RF signal is detected based on a light beam 108 of 0th order from a diffraction grating, a focus error signal and a tracking error signal are detected based on a light beam of a 1st order light 109. In this device, since the rectangular prism 102, optical sensors form detecting a focus error signal, a tracking error signal, and a RF signal, and head amplifier are stored in a capsulation 110 for emitting a laser beam, a size of the device is largely miniaturized. |
