| 摘要 |
An optical pickup apparatus is provided to acquire a stable track error signal even in an off-axis array by eliminating AC component of a sub signal with a diffraction grating. An optical pickup apparatus comprises a light emitting unit, a diffraction grating(140a,140b,140c), and a light receiving unit. The light emitting unit is configured to generate beam projected to a recording medium. The diffraction grating divides diffraction light, which is diffracted by the recording medium, according to the number of diffraction. The light receiving unit is configured to receive the beam divided by the diffraction grating. The light emitting unit projects one beam to the recording medium. The diffraction light includes a 0 beam and a ±1 beam. 0 beam and +1 beam, and 0 beam and -1 beam overlap partially when reflected from the optical disk. The light receiving unit receives a main signal and a sub signal. The 0 beam, passed through the diffraction grating, is the main signal. The ±1 beam, passed through the diffraction grating, is the sub signal. |
