Stein, McEwen & Bui, LLP
Optical pickup apparatus
An optical pickup apparatus includes a detection unit detecting a light beam reflected/diffracted by the recording medium and passing through the objective lens by dividing the light beam into a plurality of light areas, and a signal processor detecting a difference between widths T1 and T2 indicating that first and second focusing signals are greater than a predetermined threshold value and a thickness signal of the recording medium by using the detected difference when an S-curve of a focus error signal detected by using detection signals of the light areas output from the detection unit is obtained by subtracting a second detecting signal from a first detecting signal or by subtracting the first focusing signal from the second signal. Thus, a spherical aberration due to a change in thickness of the recording medium can be corrected by driving a spherical aberration correcting device according to a thickness signal corresponding to the change in thickness of the recording medium.
Samsung Electronics Co., Ltd.
G G G G
G11B G11B G11B G11B
inventional inventional inventional inventional
Jong-bae Young-man Tatsuhiro
Kim Ahn Otsuka