| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup system simpler in structure and capable of reading plural optical disks different from each other in thickness by providing an optical device having different focal distances instead of an objective lens and a holographic optical element(HOE). SOLUTION: A beam splitter 204 reflects a part of light beams from a light source 202 on the recording surface 214 or 220 of the optical disk selected from a thick optical disk 216 and a thin optical disk 218. The optical device 206 is composed of a first port 208 and a second part 212 having the different focal distances corresponding to the respective thicknesses of the optical disks 216 and 218. The light beams reflected on the beam splitter 204 are passed through the parts 208 and 212 of the optical device 206 and divided into two parts, one of them is converged on the recording surface of the corresponding optical disk and another one is not converged. The converged light beams are reflected, made incident on a photodetector 222 through the optical device 206 and the beam splitter 204 and detected. |
