| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical head device which has two light sources and one photodetector, can carry out recording and reproduction to either of a disk of a DVD standard and the disk of a CD standard, does not cause a loss of a light quantity in an outward path and a return path, and can obtain a high light output in recording and high S/N at reproduction. SOLUTION: Most of emitted lights each having a wavelength of 650 nm from semiconductor laser 1a are reflected by a polarizing beam splitter 4a, and most of the lights transmit a polarizing beam splitter 4b, and are led to a disk 9. Most of emitted lights each having a wavelength of 780 nm from semiconductor laser 1b are reflected by the polarizing beam splitter 4b, and are led to the disk 9. Most of the reflected lights from the disk 9 transmit the polarizing beam splitters 4b and 4a, and are led to the photodetector 11a. |
