| 摘要 |
PROBLEM TO BE SOLVED: To enable the recording and reproducing in two kinds of optical recording mediums having substrates of different thicknesses. SOLUTION: An outgoing light having a wavelength of 635nm from a semiconductor laser in the inside of a module 1 is converged on a disk 7 having a 0.6mm thick substrate such as a digital video disk. Reflected light from the disk 7 is received with a photodetector in the inside of the module 1. The outgoing light having a wavelength of 785nm from the semiconductor laser in the inside of the module 2 is converged on a disk 8 having a 1.2mm thick substrate such as a compact disk. Relected light from the disk 8 is received with a photodetector in the inside of the module 2. The length of the optical path with respect to a light having a wavelength of 785nm from the module 2 to a collimating lens 4 is shorter than the length of the optical path with respect to a light having a wavelength of 635nm from the module 1 to a collimating lens 4. |
