| 摘要 |
PROBLEM TO BE SOLVED: To deal with two kinds of optical disks with different standards by also light receiving return light of respective light beams from two light emitting elements emitting the light beams having different wavelengths with two light receiving elements. SOLUTION: An integrated optical element 11 is provided with first, second laser diodes 17, 19 respectively emitting light beams with different wavelengths to receive the return light of respective light beams by first, second photodetectors 13, 14 also. Thus, a regenerative signal and a control signal are read out from optical disks with different optimum wavelengths such as a CD and a CD-ROM, and the constitution is simplified. At this time, when the first laser diode 17 emits the light beam of the wavelength 780 nm, and the second laser diode 19 emits the light beam of the wavelength 650 nm, by using two optical thin films respectively having wavelength dependency, the light receiving amount of the first photodetector 13 is nearly equalized with the same of the second photodetector 14. |
