| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a simple and low cost optical pickup apparatus by preventing a decrease of light utilization efficiency when an outgoing light of a semiconductor laser generating the lights of two or more wavelengths is divided into three beams. <P>SOLUTION: This optical pickup apparatus 200 comprises the semiconductor laser 201 emitting the lights of two or more wavelengths, a photodetector 202, a diffraction element 203, a hologram element 204 and a converging means 205. The diffraction element 203 is divided into two areas on the same plane, includes two areas such as the area 203A for reshaping the light beam L1 of wavelength λ1 to three beams and the area 203B for reshaping the light beam L2 of wavelength λ2 to three beams. Also, the diffraction element 203 is divided so that an effective portion of the light beam L1 does not be made incident to the area 203B and an effective portion of the light beam L2 does not be made incident to the area 203A. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
