| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve a reduction in the number of components of an optical head device and the miniaturization of the optical head device. <P>SOLUTION: An optical head device includes: a single photodetector for receiving reflected light corresponding to light of a first wavelength range, light of a second wavelength range and light of a third wavelength range; first deflection means for transmitting S-polarized light of the second wavelength range and the third wavelength range and reflecting S-polarized light of the first wavelength range; second deflection means for reflecting S-polarized light of at least the second wavelength range and the third wavelength range and transmitting P-polarized light of the first wavelength range, the second wavelength range and the third wavelength range; a polarization hologram element for transmitting light of the second wavelength range and light of the third wavelength range in outward paths of the light of the second wavelength range and the light of the third wavelength range, and diffracting a portion of light of the first wavelength range in return paths of the light of the first wavelength range, the light of the second wavelength range and the light of the third wavelength range; and a 1/4 wavelength plate. The polarization directions of return path incident light to the polarization hologram element are aligned in the three wavelength ranges. <P>COPYRIGHT: (C)2013,JPO&INPIT |
