| 摘要 |
PROBLEM TO BE SOLVED: To enhance utilization efficiency of light emitted from a semiconductor laser as a light source, and also to realize a satisfactory light pickup function. SOLUTION: In a light pickup unit with which a recording surface 101 of an optical recording medium 100 is irradiated with a luminous flux from a semiconductor laser 10 as a light source, through a diffraction grating (formed at a diffraction grating element 12), and executes write-in and/or reproduction of information while receiving a return luminous flux reflected by the recording surface 101 by a light receiving means 30 through a diffraction grating 12, the diffraction grating has different diffracting actions according to polarized states of transmitted luminous flux and is a polarization hologram diffracting the return luminous flux, and the light receiving means 30 which receives the return luminous flux diffracted by the diffraction grating has its light transmission part 31 and light receiving part 32 which are integrated with each other and is arranged near the light source, while the light transmissing part 31 is made facing opposite to a light emitting part 11 of the light source. |
