| 摘要 |
PROBLEM TO BE SOLVED: To suppress the rise of the noise level of a laser noise generated when a returned laser beam is returned again to a semiconductor laser even when an I/O length is shortened accompanying miniaturization of a device. SOLUTION: By irradiating an optical disk 2 with a laser beam oscillated by a laser coupler 3 through an objective lens, a signal is recorded in the optical disk or by receiving the returned light beam with the laser coupler through the objective lens, the recorded signal of the optical disk is read out. In the optical pickup device, by forming a half transmissive film 8 on the surface 4a of the objective lens, the transmissivity of the objective lens is made to be 80% and the coupling efficiency is attenuated by 36%. |
