| 摘要 |
PURPOSE:To obtain a small-sized optical pickup by a utilizing a polarization beam splitter as a 4-terminal network, and nearly superposing an optical path for incident luminous flux on that for reflected luminous flux spatially. CONSTITUTION:A polarization beam splitter 30 is formed by sticking two right- angled prisms and fixing the 1st-3rd lambda/4-wavelength plates 50a-50c to respective sides. The 1st and 2nd reflecting mirros 160a and 160b are provided on the left and right-hand sides of the splitter 30, and an electrostrictive element left and right-hand sides of the splitter 30, and an electrostrictive element is fitted to a metallic cantilever instead of a conventional oscillatory mirror; and a semiconductor laser 100 performs self-exited oscillation to wobble. Consequently, the splitter 30 is utilized as a 4-terminal network and an optical path of incidence is nearly superposed upon an optical path of reflection from a disk 100 spatially to reduce the size of the device because the oscillatory mirror and an actuator are removed. |
