| 摘要 |
PURPOSE:To obtain a miniaturized and light weight optical pickup which does not need to adjust the optical axis of a lens system by making the structure of a waveguide path type lens on a side, which projects a light beam from a semiconductor laser to a recording medium, different from that of a waveguide path type lens on a side which detects the reflected light from the recording medium. CONSTITUTION:The titled optical pickup has the waveguide path type lens 14 having the pattern of grating, which converts the divergent waveguide light 20 from the semiconductor laser 17 into a convergent light which is condensed on one point in the space and the waveguide path type lens 15 having the pattern of grating, which introduces the reflected divergent light from the recording medium 19 arranged in the position of the condensing point 24 in the waveguide path again and converts it into parallel waveguide light 21, as entities. The asymmetry against the center of lens of electric field components caused by a Kerr rotation in the recording medium 19 is fetched as the difference of a two-division photodiode 18 so as to detect the direction of vertical magnetization, that is a signal, recorded in the recording medium 19. Thus, a bulk-shaped lens and a prism, etc., are not needed, so that the miniaturized and light weight optical pickup can be obtained. |
