| 摘要 |
PURPOSE:To make the device compact and to facilitate its assembling by providing optical fibers for maintaining polarization plane between a polarizing prism and a light head and dividing the optical system constituted of the optical fibers for maintaining polarization plane. CONSTITUTION:Light from a laser light source 10 enters a polarizer 12 through a coupling lens 11 and linearly polarized. The linearly polarized light passes a polarizing prism 13, and after condensed by a coupling lens 14, projected in conformity to a principal axis 20 of the optical fiber for maintaining polarization plane. The light irradiated on the disk face 15 is converted to linearly polarized light perpendicular to the light at the time of incidence, condensed by a condenser lens 16 and projected again to the optical fiber 19 for maintaining of polarization plane in conformity to its another principal axis 21. Thus, the Whole optical system of the laser pickup is divided into two independent optical systems, i.e. an optical system of the laser light source side 10 and an optical system of disk face 15 side. Accordingly, restricting conditions for relative geometric arrangement of optical parts such as the polarizer 12, polarizing prism 13, quarter-wavelength plate 17, etc. are required for each optical system. Therefore, restricting conditions relating to geometrical arrangement between optical parts are relaxed. |
