| 摘要 |
PURPOSE:To eliminate the position shift between a beam splitter and a reflecting surface and to facilitate the arrangement of various optical system devices by uniting the reflecting surface by which the beam splitter splits information luminous flux into pieces of luminous flux for focusing and tracking. CONSTITUTION:The information luminous flux S1 from an optical disk is made incident on the information luminous flux incidence surface 41 of the beam splitter 40 for an optical head. The ridge part between a projection surface 43 for information luminous flux where the incident information is reflected and projected by a splitting and reflecting surface 42 and the luminous flux incidence surface 41 is beveled in a plane and the beveled part is a reflecting surface 44. This splitter 40 is used for the optical head and light from a semiconductor laser 10 is made incident through a coupling lens 12 together with reflected light from the optical disk 20. The beveled reflecting surface 44 splits the information luminous flux into two pieces of luminous flux, which are projected from the splitter 40 and incident on a photodetection part 30 thereby eliminating the position shift between the splitter and reflecting surface.
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