| 摘要 |
PURPOSE:To reduce the size and weight of the optical pickup by using the multifunction type Wollaston prism having the functions of a polarization beam splitter and a cylindrical lens in combination. CONSTITUTION:The multifunction type Wollaston prism which is constituted by providing a polarization separating film 17 for transmitting and reflecting the components of P polarized light and S polarized light respectively at prescribed ratios on the incident surface of the Wollaston prism formed by constituting and coupling rectangular prisms 19, 20 consisting of two pieces of crystalline bodies, for example, rock crystals and having 45 deg. other two angles in such a manner as to have <45 deg. angle psiformed of, for example, the incident surface and the coupling surface and to have the relation of the optical axes similar to the relation of the conventional prisms, is formed to a planar shape and is reduced in the size and weight is used. The reflected light of the luminous fluxes with which the incident surface is irradiated is condensed by an objective lens to an optical recording medium and the incident surface is again irradiated with the luminous flux reflected by the recording medium via the objective lens. The luminous flux transmitted through the incident surface is split to at least three pieces of the luminous fluxes according to the polarized light components thereof. These luminous fluxes are detected by a photodetector. |
