| 摘要 |
PURPOSE:To minimize the number of optical parts by using polarized separated film to a dividing optical element to divide a reflecting optical flux from an information medium into two semicircle light fluxes for detecting a reflecting light flux, dividing it for a focus dislocation detection, simultaneously, separating it into two polarized components and obtaining even a magneto-optical signal from the difference of the light strength of two polarized components. CONSTITUTION:A P-polarizing component to the polarizing separating surface of a dividing prism 50 transmits polarizing separating films 55, 56 and 57 and comes to be a circular light flux 65 focused to a point 70. The right side half of an optical axis out of S-polarizing components of a reflecting light 5 is reflected by the polarizing separating film 55, comes to be a semicircle light flux 66, reflected by whole reflecting surfaces 59 and 60 of a rectangular triangular prism 58 and further, reflected by the polarizing separating film 57. The left side half of the optical axis out of S polarizing components of the reflecting light 5 is reflected by the polarizing separating film 56, comes to be a semicircle light flux 67 and further, reflected by the polarizing separating film 55. When the dividing prism 50 and the rectangular triangular prism 58 are used, three light fluxes 65, 66 and 67 can be arranged in the same direction. Thus, one photodetector to receive these light fluxes may be sufficient. |
