| 摘要 |
PURPOSE:To obtain a separation type optical pickup device with unreduced incident light quantity to an information recording medium and detecting the inclination angle of 5 tracking mirror with high sensitivity. CONSTITUTION:On a fixed optical system 10, a prism 14 for shaping a beam is arranged on the objective side of a tracking mirror 13 and a part of an incident beam on the prism 14 is reflected by the incident end surface of a light shielding part consisting of a reflection film 42 formed on the prism incident surface and taken out, and the inclination angle of the tracking mirror 13 is detected by a bisected photodetector 16. Another beam splitter for detecting the inclination angle is unnecessary, as well to be provided. No shortage of the light quantity of an irradiating beam to a magneto-optical disk 80 occurs and the inclination angle of the tracking mirror 13 is detected before the beam is shaped and the angle is detected with high sensitivity and with large angle change and then detective sensitivity is improved. The light shielding part of the reflection film 42 serves also as a means realizing a super resolution optical system. |
