| 摘要 |
PURPOSE:To perform stable tracking servo, by forming the light receiving section of reflected luminous fluxes from an optical recording body at both sides of a track guiding groove, upon which the luminous fluxes are projected, from the 1st and 2nd light receiving areas and detecting the inclination through the difference in the output of the light receiving quantity. CONSTITUTION:A luminous flux of a semiconductor laser, etc., is made incident to an optical disk D and its returning luminous flux reflected by a thin film 2 is made incident to the light receiving section PD of a light detecting body. When the optical disk D with track guiding grooves PG at intervals of a pitch (q) in the direction normal to the length is read out, the returning luminous flux is determined by the overlap of diffracted lights and its location is decided by the pitch (q) and the numerical aperture NA and wave length lambda of an objective lens 3. Since the phase difference varies in accordance with the inclination of the optical disk D, the distribution of light quantity varies in accordance with the inclination of the optical disk D only. The deviation quantity of the difference in the light quantities of the 1st and 2nd light receiving sections PD1 and PD2 at both sides of the track guiding groove PG is detected as the information regarding the inclination of the optical disk D and errors in tracking error signals can be corrected. |
