| 摘要 |
PURPOSE:To measure the quantity of surface deflection and the quantity of inclination variation of the surface of an optical disk by measuring the upper and lower positions and inclination of the surface to be measured on the basis of an output which varies according to the spot position of the photodetection surface of a photodetecting element. CONSTITUTION:The position of the spot on the light receiving surface of the light receiving element 8 which is obtained through the 2nd optical systems 4 and 7 varies according to the up/down movement and inclination of the surface 3f to be measured. The position of the spot on the light receiving surface of the light receiving element 6 which is obtained through the 3rd optical systems 4 and 5 varies with only the inclination of the surface 3f to be measured because the light receiving surface is at the focus positions of the optical systems 4 and 5. The up/down position and inclination of the surface 3f to be measured is measured on the basis of outputs SX6 and SY6, and SX8 and SY8 which vary with the spot positions on the light receiving surfaces of the light receiving elements 6 and 8 to know the quantity of surface deflection and the quantity of inclination variation of the surface 3f to be measured. |
