| 摘要 |
PURPOSE:To attain to enhance the reliability and speed in measurement, by measuring the distance from the surface of a specimen in a non-contact state while controlling the accurate setting of a pick-up to a measuring position, and outputting a signal capable of also separating a waviness component. CONSTITUTION:The measuring surface of a specimen 6 is illuminated with laser beam from a beam source 1 to form the bright spot on the surface of the specimen 6 onto a sensor 5 by an image forming lens 3 and a cylindrical lens 4. The image 7 of the bright spot is obtained in the protruded part of the surface of the specimen 6 on the sensor 5 consisting of four split photoelectric converter elements 5a-5d and an image 9 is obtained in the recessed part of the surface of the specimen while an image 8 in the intermediate part thereof. On the basis of the outputs of the photoelectric converter elements 5a-5d, an averaged unevenness degree in the minute measuring region of the measuring surface is detected by simple operation. |
