DEVICE FOR OPTICALLY MEASURING SURFACE HEIGHT OF OBJECT

摘要

PURPOSE: To measure the height of an object optically with high sensibility. CONSTITUTION: An optical height measuring apparatus according to the trigonometrical measuring principle is provided with a first imaging system 20 for imaging a radiation spot on a surface 10 to be measured on a screen 30. The radiation spot 11 is formed of beams 2 impinging on the surface 10. The screen 30 is imaged on a position-detection radiation detecting system 50 by a second imaging system 40. The screen 30 is formed such that the radiation impinging from the surface 10 close to the screen 30 exits the screen toward a detecting system 50 nearly in the vertical direction, and the high correlation between the height ΔZ of the surface 10 and an image 51 in the position of an image 51 on the detecting system 50 is combined with the nearly vertical impingement of the radiation on the surface of the detecting system, so that the reflection from the surface of the detecting system 50 almost disappears.