A new method is proposed for profile measurements using a right-angle prism. With this method, the distance to an object surface is measured by using triangulation based on a change of the critical angle of total reflection. An object surface is illuminated by a scanning laser beam and the incident angle of the scattered light into the prism is measured using the change in the critical angle. Three-dimensional profiles of objects with rough surfaces can be measured with high accuracy.
© 1991 Optical Society of America
Tetsuya Matsumoto, Yoichi Kitagawa, Masaaki Adachi, and Takumi Minemoto, "Profile measuring method based on reflection characteristics at a critical angle in a right-angle prism," Appl. Opt. 30, 3205-3209 (1991)