Straightness measurements by use of a reflection confocal optical system

Straightness measurement is a very important technique in the field of mech anical engineering. A particular application for straightness measurement i s high-accuracy machining on a diamond-turning lathe. We propose a novel, t o our knowledge, optical method for measuring the straightness of motion, a nd its mathematical analysis is outlined. The technique is based on measure ment of the lateral displacement of point images by use of reflection confo cal optical systems. The advantages of this method are that (i) the lateral displacements in the direction of the two axes perpendicular to the optica l axis can be measured, (ii) the rotation angles around all three axes can be measured, and (iii) reflection optical systems are more compact in lengt h than are transmission optical systems. (C) 1999 Optical Society of Americ a. OCIS codes: 080.0080, 220.1140.