粗さ測定のための光スキッド法(第1報)

原理と試作機の基本性能

抄録

A noncontact optical method for roughness measurement named optical skid method is presented. This method is developed to measure surface roughness accurately under large datum errors introduced by scanning motion, vibration, and thermal deflection. The principle of this method is similar to the typical skid method. Instead of the stylus and the skid, two laser spots with different size (1.2 μm and 400 μm in diameter) are used to detect surface profile simultaneously. The difference between these two signals gives surface roughness information excluding datum, errors. Based on this principle, a very compact sensor using astigmatic focus error detection method has been developed. Experiments with this sensor have shown that it can reduce datum errors by 20 dB and can possibly be used to measure the roughness of a curved surface.