| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a measuring instrument capable of accurately measuring the thickness of a workpiece or the height position of an upper surface of the workpiece by preventing false determination due to a noise signal during the cutting of the workpiece. <P>SOLUTION: In a measuring instrument for measuring a distance between two points up to the upper surface of the workpiece in a thickness direction based on reflected light reflected on the upper surface of the workpiece held by workpiece holding means and reference reflected light having a fixed optical path length, a spectral interference waveform is found out based on a detection signal from an image sensor which receives the reflected light reflected on the upper surface of the workpiece and the reference reflected light having the fixed optical path length, waveform analysis is executed based on the spectral interference waveform and a logical waveform function, a difference between absolute values of a value outputted at present and a value outputted before in signal intensity outputted correspondingly to an optical path length difference between the optical path length of the reflected light reflected on the upper surface of the workpiece and the optical path length of the reference reflected light, the difference of the absolute values is added to the value outputted at present in the signal intensity in each optical path length difference, and the optical path length difference having the largest added value is determined as the distance between two points up to the upper surface of the workpiece in the thickness direction. <P>COPYRIGHT: (C)2013,JPO&INPIT |
