Patent ID: 7036377

Claim:
An apparatus for calculating vibration displacement of a vibrator, the apparatus comprising: a mirror attached to a predetermined portion of the vibrator; a light emitting unit installed at a predetermined position spaced apart from the mirror and irradiating light on the mirror; a light receiving unit installed side by side with the light emitting unit, receiving light reflected by the mirror and generating an output voltage corresponding to the amount of the receiving light; and a vibration displacement calculating unit for calculating vibration displacement of the vibrator based on the generated output voltage, wherein the vibration displacement calculating unit comprises: an output voltage measuring unit for measuring output voltage values generated from the light receiving unit; a peak voltage detecting unit for detecting a maximum peak voltage value and a minimum peak voltage value among the measured output voltage values; and a microcomputer for calculating vibration displacement of the vibrator on the basis of the detected maximum peak voltage value and minimum peak voltage value and a previously measured shortest distance.