| 摘要 |
PROBLEM TO BE SOLVED: To provide a position detector for accurately measuring a position, even if the ambient temperature and moisture change. SOLUTION: Light, reflected by a beam splitter 3 in a light transmitted through a collimate lens 2, is condensed on the light-receiving surface of a CCD 9 by a condensing lens 8. As shown in Figure, when a light source 1 is vibrated and the position of light beams is changed, the position of light beams entering the CCD 9 changes, thus determining the vibration center of light beams from the variations in the output of the CCD 9. A control unit 10 detects the vibrating center, and controls the voltage applied to a piezo element 11 for shaking the light source 1 so that the vibration center becomes a predetermined position. In this manner, since the vibration center position of light beams that becomes the reference of position measurement is always maintained constant with respect to the detection head, measurement errors accompanying the variations in the vibration center position of the light beams does not occur, even if the ambient temperature/moisture change, thus eliminating generation of deterioration in accuracy. COPYRIGHT: (C)2007,JPO&INPIT
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