| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent an erroneous detection of coordinates by alternately performing light emission from the light emitting parts of a plurality of optical units. SOLUTION: Two optical units 2a and 2b are driven while synchronized on the basis of a reference clock and alternately turned on and off. That is, when the light emitting part and CCD of the unit 2a are driven, the driving of the light emitting part and CCD of the unit 2b is stopped, and when the light emitting part and CCD of the unit 2b are driven, the driving of the light emitting part and CCD of the unit 2a is stopped. Since the driving of one optical unit 2a is synchronized with that of the other optical unit 2b to be alternately performed, the reflected light of laser beams emitted from the light emitting part of one optical unit 2a can be detected only by the CCD of the unit 2a, and error detection is not generated even though a part of the laser beams emitted from the light emitting part becomes diffused external light to intrude into the unit 2b.</p> |
