| 摘要 |
PURPOSE:To accurately discriminate the end part of an article to be measured even if the number of rotations of a motor vary and the article to be measured displaces, by correcting the interval of the output pulse of a binarization circuit during scanning in a correction circuit. CONSTITUTION:The light from a light projection element 1 is scanned plural times and the end part of an article 6 to be measured is discriminated from the output signal of a photodetector 7 generated by shielding the article 6 to be measured arranged between the element 1, and photodetector 7. At this time, the light receiving signal (a) of the photodetector 7 reaching from the element 1 is amplified and binarized by an amplifier 8 and inputted to a pulse converter 19 as a pulse (g). The pulse group (h) outputted from the pulse converter 19 corresponding to the rising and falling of the pulse (g) is constituted of four extremely short pulses. The clock pulse outputted from an oscillation circuit 11 is counted by a count circuit 12 and the signal thereof is transmitted to a latch circuit 20. The latch circuit 20 latches the count signal on the basis of the pulse group (h) to transmit the same to a correction circuit 21 where correction is performed on the basis of the difference between the count values of previous and present signals to measure the accurate outer diameter of the article 6 to be measured.
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