| 摘要 |
<p>PURPOSE:To eliminate a need of exact adjustment of the light intensity of a light source by detecting passage of an object to be measured based on the deviation of the phase of a signal which is obtained at the time when this object intercepts the light to each photodetector. CONSTITUTION:When an object 13 to be measured passes in front of plural light receiving elements, each light receiving element outputs a signal by light interception due to the object 13. Phases of signals from these light receiving elements are deviated because positions of photodetectors are shifted. A phase comparator 20 detects this phase deviation. Consequently, a user accurately detects passage of the object in accordance with the output of the phase comparator 20. Since the phase deviation is used, it is scarecely necessary to adjust the light intensity of the light source.</p> |
