| 摘要 |
PROBLEM TO BE SOLVED: To improve detection accuracy of position for moving subject to be detected. SOLUTION: This sensor 100 is composed of a light emitting element 101, a light receiving element 102, a constant voltage circuit 103, a signal processing circuit 104, an OSC (oscillator circuit) 105, an amplifier 110, a comparator 111, an output circuit 112, a pulse drive circuit 113, resistances R1, R2, R3, and R4, a capacitor C1, a transistor Q1, and input and output terminals of a power input terminal 120, a sensor output signal terminal 121, a first sensor input signal terminal 122, a second sensor input signal terminal 123, and a ground input terminal 124. In a method to determine if the subject to be detected 130 exists or not, lighting light 140 pulse-lighted from the light emitting element 101 is radiated to the subject to be detected 130, and reflected light 141 from the subject to be detected 130 is received by the light receiving element 102. The pulse number of reflected light 141 synchronized with the lighting light 140 is counted, and in a case where the continuously counted pulse number exceeds a predetermined value, a signal representing that the subject to be detected 130 exists is outputted from the sensor output signal terminal 121. In a case where the subject to be detected 130 moves, the predetermined value for the pulse number is varied, or lighting frequency of the lighting pulses is varied in accordance with moving speed. Irregularity due to moving speed of the subject to be detected 130 can thus be corrected, and detection accuracy of position for the subject to be detected 130 can be improved. COPYRIGHT: (C)2005,JPO&NCIPI
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