| 摘要 |
PROBLEM TO BE SOLVED: To provide a distance sensor which can further shorten the time required until a distance is sensed after an object to be detected is positioned in a sensing area. SOLUTION: By a CPU, the gain of a variable-gain amplifier is stored in a RAM when the sum C of light receiving signals is within a prescribed range (L<C<H) ((4)). When the sum C of the light receiving signals is less than a lower-limit value L (=C') even when the gain is set to be maximum, the gain of the variable-gain amplifier is set to a value stored in the RAM until the sum C is changed ((5), (6)).
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