| 摘要 |
PURPOSE:To widen a detection distance range by setting a detection distance long and to prevent erroneous operation when an object moves in a direction traversing an optical axis, by forming the light receiving lens of a light receiving means from an anamorphic lens. CONSTITUTION:Since an anamorphic lens is used as the light receiving lens 5 constituting a light receiving means 6, line-shaped condensed spots S are always formed on photodiodes 8a, 8b. These spots S move in directions S1-S3 corresponding to the movement of an object to be detected in a light projecting direction. Therefore, a detection distance is set long and a detection distance range can be widened. When the object to be detected moves in a direction traversing an optical axis, a whole of a illuminance level changes as shown by (a)-(c), the illuminance distribution of each spot in a line length direction becomes almost constant and, therefore, the ratio of the position detection signals IA, IB outputted from the photodiodes 8a, 8b does not change and an accurate distance signal is always obtained and no erroneous operation is generated.
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