| 摘要 |
PURPOSE:To expand the measuring extent in a short-distance range, by providing a reflection mirror at the end of a semiconductor incident position detecting device on the incident side of beam and making reflecting light from a short distance outside the end of incident side to be reflected inward. CONSTITUTION:The light of an LED is condensed by means of a lens l1 and projected into the front space. The reflecting light from an object Ob in the front space is made incident on an area on the left side of a semiconductor incident position detecting device PSD by means of a lens l2. The device PSD outputs the outputs I1 and I2 corresponding to the incident positions. A distance arithmetic circuit C calculates the distance to the object (ob) from the outputs I1 and I2 and outputs the calculated distance. The same lens is used for the lenses l1 and l2 and the lenses are installed to the same position. A very small reflecting plate M which leads rays of light made incident on the outside of the device PSD inward is provided on the left side of the device PSD. |
