| 摘要 |
PURPOSE:To enable selection of a distance step of a lens as desired, by detecting a distance to an object in analog signal utilizing a semiconductor position detecting element such as optical potentiometer as light receiving element to stop a photographing lens based on the signal. CONSTITUTION:Light emitted from a light emitting element 5 hits an object 7 and the reflected light forms an image on a light receiving element 2 as spot through a condenser lens 4. The position of the light spot generated on the element 2 is converted into a position signal. The ratio of currents from electrodes 2a and 2b of the element 2 is turned to a position signal VL. When the signal VL coincides with an output of a integration time constant circuit 9, an output of a voltage comparator 15 inverts to cut off an electromagnet 11, stopping the running of a lens-barrel 10. |
