| 摘要 |
PURPOSE:To make possible high focusing accuracy even in the case of the linear movement in an optical axis direction by converting distance measuring signal projection direction and the extent of the displacement of an imaging lens to digital signals and moving the imaging lens until both signals assume a predetermined relation. CONSTITUTION:Predetermined electrodes of printed patterns 120c, 121c which convert rotating phases to pulses are formed on the end faces of a distance measuring gear 120 and a focus gear 121. When a release is pushed, a diode holder 113 is oscillated vertically by way of a motor 130, distance measuring gear 120 and control arm 123, and light emitting diode light is projected to the subject field, thence the predetermined pulses indicating the measured distance are generated by the patterns 120c. On the other hand, an imaging lens 108 is moved forward and backward by way of a focus motor M3, gear 121, and room bar 109, and the pulses indicating the extent of the displacement thereof are generated from the patterns 121c. The motor M3 is driven by a predetermined electric circuit until these two output signals become equal, whereby focusing operation is accomplished. Thereby, high accuracy is obtained because the extent of the displacement is obtained by the digital signals. |
