| 摘要 |
PURPOSE:To enable automatic focus detection to be performed for multple kinds of lenses by forcefully driving a servo motor until the composite waveform of S-form charcteristics having a focus matching point reaches the preset level. CONSTITUTION:The synthesis of the S-form characteristics having a zero point being focus matching point is formed 11 by photoelectric transducers CdS1, Cds2 installed on the optical path of an optical equipment such as auto collimator or the like. At this time, a potential level setter 13 is set at the specified set level E. When the composite waveform reaches this level, a servo motor M is forcefully driven from the start point B in the G direction by way of a start direction determining circuit 16, FF circuit 15, switching amplifier circuit 19 and complementary symmetry circuit 20. Next, when the same exceeds the preset level, the force driving force is released and the motor M is scanned by the circuit 20. When the zero point A is detected, the motor M is stopped. In this way, the focus matching point may be automatically detected for multple kinds of lenses. |
