AUTOFOCUS ADJUSTING DEVICE

摘要

PURPOSE:To facilitate the assembly of the autofocus adjusting device and obtain a stable image-formation state without any partial out-of-focus state by oscillating at least one lens element in a lens system provided in front of an image pickup element by fine distance. CONSTITUTION:The lens 16 for fine variation in optical path length among lenses constituting the lens system 6 is oscillated by fine distance through a swinging device 17 in the optical-axis direction of the lens system 6. The output signal of the image pickup element 1 is amplified by an amplifier 8 and a frequency detector 9 detects a signal of the oscillation frequency of the oscillation device 17. The phase of the detected signal is compared with the oscillation output of an oscillator 4 by a phase comparator 10 to detect the direction of defocusing, and a driving device 12 such as a motor is controlled by a driving device controller 11 so that the output voltage of the image pickup element 1 has its peak; and thus at least one focusing lens 7 is moved in the optical-axis direction to perform focusing.