FOCUS DETECTOR

申请公布号：

JPH03163407(A)

申请号：

JP19900176939

申请日期：

1990.07.03

申请公布日期：

1991.07.15

申请人：

MINOLTA CAMERA CO LTD

发明人：

ISHIDA TOKUJI;HAMADA MASATAKA

分类号：

G02B7/28;H04N5/232

主分类号：

G02B7/28

摘要：

PURPOSE:To shorten the time before the start of focus detection by switching the charge transfer operation of a line sensor before or after the start of the focus detection and executing plural times of the high-speed transfer of unnecessary charges with high-speed transfer pulses before the start and the charge transfer for focus detection with low-speed transfer pulses after the start. CONSTITUTION:A photographic lens 22 is so constituted that a focusing optical system is driven by a lens driver 30 including a motor in order to automatically execute focusing by using the output of a focus detector. The central part of a reflecting mirror 24 is formed translucent and an auxiliary mirror 32 is provided behind this part. A part of subject light is introduced through this part to a photodetecting part 34 of the focus detector disposed in the low part of a mirror box. The photodetecting part 34 is constituted of a condenser lens 36, the reflecting mirror 38, an imaging lens group 40, a line sensor 42, etc., and the output of the sensor 42 is processed by a signal processing circuit 44 from which the defocusing signal indicating the deviation quantity and direction of the focus from the focusing position is outputted. The focus state is displayed on a display device 46 in accordance with this signal and the photographic lens 22 is driven to the focusing by the driver 30.