초록 ▼

An automatic focusing device controls the setting of an actuating member to effect automatic focusing of a camera lens and is used in conjunction with a focus detecting unit which produces a focus detection signal corresponding to the object distance by photoelectrically comparing optical images tra

An automatic focusing device controls the setting of an actuating member to effect automatic focusing of a camera lens and is used in conjunction with a focus detecting unit which produces a focus detection signal corresponding to the object distance by photoelectrically comparing optical images transmitted by stationary and movable mirror systems. The automatic focusing device comprises pulse generating circuitry for generating pulses at a fixed repetition rate, a first counting circuit for counting pulses such that the number of pulses counted is a function of the angle of displacement of a movable mirror of the movable mirror system during a range scanning operation, and a second counting circuit connected to receive and memorize the pulse count counted by the first counting circuit when a focus detection signal is produced by the focus detecting unit and operative to count pulses such that the number of pulses counted is a function of the extent of movement of the actuating member. A detector detects when the pulse count counted by the second counting circuit reaches a predetermined count and produces a corresponding output signal which is used to terminate the movement of the actuating member to thereby effect focusing of the camera lens.

대표청구항 ▼

An automatic focusing device for use with a focus detecting unit which transmits a focus detection signal corresponding to the object distance by photoelectrically comparing optical images transmitted through a stationary mirror system having a stationary mirror and a movable mirror system having a

An automatic focusing device for use with a focus detecting unit which transmits a focus detection signal corresponding to the object distance by photoelectrically comparing optical images transmitted through a stationary mirror system having a stationary mirror and a movable mirror system having a movable mirror comprising: pulse generating means for generating a pulse signal corresponding to an angle of rotation of the movable mirror of the movable mirror system; first counting means for counting the pulses generated by said pulse generating means; second counting means receptive of the pulse count counted by said first counting means when a focus detection signal is generated by said focus detecting unit for counting the pulses generated by said pulse generating means and generating a pulse signal corresponding to the movement of an actuating means; detecting means for detecting when the pulse count counted by said second counting means reaches a fixed count and producing a corresponding output; and control means for interrupting the movement of the actuating means in accordance with the output of said detecting means.