Seiko Koki Kabushiki Kaisha

Takashi Segawa

Takeo Saito

Shinji Nagaoka

Yuzuru Takazawa

Yoichi Seki

Kiyoshi Kitai

Hiroaki Ishida

A device for detecting coincident focusing points for use in the controlling of the focusing of an automatically focusable lens comprises a single array of light receiving transducers for converting the distribution of light intensity of an image applied thereon to a set of corresponding electrical signals. The image applied to the array is from a first optical path from an object through the lens and from a second optical path from the object. At least one shutter is provided for cutting off one of the optical paths to alternatively effect the application of light from the one optical path on to the array to produce a first set of signals and thereafter the light from either the other optical path or the sum of the two optical paths on to the array to produce a second set of signals. The first set of signals are processed to produce a third set of signals which correspond to the ratio of each signal therein with respect to another of the signals and the second set of signals is processed to obtain a fourth set of signals corresponding to the ratio of each signal with respect to another of the signals. The third and fourth sets of signals, for each transducer, are compared and a signal is produced when a favorable comparison is obtained.

Device for detecting coincident focusing points

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.

Automatic focusing device

Automatic focusing adjustor device provided with a focusing sensor signal corresponding to an object distance by photoelectrically comparing an optical image obtainable through a fixed mirror and another optical image obtainable through a movable mirror wherein when the focusing sensor signal is not obtained, two steps of distance adjustment may be made by an output signal from a brightness sensor circuit for use in sensing a brightness of the object.

Automatic focusing adjustor device

A light emitting indicating circuit comprises a first and second inverter circuit which are each comprised of a pair of complementary transistors connected in series. A motor driving coil and a capacitor are connected in series between respective outputs of the inverter circuits, and the inverter circuits are effective for applying repetitive complementary electrical driving signals for repetitively flowing a current in alternating directions through the series combination of motor driving coil and capacitor to repetitively energize the motor driving coil. An indicating circuit responsive to the electrical driving signals indicates energization of the motor driving coil. The indicating circuit is comprised of a light emitting diode connected in parallel with the motor driving coil for emitting light to indicate energization of the motor driving coil.

Growing community of inventors

Shikawatashi, Japan

Takashi Segawa