Copal Company Limited

Konishiroku Photo Industry Co., Ltd.

Kabushiki Kaisha Copal

Yasuo Ishiguro

Kenji Wakazono

Toshihisa Saito

Tomio Kurosu

Masao Nakamori

An exposure control unit including an element having electrostrictive properties and a fixed end and a deformation quantity of which is determined in accordance with a voltage applied thereto drives a programming shutter provided with shutter blades having the function of the diaphragm by a driving source composed of the deformation produced at a free end of the electrostrictive element when the voltage is applied to the element. The shutter blades having the function of the diaphragm are opened by the deformation produced at the free end of the electrostrictive element in accordance with the voltage applied to the element and the voltage is increased with the lapse of time in interlocked relationship with the opening operation of the shutter blades so that the electrostrictive element is gradually deformed and the shutter blades are also gradually opened. The electrostrictive element is then short-circuited at a time when a proper exposure is obtained so that the exposure operation is immediately terminated.

Exposure control unit

A quick-return mirror driving mechanism for single-lens reflex cameras so formed that the release of a mirror-up operating member and the release of a mirror-down operating member are effected by a single electromagnetic means, in order to eliminate a mechanical connection between the shutter mechanism and quick-return mirror driving mechanism and, therefore, to simplify the mechanism as a whole.

Quick-return mirror driving mechanism for single-lens reflex cameras

An exposure controlling device comprising a means of discriminating to what zone of exposure zones sectioned in advance an exposure value determined by considering the brightness information of an object to be photographed obtained by a TTL light measurement under the maximum diaphragm aperture and the film sensitivity of the film to be used belongs, a means of determining a diaphragm value simultaneously with and in response to the discrimination of the exposure zone and a means of comparing the determined diaphragm value with the F-number of a photographing lens to be used and controlling a proper exposure time corresponding to said diaphragm value so that a diaphragm aperture and shutter speed for obtaining a proper exposure can be automatically set without making any special switching operation even in the case of using any photographing lens different in the F-number. The means of determining the diaphragm value includes a member which can be intermittently driven by a pulse signal. By the initial motion of this member, a mirror mechanism or automatic focus adjusting device can be released.

Exposure controlling device adapted to cameras using interchangeable

Exposure rate controlling mechanism for camera

An electric shutter for cameras wherein a shutter closing motion can be started by a manual operation from outside the camera body even when the automatic closing motion of the shutter can be no longer made due to the consumption of the current source battery.

Electric shutter for cameras

An automatic diaphragm aperture controlling device which includes an exposure information pulse generation circuit to generate a pulse in a number corresponding to an aperture value to be controlled, the obtained pulses being based on exposure informations such as a scene brightness or the like. A counter circuit is provided for counting the output of the exposure information pulse generation circuit, together with an aperture value pulse generation circuit for generating pulses in a number corresponding to an aperture value of a diaphragm stopped down in association with a diaphragm drive, and diaphragm fixing means for fixing the diaphragm aperture which fixing means is actuated when an aperture value pulse number is coincident with an exposure information pulse number. The aperture value pulse generating circuit includes a light source, a photo-responsive element, and an intermittent light transmitter adapted for movement between the light source and the photoresponsive element in coupled relationship to the activation of the diaphragm.

Device for automatically controlling diaphragm aperture

An exposure controlling circuit for electric shutters comprising a timer circuit which can determine a proper exposure time in response to the brightness of an object to be photographed and another time circuit which can determine the specific shortest exposure time in order to regulate the exposure time to be determined by the brightness of the object to be photographed to be less than the shortest exposure time obtainable by the inherent performance of the shutter mechanism to be used, whereby when the states of the above mentioned two time circuit started to act simultaneously in relation to the shutter release operation are reversed to each other, the shutter is closed. The above mentioned specific shortest exposure time can be selected.

Exposure controlling circuit for electric shutter

The digital shutter control circuit comprises a reference clock pulse generating circuit, a binary counter circuit having a plurality of output stages each issuing, upon counting the pulses from the reference pulse generating circuit, output signals corresponding to the exposure time to be set in the shutter in terms of 2.sup.n where n is an integer and a selector circuit connected to the shutter closing means and selectively connectable to any of the output stages. The binary counter circuit is actuated simultaneously with the actuation of the shutter opening means for opening the shutter so that the shutter closing means is actuated when the output signal is issued from the output stage to which the selector circuit is connected thereby closing the shutter to provide the selected shutter speed. The shutter control circuit incorporates an AND circuit the inputs of which are connected to at least two output stages selected from the plurality of output stages and the output is selectively connectable to the selector circuit so that, when connected, an exposure time is obtained which is intermediate the values obtained from the above selected two output stages. The exposure times may comprise the series of 1/1000 sec., 1/500 sec.-1/2 sec. and 1 sec. and the selected two output stages may be made 1/1000 sec. and 1/125 sec. so that substantially 1/114 sec. of the exposure time is obtained which exposure time is effective to insure the synchronization of an electric flash device with the shutter in which shutter opening and closing blades are actuated in parallel to the minor sides of the frames of 35 mm film.

Digital shutter control circuit

An electroflash controlling circuit wherein, in order to make the fully open time of a shutter and the flashing time of a flash accurately coincide with each other, a delaying circuit operated by an electric signal for starting a shutter blade opening motion or an electric signal for starting a shutter blade closing motion is provided so that a flashing circuit may be triggered after the lapse of a delay time made by the delaying circuit.

Electroflash controlling circuit including a delay circuit for

A shutter driving circuit including a voltage judging circuit and indicating circuit in order to always properly make shutter opening and closing operations, whereby an electric current is prevented from flowing to driving coils and such state can be indicated by the indicating circuit when the voltage of a current source for feeding a current to a pair of driving coils to be made to make opening and closing motions of the shutter by the voltage judging circuit is below a predetermined value.

Driving circuit for camera shutters

An exposure controlling circuit for electric shutters incorporating therein a voltage drop detecting circuit which will issue a signal for passing a current to a coil for closing a shutter when a current source voltage becomes lower than a predetermined voltage in order to prevent the shutter closing motion from being made unable to be made by the drop of the current source voltage after the shutter is opened. This controlling circuit further includes a driving circuit for making an indication within the field of vision of the view finder of a photographic camera when a signal is issued from the voltage drop detecting circuit.

Exposure controlling circuit for electric shutters

A controlling circuit for electric shutters wherein, in an electric shutter adapted to start a shutter closing moton by energizing a driving coil with a discharge current from a capacitor, the capacitor is made to be discharged by a voltage drop detecting circuit provided so that the shutter may be positively closed even in case a current source switch is opened by an unexpected accident in the course of an exposure controlling operation.

Controlling circuit for electric shutters

A device is provided for indicating fading operation in cinecamera. A control circuit receives the scene light indicating voltage and a manually adjusted output voltage for operating a diaphragm driving means to adjust the aperture to a proper value for the scene brightness an RC circuit is connected to the diaphragm control circuit which selectively applys either a constant charging or discharging voltage to the diaphragm control circuit, this causes the control circuit to drive the diaphragm to continuously vary the aperture for effecting the fading-out and the fading-in of the scene. A first comparator receives the output voltage of the RC circuit and the output voltage of the diaphragm control circuit and produces a signal when both voltages are coincident. A second comparator connected to the RC circuit produces a signal when the output voltage of the RC circuit reaches a constant charging an indicator receives the output signals of the first and the second comparator for indicating the completion of both fading-out and fading-in of the scene.

Device for indicating fading operation

The automatic diaphragm controlling device comprises an electric source, a servomotor having a single driving coil for driving a diaphragm of an objective lens, a scene light indicating voltage generating circuit and a reference voltage generating circuit energized by the electric source, respectively, the servomotor being controlled by the difference between the output voltages of both circuits so that a proper exposure is obtained. The servoamplifier comprises a first operational amplifier with its inverted input terminal connected to the non-inverted input terminal of a second operational amplifier through a first resistor while the non-inverted input terminal of the first operational amplifier is connected to the inverted input terminal of the second operational amplifier through a second resistor, the junction between the first resistor and the non-inverted input terminal of the second operational amplifier being connected to the reference voltage generating circuit while the junction between the non-inverted input terminal of the first operational amplifier and the second resistor is connected to the scene light indicating voltage generating circuit, a negative feedback resistor being connected between the output terminal and the inverted input terminal of each operational amplifier, the servomotor being connected between the output terminals of both operational amplifiers. The use of two operational amplifiers permits a simple construction of the circuit while one source -- one coil system of the controlling device is insured and power is greatly saved.

Servoamplifier in an automatic diaphragm controlling device of a camera

A controlling circuit for electric shutters comprising at least one constant current circuit, a pair of capacitors to be charged in advance by a current source battery through the constant current circuit and a pair of driving coils to be energized in turn by discharge currents of the pair of capacitors to start a shutter blade opening motion and closing motion so that the current source battery of a comparatively small capacity may be effectively used.

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Tokyo, Japan

Yasuo Ishiguro