Agfa-gevaert Ag

Alois Rieder

Eduard Wagensonner

Bernhard Von Fischern

Peter Lermann

Horst Rossbach

Norbert Burgermann

Stefan Vogt

A motion picture apparatus and preferably a motion picture projector. A rotary disc shutter is actuated by an electric drive and comprises a shutter sector. A claw mechanism controlled by the electric drive provides for transport of a film and the motion of the film is controlled by a solenoid having associated a solenoid plunger suitable for disengaging the claw transport mechanism after a frame transport phase. A position pulse generator provides a shutter position pulse depending on the position of the shutter sector. An output memory element connected to the electromagnet solenoid controls the energization of the electromagnet and in turn is connected to a switch and to the position pulse generator. Preferably additional memories are provided for performing functions such as controlling the advance and the reverse motion or providing for a timer or individual frame operation.

Memory controlled motion picture apparatus

The output of a bridge circuit which is unbalanced when the quantity of light falling on a light-sensitive element is less than or more than a predetermined light quantity is applied to a differential amplifier circuit whose output varies from a minimum amplitude to a maximum amplitude. The output of the differential amplifier is connected to a first and second threshold circuit whose threshold values are symmetrical to the output value of the differential amplifier when the bridge is in balance. The gain of the differential amplifier is adjusted so that the differential output signal has an amplitude exceeding the first threshold value and less than the second threshold value for variations of light within an allowable range. Within this range the first threshold circuit furnishes an output signal and the second threshold circuit does not. When the first threshold circuit does not furnish an output signal or if the second threshold circuit does, a pulse generator is energized whose pulses are counted by a counter which is controlled to energize the windings of the stepmotor controlling the diaphragm aperture in pairs in a predetermined sequence for opening and the reverse sequence for closing the diaphargm. The operation of the pulse generator and thereby of the motor is impeded when a switch furnishes a signal indicating that the diaphragm is fully open.

Control system for controlling the diaphragm in a photographic camera

The output of a bridge circuit which is unbalanced when the quantity of light falling on a light-sensitive element is less than or more than a predetermined light quantity is applied to a differential amplifier circuit whose output varies from a minimum amplitude to a maximum amplitude. The output of the differential amplifier is connected to a first and second threshold circuit whose threshold values are symmetrical to the output value of the differential amplifier when the bridge is in balance. The gain of the differential amplifier is adjusted so that the differential output signal has an amplitude exceeding the first threshold value and less than the second threshold value for variations of light within an allowable range. Within this range the first threshold circuit furnishes an output signal and the second threshold circuit does not. When the first threshold circuit does not furnish an output signal or if the second threshold circuit does, a pulse generator is energized whose pulses are counted by a counter which is controlled to energize the windings of the stepmotor controlling the diaphragm aperture in pairs in a predetermined sequence for opening and the reverse sequence for closing the diaphragm. The operation of the pulse generator and thereby of the motor is impeded when a switch furnishes a signal indicating that the diaphragm is fully open.

A bridge circuit which includes a photoelectric transducer furnishes input signals to a differential amplifier whose analog output signal varies in correspondence to the bridge unbalance. A first and second bistable threshold circuit changes the analog output signal into digital signals signifying bridge unbalance in a first direction, balance, and unbalance in the opposite direction, a motor is energized to rotate in a direction corresponding to the direction of bridge unbalance. The motor can be utilized to move the objective lens of a slide projector or change the aperture of a diaphragm.

Analog/digital control arrangement for photographic apparatus

A prism positioned behind the objective rotates at a predetermined frequency. The pulsed light beam produced thereby is split into a first and second pulsed beam, each falling on a photoelectric transducer element. The first photoelectric transducer element is positioned at a distance from the objective which is less than the distance between the film plane and the objective plane by a predetermined distance. The second photoelectric transducer is positioned away from the objective by a distance exceeding the distance between the film plane and the objective plane by the same predetermined distance. The first and second electrical signals produced by the first and second photoelectric transducer are differentiated and stored. The so-stored signals are compared and a control signal for driving a motor in a first or second direction is furnished corresponding to the difference therebetween. The motor drives the objective either closer to or away from the film plane in response to the control signal.

Growing community of inventors

Munich, Germany

Alois Rieder