Camera diaphragm aperture control device
AssigneeMinolta Camera Kabushiki Kaisha
InventorsMasayoshi Sahara, Masaaki Nakai
Life of this patent
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Abstract
An electromechanical device such as a camera diaphragm control device includes a compensation means which compensates for a time lag from generation of a stop signal to actual stoppage of a movable member such as a diaphragm or a diaphragm drive member. The amount of compensation is varied in accordance with determination of the amount of the movement of the movable member from an initial end position to a position where the movable member is to be stopped. In the case of automatic diaphragm control, the amount to be determined may be the steps from the full open position to a position corresponding to a diaphragm aperture to be determined.
Claims12
A camera exposure control device comprising:
- a diaphragm member movable from an initial end position towards a terminal position to change diaphragm aperture;
- light measuring means for measuring, through the diaphragm aperture, light from an object to be photographed and generating a first signal as a function of the measured light, said first signal changing with the change of said diaphragm aperture;
- reference means for generating a reference signal;
- comparison means for comparing said first signal with said reference signal and generating a stop signal when the difference between said first and reference signals reaches a selected one of a plurality of given values;
- electromagnetic stop means responsive to said stop signal for stopping the movement of said diaphragm member to determine the aperture thereof;
- means for determining, before the actuation of said diaphragm member, the amount of movement of said diaphragm member from said initial end position to a position where it is to be stopped by said stop means, and generating a control signal in accordance with the determined amount;
- and
- selection means responsive to said control signal for selecting the one of said given values at which the stop signal is generated.
A control device for a photographic camera comprising:
- a movable member movable from an initial end position towards a terminal position;
- a signal means for generating a variable signal which varies with the movement of said movable member;
- a reference means for generating a reference signal;
- comparison means for comparing said variable and reference signals and generating a stop signal when the difference between the signals reaches a selected one of a plurality of given values;
- electromechanical means for stopping the movement of said movable member in response to said stop signal;
- means for determining, before the actuation of said movable member, the amount of movement of said movable member from said initial end portion to a position where it is to be stopped by said electromagnetic means, and generating a control signal in accordance with the determined amount;
- and
- selection means responsive to the control signal for selecting the one of said given value at which the stop signal is generated.
Dependencies are inferred from the claim text.