Copal Company Limited

Kiyoshi Touma

Akira Suzuki

Haruki Oe

Takashi Shimamura

Toyonori Sasaki

Jun-ichi Matsumoto

A compact camera has a zooming lens system for regulating a focal distance and a shutter blade member for opening and closing the lens system. The blade member is shifted forwardly from its rest position to open the lens system through a given shift amount effective to determine a lens aperture size to effect exposure, and subsequently is shifted reversely to close the lens system to return to the rest position. A driving mechanism is connected to the blade member to undergo a reciprocating stroke to drive the blade member forwardly and reversely to effect opening and closing of the lens system. The blade member and the driving mechanism are disposed on a substrate. An adjusting mechanism is disposed around the substrate. The adjusting mechanism includes a stopper member undergoing displacement in response to the zooming of the lens system. The stopper member acts on the driving mechanism to control the reciprocating stroke of the driving mechanism according to the displacement of the stopper member so as to limit the shift amount of the blade member to thereby effect adjustment of the lens aperture size according to the lens focal distance or the zooming. Generally, the adjustment is carried out such as the smaller the focal distance, the smaller the lens aperture size.

Compact camera with apparatus size adjustment by zooming

The device for opening/closing the shutter blade(s) of a photographic camera comprises an electromagnetic actuator coupled with the shutter blade(s) and adapted to open or close the same upon supply of a current from an electrode source through a driver and/or a control circuit to the actuator in one direction or in the opposite direction. The electric source is a constant current circuit and a current regulating circuit is interposed between the constant current circuit and the driver thereby permitting the shutter opening speed to be adjusted by regulating the current regulating circuit. Alternatively, the electric source is a constant voltage circuit and a resistor is connected in series between the driver and the actuator thereby permitting the shutter opening speed to be adjusted by regulating the resistance of the resistor. The control circuit may be so constructed that the shutter opening current is interrupted a predetermined time prior to the fully opened position of the shutter blade(s) and the shutter closing current is supplied for a predetermined time period after interruption thereof to avoid the bounce of the shutter blade(s). One of a pair of symetrically shaped and actuated shutter blades is stopped by stopper means at the fully opened position so as to be bounced therefrom and the bouncing movement is cancelled by the inertia of the opening movement of the other shutter blades at the fully opened position by virtue of the coupling of the pair of shutter blades commonly with the actuator.

Device for opening and closing shutter blade without bounce

A camera shutter using an electrostrictive strain element as a driving source wherein, in order to make it possible to make the driving voltage small and to make an accurate exposure, when the shutter is released, first a reverse voltage is applied to an electrostrictive strain element to drive a shutter blade opening and closing member in the direction of completely closing the shutter blades, then the charge accumulated in the electrostrictive strain element is discharged and finally a forward voltage is applied to the electrostrictive strain element to open the shutter blades.

Camera shutter using an electrostrictive strain element as a driving

A lens shutter using an electrostrictive strain element as a driving source, arranging a shutter blades opening and closing lever and the electrostrictive strain element driving the opening and closing lever so that inertia forces acting on the opening and closing lever through engagement with the electrostrictive strain element and acting on the electrostrictive strain element through engagement with the opening and closing lever are counterbalanced by each other, in order to eliminate variations of exposure caused by various positions of a camera. The basic portion of the electrostrictive strain element is secured to a retaining member supported rotatably on a shutter base plate and the retaining member may well be biased by a spring to increase the inertia force of the electrostrictive strain element. Thereby, even if a shock is applied to the shutter from the outside, it does not occur that the shutter blades are inadvertently opened and closed. The rotation of the retaining member to rotate the opening and closing lever in a direction to open the shutter blades through the electrostrictive strain element is prevented by an eccentric pin.

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Tokyo, Japan

Kiyoshi Touma