Copal Company Limited

Haruki Oe

Akira Suzuki

Kiyoshi Touma

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

Haruki Oe