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US 4,290,678 AGranted
Piezoelectric flash-ready indicator for photographic camera
AssigneeEastman Kodak Company
InventorMichael A. Marcus
Life of this patent
Estimating the term…
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AssigneeEastman Kodak Company
InventorMichael A. Marcus
Estimating the term…
A piezoelectric flexure device, mounted on a photographic camera, is used to indicate the "state of readiness" of the camera's electronic flash unit. The flexure device is operatively connected with the flash unit's storage capacitor so that the flexure device is subjected to an electric field proportional to the level of charge on the storage capacitor. Since the shape of a flexure device depends upon the electric field across it, its appearance provides a visual indication to the camera user of the level of charge on the flash capacitor and, hence, the "readiness" of the energizing circuit. Preferably, the flexure device is made of a piezoelectric plastic film, such as PVF.sub.2, which exhibits substantial deformation in the presence of an electric field which can be readily produced by the DC power supply in conventional flash units.
In a photographic camera comprising a housing, circuit means, including a charge storing element, for selectively energizing a flashlamp, such circuit means including means for charging such element to a predetermined level sufficient to ignite the flashlamp, and means for indicating to the camera user when the charge stored by the charge storing element has reached such predetermined level, the improvement wherein said indicating means comprises a piezoelectric flexure device, operatively coupled to said charge storing element, said device being adapted to change its shape in accordance with the level of charge stored by said charge storing element.
In a photographic camera of the type which is adapted to receive, as an accessory, a flash unit comprising a flashlamp and circuit means, including a charge storing element, for selectively energizing the flashlamp, such circuit means including means for charging the charge storing element to a predetermined level sufficient to ignite the flashlamp;
Dependencies are inferred from the claim text.