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US 5,351,101 AGranted
Photographic camera and film cartridge with double exposure prevention
AssigneeEastman Kodak Company
InventorWilbert F. Janson, Jr.
Life of this patent
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AssigneeEastman Kodak Company
InventorWilbert F. Janson, Jr.
Estimating the term…
A photographic film cartridge has one or more resistive elements formed on the exterior surface of the cartridge with associated visual indicator elements to indicate exposure status of film in the cartridge. The camera is provided with a drive circuit to change the resistance values of the resistive elements to provide an electrically sensed indication of the film exposure status when next the cartridge is placed in the camera. Provision can be made for both full exposure and mid-roll interrupt indications. At the same time, the heat generated by the resistive element during its change in resistance value is useful to change a characteristic of the associated visual indicator to provide a visual indication of the exposure status of the film in the cartridge.
Film cartridge having a housing with an outer surface and having provision thereon for indication of the usage condition of film in the cartridge, the cartridge comprising:
A photographic film camera having a chamber for receiving a film cartridge having a resistive element on the outer surface of the cartridge, the resistive element being formed of a material normally having a first resistance value and being responsive to an applied electrical stimulus to change to a second resistance value indicating a change in usage condition of film in the cartridge, the cartridge having electrical contacts connecting with the resistive element, the camera comprising:
Dependencies are inferred from the claim text.