ELECTRICALLY CONTROLLED PHOTOGRAPHIC CAMERA SHUTTER APPARATUS
First Claim
1. In a camera having circuitry for automatically determining the extent to which film in the camera is exposed, a power source electrically connected with said circuitry for supplying energy thereto, said circuitry including an electromagnetic means for terminating an exposure when said electromagnetic means becomes unenergized, switch means electrically connected between said power source and said electromagnetic means for energizing the latter just prior to opening of a shutter to start an exposure, and means electrically connected to said electromagnetic means through said switch means for supplying said electromagnetic means upon closing of said switch means with energy in addition to that supplied only by connecting said electromagnetic means to said power source through said switch means for reducing the time lag required for energizing of said electromagnetic means to a minimum.
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Accused Products
Abstract
A camera capable of automatically determining the exposure time and having interchangeable objectives. One of the factors which determines the extent of exposure is the magnitude of the aperture through which light enters the camera. This factor is introduced either by way of one variable resistor which coacts with an objective which remains wide open and which is automatically stopped down to a preselected aperture just prior to exposure, or by way of a second variable resistor adapted to be used in the situation where the objective is not automatically stopped down just prior to exposure and instead has its diaphragm in a stopped down condition restricting travel of light passing through the objective with this light being measured after passing through the stopped down diaphragm. These variable resistors are connected in parallel and a selecting switch is provided for utilizing one or the other of the variable resistors depending upon the type of objective which is used. In addition, in order to render an electromagnet operative in the shortest possible time, the electromagnet is supplied with power not only from a conventional voltage source but also from a capacitor which is preliminarily charged.
2 Citations
4 Claims
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1. In a camera having circuitry for automatically determining the extent to which film in the camera is exposed, a power source electrically connected with said circuitry for supplying energy thereto, said circuitry including an electromagnetic means for terminating an exposure when said electromagnetic means becomes unenergized, switch means electrically connected between said power source and said electromagnetic means for energizing the latter just prior to opening of a shutter to start an exposure, and means electrically connected to said electromagnetic means through said switch means for supplying said electromagnetic means upon closing of said switch means with energy in addition to that supplied only by connecting said electromagnetic means to said power source through said switch means for reducing the time lag required for energizing of said electromagnetic means to a minimum.
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2. The combination of claim 1 and wherein said means connected electrically to said electromagnetic means through said switch means for providing said additional energy is a capacitor means.
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3. The combination of claim 2 and wherein a second switch means is electrically connected between said capacitor means and said power source for charging said capacitor means prior to closing of said first-mentioned switch means.
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4. The combination of claim 3 and wherein said second switch means is connected in series between said first-mentioned switch means and said power source, said first-mentioned switch means being connected in series between said second switch means and said electromagnetic means, and said capacitor means being electrically connected to a junction between both of said switch means.
Specification