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US 4,048,643 AGranted
Exposure computation system
AssigneeTokyo Shibaura Electric Co., Ltd.
InventorIsao Arita
Life of this patent
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AssigneeTokyo Shibaura Electric Co., Ltd.
InventorIsao Arita
Estimating the term…
A diaphragm aperture value which has been set is transformed into corresponding frequency information. A local oscillator starts sweeping upon pushing of the shutter button. The output of the local oscillator and the frequency information are inputted to a mixer, and the output of the mixer is fed to a filter circuit, whose center frequency is variable according to the luminance information of an object to be photographed. Only a specific output frequency of the mixer passes through the filter circuit, and the output of the filter circuit generates a control signal which closes the shutter at a suitable diaphragm aperture time.
An exposure computation system comprising:
An exposure computation system comprising:
An exposure computation system comprising:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
Analogue circuits: for control of both exposure time and aperture
Apparatus or arrangements for taking photographs or for projecting or viewing them
Term ended 13 Sep 1994 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The present invention relates to an exposure computation system wherein a computation is carried out with frequency information which corresponds to the exposure factors.
2. Description of the Prior Art
The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:
FIG. 1 shows a block diagram of a preferred embodiment of the present invention.
FIG. 2 shows a detailed diagram of the exposure computation circuit shown in FIG. 1.