1986-08-07
1987-12-08
Adams, Russell E.
354456, G03B 708
Patent
active
047115467
ABSTRACT:
A photometric circuit which has an operational amplifier and produces a result of light measurement with a logarithmic compression element arranged between the input and output terminals of the operational amplifier to logarithmically compress a signal obtained by photo-electric transducing a measured light is characterized by inclusion of a circuit which selectively switches the logarithmic compression element to short-circuit the input and output terminals of the amplifier between them. The photometric circuit includes a capacitor to be charged with a photo current; a switching circuit for discharging the electric charge of the capacitor; an amplifying circuit for amplifying the voltage of the capacitor; a computing circuit for performing a computing operation on the amplifying circuit and a reference value; a setting circuit for setting the reference value according to the output of the amplifying circuit produced while the electric charge of the capacitor is being discharged by the switching circuit. The photometric circuit is capable of accurately performing light measurement by virtue of these features.
REFERENCES:
patent: 3852774 (1974-12-01), Taguchi et al.
patent: 4072961 (1978-02-01), Yamada
patent: 4076977 (1978-02-01), Tsunekawa et al.
patent: 4209245 (1980-06-01), Kawasaki et al.
patent: 4241279 (1980-12-01), Numata
patent: 4329030 (1982-05-01), Aihara et al.
Adams Russell E.
Canon Kabushiki Kaisha
LandOfFree
Photometric circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photometric circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photometric circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-20611