Automatic control device for cameras

Communications: electrical – Audible indication – Percussion-type sound producer

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

354 23D, 356218, H03K 1303

Patent

active

041329856

ABSTRACT:
This invention relates to an automatic camera exposure control device comprising a first light measuring circuit including a photoelectric element receiving light through the objective lens of the camera and generating a first output proportional to the logarithm of the brightness of an object to be photographed, and a circuit for providing a second output indicative of the film sensitivity and the lens aperture value, the light measuring circuit for providing a first signal indicative of the sum of the first and second outputs and a second circuit including a pulse genrator circuit for generating clock pulses and a counter for counting the clock pulses and for producing a second signal of a stairstep waveform corresponding to the counting of a pulse; a voltage comparator circuit for comparing the second signal with the first signal and for producing a signal when the level of the second signal exceeds that of the first signal; a third circuit composed mainly of a gate circuit for stopping the counting of the pulse upon receipt of the threshold level signal from the voltage comparator circuit; and a shutter control circuit including a transistor for inverse logarithmic conversion and for producing a collector current proportional to the exponent of the second signal applied to its base, and a capacitor to be charged by the collector current of the transistor and a switching circuit responsive to the voltage charged in the capacitor in excess of a predetermined level for actuating the shutter to terminate the exposure interval.

REFERENCES:
patent: 3124794 (1964-03-01), Patmore
patent: 3553443 (1971-01-01), Neil
patent: 3807879 (1974-04-01), Mori

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Automatic control device for cameras does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Automatic control device for cameras, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic control device for cameras will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-1520059

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.