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US3909137A Expired / Lapsed US ⏱️ 0.0 years remaining

Digital indication exposuremeter

Assignee: Minolta Co Ltd
•
Filing: 1974-06-18
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Granted: 1975-09-30
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Expires: 1994-06-18
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Abstract

Abstract A digital indication exposure meter includes a photoelectric transducer circuit which produces an output current proportional to the intensity of lights incident to a photoelectric element, said transducer circuit including a circuit wherein an integrating capacitor is charged up by a photoelectric current of the photoelectric element in a manner that the voltage across both ends of the capacitor is proportional to the logarithm of the quantity of light received during a time of light measuring, a timer circuit which produces electric signals corresponding to the time of light measuring, an analog-digital converter which converts the analog output signal of the voltage in the integrating capacitor into a digital form and retains the information in a digital form, a coding circuit which is set to produce digital signals corresponding to film sensitivity, an adder circuit which computes the digital output of the analogdigital converter together with the digital information from the coding circuit, a decoder for converting the digital output from the adder into another digital output suitable for numeral displaying, and numeral displaying devices for indicating the output of the decoder.

Inventors

  • 👤 Toru Kisanuki

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 22:03
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/42; G01J1/44; G01J1/46; H; H03; H03M; H03M1/00; H03M1/12; H03M1/50

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 180 words
A digital indication exposure meter comprising: a photoelectric transducer circuit which produces an output current proportional to the intensity of lights incident to a photoelectric element, said transducer circuit including a circuit wherein an integrating capacitor is charged up by a photoelectric current of the photoelectric element in a manner that the voltage across both ends of the capacitor is proportional to the logarithm of quantity of light received during a time of light measuring, a timer circuit which produces electric signals corresponding to the time of light measuring, an analog-digital converter which converts the analog output signal of the voltage in the integrating capacitor into a digital form and retain the information in a digital form, a coding circuit which is set to produce digital signals corresponding to film sensitivity, adder circuit which computes the digital output of the analogdigital converter together with the digital information from the coding circuit, a decoder for converting the digital output from the adder into another digital output suitable for numeral displaying, and numeral displaying devices for indicating the output of the decoder.
Claim 2
Dependent Claim 180 words
A digital indication exposure meter comprising: a photoelectric transducer circuit which produces an output current proportional to the intensity of lights incident to a photoelectric element, said transducer circuit including a circuit wherein an integrating capacitor is charged up by a photoelectric current of the photoelectric element in a manner that the voltage across both ends of the capacitor is proportional to the logarithm of quantity of light received during a time of light measuring, a timer circuit which produces electric signals corresponding to the time of light measuring, an analog-digital converter which converts the analog output signal of the voltage in the integrating capacitor into a digital form and retain the information in a digital form, a coding circuit which is set to produce digital signals corresponding to film sensitivity, adder circuit which computes the digital output of the analogdigital converter together with the digital information from the coding circuit, a decoder for converting the digital output from the adder into another digital output suitable for numeral displaying, and numeral displaying devices for indicating the output of the decoder.
Claim 3
Dependent Claim 44 words
A digital indication exposure meter according to claim 1, characterized in that the indicator comprises at least two numeral display devices which display integral part of the computed stop value, and at least one lamp which displays decimal part of the computed stop value.

References Cited (Backward Citations)

US2761968A Cited
US3709615A Cited
US3649128A Cited
US3829865A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-09-29 1979-03-31 1979-09-30 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-09-29 1983-03-31 1983-09-30 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-09-29 1987-03-31 1987-09-30 $7700.00 Window Closed / Lapsed

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