Patent US4306807A successfully refreshed from Google Patents.
← Back to Patent Explorer
US4306807A Expired / Lapsed US ⏱️ 0.0 years remaining

Light measuring system

Assignee: Canon Inc
•
Filing: 1979-06-04
•
Granted: 1981-12-22
•
Expires: 1999-06-04
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract In the disclosed system, a light measuring circuit having a logarithmical amplifier, is constructed to produce pulses at a frequency corresponding to the output of the light measuring circuit. Pulses are counted during a time interval corresponding to the temperature characteristic of the light measuring circuit so as to obtain a count value corresponding to the light input free of the influence of temperature.

Inventors

  • 👤 Toshio Sakane
  • 👤 Tokuichi Tsunekawa

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 06:10
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/42; G01J1/44

Claims Analysis

Total Claims: 19
Claim 1
Independent Claim 109 words
A light measuring system comprising: (a) a light measuring circuit having given temperature characteristics for producing an output determined by incident light and influenced by temperature, (b) a pulse generating circuit for producing pulses with a frequency determined by the output of the light measuring circuit (c) a count control circuit having counter means for counting the pulses produced by temperature characteristics corresponding to the pulse generating circuit and control means for actuating the counting of said counter means for a period of time determined by the temperature characteristics of the light measuring circuit, so that the counting of said counter means varies in response to the temperature changes.
Claim 2
Dependent Claim 109 words
A light measuring system comprising: (a) a light measuring circuit having given temperature characteristics for producing an output determined by incident light and influenced by temperature, (b) a pulse generating circuit for producing pulses with a frequency determined by the output of the light measuring circuit (c) a count control circuit having counter means for counting the pulses produced by temperature characteristics corresponding to the pulse generating circuit and control means for actuating the counting of said counter means for a period of time determined by the temperature characteristics of the light measuring circuit, so that the counting of said counter means varies in response to the temperature changes.
Claim 3
Dependent Claim 148 words
A light measuring system comprising: (a) a light measuring circuit including a light sensing element and a first logarithmic conversion element having given temperature characteristics for logarithmically compressing the output of the light sensing element so as to produce an output responsive to the logarithmic value of the incident light, (b) a pulse generating circuit for producing pulses with frequency corresponding to the output of the light measuring circuit, (c) a standard voltage forming circuit including a second logarithmic conversion element having the same temperature characteristics as that of the logarithmic conversion element of the light measuring circuit so as to produce a standard voltage corresponding to the temperature characteristics of the first logarithmic conversion element, and (d) a counter circuit for counting the pulses from the pulse forming circuit during a time interval depending on the standard voltage and, when the temperature changes, upon the temperature characteristics.
Claim 4
Dependent Claim 148 words
A light measuring system comprising: (a) a light measuring circuit including a light sensing element and a first logarithmic conversion element having given temperature characteristics for logarithmically compressing the output of the light sensing element so as to produce an output responsive to the logarithmic value of the incident light, (b) a pulse generating circuit for producing pulses with frequency corresponding to the output of the light measuring circuit, (c) a standard voltage forming circuit including a second logarithmic conversion element having the same temperature characteristics as that of the logarithmic conversion element of the light measuring circuit so as to produce a standard voltage corresponding to the temperature characteristics of the first logarithmic conversion element, and (d) a counter circuit for counting the pulses from the pulse forming circuit during a time interval depending on the standard voltage and, when the temperature changes, upon the temperature characteristics.
Claim 5
Dependent Claim 43 words
A light measuring system in accordance with claim 2, wherein the light measuring, circuit includes an amplifier circuit between whose input terminals the light sensing element is connected and between whose input terminal and whose output terminal a logarithmic conversion element is connected.
Claim 6
Dependent Claim 180 words
A light measuring system comprising: (a) a light measuring circuit including an amplifier circuit, a light sensing element connected between the input terminals of the amplifier circuit, and a first logarithmic conversion element connected between the input terminal and the output terminal of the amplifier circuit, said logarithmic conversion element having given temperature characteristics, (b) a pulse generating circuit for producing pulses with a frequency depending upon the output of the light measuring circuit, (c) a standard voltage producing circuit including an amplifier circuit and a second logarithmic conversion element connected between the input terminal and the output terminal of the amplifier circuit, the second logarithmic conversion element having the same temperature characteristics as that of the the first logarithmic conversion element of the light sensing circuit so that said circuit produces an output of the standard voltage depending upon the temperature characteristics of the first conversion element, and (d) a counter circuit for counting the pulses from the pulse forming circuit during a time interval depending upon the standard voltage and, when the temperature changes, upon the temperature characteristics.
Claim 7
Dependent Claim 180 words
A light measuring system comprising: (a) a light measuring circuit including an amplifier circuit, a light sensing element connected between the input terminals of the amplifier circuit, and a first logarithmic conversion element connected between the input terminal and the output terminal of the amplifier circuit, said logarithmic conversion element having given temperature characteristics, (b) a pulse generating circuit for producing pulses with a frequency depending upon the output of the light measuring circuit, (c) a standard voltage producing circuit including an amplifier circuit and a second logarithmic conversion element connected between the input terminal and the output terminal of the amplifier circuit, the second logarithmic conversion element having the same temperature characteristics as that of the the first logarithmic conversion element of the light sensing circuit so that said circuit produces an output of the standard voltage depending upon the temperature characteristics of the first conversion element, and (d) a counter circuit for counting the pulses from the pulse forming circuit during a time interval depending upon the standard voltage and, when the temperature changes, upon the temperature characteristics.
Claim 8
Dependent Claim 18 words
A light measuring system in accordance with claim 2, wherein the first logarithmic conversion element is a diode.
Claim 9
Dependent Claim 17 words
A light measuring system in accordance with claim 1, wherein the measuring circuit includes a logarithmic amplifier.
Claim 10
Dependent Claim 77 words
A light measuring system comprising: a light measuring circuit having given temperature characteristics for producing an output determined by incident light and, when the temperature changes, upon the temperature characteristics, a pulse forming circuit for producing pulses with a frequency determined by the temperature characteristics of the light measuring circuit, and (c) a counter circuit for counting the pulses from the pulse forming circuit during a time interval corresponding to the output of the light measuring circuit.
Claim 11
Dependent Claim 77 words
A light measuring system comprising: a light measuring circuit having given temperature characteristics for producing an output determined by incident light and, when the temperature changes, upon the temperature characteristics, a pulse forming circuit for producing pulses with a frequency determined by the temperature characteristics of the light measuring circuit, and (c) a counter circuit for counting the pulses from the pulse forming circuit during a time interval corresponding to the output of the light measuring circuit.
Claim 12
Dependent Claim 150 words
A light measuring system comprising: (a) a light measuring circuit including a light sensing element and a first logarithmic conversion element for logarithmically compressing the output of the light sensing element so as to produce an output depending upon the logarithmic value of the incident light, said first logarithmic conversion element having given temperature characteristics, (b) a standard voltage forming circuit including a second logarithmic conversion element having the same temperature characteristics as that of the logarithmic conversion element of the light measuring circuit as to produce a standard voltage depending upon the temperature characteristics of the first logarithmic conversion element, (c) a pulse forming circuit for producing pulses with a frequency determined on the basis of the standard voltage, and (d) a counter circuit for counting the pulse from the pulse forming circuit during a time interval determined on the basis of the output of the light measuring circuit.
Claim 13
Dependent Claim 150 words
A light measuring system comprising: (a) a light measuring circuit including a light sensing element and a first logarithmic conversion element for logarithmically compressing the output of the light sensing element so as to produce an output depending upon the logarithmic value of the incident light, said first logarithmic conversion element having given temperature characteristics, (b) a standard voltage forming circuit including a second logarithmic conversion element having the same temperature characteristics as that of the logarithmic conversion element of the light measuring circuit as to produce a standard voltage depending upon the temperature characteristics of the first logarithmic conversion element, (c) a pulse forming circuit for producing pulses with a frequency determined on the basis of the standard voltage, and (d) a counter circuit for counting the pulse from the pulse forming circuit during a time interval determined on the basis of the output of the light measuring circuit.
Claim 14
Dependent Claim 179 words
A light measuring system comprising: (a) a light measuring circuit including an amplifier circuit, a light sensing element connected between the input terminals of the amplifier circuit and a first logarithmic conversion element connected between the input terminal and the output terminal of the amplifier circuit, said first logarithmic conversion element having given temperature characteristics, (b) a standard voltage producing circuit including an amplifier circuit and a second logarithmic conversion element connected between the input terminal and the output terminal of the amplifier circuit, the second logarithmic conversion element having the same temperature characteristics as the first logarithmic conversion element of the light sensing circuit so that said standard voltage producing circuit produces an output of the standard voltage corresponding to the temperature characteristics at the first logarithmic conversion element, (c) a pulse forming circuit for producing pulses with a frequency determined on the basis of the standard voltage, and (d) a counter circuit for counting the pulses from the pulse forming circuit during a time interval determined on the basis of the output of the light measuring circuit.
Claim 15
Dependent Claim 179 words
A light measuring system comprising: (a) a light measuring circuit including an amplifier circuit, a light sensing element connected between the input terminals of the amplifier circuit and a first logarithmic conversion element connected between the input terminal and the output terminal of the amplifier circuit, said first logarithmic conversion element having given temperature characteristics, (b) a standard voltage producing circuit including an amplifier circuit and a second logarithmic conversion element connected between the input terminal and the output terminal of the amplifier circuit, the second logarithmic conversion element having the same temperature characteristics as the first logarithmic conversion element of the light sensing circuit so that said standard voltage producing circuit produces an output of the standard voltage corresponding to the temperature characteristics at the first logarithmic conversion element, (c) a pulse forming circuit for producing pulses with a frequency determined on the basis of the standard voltage, and (d) a counter circuit for counting the pulses from the pulse forming circuit during a time interval determined on the basis of the output of the light measuring circuit.
Claim 16
Dependent Claim 81 words
A light measuring system comprising: (a) a light measuring circuit having given temperature characteristics for producing an output responsive to incident light and varying in response to temperature temperature changes on the basis of the temperature characteristics; (b) a pulse generating circuit for producing pulses with a frequency proportional to the output of the light measuring circuit; and (c) a count control circuit for counting pulses produced by the pulse generating circuit during a time interval proportional to the temperature characteristics.
Claim 17
Dependent Claim 81 words
A light measuring system comprising: (a) a light measuring circuit having given temperature characteristics for producing an output responsive to incident light and varying in response to temperature temperature changes on the basis of the temperature characteristics; (b) a pulse generating circuit for producing pulses with a frequency proportional to the output of the light measuring circuit; and (c) a count control circuit for counting pulses produced by the pulse generating circuit during a time interval proportional to the temperature characteristics.
Claim 18
Dependent Claim 78 words
A light measuring system comprising: (a) a light measuring circuit having given temperature characteristics for producing an output responsive to incident light and in response to temperature changes on the basis of the temperature characteristics; (b) a pulse generating circuit for producing pulses with a frequency proportional to the temperature characteristics; and (c) a counter circuit for counting the pulses from the pulse generating circuit during a time interval proportional to the output of the light measuring circuit.
Claim 19
Dependent Claim 78 words
A light measuring system comprising: (a) a light measuring circuit having given temperature characteristics for producing an output responsive to incident light and in response to temperature changes on the basis of the temperature characteristics; (b) a pulse generating circuit for producing pulses with a frequency proportional to the temperature characteristics; and (c) a counter circuit for counting the pulses from the pulse generating circuit during a time interval proportional to the output of the light measuring circuit.

References Cited (Backward Citations)

US3820126A Cited
US3863263A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1984-12-21 1985-06-22 1985-12-22 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1988-12-21 1989-06-22 1989-12-22 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1992-12-21 1993-06-22 1993-12-22 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag