US3700337A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Structure of exposure measuring device using two galvanometers
Assignee: Nikon Corp
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Filing: 1970-06-12
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Granted: 1972-10-24
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Expires: 1990-06-12
Abstract
Abstract An electrical photo-exposure meter comprising at least one variable resistor operatively associated with an exposure factor whereby an accurate exposure free of any error resulting from a variation in the source voltage can always be obtained without checking the source voltage.
Inventors
- 👤 Tatsuo Fujii
- 👤 Toshio Tomomitsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:35
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/04; G03B7/06; G01; G01J; G01J1/00; G01J1/42
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
171 words
An electrical photo-exposure meter comprising, in combination, a source of potential; a first circuit connected in series with the source and including a first galvanometer with a movable pointer, a variable resistor, and a photosensitive element connected in series with the first galvanometer and the variable resistor, the photosensitive element having a resistance which varies as a function of the light incident upon it, the variable resistor regulating the current flowing through the first galvanometer; a second circuit including a second galvanometer with a movable pointer and a resistor connected in series with the second galvanometer, the second circuit being connected in parallel with the first circuit, the first and second galvanometers being coaxially arranged; and two fixed indicia for cooperation with the two pointers, the two indicia being spaced from each other to define a range therebetween, whereby the proper exposure is obtainable when the two pointers overlap each other within the range between the two indicia by adjusting the variable resistor to deflect the pointer of the first galvanometer.
Claim 2
Dependent Claim
171 words
An electrical photo-exposure meter comprising, in combination, a source of potential; a first circuit connected in series with the source and including a first galvanometer with a movable pointer, a variable resistor, and a photosensitive element connected in series with the first galvanometer and the variable resistor, the photosensitive element having a resistance which varies as a function of the light incident upon it, the variable resistor regulating the current flowing through the first galvanometer; a second circuit including a second galvanometer with a movable pointer and a resistor connected in series with the second galvanometer, the second circuit being connected in parallel with the first circuit, the first and second galvanometers being coaxially arranged; and two fixed indicia for cooperation with the two pointers, the two indicia being spaced from each other to define a range therebetween, whereby the proper exposure is obtainable when the two pointers overlap each other within the range between the two indicia by adjusting the variable resistor to deflect the pointer of the first galvanometer.
Claim 3
Dependent Claim
23 words
An electrical photo-exposure meter according to claim 1, wherein the first galvanometer and the variable resistor are connected in parallel with each other.
Claim 4
Dependent Claim
19 words
An electrical photo-exposure meter according to claim 2 further comprising a resistor connected in parallel with the second galvanometer.
Claim 5
Dependent Claim
162 words
An electrical photo-exposure meter comprising, in combination, a source of potential; a first circuit connected in series with the source and including a first galvanometer with a movable pointer and a photosensitive element connected in series with the first galvanometer, the photosensitive element having a resistance which varies as a function of the light incident upon it; a second circuit connected in parallel with the first circuit and including a second galvanometer with a movable pointer and a variable resistor connected in series with the galvanometer, the variable resistor regulating the current flowing through the second galvanometer, the first and second galvanometers being coaxially arranged; and two fixed indicia disposed to cooperate with the two pointers, the two indicia being spaced from each other to define a range therebetween, whereby the proper exposure is obtainable when the two pointers overlap each other within the range between the two indicia by adjusting the variable resistor to deflect the pointer of the second galvanometer.
Claim 6
Dependent Claim
162 words
An electrical photo-exposure meter comprising, in combination, a source of potential; a first circuit connected in series with the source and including a first galvanometer with a movable pointer and a photosensitive element connected in series with the first galvanometer, the photosensitive element having a resistance which varies as a function of the light incident upon it; a second circuit connected in parallel with the first circuit and including a second galvanometer with a movable pointer and a variable resistor connected in series with the galvanometer, the variable resistor regulating the current flowing through the second galvanometer, the first and second galvanometers being coaxially arranged; and two fixed indicia disposed to cooperate with the two pointers, the two indicia being spaced from each other to define a range therebetween, whereby the proper exposure is obtainable when the two pointers overlap each other within the range between the two indicia by adjusting the variable resistor to deflect the pointer of the second galvanometer.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |