US3575508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure time control arrangement
Assignee: Agfa Gevaert AG
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Filing: 1968-08-15
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Granted: 1971-04-20
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Expires: 1988-08-15
Abstract
Abstract Photo sensitive material is illuminated through a color original. Three secondary electron multipliers furnish currents proportional to the light illuminating the photo sensitive material, one for each of three colors. Each current charges a capacitor. One terminal of each of the capacitors is connected to the corresponding secondary electron multiplier, and is also connected to a potentiometer. The other terminals of all three potentiometers are connected to a common point. The voltage at the wiper arm of each potentiometer is compared to a corresponding reference voltage. Illumination in a given color is terminated when the voltage at the wiper arm and the corresponding reference voltage have a predetermined relationship.
Inventors
- 👤 Berthold Fergg
- 👤 Walter Knapp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:26
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72; G03B27/73; G03B27/735
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
178 words
In an apparatus for producing color copies of a color original on photosEnsitive material, an arrangement for controlling the exposure time in each of a plurality of colors, comprising in combination, illuminating means illuminating said photosensitive material through said color original beginning at an exposure starting time; a plurality of photoelectric transducing means for producing a plurality of photocurrents, each corresponding to the light illuminating said photosensitive material in one of said plurality of colors; a corresponding plurality of integrator means for integrating each of said photocurrents, each of said integrator means thus furnishing a color signal corresponding to the total illuminating energy having impinged on said photosensitive material in the corresponding color since said exposure starting time; means for interconnecting said integrator means with each other in such a manner that an average signal, corresponding to the average amount of illuminating energy impinged on said photosensitive material since said exposure starting time is derived therefrom; and means for terminating the illumination in any given color in dependence on both the corresponding color signal and said average signal.
Claim 2
Dependent Claim
178 words
In an apparatus for producing color copies of a color original on photosEnsitive material, an arrangement for controlling the exposure time in each of a plurality of colors, comprising in combination, illuminating means illuminating said photosensitive material through said color original beginning at an exposure starting time; a plurality of photoelectric transducing means for producing a plurality of photocurrents, each corresponding to the light illuminating said photosensitive material in one of said plurality of colors; a corresponding plurality of integrator means for integrating each of said photocurrents, each of said integrator means thus furnishing a color signal corresponding to the total illuminating energy having impinged on said photosensitive material in the corresponding color since said exposure starting time; means for interconnecting said integrator means with each other in such a manner that an average signal, corresponding to the average amount of illuminating energy impinged on said photosensitive material since said exposure starting time is derived therefrom; and means for terminating the illumination in any given color in dependence on both the corresponding color signal and said average signal.
Claim 3
Dependent Claim
16 words
An arrangement as set forth in claim 1 wherein said plurality of colors comprises three colors.
Claim 4
Dependent Claim
95 words
An arrangement as set forth in claim 2 wherein each of said integrator means comprise a capacitor, the voltage on said capacitor corresponding to the integral of the corresponding photocurrent; and wherein said interconnecting means comprise three voltage dividers, one for each of said capacitors, each having a first and second voltage divider terminal and a wiper arm, each of said first voltage divider terminals being connected to a corresponding capacitor, all of said second voltage divider terminals connected to a common point, each of said wiper arms being connected to the corresponding terminating means.
Claim 5
Dependent Claim
17 words
An arrangement as set forth in claim 3 wherein all of said wiper arms are mechanically intercoupled.
Claim 6
Dependent Claim
24 words
An arrangement as set forth in claim 4, also comprising cathode follower means connected between each of said capacitors and the corresponding voltage divider.
Claim 7
Dependent Claim
86 words
An arrangement as set forth in claim 5 wherein said terminating means comprise comparison means for comparing the voltage at each of said wiper arms to a corresponding reference voltage and generating a terminating signal for terminating the illumination in the corresponding color when the voltage at a given wiper arm has reached a predetermined value in relation to the corresponding reference voltage; and relay means, one for each of said colors for terminating the exposure in the corresponding color upon receipt of said terminating signal.
Claim 8
Dependent Claim
31 words
An arrangement as set forth in claim 6 wherein the value of a particular reference voltage is a function of the Schwarzschild exponent of the light sensitive material in said color.
Claim 9
Dependent Claim
32 words
An arrangement as set forth in claim 6 wherein the value of said reference voltage for a given color is a function of the sensitivity of said photosensitive material in said color.
Claim 10
Dependent Claim
18 words
An arrangement as set forth in claim 6 wherein each of said comparison means comprises an operational amplifier.
Claim 11
Dependent Claim
24 words
An arrangement as set forth in claim 6 also comprising means for discharging all of said capacitors after generation of the last terminating signal.
Claim 12
Dependent Claim
116 words
An arrangement as set forth in claim 10 wherein said relay means each have an additional pair of contacts, all said pairs of contacts being connected in series; also comprising addition relay means having an activating coil connected in series with said series connection of contacts, said additional relay means having three pairs of additional relay contacts, each pair so connected to each of said capacitors that closing of said contacts causes said capacitors to be short circuited; and a voltage source connected to said series connection of contact pairs and said activating coil in such a manner that current flows through said activating coil upon closing of all three of said additional relay contact pairs.
References Cited (Backward Citations)
US3293033A
Cited
US3120782A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |