US3576370A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure time control system for photographic apparatus
Assignee: Agfa Gevaert AG
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Filing: 1968-10-23
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Granted: 1971-04-27
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Expires: 1988-10-23
Abstract
Abstract Light is transmitted through the original onto photosensitive material in each of three primary colors. Three secondary electromultipliers furnish electrical currents which vary as a function of the light received by the photosensitive material in each color. Each current is integrated by a capacitor, the voltage on the capacitor compared to a reference voltage, and a relay energized when the capacitor voltage and the reference voltage have a predetermined relationship. Each relay has a first set of contacts for terminating the illumination in the corresponding color and a second set of contacts for shorting out part of a resistance connected in series between the supply voltage terminal and a transformer supplying voltage to the secondary electron multiplier corresponding to the other colors. This increases the sensitivity of the other electron multipliers, increasing the charging rate of the capacitor, and thus decreasing the exposure time in the other colors.
Inventors
- 👤 Gerhard Kuhn
- 👤 Wolfgang Zahn
- 👤 Walter Knapp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:35
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72; G03B27/73; G03B27/735
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
152 words
In an apparatus for producing color copies of a color original on photosensitive material; an exposure control arrangement, comprising in combination, illuminating means for illuminating said photosensitive material through said original in each of a predetermined plurality of colors, the illumination in a color starting at a corresponding illumination starting time; a plurality of measuring means corresponding in number to said plurality of colors, each for furnishing, subsequent to the corresponding illumination starting time, a color measurement signal corresponding to the total amount of light having illuminated said photosensitive material in the corresponding color since the corresponding illumination starting time; terminating means for individually terminating the exposure in each of said colors when the corresponding color measurement signal has reached a predetermined value; and exposure time changing means for changing the exposure time for at least one color still being illuminated upon termination of the illumination in at least one other color.
Claim 2
Dependent Claim
152 words
In an apparatus for producing color copies of a color original on photosensitive material; an exposure control arrangement, comprising in combination, illuminating means for illuminating said photosensitive material through said original in each of a predetermined plurality of colors, the illumination in a color starting at a corresponding illumination starting time; a plurality of measuring means corresponding in number to said plurality of colors, each for furnishing, subsequent to the corresponding illumination starting time, a color measurement signal corresponding to the total amount of light having illuminated said photosensitive material in the corresponding color since the corresponding illumination starting time; terminating means for individually terminating the exposure in each of said colors when the corresponding color measurement signal has reached a predetermined value; and exposure time changing means for changing the exposure time for at least one color still being illuminated upon termination of the illumination in at least one other color.
Claim 3
Dependent Claim
18 words
An exposure control arrangement as set forth in claim 1 wherein said plurality of colors comprises three colors.
Claim 4
Dependent Claim
42 words
An exposure control arrangement as set forth in claim 2 wherein said exposure time changing means comprise means for shortening the exposure time for at least one color still being illuminated upon termination of the illumination in at least one other color.
Claim 5
Dependent Claim
61 words
An exposure control arrangement as set forth in claim 3 wherein said measuring means comprise photoelectric transducing means for generating three electrical signals, each varying as a function of the amount of light illuminating said photosensitive material in a corresponding one of said colors; and electrical integrator means for integrating each of said electrical signals thus furnishing said color measurement signals.
Claim 6
Dependent Claim
29 words
An exposure control arrangement as set forth in claim 4 wherein said electrical integrator means comprise capacitors; and wherein said electrical signals comprise the charging currents for said capacitors.
Claim 7
Dependent Claim
78 words
An exposure control arrangement as set forth in claim 5 wherein said photoelectric transducing means comprise a plurality of photoelectric transducing means, one for each of said colors; wherein said charging currents also vary as a function of voltage applied to the corresponding photoelectric transducing means; and wherein said exposure time changing means comprise means for changing said applied voltage of at least one other of said photoelectric tRansducing means upon termination of illumination in any one color.
Claim 8
Dependent Claim
54 words
An exposure control arrangement as set forth in claim 6 wherein said terminating means comprise a plurality of relay means, one for each of said colors; and energizing means, one for each of said relay means, for energizing the corresponding relay means when the voltage on the corresponding capacitor has reached a predetermined value.
Claim 9
Dependent Claim
70 words
An exposure control arrangement as set forth in claim 7 further comprising means for furnishing a reference voltage; and wherein said energizing means comprise electronic switching means connected to said means for furnishing a reference voltage, to the corresponding capacitor, and to the corresponding relay means in such a manner that said relay means are energized when the corresponding capacitor voltage has reached a predetermined relationship to said reference voltage.
Claim 10
Dependent Claim
67 words
An exposure control system as set forth in claim 8 further comprising voltage supply means to furnish a supply voltage; and resistance means, series connected between said voltage supply means and said photoelectric transducing means; and wherein said means for changing said applied voltage comprise means for short circuiting a predetermined corresponding part of said resistance means upon termination of the illumination in each of said color.
Claim 11
Dependent Claim
40 words
An exposure control system as set forth in claim 9 wherein said means for short circuiting a predetermined part of said resistance means comprise three pairs of normally opened relay contacts, one pair associated with each of said relay means.
Claim 12
Dependent Claim
36 words
An exposure control system as set forth in claim 10 wherein said predetermined parts of said resistance means each comprise a potentiometer having a wiper arm; and wherein all of said wiper arms are mechanically intercoupled.
Claim 13
Dependent Claim
56 words
An exposure control system as set forth in claim 10, wherein each of said predetermined parts of said resistance means comprises a fixed resistor; further comprising additional resistors for each of said parts; and means for selecting different ones of said additional resistors to constitute said predetermined parts, in dependence upon the desired degree of undercorrection.
References Cited (Backward Citations)
US3100419A
Cited
US3293033A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-26 | 1974-10-26 | 1975-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-26 | 1978-10-26 | 1979-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-26 | 1982-10-26 | 1983-04-27 | $7700.00 | Window Closed / Lapsed |