US3812503A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure indicator for a photographic camera
Assignee: Agfa Gevaert AG
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Filing: 1972-11-28
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Granted: 1974-05-21
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Expires: 1992-11-28
Abstract
Abstract A photosensitive element is mounted to receive the light available for exposure and constitutes part of a voltage divider which has a number of taps. Each of the taps is connected to the input of a bistable stage. As the threshold of each bistable stage is passed, it serves to connect a corresponding one of a plurality of indicators to a battery, thereby energizing it. Passing of the threshold of the next-following indicator then causes a diode to short circuit the first indicator and the energization of the second indicator. Each bistable stage thus in turn energizes its indicator and short circuits the previous indicator. Thus only that indicator remains energized for which the voltage at its corresponding voltage divider tap is most closely equal to the threshold voltage of the corresponding bistable stage.
Inventors
- 👤 D Engelsmann
- 👤 E Wagensonner
- 👤 A Rieder
- 👤 Fischern B Von
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:57
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/18; G03B17/20
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
296 words
In a photographic camera, an indicator arrangement, comprising, in combination, a plurality of indicator means, each for indicating a predetermined exposure value upon receipt of an activation signal; photosensitive transducing means for furnishing an electrical signal varying as a function of light incident thereon; a plurality of switching stages each having a first circuit element connected to said photosensitive transducing means, each of said first circuit elements having a first state when said electrical signal is less than a corresponding threshold value and a second state when said electrical signal is greater than said corresponding threshold value, and a second circuit element connected to said first circuit element in such a manner that said second circuit element is in said second and first state respectively when said first circuit element is in said first and second state respectively; connecting means for connecting each of said second circuit elements to a corresponding one of said indicator means in such a manner that said second circuit element furnishes said activation signal to said corresponding one of said indicator means when in said second state; means for interconnecting said switching stages in a predetermined sequence of increasing threshold values; and a plurality of third circuit elements each having a first terminal connected to a corresponding one of said indicator means and a second terminal connected to said second circuit element of the next subsequent one of said switching stages in said predetermined sequence, for shunting said activation signal from said corresponding one of said indicator means when said second circuit element of said subsequent switching stage is in said first state, whereby application of said activation signal to a given one of said indicator means causes deactiVation of the previous one of said indicator means in said predetermined sequence.
Claim 2
Dependent Claim
296 words
In a photographic camera, an indicator arrangement, comprising, in combination, a plurality of indicator means, each for indicating a predetermined exposure value upon receipt of an activation signal; photosensitive transducing means for furnishing an electrical signal varying as a function of light incident thereon; a plurality of switching stages each having a first circuit element connected to said photosensitive transducing means, each of said first circuit elements having a first state when said electrical signal is less than a corresponding threshold value and a second state when said electrical signal is greater than said corresponding threshold value, and a second circuit element connected to said first circuit element in such a manner that said second circuit element is in said second and first state respectively when said first circuit element is in said first and second state respectively; connecting means for connecting each of said second circuit elements to a corresponding one of said indicator means in such a manner that said second circuit element furnishes said activation signal to said corresponding one of said indicator means when in said second state; means for interconnecting said switching stages in a predetermined sequence of increasing threshold values; and a plurality of third circuit elements each having a first terminal connected to a corresponding one of said indicator means and a second terminal connected to said second circuit element of the next subsequent one of said switching stages in said predetermined sequence, for shunting said activation signal from said corresponding one of said indicator means when said second circuit element of said subsequent switching stage is in said first state, whereby application of said activation signal to a given one of said indicator means causes deactiVation of the previous one of said indicator means in said predetermined sequence.
Claim 3
Dependent Claim
27 words
An arrangement as set forth in claim 1, wherein said photographic camera has a view finder; and wherein said indicator means are arranged in said view finder.
Claim 4
Dependent Claim
15 words
An arrangement as set forth in claim 1, wherein said indicator means comprise luminescent diodes.
Claim 5
Dependent Claim
15 words
An arrangement as set forth in claim 1, wherein said indicator means comprise incandescent lamps.
Claim 6
Dependent Claim
39 words
An arrangement as set forth in claim 1, wherein said indicator means comprise fluid crystals having a light transmissive and an opaque state and changing from said light transmissive to said opaque state upon application of a voltage thereto.
Claim 7
Dependent Claim
51 words
An arrangement as set forth in claim 5, wherein each of said fluid crystals has a light transmissive wall, and wherein each of said predetermined exposure values is represented by a symbol arranged on said light transmissive wall, said symbol being visible when said fluid crystal is in said opaque state.
Claim 8
Dependent Claim
37 words
An arrangement as set forth in claim 5, wherein said indicator means further comprise light transmissive disk means having indicator symbols, said light transmissive disk means being positioned in a predetermined position relative to said fluid crystals.
Claim 9
Dependent Claim
38 words
An arrangement as set forth in claim 5, wherein said fluid crystals are arranged next to each other; further comprising a plurality of opaque walls separating each of said crystals from the next subsequent one of said crystals.
Claim 10
Dependent Claim
92 words
An arrangement as set forth in claim 1, wherein said photographic camera further has a diaphragm and f-stop adjusting means for adjusting the opening of said diaphragm; further comprising auxiliary diaphragm means mechanically coupled to said f-stop adjusting means for movement therewith, said auxiliary diaphragm means transmitting light varying as a function of the position thereof; and wherein said photosensitive means is mounted behind said auxiliary diaphragm means in the direction of light propagation, whereby the position of said auxiliary diaphragm means varies the quantity of light falling on said photosensitive means.
Claim 11
Dependent Claim
86 words
An arrangement as set forth in claim 9, wherein said photographic camera further comprises exposure time setting means and a view finder; wherein each of said plurality of indicator means is mounted in a fixed position in said view finder; further comprising indicator selector means coupled to said exposure time setting means in such a manner that the exposure time is set for the desired exposure time when said indicator selector means is in a predetermined position relative to the activated one of said indicator means.
Claim 12
Dependent Claim
39 words
An arrangement as set forth in claim 9, further comprising variable resistor means having a variable arm connected to said f-stop adjusting means for movement therewith; and means connecting said variable resistor means in series with said photosensitive means.
Claim 13
Dependent Claim
62 words
An arrangement as set forth in claim 1, wherein said indicator means comprise fluid crystal means having a a light transmissive state for suppressing said indication and a light diffusely reflecting state for furnishing said indication; and wherein said fluid crystal means is adapted to change from said light transmissive state to said diffusely reflecting state upon application of a voltage thereto.
Claim 14
Dependent Claim
68 words
An arrangement as set forth in claim 1, further comprising a source of electrical energy; wherein said means for interconnecting said switching stages comprise voltage divider means, having a plurality of voltage divider taps, connected to said source of electrical energy and said photosensitive means; and wherein each of said first circuit elements of said switching stages is connected to a corresponding one of said voltage divider taps.
Claim 15
Dependent Claim
83 words
An arrangement as set forth in claim 13, wherein said source of electrical energy has a first and a second terminal; wherein each of said indicator means has a first terminal connected to said first Terminal of said source of electrical energy and a second terminal; and wherein each of said second circuit elements connects said second terminal of said corresponding one of said plurality of indicator means to said second terminal of said source of electrical energy when furnishing said activation signal.
Claim 16
Dependent Claim
31 words
An arrangement as set forth in claim 14, further comprising resistance means interconnected between said first terminal of said source of electrical energy and said first terminals of said indicator means.
Claim 17
Dependent Claim
105 words
An arrangement as set forth in claim 15, wherein said first and second state are a conductive and blocked state respectively; wherein each of said second circuit elements constitutes a low resistance path to ground potential when in said first state; and wherein each of said third circuit elements is a diode having a first terminal connected to said first terminal of said indicator means and a second terminal connected to said second circuit element of said next subsequent switching stage, whereby each of said diodes short-circuits the corresponding one of said indicator means upon activation of the next subsequent one of said indicator means.
Claim 18
Dependent Claim
52 words
An arrangement as set forth in claim 16, wherein said voltage divider means comprise a plurality of voltage divider resistors; and wherein said photosensitive means has a first terminal connected to said second terminal of said source of electrical energy and a second terminal connected to one of said voltage divider resistors.
Claim 19
Dependent Claim
56 words
An arrangement as set forth in claim 16, wherein said voltage divider means comprise a plurality of voltage divider resistors; and wherein said photosensitive means has a first terminal connected to said first terminal of said source of electrical energy and a second terminal connected to a selected one of said plurality of voltage divider resistors.
Claim 20
Dependent Claim
201 words
An arrangement as set forth in claim 13, wherein said source of electrical energy has a first and second terminal; wherein each of said indicator means has a first terminal connected to said first terminal of said source of electrical energy and a second terminal, each of said indicator means furnishing the indication of said corresponding exposure value when the voltage across said indicating means is substantially zero and suppressing said indication when the voltage across said indicator means is a predetermined voltage substantially exceeding zero; wherein each of said switching stages applies a voltage substantially equal to the voltage at said first terminal of said indicator means to said second terminal of said indicator means when furnishing said activation signal; and wherein each of said third circuit elements comprise a transistor having an emitter-collector circuit connected from said second terminal of a corresponding one of said indicator means to said second terminal of said source of electrical energy when conductive, and a base connected to said second circuit element of said subsequent one of said switching stages in said predetermined sequence in such a manner that said emitter-collector circuit is conductive when said next subsequent stage furnishes said activation signal.
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |