US3166674A - Time switch for photographic apparatus - Google Patents

Time switch for photographic apparatus Download PDF

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Publication number
US3166674A
US3166674A US147791A US14779161A US3166674A US 3166674 A US3166674 A US 3166674A US 147791 A US147791 A US 147791A US 14779161 A US14779161 A US 14779161A US 3166674 A US3166674 A US 3166674A
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Prior art keywords
exposure
potential
capacitors
tube
circuit
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US147791A
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English (en)
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Wick Richard
Schneider Othmar
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/72—Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus
    • G03B27/80—Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus in dependence upon automatic analysis of the original
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/28—Modifications for introducing a time delay before switching
    • H03K17/288—Modifications for introducing a time delay before switching in tube switches
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H05G1/30—Controlling
    • H05G1/38—Exposure time
    • H05G1/42—Exposure time using arrangements for switching when a predetermined dose of radiation has been applied, e.g. in which the switching instant is determined by measuring the electrical energy supplied to the tube

Definitions

  • the present invention concerns an electric time switch arrangement for controlling the duration of exposures of photo-sensitive material to radiating energy. Arrangements of this type are most conveniently applied to apparatus for making photoprints in black and white or in colors, but it may as well be applied to apparatus for making X-ray pictures.
  • Apparatus of the type to which the present invention is applicable contain control means for limiting the exposure time in accordance with .the amount of radiating energy impinging during an exposure on the photo-sensitive material.
  • the invention provides in an electric time switch arrangement for controlling the duration of exposures of photo-sensitive material to radiating energy, in combination.
  • Control means for limiting the exposure time in accordance with the amount of radiating energy impinging during an exposure on said photo-sensitive material, said control means including an electron tube controlling, upon being rendered non-conductive, the start, and upon being returned to conductive condition, the end of the exposure, the conductive condition of said tube depending upon a predetermined potential relation between two electrodes of-said tube, and photo-responsive means exposed to said radiating energy and furnishing to one of said electrodes a potential gradually varying depending upon said India"- ing energy impinging on said photo-responsive means and thereby changing the potential and said one of said electrodes; and
  • correction means for modifying the time limiting action of said control means, said correction means includ ing means for applying a first predetermined potential to the other one of said electrodes, chargeable RC-circuit means having a predetermined charging time constant and being connected in circuit with said other one electrode for changing said first potential at said other electrode depending upon the charge potential of said RC-circuit 3,166,674 Patented Jan.
  • the RC- circuit means comprise at least two RC-circuits having time constants differing from each other, the capacitors of all of these RC-circuits being connected in series.
  • the electron tube and a control relay controlled thereby may be arranged in a separate control circuit, while the above mentioned potentiometer forms part of the timing circuit of the time control arrangement, whereas the capacitors of the above mentioned RC-circuits are arranged in a separate adjustment circuit, each of these circuits having preferably separate power supply circuits.
  • the potentiometer arranged in the timing circuit may be connected in parallel with a series combination comprising conventional photocell and timing capacitor of the timing arrangement.
  • the means for changing the potential applied to one electrode of the electron tube are connected with the respective power supply in such a manner that the polarity of the potential derived from the adjustment means can be reversed.
  • a potentiometer is included in the charging circuit of each of the capacitors of the RC-circuits, each capacitor having one terminal connected with a fixed center tap of the respective potentiometer, while the other terminal of the capacitor is connected with the movable tap of that potentiometer. It is advisable to couple mechanically the movable taps of these potentiometers.
  • potentiometers are connected in parallel with each other and that their movable taps, when moved simultaneously, have an opposite effect on the respective potentiometers.
  • all these movable potentiometer taps mentioned above may be controlled by one single control knob having an index cooperating with a corresponding scale.
  • the arrangement according to the invention as illustrated applies to a photographic printing apparatus, not shown, having a light source 1 connected by lines 2 and 3 with a general supply 4, 5 of alternating current, controllable by a main switch 6.
  • the main purpose of the arrangement described below is to control the duration of an exposure of photo-sensitive material to the radiating energy furnished by the light source 1.
  • the arrangement according to the invention as shown comprises three main circuits, namely a light control circuit 7, a time control circuit 8 and an adjustment circuit 9. Each of these circuits comprises a separate power supply circuit 10, 11, 12, respectively.
  • These supply circuits 1'0, 11 and 12 obtain energy through secondary windings 13, 14 and 15, respectively, of a transformer 16 having a primary 17 connected to the main power supply 4, 5.
  • the power supply circuit co. prises in conventional manner a four-way rectifier 18 and a filter circuit composed of the capacitors 19 and 2t) and a resistor 21.
  • the power supply circuits 11 and 12 are constructed in the same manner.
  • the light control circuit 7 comprises in series arrangement a control tube 22, preferably a thyratron, a relay coil 23 operating, among others, a relay switch 23a in the connection 3 of the light source 1, and a starter switch 24 movable between two stationary contacts 25 and 26 for the purpose of briefly interrupting the light control circuit 7 when the switch 24 is moved from one of the contacts 25, 26 to the other.
  • the time control circuit 8 comprises a conventional timing capacitor 27 connected in series with a photocell 28 which is arranged to be exposed to the radiating energy furnished by the light source 1 and impinging on the photo-sensitive material.
  • the junction point 29 between the capacitor 27 and the photocell 28 is connected via line 30 with the control grid 31 of the tube 22.
  • a relay switch 23b operable by the coil 23 is connected in parallel with the capacitor 27 so that the latter is shunted when switch 23b is in closed position.
  • the photocell 28 may be an electron multiplier phototube. It operates in the well known manner.
  • the adjustment circuit 9 comprises two RC-circuits 32, 33 and 34, 35.
  • the capacitors 32 and 34 of these circuits are connected in series and the pertaining adjustable resistors 33 and 35 are arranged, as shown, in separate charging circuits for the respective capacitors 32 and 34.
  • the capacitors 32 and 34 can be charged with potentials determined by the potentiometers 36 and 37, respectively, which are connected in parallel between the supply lines 38 and 39 connected with the supply circuit 12 and carrying direct current voltage.
  • the junction point 40 between the capacitors 32 and 34 is connected by a line 41 with both the fixed center taps 42 and 43 of the potentiometers 36 and 37, respectively.
  • the resistors 33 and 35 are connected via lines 44 and 45, respectively, with the movable potentiometer taps 46 and 47, respectively.
  • a relay switch 23c is connected in parallel with the capacitor 32, and similarly a relay switch 23d is connected in parallel with the capacitor 34. Both these last mentioned relay switches are also operated by the relay coil 23.
  • the capacitor 32 is connected by the line 48 with the cathode 49 of the control tube 22 of the light control circuit 7, while the capacitor 34 is connected by line 50 with the movable tap 52 of the potentiometer 51 of the time control circuit 8.
  • the potentiometer 51 is connected across the supply lines 53 and 54 of the power supply circuit 11 and at the same time in parallel with the seriescombination consisting of the timing capacitor 27 and the photocell 28.
  • the movable tap 52 of the potentiometer 51 is mechanically coupled with the movable taps 46 and 47 of the potentiometers 36, 37 of the adjustment circuit 9, e.g. by means of a common shaft 55 indicated only symbolically by dash-dotted lines in the drawing and turnable by means of a control knob 56.
  • This knob is equipped with an index or pointer 57 which cooperates with an adjustment scale or graduation 58 that may be arranged on the outside wall of the printing apparatus not shown in the drawing.
  • the starting switch 24 is moved from the position contacting the contact 25 to its second position contacting the contact 26.
  • the movement of the switch 24 causes a transitory interruption of the circuit whereby the tube 22 is changed to non-conductive condition, the relay coil 23 is de-energized so that relay switch 23a moves to closed position while the relay switches 23b, 23c and 23d are moved to open position.
  • the closing of relay switch 23a the source of light 1 is switched on and the exposure of the photo-sensitive material is started.
  • the capacitors 32 and 34 are connected in series and since the positioning of the movable taps 46, 47 of the potentiometers 36, 37, respectively, in relation to their center taps 42, 43, respectively, occurs in mutually opposite directions, the charging potentials of the capacitors 32 and 34 are superimposed on each other and simultaneously added to the potential tapped from the potentiometer 51, so that the potential at the cathode 49 of the tube 22 is gradually increased in accordance with the charging rate of the capacitors 32, 34, starting with the potential of the movable tap 52, from the start of the exposure on- Ward.
  • timing capacitor 27 of the time control circuit 8 is also charged by the photo-current of the photocell 28 illuminated by the radiating energy furnished by the source 1, the charge potential of the capacitor 27 being applied to the grid 31 of the tube 22 via the line 30.
  • the tube 22 is rendered conductivewhereby the relay coil 23 is returned to energizedv condition and the relay switches 23a, 23b, 23c and 23d are returned to the positions shown in the drawing.
  • the source of light 1 is switched off and the exposure is terminated While the capacitors 27, 32 and 34 are shunted and thus discharged. Consequently, the potential of the cathode 49 of the tube 22 drops back to the potential of the movable tap 52 of the potentiometer 51 while the grid 31 assumes again groundpotential.
  • the tube 22 remain in conductive condition and the relay coil 23 remains in energized condition. In this manner the time switch arrangement is now ready for another cycle of operations, i.e. for another exposure.
  • the gradual raising of the cathode potential of the tube 22 in accordance with the charging of the capacitors 32, 34 has the effect that-relative to a medium exposure'time selected for the purpose of calibration exposure times of comparatively long duration can be extended still further and exposure times of comparatively short duration can be shortened still further.
  • the relation between the adjustable resistors 33 and 35 and the associated capacicumstances the RC-circuit with the shorter charging time causes a substantial increase of the potential at the cathode 490i the tube 22 during the first portion of an exposure, while the RC-circuit with the longer charging time causes the potential rise at the cathode 49 to continue for a longer period commencing with the start of the exposure. Nevertheless the operating voltages involved remain comparatively low.
  • the charging times of the RC-circuits containing the capacitors 32, 34 can be varied by adjustment of the resistors 33, 35, respectively, and can be adjusted arbitrarily with respect to each other.
  • the potential rise at the cathode 49 of the tube 22 during an exposure can be varied by corresponding setting of the control knob 56 and is increased by turning the knob 56 in counter-clockwise direction.
  • the knob 56 and the shaft 55 increasing portions of the upper half of the potentiometer 36 and of the lower half of the potentiometer 37 are introduced into the charging circuits of the capacitors 32 and 34, respectively, whereby the maximum charge potentials of these capacitors are increased, while simultaneously the starting potential of the cathode 49 is reduced due to the simultaneous turning of the movable tap 52 of the potentiometer 51.
  • cathode 49 of thetube 22 is decreased with increasing exposure time and the starting potential of the cathode 49 and the degree of potential decrease are both increased,
  • the blackening exponent characteristic of the photo-sensitive material being used can be taken into account by using the arrangement according to the invention. This applies both to blackening exponents smaller than 1 as well as to blackening exponents equal to 1 or larger than 1.
  • the blackening exponent and a mismatch between the lightsensitive member and the photo-sensitive material in the case of making color prints.
  • different blackening exponents apply 'to the different layers or" the color print material sensitive to light of different basic colors.
  • the character and degree of a mismatch between the light-sensitive member and the color print material may differ for different basic colors so that in the production of color prints notonly wrong densities but also wrong colors may result if the blackening exponent and a mismatch are not taken into account.
  • the arrangement as described and illustrated may be modified in such a manner that the potentiometer taps 46, 47, 52 are moved automatically into predetermined positions before the start of each indi vidual component exposure.
  • the arrangement as described and illustrated may be modified in various respects.
  • the two RC-circuits 32, 33 and 34, 35 in the adjustment i) circuit 9 may be supplemented by additional RC-circuits having time constants dvering from the time constants of the other RC-circuits. In such case it is advisable to connect also the capacitors of the additional RC-circuits in series with the capacitors 32, 34.
  • Each of the potentiometers 36, 37 having fixed center taps 42, 43 and movable taps 46, 47, respectively, is Well suited for reversing the polarity of the means influencing the cathode potential of the tube 22 also if only one capacitor is used instead of a plurality of capacitors 32, 34, Generally it is advisable to use one single device for producing, by polarity reversal, an increase as Well as a decrease of the potential of the cathode 49 of the tube 22.
  • the start and termination of an exposure may be effected, instead of switching on and off the light source 1, also in such a manner that the light source 1 is left witched on continuously while a shutter arranged across the path of the radiating energy furnished by the source 1 is opened and closed by means of electromagnetic means controlled by the relay coil 23.
  • the capacitor 32 or" the adjustment circuit 9 may be connected, instead of to the cathode 49 of tube 22, also to another electrode of the tube, e.g. to a screen grid not shown in the drawing but existing in a ditierent type of'a control tube in which case of course a corresponding change of poential at the capacitors 32, 34 is to be providcd.
  • time switch arrangement is applicable not only to photographic printing apparatus but also to other devices, e.g., X-ray picture apparatus.
  • an electron tube controlling said exposure interrupting means in dependence of a conductive condition of said tube whereby said conductive condition itself depends upon a predetermined potential.
  • correction means including at least two RC-circuit means including second capacitors, respectively, means which at the beginning of the exposure period commence the bringing about of the charging of each of said second capacitors to respective predetermined charge potential condition, and means for varying the electric charge of each of said second capacitors during the exposure of said material, each or" said RC-circuit means having a predetermined charging time constant different from that of the other one and said second capacitors being connected in series with each other and in circuit with said other one of said electrodes for changin said first potential applied to said other electrode in accordance with the change of charge potentials of said second capacitors during the exposure of said material.
  • control means for limiting the exposure time in accordance with the amount of radiating energy impinging during an exposure on said photosensitive material, said control means including an electron tube controlling, upon being rendered non-conductive, the start, and upon being returned to conductive condition, the end of the exposure, the conductive condition of said tube depending upon a predetermined potential relation between two electrodes of said tube, and photoelectric means exposed to said radiating energy and furnishing to one of said electrodes a potential gradually varying depending upon said radiating energy impinging on said photo-electric means and thereby changing the potential at said one of said electrodes; and correction means for modifying the time limiting action of said control means, said correction means including means for applying a first predetermined potential to the other one of said electrodes, at least two chargeable RC-circuit means including capacitors, respectively, connected in series with each other, each of said RC-circuit means having a predetermined charging
  • control means for limiting the exposure time in accordance with the amount of radiating energy impinging during an exposure on said photo-sensitive material, said control means including an electron tube controlling, upon being rendered non-conductive, the start and, upon being returned to conductive condition, the end of the exposure, the conductive condition of said tube depending upon a predetermined potential relation between the cathode and at least one of the electrodes of said tube, and photo-electric means exposed to said radiating energy, and capacitor means constituting .a series-combination with said photo-electric means, said series-combination furnishing to one of said electrodes a potential gradually varying depending upon said radiating energy impinging on said photoelectric means and thereby changing the potential at said one of said electrodes; and correction means for modifying the time limiting action of said control means, said correction means including potentiometer means for applying a first predetermined.
  • At least two chargeable RC-circuit means including second capacitor means, respectively, connected in series with each other, each of said RC-circuit means having a predetermined charging time constant difierent from that of the other one and one of said second capacitor means being connected in circuit with said cathode, and the other one of said second capacitor means being connected with the movable tap of said potentiometer means for changing said first potential at said cathode depending upon the charge potentials-of said RC-circuit means, means which at the beginning of the lighting period commence the bringing about of the charging of each of said capacitors to a respective predetermined charge potential condition, and adjustment means for varying said charge potentials in accordance with the blackening exponent of the photosensitive material being used, the superposition of said charge potentials on said firstpotential applied to said cathode by said correction means modifying the time period required for establishing said predetermined potential relation between the cathode and at least one of the electrodes and thus determining the duration of said conductive condition of said
  • An arrangement according to claim 3, comprising a control circuit including a first power supply unit, said electron tube and relay means controlled by said electron tube and controlling the source of radiating energy, further comprising a time control circuit including a second power supply unit, said photo-electric means, said first capacitor means and said potentiometer means, and further comprising an adjustment circuit including a third power supply unit and said RC-circuit means.
  • correction means include means for reversing the polarity of said first predetermined potential with respect to an intermediate potential value.
  • said adjustment means include a first and a second control potentiometer connected in parallel with each other and in circuit with said second power supply unit, one of said RC-circuit means being connected between a fixed intermediate tapping point and the movable tap of said first control potentiometer, the other one of said RC-circuit means being connected between a fixed intermediate tapping point and the movable tap of said second control potentiometer.
  • An arrangement according to claim 10 including control means for controlling all of said movable taps and including indexing means for determining the adjustment of said taps.
  • an electric timing arrangement for controlling the duration of exposures of photo-sensitive material to radiating energy
  • means for interrupting the exposure of said material to said radiating energy an electron tube controlling said exposure interrupting means in dependence of a conductive condition of said tube whereby said conductive condition itself depends upon a predetermined potential relation between two electrodes of said tube, a first condenser connected to one of said electrodes of said tube, means for varying the electric charge of said first condenser during the exposure of said material, potentiometer means for applying a first predetermined potential to the other one of said electrodes, said potentiometer means including a resistance connected with a power supply circuit and a tap movable along said resistance and connected with said other one of said electrodes, and correction means for modifying the time limiting action of said timing arrangement, said correction means including at least two RC- circuit means including second capacitors, respectively, means which at the beginning of the exposure period commence the bringing about of the charging of each of said second capacitors to a respective predetermined charge potential condition, and means for
  • An arrangement according to claim 12, comprising a relay arranged in the circuit of said electron tube, and switches each of them shunting one of said first and second condensers, respectively, said switches and said exposure interrupting means being controlled by said relay.
  • each of said first and second control potentiometers has two portions extending in opposite direction from the respective fixed intermediate tapping point thereof, the outer ends of said first and second control otentiometers being connected with the terminals, respectively, of said third power supply unit so that also the polarity of said variable charging potentials of said RC-circuit means is changeable depending upon whether said movable taps of said control potentiometers are moved from said intermediate tapping point in one or the other direction over said portions thereof.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • X-Ray Techniques (AREA)
US147791A 1960-10-28 1961-10-26 Time switch for photographic apparatus Expired - Lifetime US3166674A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEA35907A DE1146366B (de) 1960-10-28 1960-10-28 Zeitschaltvorrichtung fuer fotografische Geraete

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US3166674A true US3166674A (en) 1965-01-19

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US147791A Expired - Lifetime US3166674A (en) 1960-10-28 1961-10-26 Time switch for photographic apparatus

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US (1) US3166674A (fr)
BE (1) BE609699A (fr)
DE (1) DE1146366B (fr)
GB (1) GB949517A (fr)
NL (1) NL270378A (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2803138B1 (fr) * 2012-01-12 2020-07-15 Wallac OY Procédé et dispositif de commutation pour produire un signal électrique en réponse à une force mécanique

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2078677A (en) * 1932-10-19 1937-04-27 Westinghouse Electric & Mfg Co Lighting control
GB564500A (en) * 1942-07-04 1944-09-29 Westinghouse Electric Int Co Improvements in or relating to electrical measuring systems for x-ray apparatus
US2472815A (en) * 1946-08-23 1949-06-14 William D Fleming Automatic light control
GB706671A (en) * 1951-08-16 1954-03-31 Westinghouse Electric Int Co Improvements in or relating to timing devices for use with x-rays and other penetrating radiations
US2749799A (en) * 1953-08-13 1956-06-12 Strem Thomas Photographic exposure timing device
US2885563A (en) * 1954-10-05 1959-05-05 W M Welch Mfg Company Photographic exposure timer
US2929000A (en) * 1953-06-29 1960-03-15 Gen Electric Means for and method of interval timing
US2993124A (en) * 1959-02-02 1961-07-18 Gen Electric Timing apparatus
US3033988A (en) * 1957-04-05 1962-05-08 Edgerton Germeshausen & Grier Method of and apparatus for the control of electric impulses

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2078677A (en) * 1932-10-19 1937-04-27 Westinghouse Electric & Mfg Co Lighting control
GB564500A (en) * 1942-07-04 1944-09-29 Westinghouse Electric Int Co Improvements in or relating to electrical measuring systems for x-ray apparatus
US2472815A (en) * 1946-08-23 1949-06-14 William D Fleming Automatic light control
GB706671A (en) * 1951-08-16 1954-03-31 Westinghouse Electric Int Co Improvements in or relating to timing devices for use with x-rays and other penetrating radiations
US2929000A (en) * 1953-06-29 1960-03-15 Gen Electric Means for and method of interval timing
US2749799A (en) * 1953-08-13 1956-06-12 Strem Thomas Photographic exposure timing device
US2885563A (en) * 1954-10-05 1959-05-05 W M Welch Mfg Company Photographic exposure timer
US3033988A (en) * 1957-04-05 1962-05-08 Edgerton Germeshausen & Grier Method of and apparatus for the control of electric impulses
US2993124A (en) * 1959-02-02 1961-07-18 Gen Electric Timing apparatus

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Publication number Publication date
DE1146366B (de) 1963-03-28
NL270378A (fr)
BE609699A (fr) 1962-02-15
GB949517A (en) 1964-02-12

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