US3918884A - Arrangement provided with some combustion flash bulbs - Google Patents

Arrangement provided with some combustion flash bulbs Download PDF

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Publication number
US3918884A
US3918884A US463730A US46373074A US3918884A US 3918884 A US3918884 A US 3918884A US 463730 A US463730 A US 463730A US 46373074 A US46373074 A US 46373074A US 3918884 A US3918884 A US 3918884A
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United States
Prior art keywords
resistance
ignition
bulbs
bulb
assembly
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Expired - Lifetime
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US463730A
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English (en)
Inventor
Johannes Gerardus Bok
Petrus Johannes Juli Witterick
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US Philips Corp
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US Philips Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K5/00—Light sources using charges of combustible material, e.g. illuminating flash devices
    • F21K5/02—Light sources using charges of combustible material, e.g. illuminating flash devices ignited in a non-disrupting container, e.g. photo-flash bulb
    • F21K5/023—Ignition devices in photo flash bulbs
    • F21K5/026—Ignition devices in photo flash bulbs using mechanical firing, e.g. percussion of a fulminating charge
    • 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
    • G03B15/00—Special procedures for taking photographs; Apparatus therefor
    • G03B15/02—Illuminating scene
    • G03B15/03—Combinations of cameras with lighting apparatus; Flash units
    • G03B15/04—Combinations of cameras with non-electronic flash apparatus; Non-electronic flash units
    • G03B15/0452—Electrical ignition means connected to the shutter
    • G03B15/0457—Ignition mechanisms for sequential ignition of flash lamps

Definitions

  • the succession of the flashes is obtained by choosing the resistive values of heating wires present in the flash bulbs to be unequal prior to flashing, and to have a low resistance of the flashed bulbs.
  • the invention relates to an arrangement provided with at least two series-arranged combustion flash bulbs which bulbs can be ignited one after the other and in which each of the bulbs includes a heating wire and an ignition paste, a means being provided in at least one bulb to render the internal resistance of said bulb one ohm at a maximum after flashing, the thermal capacities of the heating wires of the bulbs being substantially equal.
  • the thermal capacity of the heating wire is understood to mean the energy (for example, expressed in wattsecond or in joule) to be produced with an electrical current through this heating wire in order to raise the temperature of this wire by one degree Celcius.
  • the heat conducted away from the thin heating wires commonly used for this purpose is negligibly small during this time interval.
  • the required energy for bringing the heating wire from the ambient temperature (room temperature) to the ignition temperature of the ignition paste is substantially equal to the product of the above-mentioned thermal capacity and the difference between the said ignition temperature and the ambient temperature.
  • a drawback of the said known arrangement is that prior to flashing the greater part of the heating wires of the bulbs is to be shunted by branches which have a relatively low resistive value. This is necessary to provide the next bulb to be flashed with current. This, however, makes the electrical circuit of the known arrangement complicated.
  • the invention has for its object to provide an arrangement of the kind described in the preamble which does not have the said drawback or has this drawback to a lesser extent.
  • an arrangement provided with at least two series-arranged combustion flash bulbs in which said bulbs can be ignited one after the other and in which each of the bulbs includes a heating wire and an ignition paste, while a means is present in at least one bulb to render the internal resistance of said bulb one ohm at a maximum after flashing and the thermal capacities of the heating wires of the bulbs being substantially equal, is characterized in that prior to flashing the resistive values of the heating wires of the bulbs are different and this in such a manner that when arraying the bulbs in accordance with a decreasing resistance the heating wire of a subsequent bulb is 60 at a maximum of the resistance of the heating wire of the preceding bulb.
  • a supply source is of course also required. It may consist of, for example, a batterywhose terminals are connected by the said series arrangement of bulbs. However, this leads to very fast successive flashing of the bulbs which may be desired, for example, for stroboscopic purposes. Due to the higher thermal development the bulb including the heating wire which had the highest resistance flashes first and subsequently the bulb flashes which includes the heating wire having the highest resistance but one, etc.
  • the capacitance of the supply capacitor has been chosen to be so low that the residual charge still present after flashing of a bulb in this supply capacitor corresponds to a quantity of energy which after multiplication by (Rh/Rt) is smaller than the energy required at that moment to ignite the remaining unflashed bulb having the highest resistance in the arrangement, where:
  • Rh is the resistive value of the heating wire of the said unflashed bulb having the highest resistance and Rt is the total resistive value of the discharge circuit of the supply capacitor.
  • Rt also includes the possible internal resistance of the supply capacitor.
  • An advantage of this preferred embodiment is that no double flashing (that is to say: two bulbs flashing almost simultaneously) can occur. This is advantageous when taking photographs.
  • the different resistive values of the flash bulbs may be realised, for example, by using a plurality of parallel-arranged heating wires in the bulbs in which, for example, the length of the heating wires is shortened to maintain the thermal capacity constant.
  • These wires may then be made of, for example, the same material, but in one bulb of the arrangement the number of parallel heating wires may be chosen to be different from that in other bulbs of the arrangement' Instead of several parallel heating wires it is of course alternatively possible to use one heating wire having a larger thickness.
  • the material of the heating wire of a bulb is different from the materials of the heating wires of the other bulbs.
  • An advantage thereof is that one heating wire which is not too thick may be sufficient for each bulb. This simplifies the manufacture of the bulbs.
  • the heating wire of one bulb is made of kanthal and the heating wires of the other bulbs are made of chromel, alumel and molybdenum.
  • An advantage of this embodiment is that the specific heats of these materials (conductors) are fairly close so that also in case of mutually equal length and diameter of the heating wire the thermal capacity of the bulbs may be reasonably equal and the resistive values may be sufficiently different from each other.
  • the said means to render the internal resistance of a bulb after flashing to a maxi- 3 mum of 1 ohm consists of an electrically conducting bush surrounding the supply conductors of the heating wire at an area located within the bulb, which bush melts upon flashing thereby shortcircuiting said supply conductors.
  • An advantage of this preferred embodiment is that switching over to a subsequent bulb may be very reliable.
  • FIG. 1 is a diagrammatical view of an electrical circuit of an arrangement according to the invention.
  • FIG. 2 is a longitudinal cross-section through one of the combustion flash bulbs of the arrangement of FIG. 1.
  • l and 2 are input terminals intended to be connected to a charge device of the capacitor 3 including a resistor.
  • the electrodes of the capacitor 3 are connected by means of a series arrangement of a switch 8 and four low-voltage combustion flash bulbs 4, 5, 6 and 7.
  • FIG. 2 shows such a bulb.
  • 10 is an envelope which is provided with two leadthrough conductors 11 and 12. These also pass through a bead 13 in which a metal bushing 14 is anchored. A heating wire 15 is present between the ends of the conductors 11 and 12 present in the envelope 10.
  • the length of the bulb is approximately 25 mm and its diameter is approximately 9 mm.
  • the length of the heating wire 15 is approximately 1.4 mm and its diameter is approximately 25 microns.
  • the heating wire was made of kanthal, in bulb 5 it was chromel, in bulb 6 alumel and in bulb 7 molybdenum.
  • the envelope 10 of FIG. 2 some ignition paste was present on the heating wire 15. That paste has an ignition temperature of approximately 500C. Furthermore the envelope was filled with a wire filling 16 of zirconium.
  • the capacitor 3 (see FIG. 1) had a capacitance of approximately 200 p. Farad. This capacitor was charged to 6 volts. When the switch 8 closed for the first time the bulb 4 flashed. At a subsequent renewed charge of the capacitor 3, and a renewed closure of the switch 8, the bulb 5 flashed etc.
  • Volume x specific heat 1r (25 10*) 1.4 X 3.93 10 Joule is approximately 3 l0 Joule.
  • An important advantage of an arrangement according to the invention is that all the parts to be heated, for example, for interconnection are present within the bulb envelopes so that their operation is very reliable.
  • a flash bulb assembly for cooperation with an associated camera providing sequential flashes, said assembly comprising a plurality of flash bulbs means connecting said flash bulbs in series each of said bulbs having a heating wire, two lead-through conductors connected to said ignition wire, and means for reducing the resistance between said lead-through conductors upon ignition of said bulb, one of said bulbs having a first resistance before ignition and a second resistance after ignition, a second of said bulbs having a third resistance before ignition and a fourth resistance after ignition, said third resistance being smaller than said first resistance.
  • the apparatus as described in claim 1 further including a third bulb, said third bulb having an ignition wire having a fifth resistance before ignition and sixth resistance after ignition, said fifth resistance being a less than said third resistance 3.
  • the apparatus as described in claim 2 further including additional bulbs each having ignition wires having successively smaller resistances before firing than said other resistances.
  • the apparatus as described in claim 4 further including means for ignitin said bulbs, said means including a supply capacitor chargeable from an associated power supply, said capacitor having a capacitance sufficiently low so that the residual charge in said supply capacitor after flashing of one of said bulbs corresponds to a quantity of energy which after multiplication by the factor (Rh/Rt) is smaller than the energy required at that moment to ignite the remaining unflashed bulb having the highest resistance in said assembly, Rh being the resistive value of the unflashed lamp having the highest resistance in the assembly and Rt is the total resistive value of the discharge circuit of the supply capacitor.
  • said means for changing said resistance comprises an electrically conducting bushing which surrounds said supply conductors of the heating wire within said bulb, said bushing melting upon ignition of said bulb to complete. a circuit between said lead-through conductors.
  • Claim 7, line 2 change "ignitin” to igniting.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Resistance Heating (AREA)
  • Air Bags (AREA)
US463730A 1973-05-01 1974-04-24 Arrangement provided with some combustion flash bulbs Expired - Lifetime US3918884A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7306019A NL7306019A (nl) 1973-05-01 1973-05-01

Publications (1)

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US3918884A true US3918884A (en) 1975-11-11

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US463730A Expired - Lifetime US3918884A (en) 1973-05-01 1974-04-24 Arrangement provided with some combustion flash bulbs

Country Status (9)

Country Link
US (1) US3918884A (nl)
JP (1) JPS5032938A (nl)
BE (1) BE814429A (nl)
CA (1) CA1040700A (nl)
DE (1) DE2418838A1 (nl)
FR (1) FR2228342B3 (nl)
GB (1) GB1430706A (nl)
IT (1) IT1010134B (nl)
NL (1) NL7306019A (nl)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4048487A (en) * 1976-09-08 1977-09-13 General Electric Company Last-flash indicator switch in photoflash array

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443875A (en) * 1965-10-21 1969-05-13 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Series flash device
US3459488A (en) * 1966-04-02 1969-08-05 Philips Corp Flashbulb and attachment for camera
US3518487A (en) * 1967-01-31 1970-06-30 Tokyo Shibaura Electric Co Photoflashing circuit device
US3619715A (en) * 1970-05-21 1971-11-09 Gen Electric Resistor circuit for sequentially flashing photoflash lamps
US3692995A (en) * 1969-10-16 1972-09-19 Agfa Gevaert Ag Arrangement for providing a series of illuminations
US3728067A (en) * 1969-10-03 1973-04-17 Philips Corp Device for flashing combustion flash bulbs one after the other
US3864606A (en) * 1972-10-24 1975-02-04 Gen Electric Compensated sequencing circuit for firing photoflash lamps

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443875A (en) * 1965-10-21 1969-05-13 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Series flash device
US3459488A (en) * 1966-04-02 1969-08-05 Philips Corp Flashbulb and attachment for camera
US3518487A (en) * 1967-01-31 1970-06-30 Tokyo Shibaura Electric Co Photoflashing circuit device
US3728067A (en) * 1969-10-03 1973-04-17 Philips Corp Device for flashing combustion flash bulbs one after the other
US3692995A (en) * 1969-10-16 1972-09-19 Agfa Gevaert Ag Arrangement for providing a series of illuminations
US3619715A (en) * 1970-05-21 1971-11-09 Gen Electric Resistor circuit for sequentially flashing photoflash lamps
US3864606A (en) * 1972-10-24 1975-02-04 Gen Electric Compensated sequencing circuit for firing photoflash lamps

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4048487A (en) * 1976-09-08 1977-09-13 General Electric Company Last-flash indicator switch in photoflash array

Also Published As

Publication number Publication date
GB1430706A (en) 1976-04-07
BE814429A (fr) 1974-10-30
FR2228342B3 (nl) 1977-03-04
CA1040700A (en) 1978-10-17
FR2228342A1 (nl) 1974-11-29
NL7306019A (nl) 1974-11-05
JPS5032938A (nl) 1975-03-29
DE2418838A1 (de) 1974-11-21
IT1010134B (it) 1977-01-10

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