US3823994A - Method of making combustion flash bulb - Google Patents

Method of making combustion flash bulb Download PDF

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Publication number
US3823994A
US3823994A US00332119A US33211973A US3823994A US 3823994 A US3823994 A US 3823994A US 00332119 A US00332119 A US 00332119A US 33211973 A US33211973 A US 33211973A US 3823994 A US3823994 A US 3823994A
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United States
Prior art keywords
ignition
mass
envelope
bulb
combustion
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Expired - Lifetime
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US00332119A
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English (en)
Inventor
Graaf W De
J Baars
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US Philips Corp
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US Philips Corp
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Publication date
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Publication of US3823994A publication Critical patent/US3823994A/en
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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

Definitions

  • the invention relates to a method of manufacturing a combustion flash bulb without an ignition wire, in which an ignition device is mounted within an envelope while forming a bulb base, said ignition device consisting of two current conductors sealed in the bulb base and terminating outside the envelope, the parts located within the envelope terminating in a mass consisting of a mixture of a metal powder, a binder and, optionally, an oxidant.
  • Combustion flash bulbs of this type are known as such and are described in literature. Generally these bulbs contain a filling of shredded metal which an ignition burns actinically in a gas maintaining the combustion, such as oxygen. However, it is alternatively possible to accommodate the actinically burning metal in the mass to be ignited by direct current passage.
  • Combustion flash bulbs of this type may in principle be manufactured in the same manner as combustion flash bulbs of the conventional type including an ignition wire connecting the ends of the current conductors located within the bulb.
  • the ignition mass is generally located at the ends of the current conductors. This is a result of the conventional manner of providing the ignition mass.
  • the ends of the current conductors which are connected by the ignition wire are immersed in-a suspension of the ignition mass. The suspension then creeps over the ends of the current conductor, but the surface tension generally prevents the suspension from coating the extremely thin ignition wire (diameter generally between and pm). It is evident that under these circumstances the mass is ignited when the ignition wire has only evolved sufficient heat to bring the mass at the ends of the current conductors at the ignition temperature.
  • the ignition wire generally consists of a tungsten-rhenium alloy. To obtain a sufficient high resistance this wire is extremely thin and consequently thin and consequently weak. As a result of these causes the proportioning of this ignition system presents many difficulties.
  • a drawback of this type of combustion flash bulb is, however, that the resistance of the ignition mass is 100 MO or more and that the ignition voltage is comparatively high, This means that strict requirements must be imposed on the insulation resistance of the circuit.
  • the energy in the bulb may be depleted into the shredded metal filling if one'or more pieces thereof are too closely in the vicinity of the ignition mass or are in contact therewith.
  • An object of the invention is to provide a combustion flash bulb without an ignition wire in which these difficulties do not occur or occur to a'm'uch slighterextent.
  • a bulb of this kind is characterized in that the mass in a vacuum or an inert gas atmosphere is subjected to an electrical breakdown by of a voltage applied across the terminals the resistance of the ignition mass decreases irreversibly.
  • the ignition mass consists of a number of capacitors and resistors arranged in series and in paral- Iel.
  • the capacitors are constituted by the metal particles and the interpositioned binder, possibly with the oxide films on the metal particles.
  • the binder between the metal particles operating as a dielectric is probably broken down at a number of areas in the mass.
  • one or more conducting ducts are formed through the mass of a relatively low resistance.
  • the heat evolved during the successive breakdowns has the opportunity to be conducted away so that the ignition mass does not have the opportunity to reach the combustion temperature.
  • the result is that under thesecircumstances a larger energy is required for. combustion of the mass then when the voltage applied across the terminals is rapidly increased.
  • the binder is broken down simultaneously at a number of areas and locally a substantially adiabatic heating of the ignition mass may be effected so that the temperature in the masscan exceed the combustion temperature.
  • the electrical breakdown in the absence of a gas capable of reacting with the metal powder is preferably effected in 4 a vacuum, a current path of a-relatively low resistance is also formed. This is also the case if an oxidant is pres ent in the mass provided that the energy dissipated in the mass is chosen to be not too large, that is to say, preferably less than 30 pl.
  • the invention particularly relates to combustion flash bulbs in which the distance between the ends of the current conductors is l mm i 0.3 mm and in which the resistance of the ignition mass not yet subjected to a breakdown measured between these ends at a voltage of 20 V is more than 10 Q.
  • Combustion flash bulbs according to the invention may be manufactured, for example, as follows.
  • a stem is provided, for example, consisting of two current conductors connected by means of a glass bead.
  • the current conductors are sealed to one end of the tube while forming a bulb base.
  • a drop of an ignition mass suspension is provided on the ends of the current conductors located within the tube, which drop connects these ends together.
  • the liquid is evaporated and a tilling of metal chips is'introduced into the end, of the tube.
  • the tube is heated and reduced in area, the envelope space then formed is evacuated and possibly rinsed in an inert gas. At this stage, when there is no oxygen or another gas maintaining the combustion of the metal present in the lamp, the mass is subjected to an electrical breakdown.
  • a conducting duct through the ignition mass whose resistance is l 'to Q is produced between the ends of the current conductors. Subsequently the lamp is filled with oxygen and sealed.
  • aglass tubular part is sealed at one end.
  • the filling of shredded metal is inand the envelope space is shut off from the surroundings, for example, by pinching off the metal tube.
  • the stem may consist of two parallel wires which are mutually connected by means of a'glass bead or which are sealed in a cylindrical bodyprovided with a cavity for the ignition mass.
  • the stem may alternatively consist of two'metal tubes one of which is located within the other. s
  • the ignition mass comprises a metal powder, for example, a powder of a metal such as zirconium, aluminium, magnesium and titanium, possibly an oxidant such as potassium perchlorate and a binder such as nitrocellulose and possibly a semiconducting material, activators etc.
  • the ignition mass consists of astoichiometric mixture of zirco- 4 nium powderand potassium perchlorate (KCl0 and as a binder, for example, it is possible to use nitrocellulose.
  • nitrocellulose for example, 1 to 5 parts by weight of nitrocellulose in a dry state may be present per parts by weight of the stoichiometric mixture.
  • the ignition mass is provided in the form of a suspension in an organic solvent on the ends of the current conductors.
  • A-suitable suspension may be obtained, for example,
  • the metal to be burned actinically may be, for example, zirconium or hafnium.
  • inert gases are understood to mean rare gases, nitrogen and gases which upon electrical breakdown of the mass do not react therewith.
  • the gas maintaining the combustion consists of oxygen or a fluorine compound such as NF ,N F 0P or mixtures of such gases.
  • the ignition mass is preferably subjected to an electrical breakdown byconnecting the current conductors to a voltage source which provides a voltage pulse. increasing to a value in the order of 10 V within several microseconds.
  • the resistance of the mass measured at 20 V direct voltage, is more than 10 Q and after the electrical breakdown the resistance is only 10 to 10 Q.
  • a suitable voltage pulse may be obtained with the aid of apiezoelectric element.
  • the breakdown of the ignition mass may, under circumstances, alternatively be effected outside thebulb before the stem is mounted in the bulb. In that case it must be ensured that there is no combustion of the ignition mass during mounting.
  • FIGS. 1 5 show in a cross-section successive stages in the manufacture of a combustion flash bulb according to a given embodiment of the method according to the invention.
  • a stem is provided consisting of two current conductors 2 and 3 and a glass body 5 having a cavity 4 which may beobtained, for example, by fusing a glass bead'pro'vided with the current conductors 2 and 3 with a glass tube (diameter 3 mm, length 5 mm).
  • the body 5 is fused with the glass -1 while forming the bulb base 6.
  • the ignition mass 7 (0.75 .4 litre) is provided in the cavity 4 (contents 1 1.1. litre) in which the current conductors 2 and 3 terminate by providing a drop of a suspension in the cavity 4.
  • the suspension has, for example, the following composition l60 parts by weight of ziroconium powder 60 parts by weight of potassium perchlorate 2 parts by weight of nitrocellulose.
  • a filling of shredded metal 8 is introduced into the tube 1, for example, 20 mg of zirconium in the form of shredded foil having a width of approximately 40 ,um, a thickness of approximately 20 pm and a length of approximately cm.
  • the glass tube 1 is reduced in area at 9 while it is being heated.
  • the tube 1 is connected to a vacuum pump and the I 600 V.
  • the resistance is found to be less than 10 .Q
  • the bulb After breakdown has taken place, the bulb is filled with oxygen up to a pressure'of 6,000 Torr and is sealed at 9 (FIG. 4).
  • FIG. 5 is a side view of the finished bulb. I
  • the bulb according to this embodiment may be ignited with the aid of a capacitor of approximately 100 ;LF charged to approximately V or more. It is alternatively possible to ignite the bulb with the previously mentioned voltage source (piezoelectric element) and the voltage then increases to approximately 100 V.
  • the combustion flash bulb has the advantage that it can be ignited with the same voltage source as a conventional combustion flash bulb having an ignition wire of tungstenrhenium.
  • the relatively expensive wire is, however, superfluous in the combustion flash bulb according to the invention.
  • An advantage is that no extra time-consuming stages during manufacturing are to be included. The breakdown ofthe ignition mass may take place during evacuation of the bulb which has for its purpose to conduct away the air therefrom and may be a step in the process of manufacturing the lamp in question.
  • a further advantage of the flash bulbs manufactured by the method according to the invention is that a possible contact between the metal shredded foil and the ignition mass in the bulb neither affects the ignition of the finished bulb nor the breakdown if this takes place in a vacuum during manufacture. This would be the case if in such bulbs the ignition mass were not subjected to an electrical breakdown in a vacuum in advance. Under the influence of external electrical fields voltage differences between the terminals in the ignition mass which lead to combustion cannot be produced in the flash bulbs according to the invention.
  • a method for the manufacture of a combustion flash bulb without an ignition wire said bulb having an envelope, an ignition device and a finely divided combustible metal, said method including the steps of: forming a bulb base to said envelope while sealing two current conductors therein, said conductors having ends extending within said envelope to form a part of an ignition device and opposite ends terminating outside the envelope;
  • an ignition mass consisting of a mixture of a metal powder and optionally, an oxidant and binder, on the ends of the conductors within the envelope;
  • step of subjecting the ignition mass to breakdown includes connecting the current conductors to a voltage source having an internal resistance which is of the same order of magnitude as the resistance of the ignition mass and which provides a voltage pulse rapidly increasing to a value of the order of 10 V within several microseconds.
  • step of subjecting the ignition mass to breakdown includes subjecting said mass to an electrical breakdown with the aid of voltage pulse provided by a piezoelectric ele-

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Air Bags (AREA)
  • Electron Sources, Ion Sources (AREA)
US00332119A 1972-02-19 1973-02-13 Method of making combustion flash bulb Expired - Lifetime US3823994A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7202213A NL7202213A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1972-02-19 1972-02-19

Publications (1)

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US3823994A true US3823994A (en) 1974-07-16

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US00332119A Expired - Lifetime US3823994A (en) 1972-02-19 1973-02-13 Method of making combustion flash bulb

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US (1) US3823994A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS5522881B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
BE (1) BE795646A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CA (1) CA963079A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE2304607A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR2172358B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1355316A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IT (1) IT979199B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NL (1) NL7202213A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3884615A (en) * 1974-03-21 1975-05-20 Gen Electric Flash Lamp Mount Construction
US3959860A (en) * 1974-12-20 1976-06-01 General Electric Company Method of making non-shorting photoflash lamp
US3969067A (en) * 1975-03-12 1976-07-13 General Electric Company Photoflash lamp
US3972673A (en) * 1974-09-23 1976-08-03 General Electric Company Photoflash lamp
US4059388A (en) * 1975-11-05 1977-11-22 Gte Sylvania Incorporated Photoflash lamp
US4278420A (en) * 1979-07-16 1981-07-14 Gte Products Corporation Photoflash lamp, method of making same, and photoflash circuit
US4449950A (en) * 1982-03-01 1984-05-22 Gte Products Corporation Method of making photoflash lamp to prevent shred migration into tip portion of lamp envelope during sealing thereof
US4614494A (en) * 1985-12-10 1986-09-30 Gte Products Corporation Primer insulating base
US4659308A (en) * 1985-12-10 1987-04-21 Gte Products Corporation Photoflash lamp with improved primer
US4696641A (en) * 1986-08-11 1987-09-29 Gte Products Corporation Primer material and photoflash lamp

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7602231A (nl) * 1976-03-04 1977-09-06 Philips Nv Verbrandingsflitslamp.

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3752636A (en) * 1970-11-27 1973-08-14 Philips Corp Photoflash lamp

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL151491B (nl) * 1966-09-30 1976-11-15 Philips Nv Verbrandingsflitslamp.

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3752636A (en) * 1970-11-27 1973-08-14 Philips Corp Photoflash lamp

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3884615A (en) * 1974-03-21 1975-05-20 Gen Electric Flash Lamp Mount Construction
US3972673A (en) * 1974-09-23 1976-08-03 General Electric Company Photoflash lamp
US3959860A (en) * 1974-12-20 1976-06-01 General Electric Company Method of making non-shorting photoflash lamp
US3969067A (en) * 1975-03-12 1976-07-13 General Electric Company Photoflash lamp
US4059388A (en) * 1975-11-05 1977-11-22 Gte Sylvania Incorporated Photoflash lamp
US4278420A (en) * 1979-07-16 1981-07-14 Gte Products Corporation Photoflash lamp, method of making same, and photoflash circuit
US4449950A (en) * 1982-03-01 1984-05-22 Gte Products Corporation Method of making photoflash lamp to prevent shred migration into tip portion of lamp envelope during sealing thereof
US4614494A (en) * 1985-12-10 1986-09-30 Gte Products Corporation Primer insulating base
US4659308A (en) * 1985-12-10 1987-04-21 Gte Products Corporation Photoflash lamp with improved primer
US4696641A (en) * 1986-08-11 1987-09-29 Gte Products Corporation Primer material and photoflash lamp

Also Published As

Publication number Publication date
CA963079A (en) 1975-02-18
NL7202213A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1973-08-21
IT979199B (it) 1974-09-30
JPS5522881B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1980-06-19
JPS4890732A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1973-11-27
FR2172358A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1973-09-28
BE795646A (fr) 1973-08-20
FR2172358B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1976-09-10
DE2304607A1 (de) 1973-08-30
GB1355316A (en) 1974-06-05

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