US2982119A - Flash lamp - Google Patents

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Publication number
US2982119A
US2982119A US808981A US80898159A US2982119A US 2982119 A US2982119 A US 2982119A US 808981 A US808981 A US 808981A US 80898159 A US80898159 A US 80898159A US 2982119 A US2982119 A US 2982119A
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US
United States
Prior art keywords
bulb
lamp
flash
volume
flash lamp
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US808981A
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English (en)
Inventor
Robert M Anderson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US808981A priority Critical patent/US2982119A/en
Priority to GB13840/60A priority patent/GB913493A/en
Priority to CH478360A priority patent/CH382560A/de
Application granted granted Critical
Publication of US2982119A publication Critical patent/US2982119A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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

  • This invention relates in general to flash lamps of the type comprising a sealed radiation-transmitting bulb containing a loose filling of a readily combustible filamentary material and a combustion-supporting medium, such as an oxygenous gas, Which enters into a reaction with the combustible material with the resulting emission of an instantaneous flash of actinic light of high intensity. More particularly, my invention relates to a midget sized flash lamp of the above general type having an exceptionally high light output per unit volume of the lamp bulb or envelope.
  • flash lamps have generally employed so-called blown glass bulbs or envelopes, i.e., one made by blowing or expanding a molten charge of glass, or a softened length of glass tubing, into a surrounding mold.
  • blown glass bulbs i.e., one made by blowing or expanding a molten charge of glass, or a softened length of glass tubing, into a surrounding mold.
  • the bulbs do not possess substantially uniform wall thickness throughout but instead. are characterized by areas of thin wall section as compared to the remainder of the bulb, such thin wall sections generally being located at the sides of the bulb where the outward expansion of the glass into the bulb-forming mold is greatest.
  • Such relatively thin side wall areas adversely affect the safety of a flash lamp for several reasons.
  • the combustible material heretofore generally employed in miniature type flash lamps as the light-producing source therein generally consisted of a loose filling of filamentary wire or so-called shredded foil consisting essentially of aluminum or zirconium.
  • the burning characteristics of these aluminum and zirconium type filamentary combustible materials are quite different, however.
  • aluminum combustible material is ignited within a flash lamp, many hot burning particles or globules of aluminum are formed therein and are forcefully propelled in all directions within the bulb at high velocities.
  • the bulb is of too small a size to allow these hot burning aluminum particles to either travel a sufficient distance in the bulb to be completely consumed before they strike the bulb wall or else to lose a sizeable amount of their velocity
  • the burning aluminum particles will then strike the glass bulb wall with a considerable force of such magnitude that, coupled with the softening effect which the hot metal particles exert on the glass, actually results in their penetrating through the glass bulb wall with the resulting likelihood of causing either the glass bulb to explode or shatter, or the outside protective lacquer on the bulb to catch on fire.
  • the zirconium type filamentary combustible material has the property of burning more or less in place Within the lamp bulb, without the formation of hot burning metal particles and the forceful propelling thereof at high velocity throughout the interior space of the bulb and into forceful contact with the glass wall thereof.
  • a zirconium type filamentary combustible material is not nearly as likely to cause the cracking or shattering of the glass lamp bulb, or the ignition of the outside lacquer thereon, as an aluminum type filamentary combustible material.
  • so-oalled blown glass bulbs for flash lamps as has been the common practice heretofore, and particularly when coupled with the use of filamentary combustible material composed essentially of aluminum, has placed an arbitrary limitation on the amount of combustible material and combustion-supporting gas filling which could be safely loaded or incorporated Within the lamp bulb without the danger of the bulb exploding on charge flashing, with a corresponding limitation on the amount of light-output obtainable from the lamp.
  • the amount of combustible material per unit volume of bulb space i.e., the concentration of combustible material in the bulb
  • the pressure of the filling gas, in flash lamps as made heretofore has been maintained within limits of less than around 2 mg. per cc. of bulb volume and less than 2 atmospheres pressure in the case of aluminum type combustible materials, and around 6 mg. per cc. of bulb volume and less than 2 atmospheres pressure in the case of zirconium type combustible material.
  • Another object of my invention is to provide a flash lamp of the general type referred to which is of many times smaller overall size than any flash lamp heretofore available and which is capable of providing a light flash of sufficient intensity for effective picture-taking purposes.
  • Still another object of my invention is to provide an extremely small sized flash lamp of the general type referred to and containing a materially greater amount of combustible material per unit volume of bulb space, i.e., a greater concentration, than in any previous flash lamp of such type while at the same time possessing the same degree of safety from explosion on charge flashing.
  • a further object of my invention is to provide a small size flash lamp of the general type referred to having a bulb many times smaller in size than any flash lamp heretofore available yet possessing a light output per unit volume of bulb space several times greater than the highest level thereof heretofore obtainable in any previous flash lamp.
  • a very small size bulb having a volume less than about 2 cc. and consisting of a short length of drawn glass tubing closed at one end by an outwardly protruding integral stem press portion and necked down and tipped off at its other end, and
  • Fig. 1 is an elevation, partly in section and on an enlarged scale, of a flash lamp comprising my invention
  • Fig. 2 is an elevation of the lamp at right angles to Fig. 1.
  • the flash lamp according to the invention comprises a sealed glass envelope or bulb 1 approximately of tubular shape and consisting of a short length of drawn glass tubing closed at one end by an integral flattened external stem press 2 protruding axially from the bulb and necked down and closed at its other end by an end wall portion 3 terminating in an exhaust tip 4. Since drawn glass tubing, as made by conventional glass tube drawing processes, inherently possesses substantially uniform wall thickness throughout, the bulb 1 because of its formation as a drawn length of glass tubing, therefore possesses a substantially um form wall thickness, i.e., throughout at least the tubular extent thereof.
  • the bulb 1 therefore can be readily made of thicker side wall section than the conventional blown glass bulbs which have been conventionally employed for flash lamps in the past.
  • the side wall of the bulb 1 has a wall thickness in the range of about 27 mils whereas the customary blown glass bulbs conventionally employed heretofore for flash lamps have possessed wall thicknesses in the range of around 18 to 20 mils or thereabouts.
  • the bulb 1 is of a size many times smaller, e.g., to 6 times smaller, than that employed in any flash lamp commercially available at present, the bulb having an internal volume of less than 2 cc.
  • the opposite sides 5 of the stem press 2 are formed as flat surfaces preferably disposed approximately parallel to each other and to the axis of the bulb. As shown, the said flat sides 5 of the stern press 2 are provided with transversely extending guide channelways or grooves 6 for sliding engagement with cooperating guide track means of a lampholding magazine or feeding chamber (not shown) of a lamp flashing apparatus.
  • a lamp ignition mount 7 comprising a pair of lead-in wires 8 which, in the manufacture of the lamp, are sealed into the stem press 2 so as to extend therethrough and into the bulb 1 in a. direction approximately longitudinally of the bulb and in more or less side-by-side closely spaced relation.
  • the lead-in wires 8 are provided with suitable terminal contact portions which may be of the type disclosed and claimed in copendiug application Serial No.
  • the lead-in wires 8 are rigidly tied together and held in place by a support bead 19 of glass or other suitable insulating material in which the lead-in wires are embedded.
  • the lead-in wires 3 terminate at their inner ends in the lower region of the bulb near the stem press end thereof so as to be removed from the top or end wall 3 thereof, and they are bridged at their said inner ends by an ignition filament 11 preferably consisting of a short straight length of fine tungsten wire having a diameter preferably of the order of 0.7 mil.
  • the inner tips or ends of the lead-in wires 8 are provided with coatings or beads 12 of a suitable fulminating or primer material which beads 12 are in contact with the filament 11 and become ignited when the latter is energized and heated by the passage of an electric current therethrough.
  • the fulminating material of which the primer beads 12 are composed preferably is of the general type disclosed and claimed in US.
  • a suitable binder such as a 25% solution of nitrocellulose in amyl acetate.
  • the relative proportions of the above-named powder ingredients be within the particular ranges disclosed and claimed in US. Patent 2,756,577, Anderson, issued July 31, 1956 and assigned to the assignee of the present invention, such ranges being of the order of from 90% zirconium, l-8% magnesium, and 935 potassium perchlorate.
  • the bulb 1 contains a filling of oxygen or other oxygenous combustion-supporting gas and a quantity of combustible light-giving material 13 which, on ignition by the filament 11 and primer 12 constituting the ignition means of the lamp, enters into a reaction with the filling gas to produce a momentary flash of actinic light of high intensity suitable for picture-taking purposes.
  • the combustible material 13 consists of a loosely distributed quantity of filamentary strands of a readily combustible metallic material consisting essentially of zirconium or an alloy essentially composed of zirconium.
  • the filamentary combustible material 13 preferably is in the form of fine cut strands of a thin foil of the above-mentioned composition, the said fine cut strands being such as that commercially known as shredded foil and produced by the method and appar'atus described and claimed in US. Patents 2,297,368 and 2,331,230, Rippl et al., such shredded foil strands having a width ranging from approximately 0.5 to 1.5 mils and a thickness likewise ranging from approximately 0.5 to 1.5 mils.
  • the filamentary combustible material 12 is distributed loosely within the bulb and as uniformly gamma as possible throughout the space within the bulb above the ignition filament 11 in order to insure the most favorable combustion conditions for the said material.
  • the oxygen or other combustion-supporting gas is introduced into the bulb 1 through a glass exhaust tubulation at the top end 3 of the bulb which tubulation, after the evacuation of the bulb therethrough and the introduction of the oxygen or other combustion-supporting gas into the bulb, is then tipped off as indicated at 4 to hermetically seal the bulb.
  • a suitable protective lacquer coating 14 such as cellulose acetate is applied to the outer side of the bulb.
  • the inner side of the bulb may be left bare or unprotected by any such lacquer coating.
  • the amount of filamentary combustible material per unit volume of bulb space has been maintained at a concentration of less than around 2 mg. per cc. of bulb volume in the case of aluminum type combustible materials and less than around 6 mg. per cc. of bulb volume in the case of zirconium type combustible materials, and the amount of combustion-supporting gas in the bulb likewise maintained below pressures in excess of about 2 atmospheres, in order to thereby limit the intensity of the reaction in the bulb on charge flashing, and therefore the developed pressure in the bulb, to a level sufliciently low to afford the required degree of safety from explosion.
  • the bulb 1 is loaded with filamentary combustible zirconium material 13, having a unit cross-sectional area within the range of approximately 0.5 to 1.5 square mils, to a concentration of at least 15 mg. per cc. of bulb volume and ranging up to as high as 25 mg. per cc. of bulb volume, and is filled with oxygen or other combustion-supporting gas to a pressure of at least several atmospheres.
  • the bulb is filled with around 24 mg.
  • a flash lamp of such specific construction according to the invention has a concentration of filamentary combustible material within the bulb amounting to around 20 mg. per cc. of bulb volume, which is manyfold (i.e., more than thrice) that of any previous type flash lamp.
  • Flash lamps of the above specific construction having a clear outside lacquer protective coating 14 on the bulb, will generate a momentary flash of light of approximately 7500- 7800 lumen seconds with a peak intensity of between 400,000 and 500,000 lumens and which, through the control of the size of the primer beads 12, will peak at approximately 15 milliseconds following the closure of the electrical circuit through the ignition filament 10 of. a lamp.
  • the generated light output per unit volume of bulb space of flash lamps according to the invention amounts to well in excess of 3000 lumen seconds per cc. of bulb volume and, in the case of the specific lamp described, amounts to in excess of 6000 lumen seconds per cc.
  • a flash lamp having the abovedescribed flash characteristics is eminently suited as a light source for use with ordinary inexpensive type cameras not provided with flash lamp synchronizing means and wherein the so-called open-flash method of taking flash lamp pictures is employed, the flash lamp in such case being flashed during the interval when the camera shutter is in an open position such as occurs when a camera shutter set for time or bulb" is actuated.
  • A'flash lamp comprising a sealed bulb consisting of a short lengthof drawn glass tubing of substantially uniform wall thickness throughout and having an external stem press portion extending from and closing one end thereof, the other end of said length of glass tubing being necked down and closed by an end wall portion terminating in an exhaust tip, said bulb having an internal volume of less than about 2 cc., a protective lacquer coating on the exterior surface of said bulb, a filling of a combustion-supporting gas in said bulb at a pressure of at least several atmospheres, a quantity of combustible filamentary strand material loosely distributed within said bulb and consisting essentially of zirconium, said fila mentary strand material having a unit cross-sectional area within the range of approximately 0.5 to 1.5 square mils, the quantity of said filamentary material in the bulb amounting to at least approximately 15 mg.
  • a flash lamp comprising a sealed bulb consisting of a short length of drawn glass tubing of substantially uniform wall thickness throughout and having an external stem press portion extending from and closing one end thereof, the other end of said length of glass tubing being necked down and closed by an end wall portion terminating in an exhaust tip, said bulb having an internal volume of less than about 2 cc., a protective lacquer coating on the exterior surface of said bulb, a filling of a combustion-supporting gas in said bulb at a pressure of at least approximately 5 atmospheres, a quantity of combustible filamentary strand material loosely distributed 7 within said bulb and consisting essentially of zirconium, said filamentary strand material having a unit cross-sectional area within the range of approximately 0.5 to 1.5 square mils, the quantity of said filamentary material in the bulb amounting to between 15 to 25 mg. per cc.
  • a flash lamp comprising a sealed bulb consisting of a short length of drawn glass tubing of substantially uniform wall thickness throughout and having an external stem press portion extending from and closing one end thereof, the other end of said length of glass tubing being necked down and closed by an end wall portion terminating in an exhaust tip, said bulb having an internal volume of approximately 1.2 cc., a protective lacquer coating on the exterior surface of said bulb, a filling of oxygen in said bulb at a pressure of at least approximately atmospheres, a quantity of combustible filamentary strand material loosely distributed within said bulb and consisting essentially of zirconium, said filamentary strand material having a unit cross-sectional area within the range of approximately 0.5 to 1.5 square mils, the quantity of said filamentary material in the bulb amounting to around 20 mg.
  • a flash lamp comprising a sealed bulb consisting of a short length of drawn glass tubing of substantially uniform wall thickness throughout and having an external stern press portion extending from and closing one end thereof, the other end of said length of glass tubing being necked down and closed by an end wall portion termimating in an exhaust tip, said bulb having an internal volume of approximately 1.2 cc., a protective lacquer coating on the exterior surface of said bulb, a filling of oxygen in said bulb at a pressure of at least approximately 5 atmospheres, a quantity of combustible filamentary material in said bulb consisting of fine cut strands of zirconium foil loosely distributed within said bulb, said strands having a thickness of about .0008 inch and a width of about .0012 inch, the quantity of combustible material in said bulb amounting to around 20 mg.
US808981A 1959-04-27 1959-04-27 Flash lamp Expired - Lifetime US2982119A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US808981A US2982119A (en) 1959-04-27 1959-04-27 Flash lamp
GB13840/60A GB913493A (en) 1959-04-27 1960-04-20 Improvements in flash lamps
CH478360A CH382560A (de) 1959-04-27 1960-04-26 Blitzlichtlampe

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US808981A US2982119A (en) 1959-04-27 1959-04-27 Flash lamp

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US2982119A true US2982119A (en) 1961-05-02

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US808981A Expired - Lifetime US2982119A (en) 1959-04-27 1959-04-27 Flash lamp

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CH (1) CH382560A (de)
GB (1) GB913493A (de)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3045460A (en) * 1960-04-27 1962-07-24 Sylvania Electric Prod Photoflash lamp
US3046769A (en) * 1960-04-29 1962-07-31 Gen Electric Flash lamp and ignition means therefor
US3111016A (en) * 1960-12-01 1963-11-19 Sylvania Electric Prod Photoflash lamp and ignition means therefor
US3156107A (en) * 1961-11-21 1964-11-10 Sylvania Electric Prod Photoflash lamp and protective coating therefor
US3158014A (en) * 1962-12-28 1964-11-24 Sylvania Electric Prod Photoflash lamp
US3178567A (en) * 1961-03-29 1965-04-13 Eastman Kodak Co Magazine type flasholder
US3208246A (en) * 1962-01-23 1965-09-28 Tokyo Shibaura Electric Co Flash lamps
US3238526A (en) * 1962-03-15 1966-03-01 Bissett Berman Corp Apparatus for remote flash photography
US3263457A (en) * 1962-02-09 1966-08-02 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Photoflash lamp
US3675004A (en) * 1970-06-15 1972-07-04 Westinghouse Electric Corp Photoflash lamp and multiple flashlamp system
US3895902A (en) * 1971-09-09 1975-07-22 Gte Sylvania Inc 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

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2272059A (en) * 1939-08-19 1942-02-03 Westinghouse Electric & Mfg Co Photoflash lamp
US2289876A (en) * 1939-09-05 1942-07-14 Westinghouse Electric & Mfg Co Photoflash lamp
US2315099A (en) * 1940-04-11 1943-03-30 Johannes Antonius Maria Liempt Flashlight lamp
US2756577A (en) * 1954-04-07 1956-07-31 Gen Electric Flash lamp and ignition means therefor
US2791112A (en) * 1953-06-10 1957-05-07 Gen Electric Flash lamp bulb

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2272059A (en) * 1939-08-19 1942-02-03 Westinghouse Electric & Mfg Co Photoflash lamp
US2289876A (en) * 1939-09-05 1942-07-14 Westinghouse Electric & Mfg Co Photoflash lamp
US2315099A (en) * 1940-04-11 1943-03-30 Johannes Antonius Maria Liempt Flashlight lamp
US2791112A (en) * 1953-06-10 1957-05-07 Gen Electric Flash lamp bulb
US2756577A (en) * 1954-04-07 1956-07-31 Gen Electric Flash lamp and ignition means therefor

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3045460A (en) * 1960-04-27 1962-07-24 Sylvania Electric Prod Photoflash lamp
US3046769A (en) * 1960-04-29 1962-07-31 Gen Electric Flash lamp and ignition means therefor
US3111016A (en) * 1960-12-01 1963-11-19 Sylvania Electric Prod Photoflash lamp and ignition means therefor
US3178567A (en) * 1961-03-29 1965-04-13 Eastman Kodak Co Magazine type flasholder
US3156107A (en) * 1961-11-21 1964-11-10 Sylvania Electric Prod Photoflash lamp and protective coating therefor
US3208246A (en) * 1962-01-23 1965-09-28 Tokyo Shibaura Electric Co Flash lamps
US3263457A (en) * 1962-02-09 1966-08-02 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Photoflash lamp
US3238526A (en) * 1962-03-15 1966-03-01 Bissett Berman Corp Apparatus for remote flash photography
US3158014A (en) * 1962-12-28 1964-11-24 Sylvania Electric Prod Photoflash lamp
US3675004A (en) * 1970-06-15 1972-07-04 Westinghouse Electric Corp Photoflash lamp and multiple flashlamp system
US3895902A (en) * 1971-09-09 1975-07-22 Gte Sylvania Inc Photoflash lamp
US3972673A (en) * 1974-09-23 1976-08-03 General Electric Company Photoflash lamp
US3969067A (en) * 1975-03-12 1976-07-13 General Electric Company Photoflash lamp

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Publication number Publication date
GB913493A (en) 1962-12-19
CH382560A (de) 1964-09-30

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