US3904348A - Photoflash lamp - Google Patents

Photoflash lamp Download PDF

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Publication number
US3904348A
US3904348A US424839A US42483973A US3904348A US 3904348 A US3904348 A US 3904348A US 424839 A US424839 A US 424839A US 42483973 A US42483973 A US 42483973A US 3904348 A US3904348 A US 3904348A
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United States
Prior art keywords
lamp
filamentary
combustible
envelope
foil
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Expired - Lifetime
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US424839A
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English (en)
Inventor
Andre C Bouchard
Thomas J Sentementes
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GTE Sylvania Inc
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GTE Sylvania Inc
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Publication date
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Priority to US424839A priority Critical patent/US3904348A/en
Priority to JP14264374A priority patent/JPS5532161B2/ja
Application granted granted Critical
Publication of US3904348A publication Critical patent/US3904348A/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

  • a photoflash lamp in which the filamentary combustible material within the lamp envelope comprises a plurality of strands of foil, such as zirconium, each of which have a selected amount of oxide coating on all surfaces of the strand, whereby the lamp exhibits a higher light output and color temperature upon ignition, in addition to changes in timing.
  • the strands of foil are preoxidized by heating in air for a predetermined time at a predetermined temperature.
  • PHOTOFLASH LAMP This invention relates to photoflash lamps and particularly to fiashlamps containing a filamentary combustible and a method for processing the combustible.
  • a typical photoflash lamp comprises an hermetically sealed glass envelope, a quantity of combustible material located in the envelope, -and a combustion supporting gas, such as oxygen, at a pressure well above one atmosphere.
  • the lamp also includes an electrically or percussively activated primer for igniting the combustible to flash the lamp.
  • the combustible material commonly employed in presently available photoflash lamps consists of a quantity of filamentary material of a type commercially known shredded foil.
  • the material is made by cut ting or shredding a thin sheet or ribbon of suitable metal foil into thin strands.
  • Aluminum and magnesium foil have been used for this purpose, although more recently, zirconium and hafnium have been found to provide significant photomeric advantages.
  • the anodizing method described by Desaulnicrs posed several problems.
  • the necessity for nitric acid baths; rejuvenation and disposal of acid solution; power requirements for depositions; rinsing and drying of the anodized foil do not lend themseleves to economical high speed production processing.
  • Further disadvantages include the difficulty of anodizing foils on a continuous basis, as well as the ability to anodize only two exposed foil surfaces. The latter disadvantage results in shredded material with only two of the exposed surfaces of each strand being oxidized.
  • FIG. 1 is an elevational view of an electrically ignitable photoflash lamp containing a preoxidized filamen tary combustible in accordance with the invention.
  • FIG. 2 is an enlarged representation of a crosssection of a single strand of the filamentary combustible material in the lamp of FIG. 1. illustrating the oxide coating on all exposed surfaces thereof.
  • the teachings of the present'invention are applicable to either percussive or electrically ignited photofiash lamps of a wide variety of sizes and shapes; however, the invention is particularly advantageous as applied to llashlamps having tubular shaped envelopes with a volume of less than one cubic centimeter. For purposes of example, the invention will be described as applied to the electrically ignitable photoflash lamps illustrated in FIG. 1.
  • the lamp comprises an hermetically sealed lamp envelope 2 of glass tubing having a press 4 defining one end thereof and an exhaust tip 6 defining the other end thereof.
  • an ignition means comprising a pair of lead-in wires 8 and 10 extending through and sealed into the press.
  • a filament l2 spans the inner ends of the lead-in wires.
  • beads of primer l4 and 16 are located on the inner ends of the lead-in wires 8 and 10, respectively, at their junction with the filament.
  • the lamp envelope 2 has an internal diameter of less than one-half inch, and an internal volume of less than one cubic centimeter.
  • a combustion-supporting gas such as oxygen, and
  • a filamentary combustible material 18 such as shredded zirconium or hafnium foil, are disposed within'the lamp envelope.
  • the cornbustion-supportirig gas is at a pressure exceeding one atmosphere, with the more recent subminiature lamp types having oxygen fill pressures of up to several atmospheres.
  • the percussive lamp also includes a sealed glass envelope containing a filamentary combustible material and a combustion-supporting gas; however, the ignition means comprises a metal primer tube sealed in and depending from one end of the glass envelope and containing a coaxially disposed wire anvil partially coated with a charge of fulminating material.
  • the ignition means comprises a metal primer tube sealed in and depending from one end of the glass envelope and containing a coaxially disposed wire anvil partially coated with a charge of fulminating material.
  • a deflectorshield is located on the wire anvil just above the inner .mouth of the primer tube.
  • the electrical and percussive lamps are similar in that in each the ignition means is attached to one end of the lamp envelope and disposed in operative relationship with respect to the filamentary combustible material. More specifically, the igniter filament 12 of the flash lamp in FIG. 1 is incandesced electrically by current passing through the metal filament support leads 8 and 10. whereupon the incandesced filament ignites the beads of primer l4 and 16 which in turn ignite the combustible 18 disposed within the lamp envelope. Operation of the percussive-type lamp is initiated by an impact onto the primer tube to cause deflagration of the fulminating material up through the tube to ignite the combustible disposed within the lamp envelope.
  • the filamentary combustible material employed in flash lamp envelopes normally comprises a shredded metallic foil, such as zirconium or hafnium.
  • the metallic foil manufactured for this application is normally provided in thickness of about or somewhat less than one mil and in widths of about four inches.
  • the foil is then processed through standard shredding equipment to produce desirable cross-sections of about 1.0 to 2.0 square mils. depending upon the characteristics of various photoflash lamps. Accordingly. the strands of shredded foil in photoflash lamps are normally about four inches long. although there are many applications in which the foil is split to provide much shorter strand lengths for the filamentary combustible.
  • the shredded metal foil forming the filamentary combustible material 18 is oxidized by controlled heating in air or oxygen. as described hereinbefore.
  • This preoxidation of the shreds of combustible foil results in an oxide coating 20 on all surfaces of each strand of metal foil 22, as illustrated in FIG. 2.
  • the metal foil 22 is zirconium.
  • our controlled preoxidation process will result in the formation of a selected amount of Zirconium oxide 20 on all four surfaces of the strand. as viewed in cross-section.
  • preoxidized shreds. or strands. of filamentary combustible material provides improved light output and color temperature in addition to increased peak time.
  • Actual comparative measurements conducted on 19.5 mg. wads of preoxidized versus nonoxidized shreds of Zirconium foil in a combustion chamber containing oxygen at 12 atmospheres pressure resulted in the following sets of averaged data for each condition of oxidation.
  • the leveling off of average light intensity at 600C indicates a maximum limit at which increased amounts of oxidation are beneficial to the average light output.
  • the luminosity output gains are even more surprising when viewed in the light that less zirconium is available for combustion. For instance. we have determined from weight measurements that 300C oxidized samples have only 97.1% as mcuh available metal for combustion as non-oxidized samples (as denoted in the data table above). This would inidcate that for equal weights of metal available for combustion. pre-oxidized shreds should yield even greater quantities of light. Viewed in another fashion, one would expect need for less oxygen in lamps containing pre-oxidized shreds. thus lowering lamp pressures and increasing lamp containment reliabilities.
  • Zr Shrcds ('ontrol $.l .303 417i! 482. 5,2 IN. Zr Shrcds ()xitli/ed 275C *1. I .336 4237 5222 o i) 20.4 Zr Shrcds () ⁇ idi/cd 425% lo.4 ,Rni 4352 53% ( ⁇ .S 1 n '/.r Shrcds (Midi/ed ( ⁇ (JUC 151i .24) 3071 4234 lll,7 l
  • the light output of the lamps containing shreds oxidizcd at 425C shows an increase of over 4% (()25msec.) and approximately lIZVr ((l- In the case of shreds oxidized at 600C, however, a sharp drop in light output was observed, again indicating a maximum limitation on the amount of oxidation.
  • the value of peak height for lamps containing shreds oxidized at 425C is observed to be somewhat askew for reasons we have not determined.
  • the filamentary material for preoxidation should comprise a combustible which burns at the surface of a molten globule by oxygen diffusion through an oxide coating thereon, such as zirconium, hafnium, thorium, yttrium, or combinations thereof. rather than a combustible which burns as a vapor, such as magnesium or aluminum.
  • a photoflash lamp comprising:
  • said lamp exhibits a higher light output and color temperature upon ignition of said oxidized filamentary material than a like lamp containing a filamentary combustible material which has not been preoxidizcd.
  • said light output increase being at least about 3% (025 msec.) and l0)? (0 and ignition means attached to one end of said envelope and disposed in operative relationship with respect to said combustible material.
  • said filamentary material comprises a combustible which when ignited burns at the surface of a molten glouble by oxygen diffusion through an oxide coating thereon.
  • a lamp according to claim 2 wherein the material comprising said filamentary combustible is selected from the group consisting of zirconium, hafnium. thorium, yttrium. and combinations thereof.
  • each of said strands of filamentary combustible material has a selected amount of oxidation which entirely covers all surfaces thereof.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Resistance Heating (AREA)
US424839A 1973-12-14 1973-12-14 Photoflash lamp Expired - Lifetime US3904348A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US424839A US3904348A (en) 1973-12-14 1973-12-14 Photoflash lamp
JP14264374A JPS5532161B2 (enrdf_load_stackoverflow) 1973-12-14 1974-12-13

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US424839A US3904348A (en) 1973-12-14 1973-12-14 Photoflash lamp

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US3904348A true US3904348A (en) 1975-09-09

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JP (1) JPS5532161B2 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4309166A (en) * 1977-12-23 1982-01-05 U.S. Philips Corporation Combustion flashbulb

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5730074U (enrdf_load_stackoverflow) * 1980-07-28 1982-02-17

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3114250A (en) * 1962-12-18 1963-12-17 Sylvania Electric Prod Photoflash lamp

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1540587A (fr) * 1966-09-30 1968-09-27 Philips Nv Lampe-éclair à combustion

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3114250A (en) * 1962-12-18 1963-12-17 Sylvania Electric Prod Photoflash lamp

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4309166A (en) * 1977-12-23 1982-01-05 U.S. Philips Corporation Combustion flashbulb

Also Published As

Publication number Publication date
JPS5532161B2 (enrdf_load_stackoverflow) 1980-08-23
JPS5093424A (enrdf_load_stackoverflow) 1975-07-25

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