US2116741A - Electric gaseous discharge device - Google Patents

Electric gaseous discharge device Download PDF

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Publication number
US2116741A
US2116741A US4371A US437135A US2116741A US 2116741 A US2116741 A US 2116741A US 4371 A US4371 A US 4371A US 437135 A US437135 A US 437135A US 2116741 A US2116741 A US 2116741A
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United States
Prior art keywords
envelope
lamp
mercury
electrodes
arc
Prior art date
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
US4371A
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English (en)
Inventor
Elenbaas Willem
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
Application granted granted Critical
Publication of US2116741A publication Critical patent/US2116741A/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/82—Lamps with high-pressure unconstricted discharge having a cold pressure > 400 Torr
    • H01J61/822—High-pressure mercury lamps

Definitions

  • the present invention relates to electric gaseous discharge devices generally, and in particular to a device having a relatively small light source of great brightness.
  • a particular object of the invention is to provide an electric gaseous discharge device which will be suitable for use as a projection lamp.
  • Another object of my invention is to provide a discharge device having a discharge of extremely 10 great surface brightness.
  • Still another object of my invention is to provide a device of this type having an extremely stable discharge of considerable length.
  • the are potential was of the order of 20 volts
  • the operating vapor density is made such that the energy consumption per centimeter length of the discharge path is more than 100 watts, and the arc is furthermore made to operate in the middle of a relatively large enclosing envelope. This latter can be easily accomplished either by makbefore it is useful for projection purposes, whereing the arc path vertical, or through a suitable magnetic control of the arc in case the arc position tends to cause it to bow out toward the envelope.
  • an are from 0.5 to 2 cm.
  • the lamp envelope can be made of any of the more refractory glasses, such as a glass containing at least 20% aluminum oxide, provided the diameter of the envelope is of the order of 30 m. m. or more. For higher surface brightness the diameter would naturally be increased, and in some cases it may be desirable to use quartz for this envelope to withstand the relatively high temperature of the mercury vapor. The are is extremely centralized and constricted, however, and hence in most cases these precautions are not necessary.
  • my novel lamp has a substantially spherical envelope I of any suitable glass, such as that known as Supremaxor one of the high alumina glassesv which are known to have both a high softening temperature and a high resistance to blackening by the mercury vapor.
  • Fused silica may likewise be used for this envelope if it-is desired.
  • a pair of thermionic electrodes land 3 are located within said en- M velope.- As here shown these electrodes each consist of a helix of tungsten or the like coated with a good thermionic emitter, such as barium or strontium oxide or the like.
  • a pair ofinleads e are connected to opposite ends of each of said electrodes 2 and 3, and provide means to pass a heating current therethrough to bring them to the temperature necessary for electron emission, in case such heating is desired, in addition to carrying the main discharge current. It is to be understood, however, that any of the other types of thermionic electrodes including those which are indirectly heated and those which are heated by the discharge, may be used in place of the type shown. Such electrodes are well known in the art and hence need not be further described here.
  • the inlead wires 4 are preferably enclosed within a bead 5 for some distance adjacent to the point where they are sealed into the envelope I.
  • the lower electrode 3 is placed nearer, by say 5 m. m. to the bottom than the upper electrode 2 is to the top of the envelope.
  • the inleads 4 are made long enough to prevent the transmission of too large an amount of heat back to the seals.
  • the envelope l preferably contains a rare gas such as argon, at a low pressure, of the order of Y 5 m. m. of mercury, which serves as a starting gas, in those instances where this particular method of starting is desired.
  • a carefully measured quantity of mercury is likewise enclosed within said envelope in an amount which will all be evaporated at a somewhat lower temperature. 2 than that at which the lamp normally comes to equilibrium, whereby said lamp normally operates with an unsaturated mercury vapor atmosphere.
  • This temperature, and therefore the quantity of -mercury varies of course with the amount of energy dissipated in the arc, on the radiation surface of the device and the like.
  • the gap between the electrodes is 10 m. m. and the bulb diameter is 55 m. m.
  • one gram of mercury is introduced into j the envelope I, since this has been found to produce the desired unsaturated vapor density when the device is in operation, the operating pressure thus being considerably in excess of atmospheric.
  • this novel lamp is especially suited for use in projecting motion pictures, inasmuch as it provides a light source of extremely high bril- "liancy which is-not only stable, but which is substantially the same size as the 'film window, or even larger if desired, whereby this brightness is not lost through a magnification of the source.
  • the envelope I may be enclosed within a heat conserving jacket 6.
  • this jacket is preferably filled with an inert gas by there is no tendency for said envelope to bulge outwardly if it chances to soften.
  • the pressure differences may be divided between the lamp envelope and'the jacket in some cases by making the pressure in the jacket of a value between that in the lamp and the atmosphere.
  • a mercury vapor lamp comprising a sealed envelope, a pair of electrodes sealed therein, at least one ofsaid electrodes being a thermionic cathode of the metal compound type, mercury within said envelope, an enclosing jacket about said envelope, and a gas filling within said jacket amount which is all vaporized at a temperature below a given temperature of said lamp, said envelope having a heat radiating capacity such that a discharge consuming at least watts per centimeter must be passed between said electrodes before said given temperature is attained.
  • a mercury vapor lamp comprising a sealed envelope, a pair of electrodes sealed therein, at
  • At least one of said electrodes being a thermionic cathode of the metal compound type, mercury within said envelope in an amount which is all vaporized at a temperature below a given temperature of said lamp, said envelope having a heat radiating capacity such that a discharge consuming at least 100 watts per centimeter must be passed between said electrodes before said given temperature is attained.
  • a vapor arc lamp comprising a sealed envelope, a pair of electrodes sealed therein, at least one of said electrodes being a thermionic cathode of the metal compound type, said electrodes being separated by a distance of 0.5 to 2 cm., and a vaporizable substance within said envelope in an amount which is all vaporized at a temperature below a given temperature of said lamp, said envelope having a heat radiating capacity such that a discharge consuming at least 100 watts per centimeter must be passed between said electrodes before said given temperature is attained.
  • a mercury vapor lamp comprising a sealed envelope, a pair of electrodes sealed therein, at least one of said electrodes being a thermionic cathode of the metal compound type, mercury within said envelope, an enclosing jacket about enema 3 said envelope, and a gas filling within said jacket said envelope, and a. gas filling within said Jacket at a pressure in excess of atmospheric pressure but less than the operating pressure within said envelope when said envelope is close to its softening temperature, whereby the pressure strain is 5 divided between said envelope and said jacket.

Landscapes

  • Discharge Lamps And Accessories Thereof (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
US4371A 1934-02-05 1935-01-31 Electric gaseous discharge device Expired - Lifetime US2116741A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE434919X 1934-02-05

Publications (1)

Publication Number Publication Date
US2116741A true US2116741A (en) 1938-05-10

Family

ID=6506703

Family Applications (1)

Application Number Title Priority Date Filing Date
US4371A Expired - Lifetime US2116741A (en) 1934-02-05 1935-01-31 Electric gaseous discharge device

Country Status (3)

Country Link
US (1) US2116741A (fr)
FR (1) FR784677A (fr)
GB (1) GB434919A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4481446A (en) * 1979-04-26 1984-11-06 Mitsubishi Denki Kabushiki Kaisha Metal vapor discharge lamp

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4481446A (en) * 1979-04-26 1984-11-06 Mitsubishi Denki Kabushiki Kaisha Metal vapor discharge lamp

Also Published As

Publication number Publication date
GB434919A (en) 1935-09-11
FR784677A (fr) 1935-07-22

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