US2663816A - Electric discharge lamp - Google Patents
Electric discharge lamp Download PDFInfo
- Publication number
- US2663816A US2663816A US118252A US11825249A US2663816A US 2663816 A US2663816 A US 2663816A US 118252 A US118252 A US 118252A US 11825249 A US11825249 A US 11825249A US 2663816 A US2663816 A US 2663816A
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- United States
- Prior art keywords
- barium
- oxide
- hafnium
- lamps
- discharge lamp
- Prior art date
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- Expired - Lifetime
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- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 229910052788 barium Inorganic materials 0.000 description 15
- 229910000449 hafnium oxide Inorganic materials 0.000 description 15
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 13
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 description 13
- 229910052735 hafnium Inorganic materials 0.000 description 11
- 238000002845 discoloration Methods 0.000 description 10
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 8
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 7
- 239000011248 coating agent Substances 0.000 description 7
- 238000000576 coating method Methods 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 5
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 description 4
- 229910052753 mercury Inorganic materials 0.000 description 4
- 229910052712 strontium Inorganic materials 0.000 description 4
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 239000011575 calcium Substances 0.000 description 3
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- CSSYLTMKCUORDA-UHFFFAOYSA-N barium(2+);oxygen(2-) Chemical class [O-2].[Ba+2] CSSYLTMKCUORDA-UHFFFAOYSA-N 0.000 description 2
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 2
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 2
- 229910000420 cerium oxide Inorganic materials 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- ZSLUVFAKFWKJRC-IGMARMGPSA-N 232Th Chemical compound [232Th] ZSLUVFAKFWKJRC-IGMARMGPSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 102000010029 Homer Scaffolding Proteins Human genes 0.000 description 1
- 108010077223 Homer Scaffolding Proteins Proteins 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 229910052776 Thorium Inorganic materials 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- AYJRCSIUFZENHW-DEQYMQKBSA-L barium(2+);oxomethanediolate Chemical compound [Ba+2].[O-][14C]([O-])=O AYJRCSIUFZENHW-DEQYMQKBSA-L 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- LTPBRCUWZOMYOC-UHFFFAOYSA-N beryllium oxide Inorganic materials O=[Be] LTPBRCUWZOMYOC-UHFFFAOYSA-N 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical class [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 235000012255 calcium oxide Nutrition 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052743 krypton Inorganic materials 0.000 description 1
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 description 1
- 239000004922 lacquer Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- ZCUFMDLYAMJYST-UHFFFAOYSA-N thorium dioxide Chemical compound O=[Th]=O ZCUFMDLYAMJYST-UHFFFAOYSA-N 0.000 description 1
- 229910003452 thorium oxide Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/04—Electrodes; Screens; Shields
- H01J61/06—Main electrodes
- H01J61/067—Main electrodes for low-pressure discharge lamps
- H01J61/0675—Main electrodes for low-pressure discharge lamps characterised by the material of the electrode
- H01J61/0677—Main electrodes for low-pressure discharge lamps characterised by the material of the electrode characterised by the electron emissive material
Definitions
- This invention relates to the prevention of discoloration and increase of life in electric discharge lamps with oxide-coated cathodes, and particularly in fluorescent lamps.
- the figure shows a fluorescent lamp according to the invention, partly in section.
- an elongated tubular envelope I of light-transmitting material such as glass, has a stem 2 sealed to each end, with the lead-in wires 3, 4 sealed therethrough and carrying a cathode 5 at each end, which may be a doublycoiled tungsten wire with an electron-emittin material held between the turns of its minor coil, as shown, for example, in U. S. Patent 2,258,158, issued October 7, 1941, to Erwin F. Lowry.
- coating 6 of fluorescent material for example of a calcium halo-phosphate activated with antimony and manganese, is applied to the inner surface of envelope l in the manner customary in the art.
- an inert gas such as argon or krypton
- the! filling may be argon ata pressure of a few millimeters of mercury, a pressure of the order of three millimeters being generally preferable.
- exhaust and filling of the lamp is effected through exhaust opening I, in communication with exhaust tube 8, shown sealed off as it would be after the manufacture of the lamp.
- a base In is affixed to the ends'of the envelope I, and may be held thereto by the cement II.
- the base itself may be of plastic, if desired.
- the contact pins l2, l3 project. through the base 10, and are connected to the lead-in wires 3, 4.
- a coating of electron emitting material may be applied to the cathode, for example as in the Patent 2,258,158 previously mentioned.
- the electron emitting material is referred to as a coating, for convenience, although it is preferably just 'a quantity of material held between the smaller turns of the coil 5, as in the patent mentioned.
- the coating material may comprise one or more of the alkaline earth oxides, preferably barium, strontium and calcium oxides, together with a small quantity of hafnium oxide.
- the alkaline earth oxides may be applied to the electrode as carbonates and later reduced to the oxides during the exhausting of the tube, for example, an
- a small amount of a nitrocellulose lacquer may be added as a vehicle for applying the coating to the oathode, the vehicle being removed by drying and decomposition during the exhaust process.
- hafnium oxide is added to the carbonates and intimately admixed therewith.
- the amount of hafnium oxide is preferably in a molal ratio to barium of about 1 to 5.5, although it may vary in amount between about 0.2 to 5.5 and 2 to 5.5.
- the lamp is exhausted and filled with'gas in the usual manner, through exhaust tube 3, prior to the sealing During this process the cathode is heated, for example by the passage of current therethrough, to convert'the carbonates into oxides and carbon dioxide, the latter being removed by the exhaust, leaving the white oxides on the cathode.
- the table clearly shows the superiority of hafnium oxide over the other similar oxides in keeping the discoloration low, and also shows that hafnium oxide gave longer life.
- the titanium and cerium oxide lamps had all failed, and at 6000 hours, the hafnium oxide lamps were the only ones still operating, the beryllium, titanium, cerium and thorium oxide lamps, together with those having no such additional oxide, having all failed.
- the discoloration in these latter lamps was of an altogether different order of magnitude than that in the hafnium oxide lamps.
- the discoloration is "greatest in lamps'containing-mercuryvaporpand my invention is particularly effective in such lamps.
- The' filament wire was flol tungsten.
- firnni ele'ctric discharge ilamp comprising 1a sealed tubular light-transmitting envelope, leadin wires sealed therethrough, a gas-filling at low pressure therein, a tungsten wire coil connected between said lead-in wires, and an electron-emitting mixture consisting essentially of hafnium oxide, barium oxide and at least one other alkaline earth oxide held in said coil, the molal ratio bfihafniu'm'to barium-"beinghbout mo: 5.5, said h'afnium -and barium oxidesconstituting the main portion of the mixture.
- An electric discharge lamp comprising a sealedtubular light-transmitting envelope, leadwires'sealed therethrough, a gas filling at low 'pressurethereinimercury vapor therein, a tunglfi stn wi re coil"'connected between said lead-in -wires,"andanelectron-emitting mixture of powderedflhafni nn andbarium oxides held in said coil, the molal ratio of hafnium to barium being between 0.2 to 5.5 and 2 to 5.5.
- An electric discharge lamp comprising a sealed tubular: light-transmitting envelope, lead- -in-wiressealed therethrough; agas filling-at -iow 'pi'essure therein, mercury vapor therein, a-tungsten wire coil connectedbetween saidu lead-in 1 wires; and an electron-emitting mixture of pow- 'dered hafnium and'barium oxides held-in-said :coil'; 'the molal. ratio of 1 hafnium to bariumbeing about 1 to 5.5.
Description
Dec. 22, 1953 H. H. HOMER ELECTRIC DISCHARGE LAMP Filed Sept. 28, 1949 Horace Homer;
INVEN TOR.
Hf: After-neg.
Patented Dec. 22, 1953.
ELECTRIC DISCHARGE LAMP HoraceH. Homer, Arlington, Mass., assignor to Sylvania Electric Products Inc., Salem, Mass., a corporation of Massachusetts Application September 28, 1949, Serial No. 118,252
9 Claims.
1 This invention relates to the prevention of discoloration and increase of life in electric discharge lamps with oxide-coated cathodes, and particularly in fluorescent lamps.
I find that the addition of a small amount of hafnium oxide to the cathode coating greatly reduces such discoloration and increases the life of the lamp.
The figure shows a fluorescent lamp according to the invention, partly in section.
In that figure, an elongated tubular envelope I of light-transmitting material such as glass, has a stem 2 sealed to each end, with the lead-in wires 3, 4 sealed therethrough and carrying a cathode 5 at each end, which may be a doublycoiled tungsten wire with an electron-emittin material held between the turns of its minor coil, as shown, for example, in U. S. Patent 2,258,158, issued October 7, 1941, to Erwin F. Lowry. A
at reduced pressure, is sealed into the envelope I.- For example, the! filling may be argon ata pressure of a few millimeters of mercury, a pressure of the order of three millimeters being generally preferable.
During manufacture, the exhaust and filling of the lamp is effected through exhaust opening I, in communication with exhaust tube 8, shown sealed off as it would be after the manufacture of the lamp.
A base In is affixed to the ends'of the envelope I, and may be held thereto by the cement II. The base itself may be of plastic, if desired. The contact pins l2, l3 project. through the base 10, and are connected to the lead-in wires 3, 4.
A coating of electron emitting material may be applied to the cathode, for example as in the Patent 2,258,158 previously mentioned. The electron emitting material is referred to as a coating, for convenience, although it is preferably just 'a quantity of material held between the smaller turns of the coil 5, as in the patent mentioned.
The coating material may comprise one or more of the alkaline earth oxides, preferably barium, strontium and calcium oxides, together with a small quantity of hafnium oxide. The alkaline earth oxides may be applied to the electrode as carbonates and later reduced to the oxides during the exhausting of the tube, For example, an
. thereof.
intimate, finely powdered mixture of 58% barium carbonate, 35% strontium carbinate, and 7% calcium carbonate will be satisfactory. A small amount of a nitrocellulose lacquer may be added as a vehicle for applying the coating to the oathode, the vehicle being removed by drying and decomposition during the exhaust process.
A small amount of finely-powdered hafnium oxide is added to the carbonates and intimately admixed therewith. The amount of hafnium oxide is preferably in a molal ratio to barium of about 1 to 5.5, although it may vary in amount between about 0.2 to 5.5 and 2 to 5.5.
After the stem 2 bearing the coated cathode 5 is sealed to the end of the envelope I, the lamp is exhausted and filled with'gas in the usual manner, through exhaust tube 3, prior to the sealing During this process the cathode is heated, for example by the passage of current therethrough, to convert'the carbonates into oxides and carbon dioxide, the latter being removed by the exhaust, leaving the white oxides on the cathode.
I have tried many oxides of metals similar in some respects to hafnium, but the results were unsatisfactory. For example, the tests summarized in the following table show that the addition of oxidesof beryllium, titanium, cerium and thorium were unsatisfactory, whereas the addition of hafnium oxide gave excellent results.
Table Relative discoloration at various hours life Added oxide 48 52 72 72 Failed. 36 42 70 Failed- Do.
0 0 4 10 30. 18 36 72 Failed.-. Failed. 26 40 73 Do. 38 40 42 94 D0.
The table clearly shows the superiority of hafnium oxide over the other similar oxides in keeping the discoloration low, and also shows that hafnium oxide gave longer life. For example at 4000 hours, the titanium and cerium oxide lamps had all failed, and at 6000 hours, the hafnium oxide lamps were the only ones still operating, the beryllium, titanium, cerium and thorium oxide lamps, together with those having no such additional oxide, having all failed. Moreover, the discoloration in these latter lamps was of an altogether different order of magnitude than that in the hafnium oxide lamps. In fact,
the discoloration in the hafnium oxide lamps at 6000 hours-a time at which all the other lamps had failed-was only about equal to the average discoloration in the other lamps at 475 hours life.
The discoloration in the lamps with other than hafnium oxides added, while somewhat erratic, were roughly about the -samefionrthemverageg as if no oxideat all had been added.
The lamps marked None in the above table had their cathode coating of the barium, strontium and calcium mixture previously described herein, while the other lamps had'adfiiixd with the barium, calcium and strontium exidessaismall quantity of the particular' oxide' specified} the quantity in each case being that which gave-a molal ratio to the barium oxide of into-5.63. :The ratio of the additional oxide to the barium oxide appears to be the important relationship-because the discoloration appears to be due chiefly to the -barium.
The discoloration is "greatest in lamps'containing-mercuryvaporpand my invention is particularly effective in such lamps.
lfThe lamps nf-the tests summarizdi in' the table were-40 watt fluorescent lamps ina glass envelope 48 inches long and L -inchesdndiameteriwith' a filling of I argon at a pressure'scf about." 3 mill'imete'rsr of mercury; :and mercury vapor. Such lamps =operate at' atemperature of: about- 40LC.,
corresponding 'to a; mercury' vapor; pressure of about: 6' microns. The' filament wire was flol tungsten.
1. A rdischarge lamp cathode'icomprising a coiled tungsten wirei and -an el'eetron emitting m'aterial held-by said .wire and "consistingimainly -of-hafniumoxide and barium oxi'deiinmolalzratio -between 0.2' to 5.5 anclzto 5.5.
I: 2;: An electric discharge lamp 1 comprising: a sealed tubular light-transmitting envelope; lead- :in wires sealed therethrough; a; gas filling ='at-':low
pressure therein, a tungsten wire coil connected between'said' lead in wires, and an :ele'ctron emitting mixture-of powdered hafniumoand barium x oxides held :in i saidi coil; .the "molal ratio of hafnium to barium: being between" 0.2" to' 5.5:and 2 =-to 5'.5.
3.x:Anelectric rdischarge lamp *comprisingiswa rs'ealed tubular--light transmitting erivelope; leadin wires sealed therethrough, a gas filling at low pressure therein, a tungsten wire coil connected between said lead-in wires, and an electron-emitting mixture or powdered hafnium and barium oxides Held in said c'oil'fthe molal ratioo'f hafnium tdbarium being about 1' to 5.5.
electric discharge lamp comprising a sealed tubular light transniitting' enveiope, leadin wires sealed -therethrou'gh, a gas-filling-atlow pressuretherein, a tungstenwire coilconnect'ed' between-said lead-in wires; and an electron-emit- --ting--mixture consisting essentially of hafnium iioxidegbarium oxide' and at least 'one bthenialka- ="=line earth oxide held inxasa'id coiL-zthermolal irafio and? to 5;5,&sa'id" hafnium and barium oxides constitiitingcthemain portion-'ofithefmixture.
firnni ele'ctric discharge: ilamp comprising 1a sealed tubular light-transmitting envelope, leadin wires sealed therethrough, a gas-filling at low pressure therein, a tungsten wire coil connected between said lead-in wires, and an electron-emitting mixture consisting essentially of hafnium oxide, barium oxide and at least one other alkaline earth oxide held in said coil, the molal ratio bfihafniu'm'to barium-"beinghbout mo: 5.5, said h'afnium -and barium oxidesconstituting the main portion of the mixture.
6. An electric discharge lamp comprising a sealedtubular light-transmitting envelope, leadwires'sealed therethrough, a gas filling at low 'pressurethereinimercury vapor therein, a tunglfi stn wi re coil"'connected between said lead-in -wires,"andanelectron-emitting mixture of powderedflhafni nn andbarium oxides held in said coil, the molal ratio of hafnium to barium being between 0.2 to 5.5 and 2 to 5.5.
7. An electric discharge lamp comprising a sealed tubular: light-transmitting envelope, lead- -in-wiressealed therethrough; agas filling-at -iow 'pi'essure therein, mercury vapor therein, a-tungsten wire coil connectedbetween saidu lead-in 1 wires; and an electron-emitting mixture of pow- 'dered hafnium and'barium oxides held-in-said :coil'; 'the molal. ratio of 1 hafnium to bariumbeing about 1 to 5.5.
.1 8.=' An' electric: discharge lamp comprising a sealed tubular light-transmitting envelope, -leadiwires sea-led therethrough; a gas siilling: at -:low pressure therein, mercury vapor -therein,--.a' tungsten wire coil: connected between: -said dead-in 'wires; and an electron-=emitting mixture consistessentiallyof hafnium oxide,- barium oxide and: at'least one other alkaline earth oxide; held .insaid coil-,ithe molal ratioof-hafnium to barium being between 0.2-'to' 5.5 and: 2 to 5.5;said-barium amihafnium oxide constituting themain portion :ofthe mixture. 7
" '9; An "electric "discharge lamp comprising a sealed tubular light-transmitting envelope, 7 leadin wires sealedtherethrough, a gas-filling atlow ypressure therein, mercury vapor therein; atungsten wire: coil connected between said-,leadein wires and an electron-emitting mixtureconsisting essentially 'of-hafnium oxide,-barium goxide and; at least one otheralkaline eat-rthoxideheld sin saidcoil; the molal ratio of hafnium -to barium 50 being about 1 to 5.5, said bariumand-- hafnium --oxide constituting-:themain *portion oftheLmiX- -=ture.
. i-HORACEsI-IQHOMER.
References Cited in'the iile of' thiapatent
Claims (1)
1. A DISCHARGE LAMP CATHODE COMPRISING A COILED TUNGSTEN WIRE AND AN ELECTRON-EMITTING MATERIAL HELD BY SAID WIRE AND CONSISTING MAINLY
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US118252A US2663816A (en) | 1949-09-28 | 1949-09-28 | Electric discharge lamp |
| GB23712/50A GB684717A (en) | 1949-09-28 | 1950-09-27 | Improvements in electric discharge lamps |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US118252A US2663816A (en) | 1949-09-28 | 1949-09-28 | Electric discharge lamp |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2663816A true US2663816A (en) | 1953-12-22 |
Family
ID=22377450
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US118252A Expired - Lifetime US2663816A (en) | 1949-09-28 | 1949-09-28 | Electric discharge lamp |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US2663816A (en) |
| GB (1) | GB684717A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2911376A (en) * | 1951-11-01 | 1959-11-03 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Activating material for electrodes in electric discharge devices |
| US3056904A (en) * | 1958-10-20 | 1962-10-02 | Minnesota Mining & Mfg | Thermoprinting apparatus and method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4044276A (en) * | 1976-04-09 | 1977-08-23 | Gte Sylvania Incorporated | High pressure mercury vapor discharge lamp having improved electrodes |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1821359A (en) * | 1928-04-13 | 1931-09-01 | Rca Corp | Wehnelt-cathode |
| US1823984A (en) * | 1926-05-13 | 1931-09-22 | Communications Patents Inc | Cathode for thermionic devices |
| US1925701A (en) * | 1926-06-09 | 1933-09-05 | Electrons Inc | Electron emissive device |
| US2142331A (en) * | 1935-03-09 | 1939-01-03 | Bell Telephone Labor Inc | Electron emitting cathode |
| US2233741A (en) * | 1938-11-21 | 1941-03-04 | Kurt F J Kirsten | Cathode electrode |
| US2258158A (en) * | 1940-11-23 | 1941-10-07 | Hygrade Sylvania Corp | Electric discharge lamp cathode |
| US2310983A (en) * | 1940-02-20 | 1943-02-16 | Samuel C Miller | Electrode for luminous tubes and method of producing the same |
| US2346553A (en) * | 1942-02-28 | 1944-04-11 | Bell Telephone Labor Inc | Coating suspension and method of preparation |
| US2457515A (en) * | 1941-11-13 | 1948-12-28 | Bell Telephone Labor Inc | Insulating coating compositions and method of making |
| US2477279A (en) * | 1946-09-11 | 1949-07-26 | Hanovia Chemical & Mfg Co | Electrical discharge device |
-
1949
- 1949-09-28 US US118252A patent/US2663816A/en not_active Expired - Lifetime
-
1950
- 1950-09-27 GB GB23712/50A patent/GB684717A/en not_active Expired
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1823984A (en) * | 1926-05-13 | 1931-09-22 | Communications Patents Inc | Cathode for thermionic devices |
| US1925701A (en) * | 1926-06-09 | 1933-09-05 | Electrons Inc | Electron emissive device |
| US1821359A (en) * | 1928-04-13 | 1931-09-01 | Rca Corp | Wehnelt-cathode |
| US2142331A (en) * | 1935-03-09 | 1939-01-03 | Bell Telephone Labor Inc | Electron emitting cathode |
| US2233741A (en) * | 1938-11-21 | 1941-03-04 | Kurt F J Kirsten | Cathode electrode |
| US2310983A (en) * | 1940-02-20 | 1943-02-16 | Samuel C Miller | Electrode for luminous tubes and method of producing the same |
| US2258158A (en) * | 1940-11-23 | 1941-10-07 | Hygrade Sylvania Corp | Electric discharge lamp cathode |
| US2457515A (en) * | 1941-11-13 | 1948-12-28 | Bell Telephone Labor Inc | Insulating coating compositions and method of making |
| US2346553A (en) * | 1942-02-28 | 1944-04-11 | Bell Telephone Labor Inc | Coating suspension and method of preparation |
| US2477279A (en) * | 1946-09-11 | 1949-07-26 | Hanovia Chemical & Mfg Co | Electrical discharge device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2911376A (en) * | 1951-11-01 | 1959-11-03 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Activating material for electrodes in electric discharge devices |
| US3056904A (en) * | 1958-10-20 | 1962-10-02 | Minnesota Mining & Mfg | Thermoprinting apparatus and method |
Also Published As
| Publication number | Publication date |
|---|---|
| GB684717A (en) | 1952-12-24 |
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