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US3758809A Expired / Lapsed US ⏱️ 0.0 years remaining

Emissive fused pellet electrode

Assignee: TDK Micronas GmbH
•
Filing: 1971-12-03
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Granted: 1973-09-11
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Expires: 1991-12-03
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Abstract

Abstract An emissive electrode of the type utilized in fluorescent lamps and a method for making such an electrode. The electrode includes a fused pellet and a metal lead extending from the bottom surface thereof. The pellet contains a fused mixture of electron emissive material and a metal having a high melting point and a low vapor pressure. The pellet has a bulk density gradient structure wherein the interior portions and exterior bottom and side portions thereof have a high bulk density relative to the bulk density of the exterior top portion of the pellet, and the exterior bottom and side surfaces of the pellet are smooth re1ative to the exterior top surface thereof. The pellet is formed by mixing a powder of said metal with a powder of said electron emissive material, compressing said mixed powder and heating it in a mold until an exothermic reaction occurs.

Inventors

  • 👤 R Menelly
  • 👤 E Kern

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 08:39
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/022; H01J1/00; H01J1/02; H01J1/30; H01J17/00; H01J17/02; H01J17/04; H01J17/06; H01J17/066; H01J2893/00; H01J2893/0064; H01J2893/0065; H01J2893/0066

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 40 words
A fused pellet electrode, according to claim 1, wherein the bottom and side surfaces of said pellet are smooth relative to the top surface of said pellet so as to confine electron emission to the top portion of said pellet.
Claim 2
Dependent Claim 41 words
A fused pellet electrode, according to claim 2, wherein the top portion of said pellet is conical in shape and the bottom portion of said pellet is cylindrical in shape, the base of said conical portion being adjacent said cylindrical portion.
Claim 3
Dependent Claim 15 words
A fused pellet electrode, according to claim 3, wherein said metal comprises a refactory metal.
Claim 4
Dependent Claim 16 words
A fused pellet electrode, according to claim 3, wherein said metal comprises a transition element metal.
Claim 5
Dependent Claim 18 words
A fused pellet electrode, according to claim 3, wherein said electron emissive material comprises an alkaline earth material.
Claim 6
Dependent Claim 17 words
A fused pellet electrode, according to claim 3, wherein said electron emissive material comprises an alkali material.
Claim 7
Dependent Claim 39 words
A fused pellet electrode, according to claim 3, wherein that portion of said metal conducting lead embedded in said pellet is formed with a nail head so as to provide good adherence between said lead and said fused pEllet.
Claim 8
Dependent Claim 35 words
A fused pellet electrode, according to claim 3, wherein said fused pellet results from an exothermic reaction in a powder mixture comprising a powder of said metal and a powder of said electron emissive material.
Claim 9
Dependent Claim 58 words
A fused pellet electrode, according to claim 9, wherein said metal powder comprises tantalum powder and said electron emissive material comprises barium peroxide powder, said tantalum powder being between 60 percent and 70 percent by weight of said powder mixture and said barium peroxide powder being between 30 percent and 40 percent by weight of said powder mixture.

References Cited (Backward Citations)

US931133A Cited
US2492142A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1976-09-10 1977-03-12 1977-09-11 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1980-09-10 1981-03-12 1981-09-11 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1984-09-10 1985-03-12 1985-09-11 $7700.00 Window Closed / Lapsed

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