Stock material or miscellaneous articles – All metal or with adjacent metals – Having aperture or cut
Patent
1979-09-13
1982-01-12
Hunt, Brooks H.
Stock material or miscellaneous articles
All metal or with adjacent metals
Having aperture or cut
313346R, 313346DC, 313344, 313355, H01J 1906
Patent
active
043106030
ABSTRACT:
A dispenser cathode is fabricated by covering a reservoir of electron emitting material with a perforated metal foil having an appropriate pattern of pore-sized apertures thereon for providing uniform electron emission from the cathode surface. The electron emitting material is in the form of a pellet of barium oxide impregnated with a wax or resinous material to minimize chemical reduction of the barium oxide in air. The impregnated barium oxide pellet is sandwiched between the apertured foil and a support structure to which the foil is welded. During tube bake-out or subsequently during cathode activation, the wax or resinous material evaporates and barium oxide migrates through the apertures to cover the surface of the foil in a uniform manner. The desired pattern of apertures in the foil is achieved by photolithography, or by forming the foil (e.g., by chemical vapor deposition, sputter deposition, evaporation, or sintering) on a substrate containing an array of protruding posts. With the photolithographic technique, the desired pattern of apertures is chemically etched directly on the foil; and with the technique in which the foil is formed on a substrate having an array of posts, the substrate with its protruding posts is removed by chemical etching after the foil has been formed. With either technique for forming the apertures, a shadow grid can also be formed as an integral part of the cathode surface by depositing a layer of reactive material such as zirconium or graphite on a selected portion of the cathode surface. This layer of reactive material prevents the formation of an emitting layer of barium oxide on a selected pattern on the cathode surface.
REFERENCES:
patent: 2874077 (1959-02-01), Joseph et al.
patent: 3159461 (1964-12-01), MacNair
patent: 3676731 (1972-07-01), Hofmann et al.
patent: 4101800 (1978-07-01), Thomas
Cole Stanley Z.
Hunt Brooks H.
Sgarbossa Peter J.
Varian Associates Inc.
LandOfFree
Dispenser cathode does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dispenser cathode, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dispenser cathode will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1541704