Method of manufacturing cathodes
AssigneeU.S. Philips Corporation
InventorReinier M. van den Heuvel
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Abstract
A method of electrophoretically coating cathode shafts with an emissive layer having excellent mechanical properties, by dipping a jig in which the shafts are placed into an electrophoresis bath. The jig includes a plate formed of electrically insulating material having an electrically conducting layer on one side, with apertures for the cathode shafts defining an opening in the layer. The conducting layer and cathode surface are immersed in an electrophoresis bath, and an electric potential is then applied between the layer and the shafts.
Claims5
A method of electrophoretically coating cathode shafts with an emissive layer, comprising the sequential steps of
- providing a plate formed of an electrically insulating material having an electrically conducting layer on at least one side, and an aperture in the plate defining an opening in the layer;
- placing a cathode shaft to be coated in the aperture, so arranged that a shaft surface to be coated is within the aperture and is exposed toward said opening and spaced from said opening a distance which is small compared with the plate thickness;
- applying a suspension containing substances for forming the emissive layer, at least so as to cover said conducting layer and said shaft surface;
- applying an electric potential between said conducting layer and said shaft;
- removing said electric potential;
- removing said suspension from application to the conducting layer and shaft surface;
- drying the emissive material layer adhering to the shaft surface;
- and
- removing the cathode shaft from the plate aperture.
Dependencies are inferred from the claim text.