Cathode structure for cathode ray tube
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorMika Yamagishi
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Abstract
In a cathode with an electron-emissive material layer formed on a base containing a reducing element, a relationship of 0.24≦B/A≦0.93 is satisfied, where A denotes a surface for layer formation of the base and B represents an area where the base and the electron-emissive material layer are in contact with each other. In addition, a relationship of 0.4≦D/C≦0.7 is satisfied, where C and D denote thicknesses of the base and the electron-emissive material layer, respectively. Thus, a cathode structure is provided in which sufficient electron emission can be obtained, a decrease in electron emission with the passage of time is not much during the operation, and variations in cut-off voltage are small.
Claims6
A cathode structure for a cathode-ray tube, comprising a base containing a reducing element and an electron-emissive material layer formed on the base,
- wherein the cathode structure satisfies a relationship of 0.24≦B/A≦0.93, where A denotes an area of a surface for layer formation of the base and B represents an area where the base and the electron-emissive material layer are in contact with each other, and has a zero-electric-field saturation current density of at least 6.4 A/cm2 after an implementation of an accelerated life test for 5000 hours under conditions of a vacuum of 10−7 mmHg, a cathode temperature of 820° C., and a current led out from a cathode of DC 300 μA.
Dependencies are inferred from the claim text.