Ir-coated dispenser cathode for CRT

Author

Kimura, Sakae ; Yakabe, Toru ; Matsumoto, Sadao ; Miyazaki, Daisuke ; Yoshi, Tsuyoshi ; Fujiwara, Minoru ; Koshigoe, Shimpei

Author_Institution

Toshiba Corp., Kawasaki, Japan

Volume

37

Issue

12

fYear

1990

fDate

12/1/1990 12:00:00 AM

Firstpage

2564

Lastpage

2567

Abstract

A compact dispenser cathode has been developed for application to cathode ray tubes (CRTs). A cathode emitter, comprising BaO, CaO, and Al ₂O₃ in a molar ratio of 4:1:1, was impregnated into a porous tungsten pellet. An intermetallic compound of tungsten and iridium was formed on the cathode pellet. Heater ratings were 6.3 V×0.2 A. Emission characteristics were measured by using color CRTs. As a result, a cathode peak loading of 15 A/cm² was ensured in the space-charge region. Furthermore, life tests with a peak loading of 7.5 A/cm² were conducted over 10000 h. The decrease in emission current after 10000 h was within only 10% of the initial value. Reliability of cathode performance was assured in terms of breakdown potential between the heater and the cathode, emission characteristics, life performance, grid emission, and the drift in cutoff potential. In addition, the effects of the coating thickness on the emission characteristics are discussed

Keywords

cathode-ray tubes; cathodes; iridium; life testing; BaO-CaO-Al₂O₃; Ir coating; W-Ir; breakdown potential; cathode emitter; cathode peak loading; cathode ray tubes; coating thickness; color CRTs; cutoff potential drift; dispenser cathode; emission characteristics; emission current; grid emission; heater ratings; life performance; life tests; porous W pellet; reliability; space-charge region; Aluminum oxide; Cathode ray tubes; Coatings; Electric breakdown; Fabrication; Intermetallic; Life testing; Temperature; Tungsten; Welding;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.64533

Filename

64533