In the conventional oxide-coated cathode, saturated current density is usually limited to 2 A/㎠ approximately which is insufficient for the larger-size high-resolution CRT. In this paper, the author analyses the resistive effect of the interface lay...
In the conventional oxide-coated cathode, saturated current density is usually limited to 2 A/㎠ approximately which is insufficient for the larger-size high-resolution CRT. In this paper, the author analyses the resistive effect of the interface layer using an electrical model of beam current circuit and explains how the current density can be increased by suppressing the accumulation of the layer.
Through a series of experiments, the author has found that, by dispersing approximately 1% of scandium oxide into the conventional mixture of (Ba, Ca, Sr)CO₃ at coating process, followed by careful decomposition and activation, the accumulation of the layer can be successfully suppressed and satuation current incresed up to 4.51 A/㎠. The V-Ⅰ characteristics measured on the sample fairly matched with the results of theoretical analysis.