| 摘要 |
PROBLEM TO BE SOLVED: To provide a cathode of an electric tube and its manufacturing method. SOLUTION: The emission material layer includes acicular conductive materials and the surface roughness actually measured as the distance between the highest point and the lowest point of the emission material layer surface is controlled to be 10 μm or less. Hence, by including acicular conductive material to the emission material layer and forming the conductive path effectively, generation of Joule heat by self-heating is minimized. In addition, by controlling the diameter of the particles and pores forming the emission material layer to be even and controlling the density and porosity of the layer, the compactness and the surface roughness are improved in comparison with a cathode made by existing spray method. As the result, contraction phenomenon of cathode on operation can be prevented and even interval between the cathode and the first grid can be kept, and thus the electron emission characteristics becomes stable and the product life becomes longer. Thus, the life property under high current density region can be considerably improved to satisfy the recent needs for higher precision and larger size of the television cathode-ray tubes. |
