| 摘要 |
PURPOSE:To enlarge the aperture of a main lens as well as to improve the assembling accuracy of an electron gun and make the focusing characteristic ever so better, by constituting at least a part of more than one unit of electrodes with a compact sintered body of metallic powder. CONSTITUTION:A part of at least mone than one unit of electrodes is composed of a compact sintered body of metallic powder. For example, an upper forcusing electrode 50 and an anode 60 both are sintered and formed upon compression molding of metallic powder into compact. Formation of the electrode 50 and the anode 60 by means of a powder metallurgy process consists in the following that a binder of acrylic resin or the like is added to metallic powder, for example, of atainless steel, etc., as nonmagnetic material and compressed and molded with a specified metal mold, then temporarily sintered at a temperature of 600-700 deg.C in a vacuum or an reducing atmosphere. And, further it is sintered in the vacuum or the reducing atmosphere at a temperature of 1,200-1,300 deg.C. At this time, a infinitesimal size variation is shaped up and recompresseed whereby such accuracy as being way above that of conventional sheet metal pressed parts can be secured. |
