Abstract: Body (1) formed from a porous matrix impregnated with an electron-emitting material, defined by external faces (11, 12, 13) that all have a roughness of less than 0.2 ?m. Because of this surface finish, the operation and the lifetime of the cathodes provided with such cathode emissive bodies are substantially improved.

Abstract: A process for assembling a cathode for electron gun comprising a body of emissive material, a cup into which the body of emissive material is inserted, a substantially cylindrical metal skirt, the said process comprising the following successive steps: insertion of the cup into one of the open ends of the metal skirt, welding of the cup to the skirt, crimping of the body/cup/skirt assembly by lateral squeezing at the level of the weld zone in such a way as to cause an indent-like deformation of the lateral face of the body.

Abstract: Body (1) formed from a porous matrix impregnated with an electron-emitting material, defined by external faces (11, 12, 13) that all have a roughness of less than 0.2 &mgr;m.

Abstract: Process for assembling a cathode for electron gun comprising a body (1) of emissive material, a cup (13) into which the body of emissive material is inserted, a substantially cylindrical metal skirt (2), the said process comprising the following successive steps: insertion of the cup into one of the open ends of the metal skirt; welding of the cup to the skirt; crimping of the body/cup/skirt assembly by lateral squeezing at the level of the weld zone in such a way as to cause an indent-like deformation (24) of the lateral face of the body.

Abstract: The invention relates to a cathode structure intended to be inserted into an electron gun for a cathode-ray tube. The cathode comprises a cathode body on the end of which is placed an emissive pellet, the cathode body being held in place inside a sheath by supporting means which comprise: a first series of branches, each branch being connected on one side to the cathode body and on the other side to an intermediate piece 30; and a second series of branches, each branch being connected on one side to the sheath and on the other side to the same intermediate piece.

Abstract: An improved cathode structure for a cathode ray tube includes a first metal tube which can receive an emission part and a heating element, a second metal tube constituting the cathode shielding, and means for retaining the first tube in position inside the second, wherein the retaining means are constituted by a single metal piece. In a preferential mode of implementation, the metal retention piece is constituted by a crown having branches extending in the direction of the axis of the crown.