A cathode which allows simple and easy variance in the amount of emission and is constructed of a minimum number of different parts comprises first and second generally concentric cylinders of different diameters such that the cylinders have a space therebetween, which space may receive a heating unit therein. Each of the first and second cylinders have radially extending overlapping flanges joined to each other and one of the cylinders has a lower flange generally below and generally parallel to the upper flanges. At least three hollow tubular emission carriers are positioned between the upper and lower flanges and evenly distributed around the cylinders. The method of making the cathode and particularly the emission carriers comprises the steps of applying a thick layer of tungsten suspended in a liquid coating to the outer surface of a form, pre-sintering the coating to rigidify it, removing the rigidified coating from the form and finally sintering the coating to form a shell for the tubular emission carrier. Upper and lower plugs close opposite ends of the shell whereby it serves as a container or carrier for the cathode emission material. Three or more of the emission material carriers are inserted into aligned holes in flanges of a cylindrically shaped support unit. A cylindrically shaped member of a thin or foil material is connected to the support unit to the dispenser cathode to the tube envelope.
The invention provides an electro-optical device and a manufacturing method therefor which makes it possible to manufacture power source wiring lines more simply. Power source wiring lines are formed by an inkjet method.
