Patent ID: 7223148

Claim:
A method of fabricating a tetra-polar field-emission display using shadow masking to form an opening of a converging electrode to improve converging effect of an electron beam, comprising: forming an anode electrode structure; and forming a cathode electrode structure, further comprising: forming a first dielectric layer, a gate layer, a second dielectric layer and a converging layer on a substrate; patterning the converging layer, the second dielectric layer, the gate layer and the first dielectric layer to form a window exposing the substrate; forming a cathode electrode layer on the substrate exposed by the window, including a conductive layer formed on the substrate and a carbon nanotube layer formed on the conductive layer; wherein the converging layer is patterned into a converging electrode having a top surface, a bottom surface, and a pair of side surfaces, the side surfaces are so configured that the window is linearly reduced from the top surface towards a turning point between the top surface and the bottom surface, and then linearly enlarged from the turning point towards the bottom surface, wherein the turning point is lower than the top surface by a first vertical distance and higher than the bottom surface by a second vertical distance, respectively, and a ratio of the first and second vertical distances is controlled for focus adjustment, and wherein the window has a first width at the top surface, a second width at the turning point and a third width at the bottom surface of the converging electrode, and the first width is larger than the third width and the second width is equal to a diameter of the nanotube layer.