PURPOSE: To easily concentrate the electric field at an edge section when fluctuation occurs in the pattern precision of a negative electrode material layer and a control electrode and improve electron emission efficiency by forming the negative electrode material layer into a pattern with a gradually changed width.
CONSTITUTION: A base electrode 2 is formed on an insulating substrate l, and a negative electrode material layer 3 is formed on the electrode 2. The layer 3 is formed into a shape with the width (w) gradually and linearly changed from the tip side to the center side. An insulating layer 4 is formed on the lower outer edge section of the layer 3 on the electrode 2 and the portion where the layer 3 is not formed, and an insulating layer 5 and a control electrode 6 are formed in sequence on the layer 4 at the preset interval from the layer 3. When voltage is applied so that the layer 3 is made negative and the electrode 6 is made positive, lines of electric force are concentrated at the edge section 3a of the layer 3. The widths of the layer 3 and electrode 6 are gradually changed according to location, and the field intensity is changed. A stable electron emission characteristic is obtained even when dispersion occurs on the pattern precision of the layer 3 and electrode 6 when they are manufactured.
SUGANO SUSUMU
KANEKO AKIRA
