ELECTRON SOURCE FORMATION SUBSTRATE, ELECTRON SOURCE, IMAGE FORMING DEVICE AND THEIR MANUFACTURE

PROBLEM TO BE SOLVED: To prevent the adverse effect of the diffusion of sodium into a conductive film composed of an electron emission element by setting the sodium content of at least a surface layer region for arranging the electron emission element to be smaller than those of the other regions in a substrate containing sodium for arranging the electron emission element. SOLUTION: An Na removed layer, an Na captured layer or the stacked layer structure of both or a surface treated layer 6 such as a desulfurized layer are formed in the surface of a blue glass substrate 1, and then element electrodes 2 and 3 are formed. A conductive film 4 is formed to cover the element electrodes 2 and 3 and the surface of the surface-treated layer 6. Then, an electron emission part 5 is constructed to have a changed structure where the conductive film 4 is locally broken, deformed or transformed by conductive forming. Thus, variance in the characteristics of the electron emission element or the deterioration of characteristics is suppressed, and the electron emission element is formed by using the blue glass substrate 1 excellent in machining such as joining and advantageous in costs.