IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To improve the dielectric withstand voltage, mechanical strength so as to enable application of a high acceleration voltage and visualization of clear image by supporting a substrate on which a plurality of electron radiation elements are formed and a transparent substrate in which a luminous material is formed by means of an aluminum nitride and a spacer covering its surface with the aluminum nitride. SOLUTION: A spacer 10 is fabricated on an aluminum nitride plate of 1.0mm in thickness by processing a hole of 0.25mm in diameter corresponding to an electron source by a carbonate gas laser. A face plate 7 is sufficiently aligned upwardly of a rear plate 2 and disposed via a side wall 3 and a spacer 10, and each bonding part is sealed with a flit glass. Thus, by forming the spacer 10 by the aluminum nitride, since a secondary electron emission rate is small, charge due to electron radiation is small, a creeping discharge is hardly generated, the dielectric withstand voltage is enhanced, and heat resistance and mechanical strength are enhanced.