Photoelectron generating plate, negative particle generating device and charge removing device and equipment using such device

摘要

The photoelectron generating plate includes on a substrate a photoelectron emission layer for emitting photoelectrons by the illumination of the light and having a barrier property. A diffusion of a material of an underlying base member into the photoelectron emission layer is blocked by the barrier layer and thus the surface of the photoelectron emission layer is prevented from being coated by the material of the base member. As a result, temporal reduction in the number of generated negative ions can be considerably ameliorated. In other words, the charge removing device attains a good durability for a long time.