Space Charge Distribution Measurement in Insulation Film with Thickness of Several Tens .MU.m

Abstract

Since electronic equipment is required to be smaller and lighter, an insulating material for such equipment is consequently required to be thinner. However, under a certain DC voltage, the electric field in it becomes relatively higher according to the insulating material becomes thinner. Therefore, the insulating performance under high electric field must be important in such thin films. On the other hand, it is said that a space charge accumulation in them under DC high electric field is important because sometimes an electrical breakdown occurs in them due to an enhancement of electric field induced by the accumulated space charge. To investigate the characteristics of the space charge accumulation in them, PEA (Pulsed Electroacoustic) method is usually used. However, a spatial resolution of ordinary PEA system is not enough to observe the space charge distribution in thin films with thickness of several tens μm. Therefore, a new measurement system with high positional resolution is developed by making a thin piezo-electric film that is used as a sensor for PEA system. The obtained resolution of the developed system is 4 μm, and it is used for a typical measurement in LDPE film with thickness of 40 μm.