Abstract
The authors have reported in the previous paper about some investigation on displaying electrical charge and/or potential distribution on an insulating surface. In the present article additional results are given using an improved system.
A corona charged test plate is set on a turning table which has a constant rotating rate. (In the former experiment the rotating rate is P. L. L. controlled.) A probe head for detecting charge located above this sample is scanned, and the signal picked up with the probe is amplified by a charge sentitive amplifier followed by an A/D converter, though the I/O port, the digitized signal is fed to a 16 bit microcomputer which has a memory device capable of storing data prior to precessing it. The limitation in data memory of the former apparatus (an 8 bit microcomputer is used) can be improved by extending the memory capability. After the image data is processed the image is displayed on a color CRT screen in a form of color shade. In this apparatus the relative speed between the probe head and the sample decreases as it traverse toward the center of the table by the auxiliary scanning. To avoid image distorition arising from this speed variation, the sampling rate of data is program controlled.
Moreover the relation between probe scanning and corresponding data display is analysed closely so that the codition needed for minimaizing image distortion is clarified.
