Title :
Visualization of surface charge distribution on insulating films using spatial optical phase modulation system
Author :
Kawasaki, T. ; Terashima, T. ; Takada, T. ; Maeno, T.
Author_Institution :
Lab. of Electron. Meas., Musashi Inst. of Technol., Tokyo, Japan
Abstract :
A visualization and a quantification technique of a latent electric charge image on a dielectric material has been developed by using Pockels effect and a computer image processing. An optical phase modulation technique and computer image lock-in amplifier processing were used to improve the signal to noise ratio. The measurement system has several improved performances: a sensitivity of surface charge of 1 nC cm-2; a spatial resolution of 200 μm; and discrimination of the charge polarity. The basic principle of advanced electrooptic surface charge measurement is described and the typical surface charge distribution of a positive discharge streamer produced by an impulse high voltage (5 kVpeak) is demonstrated. A comparison is also made between the modulation method and the nonmodulation method
Keywords :
Pockels effect; automatic test equipment; automatic testing; charge measurement; electric breakdown; electric charge; electrical engineering computing; image processing; insulation testing; Pockels effect; charge polarity; computer image lock-in amplifier processing; computer image processing; dielectric material; discrimination; electrooptic surface charge measurement; impulse high voltage; insulating films; measurement system; performances; positive discharge streamer; quantification; sensitivity; signal to noise ratio; spatial optical phase modulation system; surface charge distribution; visualization; Charge measurement; Dielectric materials; Dielectrics and electrical insulation; Image processing; Optical films; Optical modulation; Optical noise; Stimulated emission; Surface discharges; Visualization;
Conference_Titel :
Properties and Applications of Dielectric Materials, 1994., Proceedings of the 4th International Conference on
Conference_Location :
Brisbane, Qld.
Print_ISBN :
0-7803-1307-0
DOI :
10.1109/ICPADM.1994.414102
