High speed electrostatic surface discharge between a charged thin film and a sphere electrode with or without a thin dielectric film on that

The electrostatic surface discharge (ESD) between a charged thin dielectric film on a conductive flat plate electrode and a sphere electrode that is connected to the plate, and is either covered with an uncharged thin dielectric film or fare, was observed. Discharge current waveform, discharge gap length, current risetime, discharge photographs, current peak value, etc. were recorded. The initial charge generation by irradiation with beta-rays or ultraviolet light was not readily apparent, so that the reproducibility of ESD experiments was not much improved. The charging polarity dependence of such a surface ESD between two dielectric films becomes small with increasing film thickness. The discharge gap length of an ESD with an 12.5 mu m uncharged film on the electrode reduces to 50 or 70% of that between a charged film and a sphere metal electrode. Peak current and transferred charge value of such an ESD also decreases to roughly one-third of that between the film and the electrode.<>