Vol. 12, No.2, pp.120-124 (2019)
Effects of Operating Frequency on Electric Field and Neutralizing Current Density of a Corona Discharge Air Ionizer
M. Okano1, T. Ikehata1, T. Terashige2
1Institute of Quantum Beam Science, Ibaraki University, Hitachi, Japan
2Teacher Education Unit, Hiroshima International University, Hiroshima, Japan
Abstract
Corona discharge air ionizers have been used to neutralize the static electricity charged on the electronic devices in inspection processes. The neutralization characteristic, that is the neutralizing current density and the electric field at working area depend on the operating conditions. The operating frequency is one of the most important operating conditions of the AC corona discharge air ionizer. The effects of operating frequency on the neutralization characteristics were investigated in the mini-environment in which laminar air flow of 0.3 m/s exists. The air ionizer was operated by a square wave alternating voltage of 15 kV (peak-to-peak) and frequency ranging from 2 to 25 Hz. The neutralization characteristics were measured using a charged plate monitor. The neutralizing current density and the electric field decrease with increasing the operating frequency. The ratio of the neutralizing current density to the electric field showed the maximum value around 10 Hz.
Keywords - Air ionizer, static electricity, neutralization characteristics, semiconductor manufacturing, inspection processes