Development of a Technique For Quantitative and Localized Charge Deposition on Dielectric Surfaces

Surface charging of solid dielectrics poses challenges in industry. To investigate the dynamics of these charges, a tool for quantitative and spatially controlled surface charge deposition is desired. However, existing charge deposition techniques lack the possibility of controlled local charge deposition. This paper presents a surface charging technique at atmospheric pressure using an X-ray ionizer. A mask is introduced to enable local charging. The surface charge accumulation is studied with an electrostatic voltmeter. This X-ray based technique proves to be highly repetitive: only 1 % variation in the potential induced by the surface charges is observed. Furthermore, it allows for quantitative charging for both polarities up to at least -600V and +300V of induced potential. Local charging is achieved for charge spots of 1x2mm2 or larger with an accuracy of at least 2 mm over a surface of several hundred square millimeters. In principle, this technique works for all solid dielectrics, but is tested for quartz, silicon dioxide and commercial display glass. Finally, the charging process happens in the order of seconds. This technique enables future research into surface charge migration.