Patent ID: 8260174

Claim:
A charging device comprising: a first dielectric layer disposed over a substrate; a first conductive layer disposed over the first dielectric layer; a second dielectric layer disposed over the first conductive layer, the second dielectric layer comprising a plurality of cavities, wherein each of the plurality of cavities exposes a portion of the first conductive layer; a plurality of micro-tips, wherein one of the plurality of micro-tips is disposed within each of the plurality of cavities and on the first conductive layer; a second conductive layer disposed over the second dielectric layer and having a plurality of openings therein; a system of interconnected air flow channels disposed in the second dielectric layer and connected to the cavities, wherein the system of interconnected air flow channels comprises a first channel having a first cross-sectional area which extends through the second dielectric layer between adjacent cavities and between adjacent micro-ties but not into one of the cavities and a plurality of second channels, each second channel having a second cross-sectional area, with each second channel extending from the first channel into one of the cavities and configured such that air injected through an air inlet exits one of the plurality of second channels laterally toward one of the plurality of micro-tips, through one of the plurality of cavities, and out through one of the plurality of openings in the second conductive layer, wherein the first cross-sectional area is larger than the second cross-sectional area; and one or more power supplies to apply a first bias voltage to the first conductive layer and a second bias voltage to the second conductive layer.