| abstract |
A particle charging device is provided with: a filter (28) dividing the interior of a housing (20) into a first space (29) and a second space (30); a particle introduction means (22) for introducing particles into the first space; a gas ion supply means (10) for supplying gas ions to the first space; potential gradient forming means (26, 27, 31) for forming a potential gradient within the housing for moving gas ions and charged particles generated by contact between the gas ions and the particles toward the second space; alternating voltage application means (32, 33) for applying alternating voltages differing in phase to electrodes (28a, b), which are included in the filter and adjacent to each other; a control means (35) for carrying out control so as to apply a prescribed voltage to the electrodes such that the charged particles are made to pass between the electrodes and the gas ions are trapped at the electrodes; and charged particle extraction means (23, 25, 34) for extracting charged particles being moved into the second space to the outside of the housing. Thus, the frequency of occurrences of polyvalent charging can be controlled. |