摘要 |
A method and a device involving an electric iris diaphragm/shutter for controlling particle transfer of electrically charged medication powder particles from a source to a defined target area or areas, of a chuck member. Spatial distribution of particles onto the target area or areas is achieved by an electro-dynamic field technique applied to the distribution and deposition of particles in a dose forming process. An electric iris diaphragm/shutter is located between a particle generator and the electrostatic chuck member such that all particles must pass the iris diaphragm for being transferred to the electrostatic chuck. By adjusting amplitude and frequency of a superimposed AC potential charged particles will oscillate in the created AC field such that only small light particles will emerge from the iris diaphragm/shutter for further transfer in the dose forming process. |