| 摘要 |
A method and a device involving an electric iris diaphragm/shutter are disclosed for controlling particle transfer of electrically charged medicati on powder particles from a source to a defined area, the target area, of a substrate. Spatial distribution of particles onto the target area or dose be d is achieved by means of electro-dynamic field technique (320) applied to the distribution and deposition of particles in a dose forming process. An electric iris diaphragm/shutter (130) is located between a particle generato r (110) and the substrate (140) such that all particles must pass the iris diaphragm for being transferred to the substrate. By adjusting amplitude and frequency of a superimposed AC potential (136) 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. Furthermore by the adjustment of amplitude and frequency a majority of charged particles emerging are accelerated and retarded in synchronism with the AC field, such that they impact on a defined target are a of the substrate with a low speed and momentum resulting in a desired dose porosity. |
