Dynamic Real-time Monitoring Of Coating Status Of Microsphere System Design

Integrated knowledge of optics, mechanism, electrics and computer science is utilized to monitor bouncing state of microshperes real-time.Microspheres, with a diameter range form 200 microns to 1000 microns, are one of the key parts of laser ICF (Inertial Confined Fusion). The microspheres are often to be coated with ablation layer (organic material), which must be uniform to better than 3%, and that coating surface defects must be less than 100nm from peak to valley. Therefore, it becomes an important subject to monitor its coating state real-time. And since the microspheres are coated in a vacuum chamber, the monitoring system must image microspheres by a tele-microscope system. Accounting to the real demand, there are two kinds of coating situations, the first is multiple microspheres being coated in a big pan, and the other is one microsphere in a small pan. Under the latter circumstances, it is necessary to enlarge the image of small pan to meet the full screen so as to observe details of the microsphere being coated. So it is needed to switch display modes and the focus of image system from monitoring big pan to observing the small one by step motors. While monitoring small pans, which are arrayed in the vacuum chamber, it is applied step motors to driving 2-dimentional scanning system to scan the pans and make image of one pan fill the full screen. In this monitoring system a personal computer communicates with microcontroller unit to drive the step motors and realize the functions of 2-dimentional scanning and focusing automatically.While the microspheres being coated in the chamber, the injected organic g as will ionize into plasma that will fluoresce and prevent the image system from shooting the microspheres. The disturbance from the fluorescence will be removed by illuminating microspheres with LED (Lighting Emitted Dioxide), then through the optical system built-up with tele-microscope and general shooting lens, microspheres image onto the CCD.The indication of the image of microspheres and controlling to motors are integrated into the same user's interface, which makes it convenient adjust the shooting system accounting to the image on display. Thus the clear image of the microsphere with suitable size for viewing would be presented on display.This monitoring system is versatile, after a slight modification it could be applied in performing medical operation, in fine machining manufacturer and microelectronic device producing enterprise.