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Explanation of the working characteristics of the vacuum plasma cleaner and the oscillation characteristics of the plasma sheath phenomenon:
Vacuum plasma cleaner equipment is widely used in various fields such as electronics, communications, automobiles, textiles, and biomedicine. For example, electronic products, LCD/OLED screen coating treatment, PC plastic frame coating treatment, mimeograph treatment on the surface of structural parts such as chassis and button buttons, de-gluing and decontamination cleaning of PCB surface, treatment before lens glue sticking, Coating treatment of wires and cables, coating treatment of lampshades, brake pads, and door sealing strips in the automobile industry, small harmless cleaning treatment of metal parts in the machinery industry, treatment before coating of lenses, joining and sealing treatment of various industrial materials , Surface modification of three-dimensional objects, etc.
Working principle of vacuum plasma cleaner:
The vacuum plasma cleaner includes a reaction chamber, a power supply and a set of vacuum pumps. Put the sample into the reaction chamber, the vacuum pump starts to pump air to a certain degree of vacuum, and the power is turned on to generate plasma. The gas enters the reaction chamber through the plasma in the reaction chamber and reacts with the sample surface to produce volatile by-products. It is pumped out by a vacuum pump.
The plasma of vacuum plasma cleaners is macroscopically electrically neutral: in general, plasma is electrically neutral, but when subjected to certain interference, there will be local charge separation inside the plasma, generating an electric field. For example, if a positively charged ball is placed in a plasma, it will attract electrons in the plasma and repel these ions, thereby forming a negatively charged spherical "electron cloud" around the ball.
The plasma of the vacuum plasma cleaner has oscillating characteristics: Generally, when the plasma is in an equilibrium state, its density distribution is uniform on the macro level, but on the micro level it rises and falls, and is not uniform, and the density fluctuation is oscillating.
The plasma of the vacuum plasma cleaner has a sheath phenomenon: since the plasma is initially in a quasi-electrically neutral state, if a non-conductive insulating substrate is suspended in the plasma, the ions and electrons in the substrate will move toward the lining. Bottom movement, the number of electrons reaching the substrate per unit time is far greater than the number of ions. The part of the electrons that reach the substrate recombine with the ions, and the rest are ions. Therefore, the surface of the substrate will accumulate negative charges, thereby forming a negative potential on the surface of the substrate. This negative potential will repel subsequent electrons while attracting positive ions. When the negative potential of the substrate reaches a certain level, the ion current will become the electron current. Because the substrate has a negative potential, a space charge layer composed of positive ions is formed at the interface between the substrate and the plasma, that is, the ion sheath.