The Effects Reseach Of Environmental Contamination To Electical Contact And Electonic Protection Reliability

The overall reliability of electronic equipments is been severely affected by electrical connection and contacts. There are a number of contacts in the electronic equipment, and their reliability requirement is higher than the machines'. Electrical contacts are combined with the effects of structure, materials, environmental and other factors, so the failure mechanism is very complex. It involved electronics, mechanics,physics, chemistry and other subjects. Electronic connectors failure caused by environmental contamination is significantly higher than other factors. The atmospheric contaminants can invade into electronic equipment and cause electrical contact failure. Therefore, it should be to strengthen the electronic device enclosure protection. This thesis is based on analysis of failure contacts. It focuses on the effects research of environmental contaminants to electrical contacts and electronic protection reliability. It has been carried out that inorganic dust particles and organic contaminants characteristics analysis and experimental research on contacts reliability. As well as, the failure analysis and contamination adhesion analysis of dust-proof mesh has been done in this thesis.Main work and achievements are stated as follows:1. In the research of dust particles characteristic analysis in electrical contact interface, the research key point is the impacts of dust particles'mechanical physical properties on interface contact status. It has established a particle-interface deformation model to analyze deformation constitutive relation which the bonding strength is main parameter. It has been gotten that the relationship between positive pressure and particles' deformed status. And finally, it can be concluded that the operation mechanism of particles with different binding strength on contact status.2. In the experimental study of dust particle effects to electrical contact interface, it is focusing on contacts actual failure caused by dust particles with different bonding strength. By two depositing methods, it has been studied that dust particle deposition features in electrical contact interface. Through the simulated static contacts experiments,some parameters have been studied for contact status which included particle bonding strength, size, deposition density, positive pressure. In simulated dynamic contacts experiments, it has been researched that effects of particles' characteristics on dynamic contacts and the influence of particle long time-staying in dynamic contacts. And combining the theoretical analysis, contact failure mechanism caused by dust particles can be inferred.3. In the research of organic contaminant characteristic analysis in electrical contact interface, it is focusing on adhesive properties analysis of organic contaminant on the contact interface. Based on the research result of organic contaminant existing in failure contacts, it has analysis of organic contaminant source and entering methods. Though physical and chemical properties analysis of organic contaminants, it should be pay much study on the influence of viscosity, surface tension and contact angles. It has established an adhesive analysis model of liquid organic and dust particles on the contact interface, and adhesion force composition can be gotten. Therefore, the adhesion mechanism between organic contaminant and dust particles on interface can be concluded.4. In the experimental study of organic contaminant effects to electrical contact interface, it is focusing on the adhesive impact of liquid organic and dust particles on the electrical contacts reliability. By two deposition methods, the deposition features of organic contaminants in the interface have been studied. Through adhesive properties experimental study, the deposited amount, dust particle deposition density and particle size have been researched as factors of adhesion status. From the dynamic contacts experiment with dust particles deposited, it has been analyzed that the effects of organic contaminant on particles entering. Finally, it can be concluded that the influence mechanism of adhesion between organic and dust particles on electrical contacts.5. In the adhesion characteristics of acoustics dust-proof mesh on actual field mobile phone earpiece, it is focusing on the parameters impact of organic contaminants and meshes for their adhesive status.From physical and chemical failure analysis, it can be inferred that the meshes' contaminants source and deposition course. It has been found that the main research points for adhesion are included contaminants viscosity or consistency, surface tension and contact angles, mesh pore size, thickness and coating. Combined with characteristics analysis and experimental results, it can conclude that the adhesion mechanism of organic contaminant and dust-proof mesh.6. In the research of assessment method for acoustic dust-proof meshes ability against contamination, it should be established a method to evaluate meshes' acoustic and protection reliability in the contaminated condition. Two organic contaminants deposited experimental method has been established. Combined with acoustic impedance assessment principle and detection method, it has been given that the contamination status assessment method. Finally, it is given that the scope and application, in order to establish a complete method for acoustic dust-proof meshes ability against contamination.In this thesis, the theoretical models of inorganic dust particles and organic contaminants on the electrical contact reliability are presented. It is also given that actual impact of experimental results. It lead that the environmental contaminants influence research are much more targeted and controllable. It is the foundation of detection and evaluation methods for electronic equipments' environment influence. This paper gives an acoustic dust-proof mesh reliability evaluation method in contaminated environments. It is the complement for existing protection requirements. This thesis improves the electrical contact reliability of electronic equipment under the influence of environmental contaminants.And it also will improve the reliability of electronic equipment enclosure protection. The research in this thesis can provide a design and testing theoretical basis and experimental guidance for the electrical connector and electronic device reliability.