Research On The Design And Diaphragm Of Electrostatic Loudspeaker

Due to the rapid development and increasingly extensive application area of acoustics and acoustic devices,they have been became one of the most appropriate and important research areas in human life.Loudspeaker is one of the most important electroacoustic devices and its key composition is diaphragm.The traditional diaphragm material is generally used paper fiber,polymer,and metal,etc.,and there are also some new materials such as graphene and carbon nanotubes,etc.This paper has done some exploratory works on the analysis of the electrostatic loudspeaker based on Polyethylene Terephthalate(PET)and electrostatic loudspeaker based on Silicon Film around the diaphragm material of the electrostatic loudspeaker.Starting from basic research,this paper takes a full discussion,analysis and simulation on mechanics theory of the loudspeaker diaphragm and concludes that the loudspeaker diaphragm should use the low density of the material to make sure the loudspeaker has higher sensitivity,the high elasticity coefficient of the material to ensure the loudspeaker has a wide frequency response range and the high rigidity of the material to insure that the loudspeaker has the low harmonic distortion.We have successfully produced the monopole electrostatic loudspeaker based on PET Film and completed the test work of several kinds of electrostatic loudspeaker that have created.The theoretical analysis of electrostatic loudspeaker includes two aspects,respectively is theoretical derivation and simulation.Since diaplrragm is driven by the electrostatic force,our loudspeaker has a flat frequency response compared with the commercial dynamic loudspeaker and achieves high fidelity sound playback.By test analysis,our loudspeaker can be directly connected to the audio voltage to play music.In addition,in order to make the electronic products more beautiful,also out of personal interest,this paper has simply made design improvement,spectrum analysis and frequency test for transparent loudspeaker,array loudspeaker and cavity-backed loudspeaker.Finally,we first use the large-area free-standing ultrathin single-crystalline silicon to work out the silicon-based electrostatic loudspeaker that its maximum sound pressure level can be reached 94dB.The large-scale ultra-thin silicon has low effective elastic coefficient and mass density;in the meantime,it gives the loudspeaker the better low and high frequency response and achieves the wide-band loudspeaker.With the higher melting point and better water-resistant,silicon makes our loudspeaker work in high temperature and wet environment,improves the aging and damage phenomenon of diaphragm material caused by the temperature and humidity change and enhances the stability of the loudspeaker.At the same time,because the diaphragm is thin enough,silicon also has certain improvement on the performances,such as frequency response and harmonic distortion.According to the simulation software of COMSOL Multiphysics,we have made intuitive simulation on the vibration of diaphragm of the electrostatic loudspeaker and done a simple comparative study about its response characteristics,thus we also have verified a series of the measurement accuracy ahead of time.We believe that this single-crystalline silicon loudspeaker not only can be applied to the field of large-scale integrated production of electrostatic loudspeaker,but also has a wide applied prospect in the silicon micro-electro-mechanical systems technology(MEMS).