Study On Deformation Prediction Of Glass Substrate Based On Gas Film Pressure Simulation-measurement Integration

With the rapid development of electronic information and television broadcasting,the display technology represented by the liquid crystal display(LCD)is widely used in various fields of human society due to its slim and lightweight characteristics.As a key component of liquid crystal displays,glass substrates are increasingly required for processing and transportation.In the vastly different modes of transportation,air-floating transportation replaces traditional contact transportation due to the advantages of no friction and no heat generation.However,In the process of air-floating transport of glass substrates,the uneven distribution of the gas film pressure will cause the glass to deform,affecting the imaging effect of the high-speed CCD camera,so that the quality of the thin film transistor(TFT)array cannot be accurately detected.Therefore,it is particularly important to monitor the deformation of the glass substrate on the transportation line.This paper proposes a method based on gas film pressure simulation-measurement integration to quickly estimate the deformation of the glass substrate,and the feasibility of the method is verified through experiments.The main contents and conclusions of this research are as follows:First of all,a kind of air-floating contactless transport guide is designed.After the guide is supplied with compressed air,a thin film of air for support will be formed between the object and guide,so as to offset the gravity and achieve suspension.In order to avoid problems such as stress concentration and electrostatic pollution,porous materials were used as throttle elements of the air-float guide,and on this basis,a mathematical theoretical model including gap flow characteristics and porous medium characteristics was established,and then through the finite volume method(FVM)solve the model and calculate the gas film pressure distribution in the gap.Secondly,based on the mathematical model,a simulation-measurement integration method is proposed to predict the deformation of the glass substrate.The experimental results show that using the outside measured points as feedback will produce large errors.In order to investigate the cause of the error,a measuring device was set up to check the changes of the gas film pressure of the glass substrate under different degrees of deformation.The results show that with the increase of the degree of deformation,the gas film pressure calculated by the external unit will gradually deviate,and the internal part can be in good agreement with the actual situation.Next,in order to determine the influence factors of deformation prediction and change the algorithm boundary conditions,the results show that the change of boundary conditions will greatly affect the prediction results.Finally,the asymmetric deformation of glass plate during transportation is analyzed,and it is determined that when the asymmetry coefficient is less than 0.2,the deformation prediction method is still valid with an error of about 3%,but when the asymmetry coefficient is too large,a large error will be generated.Finally,by evacuating the gap gas film,the deformation of the glass substrate can be adjusted.The larger the pumping volume,the smaller the deformation of the glass substrate,but the total exhaust volume cannot exceed 85% of the total air supply volume,otherwise there is a risk of damage.