Study Of COG Mura In IPS Mode LCD

COG is the abbreviation of " Chip On Glass ".It is used to connect the driver chip with the liquid crystal display panel technology.Mura is the visual effect caused by the color difference in the liquid crystal display." COG Mura" is a color difference phenomenon in the liquid crystal display near the IC area.COG Mura as a liquid crystal display devices often appear in the bad phenomenon.In TN mode," COG Mura" is weak.But in the IPS mode,"COG Mura" is particularly evident,and it became process issues that must be addressed in mass production.This thesis begins with the analysis of two kinds of wide viewing angle display mode,which are VA Mode and IPS Mode.VA mode is made of transparent protrusions,make liquid crystal molecules present multi domain alignment.IPS mode is adopted to control the planar electrode liquid level rotation angle.By comparing the advantages and disadvantages of the two kinds of wide angle of view,the research significance of this topic is clear.Secondly,the composition of the liquid crystal display and its production process are studied,and find out the influence of key technologies of COG Mura: the sealant coating and chip pressing process;find out the key factor and material: glass substrate thickness and the expansion coefficient,driving IC thickness and expansion coefficient,backlight brightness.In this thesis,the thermal balance method in the process of module are given.When the design is determined,COG Mura cannot be improved by adjusting the material factor,through the heat balance method to find the optimal process parameters,reduce the amount of material difference expansion,change of Cell Gap caused by swelling shrinkage difference,thereby reducing the effect of COG Mura.This method has been applied to a lot of production,and has achieved good results.Finally,the summary of this study,and the future of the flexible circuit board in the LCD touch screen integration in the pressing process will encounter problems in the same as this research and analysis,expansion coefficient and expansion coefficient of a driver from the LCD glass box,with the liquid crystal box frame glue width the temperature and pressure parameters in process,puts forward the improvement methods for the actual production.