Solving The Uniformity Problem Of Color Filter Photo Spacer High Using DMAIC Method

Color filter(CF)is one of the most important parts of LCD,which provides the color of the display devices.However,the display quality will be reduced because of the existence of mura of CF.Then the satisfaction of the users could be influenced.It is noteworthy that the uniformity of the height of the Photo spacer(PS)will lead to a variety kinds of mura.There are many reasons for this problem,such as equipment factors,technological conditions,material characteristics and control method.And there are two main aspects of the impact of CF Mura.On the one hand,the application effect of the users will be gradually influenced if the CF Mura have not been detected during the process of installing Cell.In this circumstance,the compensate for the costumers of CF manufacturers will be a large number.Then the orders will reduce because of the low degree of satisfaction.On the other hand,the operating costs of the CF factory remain really high because of the low yield.If the height of PS(PSH)is out of the range of spec,then the products will be judged to be unqualified.So the improvement of the homogeneity of the PSH is a key issue to elevate the quality of the CF.In this paper,a method to improve the homogeneity of the PSH has been established.And the DMAIC method of Six Sigma theory is applied in this method,and it can be briefly described as definition,measurement,analysis,improvement andflow control.In the definition part,a key issue,PSH range,affecting the yield has been found using the Pareto chart method.And the improvement target is also confirmed.In the measurement part,8 main factors were identified using the the process flow chart,fishbone method and causal C & E matrix tool.In the analysis and improvement part,the main affecting factor of thePSH Range is confirmed using the single factor ANOVA analysis,hypothesis test,multi-sample ratio test analysis and DOE test design.In this way,an optimal process parameter is established.Finally,in the flowcontrol part,a long term effective method is used to control the main factors and operating standards are established.The SPC statistics results show that the yield lost decreases from 20.5% to 0.4%.Then the method used in this paper is proved to be a useful way to reduce the company's operating costs,improve the degree of satisfaction of customers and the market competitiveness of CF factory.