The Optimum Of Sampling Plan Of TFT-LCD Backlight Unit Final Display Inspection

Now, BLUM manufacturing department in InnoLux Display corporation choose the final display inspection model of percentage of 2 out 9 (received defect quantity C=0). By different received probability of inspection lot, there are two faults in the final display inspection model of percentage as below: 1.The variation of lot will influence the guarantee degree of product quality (a large lot strict, a small lot loose); 2.Unable to adjust the sampling plan appropriately according to process capability. For this reason, it is necessary to study the sampling plan of backlight unit. We should found a series dynamic sampling plan which base on manufacturing process capability of backlight unit. In order that we can adopt the sampling plan of adequate power to hold up defect lot and ensure the quality level of product more than customer's requirements when we carry out process improvement. The study process of this subject includes three steps as below:1. Found alarm model to monitor stability of process2. Found a dynamic sampling plan model of adequate power3. Found a quantification performance evaluation modelTaking account of the characteristic of backlight unit process, we regarded design of dynamic sampling model and design of evaluation model as basic task. Our research include analysis of process stability, optimum design of inspection lot size, foundation of process monitoring model, foundation of basic sampling group, foundation of relationship between process index(Cp) and basic sampling plan and evaluation of two sampling plan. In evaluation phase, we get a result by the method of P-Value hypotheses. From result of evaluation, we verified that dynamic sampling plan is more excellent than percentage sampling plan. Finally, we picked up a sampling plan for inspection of backlight unit.