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In this study, the laser, electric impact strategies and pneumatic impact strategies were adopted to repair the MURA defect of liquid crystal display. The particle of MURA in liquid crystal display was deformed perpetually by heat and external force using laser and impact strategies, respectively. The scale and location of particle in liquid crystal display were measured by focus ion beam, scanning electron microscope and optical microscope. The sample with MURA defect and the JND(Just Noticeable Difference) value higher than 3.5 was selected for defect repair. The metal connect circuit of liquid crystal display was damaged with the laser frequencies of 40 and 20 Hz. In order to avoid the damage, the laser frequency was decreased to 10 Hz. However, the JND value of 3.75 is still high, thus the laser repair is not a reliable trimming tool. The repair conditions of pressure and impact times were set at 0.26 kg/mm2 and 10 for impact strategies. In pneumatic impact strategies, the JND values of before and after repairs were 3.95 and 3.19, respectively. Moreover, in electric impact strategies, the JND values of before and after repairs were 3.99 and 2.98, respectively. As the impact times increased to 20, the JND values after repair were 2.97 and 2.35, respectively, for the electric impact and pneumatic impact strategies. The structure of liquid crystal display was damaged as the impact times increased to 30. After impact repair for MURA defect, the liquid crystal display can pass the life time test at 50 0C and -5 0C with 500 hours. The result indicates that the MURA defect of liquid crystal display can be repaired by electric impact and pneumatic impact strategies successfully. The repair rate was higher than 80 % per year.
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