The Study & Method Of TFT LCD Bright Point Improvement

TFT LCD is a display device consisting of liquid crystal which physical's property is birefringence and a semiconductor TFT element.The production process of TFT LCD is complicated,requires high precision equipment and clean room without particle,what cause the result of high cost.If some defects in the panel would put down the panel's grade with lower price.In this paper,through scientific analysis methods and precise analysis methods,the bright spots defects are analyzed to determine the causes of bright spots.Scientific analysis methods are mainly reflected in the accurate description of lighting on phenomena,and the aggregation characteristics of bright spots coordinate points on the panel,using big data analysis to determine the possible process equipment units.The precise analysis method is reflected in the observation of the phenomena on the samples with optical microscope of 500 times or more.The samples are characterized on the micro scale or micro ampere level by using electronic tunneling microscope,current and voltage measuring instrument,stress measuring instrument,Fourier spectrum analyzer and other high-precision equipment,so as to find out the mechanism of bright spots.According to the conclusions of the above methods,the production line carries out targeted improvement,such as control the micron level small particles,the adjustment of cleaning parameters,the redesign and replacement of equipment parts,etc.However,it is impossible to completely avoid bright spots.Therefore,it is an effective way to effectively reduce the cost loss caused by bright spot defects to the products by physical examination and repair for the panels with bright spots before shipment.After the completion of the box forming process,the panel will be illuminated by the way of simulated lighting to screen out the defective products with bright spots.Through the study of the causes of the bright spot,design experiments to adjust the lighting parameters,to find out the effective method to detect the bright spot and apply it to practice.Bright spot maintenance is mainly to darken the pixel electrode where the bright spot occurs,that is,the bright spot pixel is electrically connected with the array common electrode by means of laser welding,so that the bright spot pixel will be continuously powered on by the array common electrode,and has equal potential with the public electrode,while the liquid crystal will not be driven.Therefore,the dark spot is not easy to be detected by consumers,and the display screen is not Therefore,darkening is a very effective repair method.In practice,the laser repair of bright spots is also a problem of success rate.In this paper,the author of this paper summarizes the experience through a lot of enterprise practice,designs laser repair method for different causes of bright spot,which is convenient for production line operators.At the same time,aiming at the systematic bright spot maintenance failure,the real cause is clarified,the reason of maintenance failure is analyzed from the mechanism,the improvement scheme is demonstrated by experiment,and the maintenance failure problem is fundamentally solved,such as successfully solving the problem of repairing the green bright spot into the dark particle defect,repairing the bright spot into the broken bright point,and the failure of repairing the array repair.