Research On The Detecting Signal Of GOA TFT LCD In CELL Process

At present,with the rapid development and improvememnt of China's display technology,China's TFT-LCD has occupied a pivotal position in the world.TFT-LCD has been widely used in people's daily life and industrial fields,such as electronic watches,mobile phones,TV sets,robots,high-speed rail and aircraft etc,among which the most important application is LCD TV.In the purchase of LCD TV,appearance,price,brand,brightness,color and so on become the main factors that affect whether consumers buy or not.In order to reduce the width of narrow bezel and improve the visual felling of consumers,the industry has developed the technology of gate driver on array,which is GOA technology.CELL testing is a very important and necessary process with TFT-LCD,which mainly detects the defects caused by CELL and pre-cell process.The normal TFT-LCD uses the form of shorting bar to light on in the CELL process,that is,all the same gate signals and the same data signals are integrated together to light on.For GOA products,the gate drive circuit has been integrated into the glass in the array process,and Gate singals cannot light on with the normal shorting bar mode.With the normal lighting mode,it did not control accurately gate signal,which leads to the poor uniformity of luminance Red,Green,Blue pattern,and did not light on gray patten and lowlock paatern fro detecting TFT leakage.GOA products can not detect defcts in the CELL process,resulting in the failure to ensure the effectiveness of detection defects,which results in defective products directly into the module,resulting in the waste of module parts and the loss of production capacity.This paper topic comes from technical requirements of TFT-LCD TV products Fab.The defect detection problem caused by the failure of GOA product to perform dri driving in the CELL process with the traditional way was studied.Specific research content includes:(1)For the problem of RGB pattern,we can find out the best singal parameters by analyzing the driving parameters of RGB pattern,and light on RGB pattern;(2)For the issue of gray pattern,through the research of GOA circuit,we can bypass the GOA circuit,and light on the gray pattern by DC driving;(3)For the lowlock pattern,we can find out innovatively black-and-white pattern to detect leakage bright defect through the analysis of the driving parameters of leakage bright point on the analysis of the principle and the pixel design characteristics of tri gate pixels products.Through the above new methods and schemes,it can light on all CELL test pattern,improve the detection rate of CELL defects,improve the qualification rate of GOA products,reduce the rate of MOD missing detection,reduce the rate of point missing detection from 6% down to 0.16%,and the rate of line missing detection from 4% down to 0.76%.The waste of IC,FPC,ACF and other materials unnecessary for MOD is avoided,and the material consumption cost is significantly reduced.Effectively avoid the cost loss caused by scrapping or downgrading the panel in MOD process,and improve the market competitiveness of the product.