Detection of Common Shortcomings of TFT LCD Display

There will be some defects during the production process of TFT-LCD (thin film liquid crystal display), mainly some display defects, among which point defects are more serious.

TFT LCD is composed of many sub-pixels. If some of the sub-pixels do not work properly, it will cause poor display in some areas.

There are generally two types of LCD monitors, one is a normally white screen; the other is a normally black screen and a normally white screen. That is, the screen is white when it is not powered on, and the normally black screen is black when it is powered on. If it cannot turn black after being powered on, then this point is called a bright spot. That is to say, this point is transparent under the black screen. Black spots on a white screen are called scotomas. The inspection picture of the bright spot is the LO picture and the L92 picture. The judgment standard is to compare the brightness of the head-up and simulated points at 30 cm, that is, there are no obvious visible small red, green, or blue light spots within 30 cm.

If this spot lights up and off, it is a flash point. Flash points are also a type of bright spots and their repair methods are the same as bright spots.

Inspection of defects

However, only the Array and Cell stages in the process will produce point defects. Only in the Cell stage can the Panel be lit for inspection to detect whether there are defects.

The following will introduce the inspection device and inspection method of the Cell segment. The purpose of the inspection is the final inspection and test operation of the TFT-LCD Cen segment. The inspection method to check whether the product meets the specifications required by the customer is visual inspection. The inspection specifications are generally based on customer needs. The Cell Integration Engineering Department formulates product inspections with different product inspection specifications. Specifications vary.

The inspection process mainly provides an inspection environment before the Panel reaches the module to detect point defects, line defects, mura and other defects of the Panel. It mainly consists of two parts. Among them, the signal output equipment of ITEs is a machine that provides signal output, which can Set various screens needed to test the Panel and test whether the Panel has any Defect. At the same time, these parameter screens can also be changed as needed. Another part is to provide the platform required for Panel testing. Probe platforms of different sizes can be set up according to the needs of the production line. .

Inspection methods and procedures

At present, all inspections are done by visual inspection by personnel, and some use automatic inspection by machines. However, the misjudgment rate of machine inspection is very high, and most companies use the method of visual inspection by persons.

The steps for visual inspection by personnel are as follows:

(1) When the machine is operating, it is necessary to confirm whether the protective cover is indeed closed;

(2) In the machine operation room, it is not allowed to open the protective cover or extend your head and hands into the detection area;

(3) When opening and closing the upper cover, pay attention to whether there are people or foreign objects in the dangerous area.

(4) When the operator performs the test action, in order to ensure the correctness of the appearance inspection, the operator must use a "fluorescent lamp" to assist the appearance inspection when performing the Cell appearance inspection. The position of the eye protection lamp must be fixed, and the production line personnel must not The eye protection light can be turned off when visually inspecting the appearance.

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