How to Solve The Problem of Out-Of-Control Pixels of Full-Color LED Display?

Publisher: Supplier of LED Display Time: 2018-03-08 Views: 1644

 Full-color LED display pixels are out of control is a relatively common problem, what is the cause of this phenomenon, and how to solve it? Analyze it.  

The pixel point of the LED display is out of control, which means that the smallest imaging unit (pixel) of the display is not working properly. The ratio of the number of out-of-control pixels to the total number of full-screen pixels is called the "full-screen pixel out-of-control rate". There are two types of pixel out-of-control modes. One is blind spot, that is, blind spot. When it needs to be bright, it is not bright, which is called blind spot; It's a regular highlight.  


In general, the common LED display pixels are composed of 2R1G1B (2 red lights, 1 green light and 1 blue light, the same as the following) and 1R1G1B, and the loss of control is generally not the same pixel in red, green, All blue lights are out of control at the same time, but as long as one of the lights is out of control, we consider that pixel out of control. Therefore, it can be concluded that the main reason for the loss of control of the pixels of the full-color LED display is that the LED lights are out of control. The main reasons for the failure of LED lights can be divided into two aspects: one is the poor quality of the LED itself; the other is the improper use method.


The out-of-control LED light cannot be found in the regular inspection test of the LED. Under harsh conditions such as high temperature, low temperature, and rapid temperature changes, due to the difference in thermal expansion coefficients of LED chips, epoxy resin, brackets, inner leads, die-bonding glue, PPA cups and other materials, the internal stress is different. The mechanism of LED runaway caused by electrostatic discharge is very complex. Equipment, tools, utensils and human body may have static electricity and discharge it. This static electricity is as little as a few hundred volts and as high as tens of thousands of volts. The discharge time is at the nanosecond level. . If the blue-green tube is out of control, it is often caused by the breakdown of the LED-PN junction by electrostatic discharge. Due to the complicated production process of LED display screens, electrostatic discharge is difficult to prevent. Therefore, electrostatic protection must run through the entire production process.


In different occasions, the actual requirements of the pixel out-of-control rate are different. The full-color LED display indicators are required to be controlled within one percent; the monochrome LED display indicators are required to be controlled within one-tenth. At present, there is no good solution for full-color LED display pixels. It is recommended to contact the service manufacturer to return to the factory for repair. If the repair cost is too high, you can consider replacing the module unit board in question.


At present, all domestic LED displays will undergo an aging test before leaving the factory, and the LED lights with out-of-control pixels will be repaired and replaced. There is no problem within 104, and even some manufacturers' corporate standards require that out-of-control pixels are not allowed before leaving the factory, but this will inevitably increase the manufacturer's manufacturing and maintenance costs and prolong the delivery time.


 In different applications, the actual requirements of the pixel runaway rate can be quite different. Generally speaking, when the LED display is used for video playback, it is acceptable and achievable to control the indicator requirements within 1/104; If it is used for simple character information release, it is reasonable to control the index requirement within 12/104.