Cause Analysis and Solutions of LED Display Module Plaque

With the high prosperity of commercial development, LED display, as a terminal display medium, has been paid more and more attention by advertisers. However, after nearly 20 years of development of the LED display, there are still many technical details that have not been solved, and the plaque phenomenon of the display is one of them.

The phenomenon of LED display plaque has been around for a long time, and it has almost formed an industry defect that is ignored by everyone. Although some accessories companies continue to improve their processes and work hard to solve them, they have little effect.

Plaque phenomenon of LED display

In the box photo above, the latter two are the modules of two well-known listed manufacturers in the industry. Although the plaque phenomenon has been improved, it is also obvious.

So how is the LED display plaque generated? The following analysis of materials and shapes will draw conclusions:

The back of the LED module mask is flat, and the front is designed with striped protrusions and the brim of the lamp due to the consideration of the light type. , and the shrinkage of the PC material is not considered comprehensively, which leads to the imbalance of the surface stress distribution caused by the shrinkage of the material (shrinkage refers to the shrinkage rate of the material after molding, and the shrinkage rate of different materials is different), the stripes on the front of the mask The shrinkage of the protuberance is more than that of the back plane, and the stress generated in the front is also larger than the stress generated in the back.

So what is the phenomenon? Because of material shrinkage and design defects, the stress distribution in the front and back of the mask is unbalanced, and the surface stress of the module mask is unevenly distributed. It is generally more concave from the middle to the back.

Some people may say that the module mask is soft. I use the bottom case of the module to jack up the middle of the mask, and this phenomenon should disappear? But the conclusion is ruthless – “no”.

Another phenomenon is that due to the shrinkage of the material, the reflection curvature of the surface of the mask also has an effect on the light, thus visually increasing the feeling of plaque on the display screen.

From the above analysis, we can conclude that the cause of the plaque on the display screen is caused by the material and design defects of the mask, so how to solve this problem?

Invariably, we use the ink color of the mask to make a fuss, that is, use the ink color as much as possible to blur this sense of plaque, but this method cannot completely solve the plaque sense of the display screen, and because of the strict requirements for ink color , it also brings the difficulty of processing and production to suppliers, which will lead to an increase in cost; and in the application process of the display screen, the sense of plaque will become stronger and stronger due to factors such as dust accumulated on the surface of the screen.

Method 1: Appropriately increase the thickness of the mask, so that the shrinkage stress caused by the protrusion of the front of the mask can be ignored, which can be solved, but this solution, one is to accurately calculate the thickness of the module mask, two Yes, it may lead to other problems. The third is to have a good grasp of the material.

Method 2: Design the same protrusions on the front and back of the simplest mask, that is to say, what kind of optical protrusions are designed on the front of the module mask, and what kind of protrusions are designed on the back at the same position, so that the shrinkage of the front and rear of the mask can be balanced. , so that the stress generated by the shrinkage of the front and back of the mask is balanced, and the deformation of the mask is solved.