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What is SMD and what is GOB?
SMD means surface mount led, which is a technology for led lamp package. SMD is a very stable and cost-effective package, now most led screen’s use SMD led lamps. While GOB means Glue on board, which is a treatment that put glue on the led module surface where it already has thousand of SMD lamps(pixels). Hence you can deem GOB as value-added services for SMD. Below you can see the Pros and Cons for the GOB led display.
Pros of the GOB LED display
1:Protecting the led lamp from scratches and bumps.
As the led lamp(pixels) are all attached to the PCB board. There would have gaps and spaces between adjoining lamps (pixels), and when get scratched or bumped, the lamp might be lost. When the pixel pitch is over 2.5mm, and the gaps are big enough, we would use module mask to protect the led lamp.
While when the pixel pitch smaller than 2.5mm, it does not have enough space to place the mask. That’s where GOB come to help. After the GOB treatment, all the gaps and spaces between pixels are all filled with glue, and the surface of the led lamp also have a thin layer of glue, which make the led lamp(pixels) free from scratch and bump.
2: Waterproof, dust proof, moisture proof, and erosion proof etc
After the GOB treatment, all the led lamps are filled with glue, including the electrode. No water, or dust or acid can get inside the led lamp, which makes the led module surface water proof, dust proof. Moisture proof and erosion proof etc
3: Decrease dead lamp rate
As the Glue has filled up the space between pixels. the led lamp’s soldering is also harder to be oxidized, which makes it have fewer dead lamp rate over time. Most of the dead lamps are caused by oxidized soldering which causes failure of electric contact.
4:Wider viewing angle.
With the glue covered on the surface of the led module, the light that comes out from the led lamp can have the same passing path, which can board the viewing angles. for example, the normal 140 degree led screen, after GOB treatments, it can have a viewing angle of 160 degree.
Cons of the GOB LED display
1: GOB is a little more expensive than SMD
GOB would takes long time to produce, as before GOB treatment, the led module is actually considered done. We need to do a 3 days burn-in test, to find out the dead pixels, and then do the GOB treatment. After the GOB treatment, we still need to do a 3 days burn-in test to check the modules. Hence the price of the GOB would be a little expensive then normal SMD module.
2: The repairing process is more difficult than the normal module
To repair a GOB module, first we need to remove the glue. And then repair the module like the normal module process. But the difficult part is that it also needs the same batch glue, and different batch glue would have color difference, and the color difference is very easy to notice.
3:The color uniformity might be different.
Color uniformity is the biggest challenge in GOB treatment. As different batch glue would have color differences, even when the color difference is small, after it is filled in the led module, the slight color difference would also have a bad viewing experience after the screen is powered off. Hence when using GOB treatment, we need to do the calculations carefully to avoid shortage of glue.
When do you need GOB led display
Though GOB treatment has many benefits, not all led screens need GOB treatment. For example, pixel pitch over 2.5mm normally has enough space to place mask, hence will not need GOB treatment. As GOB treatment is a little expensive, normally needs to cost 10%-15% more than a normal led screen. If you have below conditions, then would suggest you go with GOB treatment.
1: The installation site have moisture
2: The screen is installed with people walking around that would accidentally scratch the screen.
3: Pixel pitch below 0.9mm, When pixel pitch below 0.9mm, the lamp used is SMD0808, the lamp is very small, hence using GOB can protect the led lamp
4:The screen need a higher viewing angle.
While if the screen you need does not have such condition above, a normal led screen would be ok.
Different GOB led display
Normally the GOB led display is applied on the led screen with pixel pitch less than 2.5mm, which we call it small pixel pitch led screen. Due to different form of led display. It can be divided into two types
1:Small pixel pitch GOB led display
Small pixel pitch GOB led display is the normal small pixel pitch led display with GOB treatment. Our small pitch led display product can all do GOB treatment.
2:Small pixel pitch Flexible GOB Led display
Our flexible led module can also use GOB treatment. The glue itself is flexible, though after the GOB treatment, the flexible led module would be a little hard to bend. While it can still work well.
