When you buy LED displays for high-end applications, you often need to choose gold wire LED beads. So how can I be sure that my LED screen is a gold wire LED display and how to identify them? Next, SightLED experts will share this knowledge.
The importance of gold wire in LED bead packaging
Gold wire is really important in LED bead packaging. It’s used to encapsulate LED lamp beads, which are made from pure gold wire. This gold wire contains more than 99.99% gold, plus other trace elements like Ag/Cu/Si/Ca/Mg. Sometimes, welding also uses silver wire. This wire is 99.99% pure silver and contains 1% of other trace elements.
Gold wire is one of the most important parts of the LED lamp bead encapsulation process. It connects the light-emitting wafer and the welding point. It also affects how long the LED lamp bead lasts.
The advantages and disadvantages of Gold wire LED encapsulation
Pros:
- large electrical conductivity,
- good thermal conductivity,
- corrosion resistance,
- good toughness, excellent chemical stability, etc., b
Cons:
- the price of gold wire is expensive, resulting in high encapsulation costs.
Gold wire encapsulation vs. copper wire LED encapsulation:
There is much different between gold wire and copper wire in terms of conductivity, thermal conductivity, cost, and oxidation resistance:
| Property | Gold Wire | Copper Wire |
|---|---|---|
| Conductivity | Superior, lower resistivity | Good, but higher resistivity |
| Thermal Conductivity | Inferior, lower thermal conductivity | Superior, higher thermal conductivity |
| Cost | Much higher | Lower |
| Oxidation Resistance | Strong, not easily oxidized | Poor, requires protective treatment |
How to Tell if My LED Display Are Gold wire LED
LED packaging factories sometimes use alloy materials instead of LED gold wire because it’s more expensive. This can cause the LED display to appear dim. If your Nationstar LED display is not bright, you should check whether it’s the gold wire or something else.
a) Diameter Deviation
One gram of gold can be drawn to a length of 26.37m and a diameter of 50μm (2 mil) of gold wire. It can also be drawn to a length of 105.49m and a diameter of 25μm (1 mil) of gold wire.
If you keep the length of the gold wire the same and make it half the diameter, the resistance of the gold wire will be one-fourth of what it would normally be.
For LED customers, using gold wire with a smaller diameter on the cut corners will increase resistance, which could lead to a lower fusing current and shorter LED light source life.
It’s likely that a 1.0 mil gold wire will have a shorter lifespan than a 1.2 mil gold wire.
b) Chemical composition test
ICP purity test
Identify the purity grade of the gold wire and determine the added alloying elements.
LED key alloy wire is made of gold purity of 99.99% or more of the material drawn, which contains a trace of Ag, Cu, Si, Ca, and Mg and other trace elements. By designing reasonable alloy components, we can make the gold wire strong enough to withstand tension and bonding, and it won’t break easily.
Most bonding alloy wires should be high-purity alloys with a purity of 99.99% or more. The total amount of trace elements should be kept below 0.01% to maintain the characteristics of gold.
EDS composition test
Identify the type of material: gold wire, silver wire, gold-clad silver alloy wire, copper wire, and aluminum wire.
While these alternative metals are better than gold wire in some ways, they’re not as stable chemically. For instance, silver wire and gold-coated silver alloy wire are susceptible to sulfur, chlorine, and bromide corrosion, and copper wire is easily oxidized. These alternatives make the bonding wire susceptible to chemical corrosion, which reduces the reliability of the light source and makes the LED lamp beads prone to breaking the line.
c）Mechanical Properties Test (Pull-off Load and Elongation)
A good gold wire that can withstand the impact generated by the resin encapsulation must have a specified pull-off load and elongation.
At the same time, the breaking force and elongation of the gold wire play a key role in the quality of lead bonding. A high breaking rate and elongation of the bonding wire is more conducive to bonding.
Too soft gold wire will lead to the following malpractices:
- Sagging of the arch wire;
- Unstable ball shape;
- Easy shrinkage of the neck of the ball;
- The gold wire is easily broken.
Too hard gold wire will lead to the following defects:
- Pitting out the chip electrode or epitaxial;
- Breakage of gold ball neck;
- Difficulty in forming alloy;
- Difficulty in controlling the arc of the archwire.
d) Surface quality inspection
The surface of the wire should be free of more than 5% of the wire diameter of the scoring, pits, scratches, cracks, bumps, folding, and other defects that reduce the service life of the device.
Gold wire in the drawing process: any surface defects on the wire will increase the current density, making it easier for the damaged area to be burned. This also reduces the wire’s ability to resist mechanical stress, which can lead to damage to the inner lead and fracture.
Gold wire surface should be free of oil, rust, dust and other adherents, as these can reduce the bonding strength between the gold wire and the LED chip, and between the gold wire and the bracket.
Conclusion:
There’s a big difference in the price of LED displays. The LED chip package wire process plays a big part in this. Due to lower copper wire manufacturing costs, it is used for common LED display.
In practice, the copper wire process has a few issues when it comes to gold wire welding. For high-end LED displays, gold wire is the way to go.
If you’re looking for a top-quality gold wire LED screen, feel free to reach out. We can customize it to your specs.
FAQs:
What is the diameter of gold wire LED packaging?
The diameter of gold wire LED packaging usually ranges from 15 to 50 microns, with the exact choice depending on the size of the LED chip and the needs of the application.
