Has anyone tried reinforcing LED’s bond wires with solder?
The LED has to be dedomed of course. The bond wires seem to be the primary point of failure when driving XM-L2 or XP-G2 LED’s at very high currents, 6-7A and 4-5A respectively.
Here’s a thread of replacing the wires with solder, but I don’t think I’ve seen one that coated them with solder.
Thanks!
I think the solder would melt before the bond wires failed. The phrase 'chocolate fireguard' comes to mind.
Hmm that’s a good point. If the solder could lower the resistance significantly though, that’d be great.
It’s possible that the solder reduces resistance enough so that the bond wire doesn’t produce enough heat to melt it off, but I guess it’d depend on what kind of solder you use. Also it’d be a pretty finicky job - not impossible though (probably impossible for me though, I’ve only just got started).
I think we could be investigating something else as well. Applying a coating of “something” onto the LED to revert the tint shift from de-doming.
Quoted from here.
Unfortunately this is Vinz’s trade secret (not vinh from cpf) and won’t tell anyone so this would might prove tricky to figure out.
Ever since he said that it’s been bugging me what Vinz did to produce a whiter beam with ‘no more yellow’.
Interesting, that deserves its own thread, I think.
There has been a long discussion about kinfe vs. gasoline dedoming, but preventing the color shift while retaining the lumens is a whole new thing.
Some kind of UV setting glass glue possibly? I’ve applied this to warm tinted LEDs before and noticed a tint shift to the cooler side.
You can make the new thread, I won’t have the time to keep the original post updated.
You didn’t think to mention this sooner?! Why does this idea have no exposure! We need to to get some objective testing on this… for someone who has the time and patience to do this.
But but but-! he only does it for the love of the hobby, not for money, which is why the revolutionary new proprietary method has to be kept a secret! Because that makes complete sense, of course.
Sorry, i thought people knew or had tried it 
Could be worth a shot though.
I use a drop of LEDseal, and then place the star LED-side-down on glass until it cures. The silicone layer left on the die is minimal but the bond wires are no longer exposed.
The question I don't have an answer for is, are the bond wires more or less heat tolerant before the LEDseal or after? Do they run cooler when in open air, or does the silicone help draw away heat, or does it act as an insulator instead?
Post #41.
Thread title changed, this is getting exciting.
Did the LEDseal mitigate lumen loss of tint shift? We just keep bringing up the questions we can’t answer…
Now it makes me wonder if an XP-L can handle more current than an XM-L2… too many questions…
I used to work in the wire-bonding industry. Do you know the wire is real gold(>98% grade if I am not wrong)? :8)
I should start stacking dead LED”s instead of gold bars. :party:
Does lead or lead free solder work on gold wires?
LoL. Gold ingots will definitely contain much more gold in it.
Lead frame is plasma in oven then heated to >200 degree and bonded with capillary in ultrasonic speed with ball bonder machine. Doubt solder will work. Even if the joint sticks, die portion will be burnt by our huge solder bit.
That clears it up, thanks for the explanation.
Interesting thread H)
I’ve actually unintentionally soldered the 3rd bond wire on a few different dedome emitters with my reflow gun. Its interesting you posted this topic, I was just thinking about it the other day trying to save an XP-E2 that the 3rd wire broke on (I failed).
I’m not sure solder coating the bond wires would lower resistance, when I build the external shunt resistor DMM’s I sell I use a piece if stranded copper 14AWG wire and I add solder into the wire to decrease the resistance but it’s filling the space between the strands, I’m not sure just coating the single gold strand would be of any help.
Anyway I’m watching this thread, even if it couldn’t take any more current if it can help to protect the wires (especially that 3rd one out in the open) this could be a good thing.
The 'third wire' is just the ESD protection, don't really know why they bothered with it as none of my de-domes have failed even though I almost always just remove the wire and the tiny little diode it goes to.
Do you think XM-L2 has thicker bond wires than XM-L, since it only has 2?