LED Bonding Manually




Introduction: LED Bonding Manually

I will show you how to bonding a LED diode manually, soldering an LED directly.

Step 1: Get the LED

In this case I used a white LED SMD. Inside it has a blue LED diode covered with a yellow resin, It contains elements that make the blue light to appear white.

Step 2: Getting the LED (part 1)

For this work we need a microscope, also we will fix the LED on a PCB. Then we cut off the encapsulated.

Step 3: Getting the LED (part 2)

With a sharp object we remove the resin being careful not to damage the LED diode (the gold wire is not necesary, only the pads on the LED).

Step 4: Tinning the LED Pads

For tinning the pads we need small particles of welding wire. We get them scraping with a cutter. Then, we place a particle on the pad and approached the tip of the soldering iron. The heat will melt the particle on the pad. We do the same on the other pad.

Step 5: Bonding the Wires

We get the microwire from some coil, I get the coil of an old analog clock. We weld the microwire with the tip of the soldering iron. And we weld the microwire on the pads approaching the tip of the soldering iron. Finally we remove the LED from the PCB pressing carefully with a cutter.

Step 6: Using Your New LED

Now, because the LED and wires are very small, it is necessary to weld it on some base. This way you can manipulate easily.

Step 7: In a Joule Thief Circuit

I had the idea to set my LED on joule thief circuit. I used a 1.5v battery, a push button and the lens of a laser to see the LED. This is the result.



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41 Discussions


1 year ago

This reminds me of when I was in the USAF in the 1970's, working in an electronics depot in Germany. My job was to fix the unfixable, things like obsolete, out of stock parts that couldn't be ordered any more. Parts were shipped from all over Europe for me to try to fix. One of the things I did was to repair computer circuit boards for an old weird UN radar installation. The circuit boards had miniature ICs spot-welded into place instead of being soldered! Imagine the fun I had, grinding off the leads of the bad IC without ruining the runs, then spot welding the new IC into place. There were 10 leads to a side, and the ICs were 3/4" long, with the spacing one lead wide. I did this with only a standard desk magnifying lamp, a standard Dremel, and standard Dremel bits! I can tell you, my eyes were tired at the end of the day!

Man you Super Mega Man!!!


2 years ago

without microscope, can't get so clear picture of bonding wire on pad in the die of chip.
you really have good instruments to complete this work!

Welding wire? Looks like solder to me. (Plastic spool says "solder". Alloy composition not visible.) And a soldering iron wouldn't melt "welding wire" particles (typically brass). Probably an error in translation.



3 replies

You are right, I speak spanish but I try to post in english. So sorry ;D

You do far better in a second language than I do :-) (Old joke in the US: What do you call someone who can speak three languages? Trilingual. Two languages? Bilingual. One language? American :-)

Wow! I tip my hat to you for the solder-job! HAd to solder sub-mm-pitch in the past and i know how hard it can be :)

Also: The LED will shine mostly in UV-light since the yellow stuff is a mix of phosphorous which will glow in the UV-light of the LED. So Maybe you can also scavenge the phos. and sprinkle it on an object to make it somewhat glowy in the almost invisible UV-light... Just an idea.

6 replies

the Ultra violet is dangerous to eyes.

Will this exposed LED emit enough UV to damage our eyes?

some white LED use UV light + a phosphor to output white light.. thus, those would have UV.

most white LEDs today use a royal blue LED combined with a phosphor now. So a lot less UV will be there, but not none.

In any case, one single LED in the range of 5-50mA will not output enought UV to be damaging to your eyes if not stared at ultraclose range for long time.
Since the die is bare in this scenario, the emition is more or less uniform in all directions. So the power fall really really fast:
twice the distance = 1/1000the of the power per cm^2

The UV is dangerous, but this kind of LED is not powerfull. Anyway, it is better not to expose too.


2 years ago

Great project, I learned a lot, thanks for posting!

ps I think you are crazy :)

1 reply

A lot of work but for which result ? I don't see the interest except maybe for learning how a LED is built. Such LEDs, without phosphore, already exist and are available. (a danish company sells bars and points as well)

3 replies

Exactly. Satisfaction is to achieve challenges, apart from knowledge. Not everything in life is to create something commercial or useful, also build things that are simply beautiful. In my opinion. ;)