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How LEDs are Made

learn.sparkfun.com

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Re: How LEDs are Made

#81

Post by leoedin »

HeyLaughingBoy wrote: post #12
leoedin wrote: post #2

I'm surprised by how manual the whole process is. I think labour is so expensive in the west that any manufacturing of small low value items is incredibly highly automated (see youtube for lots of videos of how huge automated production lines work). There's no way you could employ someone to manually bond 80 LEDs a minute in the west and still have a competitive product.

I'm not so sure. Let's assume you're paying someone $15/hour and she actually costs you $25/hour. Assuming a 10 minute break every hour (that's gotta be tiring work and you want to hold onto your employees), then that's 2500/(80 * 50) = 0.625 cents of labor cost per LED. I don't know what all the other costs are, but that one operation seems surprisingly cheap.

Just looking on Digikey, the unit price for a 5mm LED is somewhere between 3 and 4 cents. In that price there's distributor markup, transport, supply chain markup, the cost of the components and the cost of labour. I'm not too familiar with the economics of electronic components, but I'd be very surprised if the manufacturer sees more than 30% of the final price.

That would mean the manufacturer would be spending half the cost of the finished product on a single step of the manufacturing process. I'd be surprised if that's economically viable.

Re: How LEDs are Made

#82

Post by sokoloff »

nkurz wrote: post #70
Eliezer wrote: post #66

If this is the manufacturing process and its price, why are LED light bulbs still expensive? (Serious question.)

These are not the type of LEDs used in modern light LED light bulbs. They produce a tiny amount of light (maybe 5 lumens each, with a 60W equivalent requiring 800 lumens), don't work well with a heat sink, and aren't particularly efficient. Separately, a lot more goes into an LED light bulb than just the LED. Here's a teardown with cost estimates for a recent 800 lumen Cree 60W equivalent, where they come up with an…

Home Depot has been selling those lamps for $4.97ea for quite a few months now. They're a very nice replacement for the traditional A19 60W incandescents.

My only complaint, and it's a tiny one, is that they only dim to about 10% before cutting off entirely. There's also a small dark spot on the spot of the bulb opposite the socket, but in practice that's been a non-issue for all my use cases.

Re: How LEDs are Made

#83

Post by morcheeba »

chrisBob wrote: post #39

Am I the only person that thought the shape of the metal inside an LED was a significant part of the function? I am sure if I thought about it I would have realized that it is just support for the silicon. I guess I never thought about it that much until today.

If you look closely, you'll see it's actually in the shape of a reflector - usually a cone. Also not shown is that some higher-power leds use a blob of silicone around the chip to protect the bond wire during thermal expansion -- the cone helps hold the silicone while curing.

Re: How LEDs are Made

#84

Post by nkurz »

sokoloff wrote: post #82
nkurz wrote: post #70

Earlier quoted context omitted.

These are not the type of LEDs used in modern light LED light bulbs. They produce a tiny amount of light (maybe 5 lumens each, with a 60W equivalent requiring 800 lumens), don't work well with a heat sink, and aren't particularly efficient. Separately, a lot more goes into an LED light bulb than just the LED. Here's a teardown with cost estimates for a recent 800 lumen Cree 60W equivalent, where they come up with an…

Home Depot has been selling those lamps for $4.97ea for quite a few months now. They're a very nice replacement for the traditional A19 60W incandescents. My only complaint, and it's a tiny one, is that they only dim to about 10% before cutting off entirely. There's also a small dark spot on the spot of the bulb opposite the socket, but in practice that's been a non-issue for all my use cases.

In the US, the price varies state by state, and reflects a variety of subsidies used to encourage the switch over from incandescents. Thus for certain bulbs (like this one) the production cost is often higher than the selling price. Some details for California here: http://www.designingwithleds.com/rebated-cree-philips-led-bu...

Re: How LEDs are Made

#85

Post by jpindar »

sparkman55 wrote: post #3

This is clearly an old process - when was the last time you saw a 7-segment display, or those big red round thru-hole LEDs, outside of hobby electronics? I'd be very curious to see how this process differs from the high-power lighting LED manufacturing process (e.g. CREE), which is a more modern technology by several decades. I would guess there is much more of the automation people are expecting...

"when was the last time you saw a 7-segment display, or those big red round thru-hole LEDs"

At work yesterday, at a microwave communications equipment manufacturer. Through-hole LEDs are the easiest kind to mount on the front panel of rack mount equipment. And there are 7-segment displays on two of our adjustable power supplies.

Re: How LEDs are Made

#86

Post by jotm »

HeyLaughingBoy wrote: post #9

I could do this in my basement! Years ago I answered a "for sale" newspaper ad for used office desks and some test equipment. I showed up at the address and it was a small dingy old building and most of the employees seemed to be 55+ year-old women. When I asked what they did and was told they made diodes, you could have knocked me over with a feather. Like he did, I assumed that all electronics parts manufacturing w…

This is why we need more posts like these and more of those How things are made blogs. Too often people don't even begin getting into (high) tech because they think it's too complicated or expensive.
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