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Explain to me the (de?)-evolution of LED lightbulb technology
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TimNJ:
Greetings,

In 2014, I bought some Cree LED bulbs, some of the first mainstream varieties available. Not cheap - I think they were at least $10-15/bulb, at the time. I still have one circa-2014 100W equivalent Cree I use every day in my desk lamp. Anecdotally at least, they seem reliable.

The construction of the early bulbs tended to be quite exotic - Fancy cast aluminum pieces, fancy connectors, and so on. Obviously, it was a technology in its infancy.

From an electronics perspective, these bulbs had (relatively) complex driver boards with some sort of switch-mode driver. Board was usually crammed with big inductor, one or more electrolytic caps, an MOV, fusing, EMI filter, switching MOSFET -- All the normal stuff you'd see an a power supply connected to mains.

Fast forwarding a few years, the market has reached equilibrium, seemingly at the absolute lowest cost implementation possible. These days, seems most bulbs have some simple capacitive dropper or some all-in-one current regulator IC.

How did we get here? Why is it "acceptable" or "reasonable" now to go for these super cheap implementations but 6-7 years ago we needed to cram a full-blown AC-DC power supply in the base of a bulb? Have the LED chips improved? COB style LEDs?

In my experience, the newer bulbs have poor reliability, but I can't tell if that's a result of their overall design topology or if they are just built like crap. Or both.

Anyone able to summarize what happened over the last few years?

Thanks.
NiHaoMike:

--- Quote from: TimNJ on March 23, 2021, 03:13:59 am ---In my experience, the newer bulbs have poor reliability, but I can't tell if that's a result of their overall design topology or if they are just built like crap. Or both.

--- End quote ---
Mostly just pushing the components harder to reduce cost, if you derate the power by dimming them or modifying them, they'll last a very long time.
sleemanj:
Your cree bulb has not failed.  Manufacturers want things that will fail so they can sell you another one. 

Bonus is that making them as cheap as possible...

  1. means they can sell more
  2. means they make more profit
  3. means they fail earlier
  4. goto 1

james_s:
The natural evolution has been greatly reducing the cost. This has resulted in approximately a 50% reduction in rated lifespan but has also nearly doubled the efficiency since the early Philips and Cree bulbs I bought. The modern LEDs are much more efficient which allows them to be driven at lower current. This reduces the complexity of the cooling required as well as simplifies the driver. Highly integrated driver ICs have resulted in simpler drivers with lower parts count.

So far I can't really complain, even 15,000 hours is a long time, and some of the early 30k-50k rated bulbs have not lasted as long as they were supposed to. For a long time I had almost no failures but recently two of the Philips bulbs in my bathroom had gotten substantially dimmer, a teardown revealed the LEDs themselves had deteriorated. I had a couple of the larger 800 lumen Philips bulbs fail too, those had drivers fail, the LEDs look fine.
Berni:
This is just the typical race to the bottom that happens once a technology becomes popular.

At the start when LED lighting was new technology people found it normal to be more expensive, but they bought it anyway because its shiny new tech, perhaps they bought it mostly for that reason, not because the light bulb was actually that much more superior to what they already had. Most people didn't bother but those that did care ware prepared to pay good money for it. Most new technology starts off like this.

But then as LED lighting gains popularity, the bulbs become ever more efficient more, the word gets around about how good they are...etc and more people become interested in this newfangled LED stuff. But they bought the bulb because of how much power this fancy new light is going to save them. But if they care about buying this bulb to save money they will buy the cheapest bulb they have at the store, they wont care about CRI or efficiency or lifespan. The end result is cheep bulbs sell better, so the competition will make an even cheaper bulb, the next competition will make an even cheaper bulb than that. Before you know it you will find two similarly looking 15W LED bulbs on the store shelf, one of them costing $2.99 while the other name brand costs $15, this makes the high quality expensive bulb seam even more overpriced, making them sell even worse. Eventually they just stop making these high quality bulbs because they just don't sell.

This happens with most areas. Once market volumes become large enough the cheep low quality products come in and displace the expensive high quality stuff. Its a sad reality. :(
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