[Maursault]

Thankfully, LED lighting will probably be gone within 20 years, while incandescent will be coming back more efficient than LED could dream. Already bumping up against theoretical maximum efficiency, LED lighting can't get any more efficient, and the better LED is at color rendition, the less efficient it is. But there are vast amounts of improvement available for incandescent lighting, and a group at MIT has already created incandescent light that is twice as efficient as LED.[1]

[1] https://news.mit.edu/2016/nanophotonic-incandescent-light-bu...

[seanp2k2]

Exciting, but that article is from 2016 and here we are in 2023 with no commercial availability. https://www.reddit.com/r/AskScienceDiscussion/comments/j6hwn... asked what happened with no real updates.

[Maursault]

> Exciting, but that article is from 2016 and here we are in 2023 with no commercial availability.

That is a fantastic point. If they can't revolutionizing lighting in 7 years, it will never happen. Oh, btw, LED was invented in 1962, but it only took about half a century for the commercial viability of high powered LED lighting to appear and begin to take over the lighting market in 2011.

[dredmorbius]

The concept is interesting, and reading the article reversed my initial response to treat this as a crank concept.

That said ...

... LEDs involve finding materials which exhibit specific quantum behaviours which correspond to human visual acuity.

Photonic bulbs involve the much simpler blackbody radiation concepts of not only incandescent light bulbs but hundreds to thousands of millennia of previous experience with combustion-based lighting ... and, yes, the added twist of finding viable IR-reflective / visual-spectrum emissive materials.

The second problem seems more reasonably simpler. One would hope that progress might be occuring at a more rapid rate.

(There's a similar argument I've used to contrast nuclear fission, which was commercially exploited within two decades of first demonstration, and nuclear fusion, which coming on a century from its theoretical understanding remains not even experimentally demonstrable on a continuous, energy-positive basis, let alone in commercial application. Some problems are just hard.

Yes, there are thresholds and breakthroughs, and they do occur. But given a few decades of lived experience matching advertisement to delivery, as well as a stronger awareness of historical examples and trends, patterns do become evident.

And that said: I will keep an eye on this. It does have the advantages of being simple, based on very well-proved technology, and a reasonable extension of same.

[Maursault]

Most of the capital invested in incandescent technology was related to the Phoebus cartel. The pressure to make incandescent efficient was just never there until very recently. LED has severe problems, some solvable, some not. The article mentions flicker, but really should have specified. Nearly all LED drivers employ PWM. There are constant current LED drivers, and they are more efficient than PWM drivers, but PWM drivers are cheaper to design and manufacture. While many will claim PWM doesn't bother them because they can't detect it, they're not only exhibiting callousness for those that are bothered and harmed by PWM, they're falling into a fallacious trap, i.e. what they don't know and can't detect can't harm them, which is patently false, and one counter example is carbon monoxide. PWM LED drivers are now ubiquitous, and it's effects range from annoying to painful, as anyone that has experienced migraine can attest. Regarding the actual light LED produces, nearly all LED available are weighted towards the blue spectrum, and this light has been shown to massively mess with wildlife and shorten human lifespans by years by messing with circadian rhythms, which strangely can lead to diabetes and heart disease. LED proponents are obsessed with brightness, but this is also a trap, because brightness is not as important as what can be seen. Consensus among lighting and eye experts is that more can be seen with a dimmer light that reproduces color perfectly than with a much brighter light that does not. As we mitigate these issues with LED, the drivers become more expensive and the LEDs become less efficient. And as the article mentions, the phosphors of better color-producing LEDs will fade rather quickly and over time no longer reproduce colors accurately. And best LED can ever achieve is to perfectly match what incan does with little to no development, What it looks like, if the trend can be detected, is that as we fully mitigate the problems with LED, the more expensive it becomes until its cost and durability nearly reaches parity with what we already had with incandescent. It's becoming a wash.

[Maursault]

Most of the capital invested in incandescent technology was related to the Phoebus cartel. The pressure to make incandescent efficient was just never there until very recently.

LED has severe problems, some solvable, some not. The article mentions flicker, but really should have specified. Nearly all LED drivers employ PWM. There are constant current LED drivers, and they are more efficient than PWM drivers, but PWM drivers are cheaper to design and manufacture. While many will claim PWM doesn't bother them because they can't detect it, they're not only exhibiting callousness for those that are bothered and harmed by PWM, they're falling into a fallacious trap, i.e. what they don't know and can't detect can't harm them, which is patently false, and one counter example is carbon monoxide. PWM LED drivers are now ubiquitous, and its effects range from annoying to painful, as anyone that has experienced migraine can attest.

Regarding the actual light LED produces, nearly all LED available are weighted towards the blue spectrum, and this light has been shown to massively mess with wildlife and shorten human lifespans by years by disrupting circadian rhythm, which strangely can lead to diabetes and heart disease.

LED proponents are obsessed with brightness, but this is also a trap, because brightness is not as important as what can be seen. Consensus among lighting and eye experts is that more can be seen with a dimmer light that reproduces color perfectly than with a much brighter light that does not.

As these issues with LED are mitigated, the drivers become more expensive and the LEDs become less efficient. And as the article mentions, the phosphors of better color-producing LEDs will fade rather quickly and over time no longer reproduce colors accurately. And let's realize that the best LED can ever achieve, what the technology has always been striving for, is to perfectly match what incan does with little to no development. Maybe someday LED light will perfectly match incan light, but it is not today and it isn't next year.

What it starts to look like, if the trend can be detected, is that as we fully mitigate the problems of LED, the more expensive it becomes until its cost and durability nearly reaches parity with what we already have with incandescent. It's starting to become a wash.

So unlike LED, if incan can be made more efficient, and there is a massive amount of room for improvement in efficiency there, then incandescent undoubtedly will return and dominate the lighting market. I liberally estimated 20 years, but it may take longer, but it really doesn't matter to my major point, which is that incandescent is coming back, and this is a very very good thing, because LED light, as efficient as it is, still absolutely sucks.

[ridgeguy]

It seems like this could be done differently, and perhaps more cost-effectively. Can't give cites right now, but here's a path I'd explore if I were in the field.

I'd pattern the inner surface of the glass envelope with a cube texture - think of taking a cube and pressing a corner normally into a clay surface, then removing the cube. This pattern is a so-called corner reflector, and returns incident light to its source. Figure the cube indentations at about 0.5mm deep, close packed. I'd deposit a dielectric film reflector stack tuned to reflect most infrared radiation onto this surface.

This combination would transmit visible light, but would reflect IR directly back to the filament, reducing the amount of electrical power needed to maintain filament temperature. Glass textural molding and dielectric film deposition are mature technologies. I think this could readily triple incandescent lamp power efficiency, maybe even better.

[lightedman]

That incandescent cant reach the theoretical 40%, at the color temp/physical temp needed, the tungsten filament would melt.