this post was submitted on 03 Feb 2026
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From what I read last time I properly looked into this (so, almost a decade ago when I was considering setting up a business importing LED lamps), the blue light emitting diode junction simply uses less power to emit the same amount of light.
Electrically speaking it's no bigger or lesser a problem in terms of circuitry to have just blue diodes or blue + red diodes in there since they're bundled in blocks of diodes in series (and then multiple blocks are in parallel) and the only thing that differs between those two kinds of junctions from a circuit point of view is the drop voltage of one kind of diode being different from that of the other (diode junctions done with different dopants have different drop voltages), something you take into account in the design stage when deciding how many LED diodes you use per block or what DC voltage will your 110v/220V AC input be converted to to feed those LED strings.
More specifically for LED light bulbs, the messy stuff in terms of electronics is the circuitry that converts the 220v/110v AC input into a lower voltage DC suitable for the LEDs whilst limiting the current (as diodes' only ability to "limit" current is them burning out from overheating due to too much current), not the actual LEDs.
But I'll put it even simpler: if the problem was indeed simplicity as you believe, then LED bulbs with only red LEDs would also be very common as they're simpler than blue+red ones.
You can't easily use a filter to turn red light into blue. Imo if you needed to light a room for a camera or something not the human eye, red seems like it would be effective for that, but given the filter situation and the eye being best at detecting green light it doesn't make sense to use red as the base color for indoor bulbs.
From what I read, red LEDs were most efficient at 1.8v and blue more near 4v. Maybe its trivial to do second voltage line but the filter situation is probably the limiting factor here.
Here are the LED drop voltages for reference.
LEDs aren't just more efficient at those voltages, those are literally the difference in voltage between one side of the LED and the other side when in operation - if you feed it less than that the LED will simply not work. (Note that these drop voltages are not actually an absolute value but rather a very steep curve relative to current, but for simplification we can treat those as absolute ON/OFF voltage values).
Also the phosphor doesn't filter light - rather it absorbs light and re-emits it in different wavelengths, the process being such that the emitted light covers a range of wavelengths even if the input light has a single wavelength as is the case for LEDs - so it's not at all light manipulation by filtering and mixing light sources.
That said I went looking at how phosphor is used in LEDs nowadays and judging from this they don't use red LEDs emitters at all nowadays, only blue and UV ones, and then chose a phosphor (which can be any substance, not just Phosphorous) whose emission range is towards the desired light range.
I've corrected my original post.
The phosphorous coating here is serving to reduce the amount of blue light as an absorptive filter. Its just also doing other stuff. Idk if there's a proper term for what its doing in whole, but your explanation is otherwise in line with what I've read.
That's not even close to reality.
Read the material linked or just google it yourself.
That's a bit incoherent.
Fwiw, I did read the article you linked. That's one of the articles I looked at originally.
I'm just saying its innapropriate to say its "not a filter" because the coating is doing more than partially filtering a wavelength of light; Its a categorical error.
The coating's primary engineering function is not a filter, so maybe its frustrating to hear it described as one but it is absolutely incorrect to say its not a filter because one of things its literally doing is filtering out a % of the blue light emitted by the diode.
A phospor absorbs the incoming light and then uses it as power for its own emission process, in a processes called "fluorescence" rather than "filtering". It's a very efficient process because almost all of the light coming in and absorbed by the fluorescent material ends up used to emit light.
A filter just cuts out (literally "filters out") things other than what it's supposed to let through. Filters just block stuff and thus cannot have on their output anything that's not present on their input. Further, filtering can be very inefficient because everything that the filter doesn't let through just ends up as waste heat.
Filtering doesn't make any sense for light emitted by a diode junction because that specific light emission process emits light of a single wavelength - it's a totally different process from incandescence and only emits photons whose energy exactly matches a specific quantum gap in that junction, hence all emitted photons have the exact same wavelength, thus there are no other wavelengths in the light emitted by the diode to filter out - thus if you filter out that specific wavelength, no light at all goes through the filter because there's nothing else there.
Calling a phospor a "filter" is like calling a system with a solar panel connected to a green LED a "filter" - sure, the spectrum of the light coming in is not the same as that of the light going out, but that's pretty much the only way the thing behaves the same as a filter - it does not share any of the other characteristics of a filter.
Anybody with a Physics or Engineering background will react the same as me when somebody describes a fluorescent material in front of a light source as "a filter" because per the scientific and engineering definitions "fluorescence" is not at all the same as "filtering".
Whatever source you learned information about LED lights from, it's really bad and shows no domain expertise, which is probably why you ended up with some things right in your explanations and others horribly wrong. If I was to guess, I would say that you "learned" it from AI, as getting the general stuff mostly right and the domain expertise details incredibly wrong is a common problem of AI.