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> No, it's not. Although as many other scientific facts it is often being stretched beyond the extreme in order to use it to legitimize crazy theories and/or sell products. That is a very common practice. As far as I've been able to tell, there's very little in the way of literature that actually supports the "blue light" claims, but quite a lot of things which just self reference to support it. > Unfortunately blue leds are extremely cheap to produce, so that pretty much every consumer gadget, especially those cheap gimmicks from the Far East, use them profusely even in places where other colors would be, also functionally, more suitable. Huh? To begin with, all modern LEDs are blue, if you see a white LED, it's a blue LED, if you see a red LED, it's a blue LED. This is just down to physics more than anything, it's also much more economical to produce the same chemistry and just use phosphors to emit the color you actually want. Blue LEDs emitting actual blue light however are vanishingly uncommon in any product at all, I don't recall the last time I've actually seen one. If you're talking about white LEDs being used in products? Well then yes, they will obviously contain blue light. |
It is true that "white" LEDs are really blue or violet LEDs coated with phosphors that glow white or yellow (RGB LEDS with independently controlled red, green and blue LEDs are rare and only used in things like color-changing light bulbs).
It is not true that "if you see a red LED, it's a blue LED". Red LEDs are still made with semiconductors that directly emit red light (and the same goes for green, etc.). You can look at the spec sheets for LEDs on a distributor like Mouser and see the material used for each LED. The first red LED I came across directly emits red light using AlInGaP. I have never seen a "red LED" that uses a blue LED to excite a red phosphor. That would be even more expensive.