Hacker News Reader

Comment by tyingq | Hacker News Reader

They talk a lot about the blue LED, but don't mention one reason that it's important.

What's important is white LEDS, probably the most used color. There isn't really a white LED. They are either three LEDS (R/G/B), or a blue led with some phosphor coating.

View on HN

So true. I'd love a miracle material that doesn't require a phosphor coating to get full spectrum lighting. Maybe some meta-material will come out in the next decade...

Meanwhile, these guys keep popping up when I search for LED spectrograms. They seem to have good phosphor coatings for their LEDs. It's certainly one of the better spectrograms I've seen for an LED lightbulb. https://www.waveformlighting.com/full-spectrum-led-lighting

Not sure you want full spectrum lighting, that would likely reduce the perceived luminosity (not sure about this? How much do rods contribute to it?).

For more efficient color conversion, try quantum dots. You could likely replace phosphor coating with it.

One answer is to stack 3 LEDs on the die, each tuned to the center wavelength of human photo-receptors. Existing RGB LEDs emulating "white" suffer from shadowing effects where shadows have a color based on the parallax between the red, green, and blue elements in the light bulb. This is no longer an issue if you co-locate the emitters.

This works for direct illumination (eg an LCD screen) but fails for reflected light (eg a light).

This video from Technology Connections helps explain https://youtu.be/uYbdx4I7STg

Technology Connections is the bomb. I think I've watched all of his videos at this point, highly recommend his channel.

Reply on news.ycombinator.com