Do the rare "violet" LEDs emit true violet (400-420nm) light, or do they mix blue and red (440nm and 700nm) light?
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3\$\begingroup\$ farnell.com/datasheets/1760173.pdf \$\endgroup\$– Wesley LeeDec 19, 2017 at 1:47
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1\$\begingroup\$ there's probably both types, but I'd expect red+blue to be called "magenta" while visble wavelenghs above blue are called "violet" the data sheet for the LED involved will probably have the details. \$\endgroup\$– Jasen Слава УкраїніDec 19, 2017 at 2:47
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1\$\begingroup\$ As a regular spectacle wearer, it's easy to spot the LEDs that use blue + red. The chromatic aberration at the edges of the spectacle lenses is sufficient that I see separate blue and red lights. \$\endgroup\$– Simon BDec 19, 2017 at 9:51
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99% sure they are a blue LED + red phosphor. That's "purple" LEDs. I recently ordered a few grams of the rare-earth red phosphor to play with.
There are also relatively inexpensive and high power 405nm "UV" LEDs which can be used to cure some UV-cured materials. I have used them to cure adhesives.
The price generally goes up as the wavelength decreases. When you get into the UVC "germicidal" category things get relatively pricey.
Generally if they are an LED without phosphor they will specify the wavelength in nm.
answered Dec 19, 2017 at 1:50