Color CRTs have three different phosphors, and the beams have to fire at the correct color phosphor. The best part of the video is the part where they tear apart an actual CRT, something you don ...

They need to either combine different LED colors (red, green, blue) or use a blue LED and cover it with yellow phosphor that filters blue wavelengths and ultimately produces a bright white light.

They're a manufacturing defect. The coating on the phosphor layer, which blocks blue wavelengths, is wearing out, throwing off the color of the light. 'AVOID THE AREA': TxDOT plans ‘full closure ...