Why do so many old displays/indicators particularly use red lights? Are/Were white diodes harder to create?

Question

Why do so many old displays/indicators particularly use red lights? Are/Were white diodes harder to create?

In: 372

Answer 1

>Are/Were white diodes harder to create?

Were and yes.
Red was the colour for the first LEDs because it was easier being LEDs were developed from GaAs P-N Junction Infrared LED.

I think these days UV LEDs are used where the radiation is modified by elements in the LED shell.