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

Yes, the red LED came first in 1962, then the green, and some yellow-ish colors. The blue wasn’t invented until the 1990s, and it won the guys who did it a Nobel prize in physics. White LEDs are related to blue. In fact, most red LEDs now are made like blue ones, not the original technique, so you don’t really see the ruby-red look anymore anyway.