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

White LED indicators weren’t just hard, they were impossible to create until the blue led was created almost 40 years after the other colors. Eventually after that we changed over to using the blue or uv led’s then using a phosphor to change the light to white.