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It’s hard to believe that the first blue LED didn’t arrive until 1993. They look simple, but looks are deceiving (Fig. 1). 1. Image showing a blue InGaN-based LED with gold wire contacts (0.4 × 0.4 mm ...

LED, or light emitting diode therapy, is a skincare treatment that uses varying wavelengths of light, including red and blue. NASA originally developed it for plant growth experiments on shuttle ...