How long have LEDs been used in lighting?
LED lighting started in the early 1960s. General Electric, RCA, and Texas Instruments discovered that miniature crystals emitted infrared radiation when electric current was applied; this turned out to be the first light emitting diode, or LED. Shortly thereafter, the first visible (red-colored) LED was developed. In the 1970’s, additional colors and wavelengths for LEDs were discovered, and LEDs were utilized commercially in calculators, digital watches, and test equipment. Attempts to expand into other markets were hindered by high failure rates…. unproven manual component assembly methods, and epoxy, crystal and substrate defects lead to short life cycles, thus limiting LED applications. The 1980s brought improved LED materials, which meant improved efficacy and brighter, longer-lasting LEDs. LEDs were incorporated into message boards, outdoor signs, barcoding and medical equipment, but end users still saw a noticeable decrease in light output after several years. During the 1990s,
