最初の実用的な可視スペクトル 導かれた was invented in 1962. This device, based on a Gallium Arsenide Phosphide (GaAsP) 半導体 substrate, emitted red light at a wavelength of approximately 650 nm. While its initial efficiency was low, it was the first LED bright enough for practical use, launching the industry of solid-state indicators and displays like those in early calculators.

















