Although considered relatively novel, the concept for LEDs first arose in 1907 when Henry Joseph Round used a piece of Silicone skylt & dekor Carbide (SiC) to emit a dim, yellow light. This was followed by experiments conducted by Bernhard Gudden and Robert Wichard Pohl in Germany during the late 1920s, in which they used “phosphor materials made from Zinc Sulphide (ZnS) [treated] with led skylt utomhus Copper (Cu)” to produce dim light.[3] However, during this time, a major obstacle existed, in that many of these early LEDs could not function efficiently företags skyltar at room temperature. Instead, they needed to be submerged in liquid nitrogen (N) for optimal performance.
This led to British and American experiments in the 1950s that used Gallium Arsenide (GaAs) as a substitute for Zinc Sulphide (ZnS) and the creation skyltar led of an LED that produced invisible, infrared light at room temperature. These LEDs immediately found use in photoelectric, sensing applications. The first “visible spectrum” LED, producing “red” light was created in 1962 by Nick Holonyak, Jr. (b. 1928) of stolpskyltar the General Electric Company who used Gallium Arsenide Phosphide (GaAsP) in place of Gallium Arsenide (GaAs). Once in existence, they were quickly adopted for use as indicator lights.
Before long these red LEDs were producing brighter light and even orange-colored electroluminescence when Gallium företagsskyltar Phosphide (GaP) substrates were used. By the mid 1970s, Gallium Phoshide (GaP) itself along with dual Gallium Phosphide (GaP) substrates were led skyltar being used to produce red, green, and yellow light. This ushered in the trend “towards [LED use in] more practical applications” such as calculators, digital watches and test fasadskylt belysning equipment, since these expanded colors addressed the fact that “the human eye is most responsive to yellow-green light.”[4]
However, rapid growth in the LED industry did not begin until the 1980s when Gallium Aluminium Arsenides (GaAIAs) were butik skyltar developed, providing “superbright” LEDs (10x brighter than LEDs in use at the time) – “first in red, then yellow and… green,” which also neonskyltar required less voltage providing energy savings. [5] This led to the concept of the first LED flashlight, in 1984.
