The invention of LEDs (light emitting diodes) was a multi-stage process involving contributions from many scientists. Here are some key historical moments in the invention of LEDs:
Early theory and experiments:
1907: British scientist H.J. Round first observed that the semiconductor material silicon carbide (SiC) emits light when electricity is applied. This was the first recorded electroluminescence phenomenon of semiconductor materials.
1920s: Russian scientist Oleg Losev further studied the phenomenon and published a paper on the principles of LEDs in 1927, but it did not attract widespread attention at the time.
Development of practical LEDs:
1962: Nick Holonyak Jr., an engineer working at General Electric (GE) at the time, invented the first practical visible light LED (red LED). Holonyak is known as the “Father of LEDs”.
1972: M. George Craford, a student of Holonyak, invented the first yellow LED and greatly improved the brightness of red and orange LEDs. He made improvements based on the gallium nitride phosphorus (GaAsP) material to increase the brightness of LEDs tenfold.
1970s and 1980s: Advancing technology led to the creation of LEDs in more colors, including green, yellow, and orange.
Blue LED Breakthrough:
1990s: Scientists at Hitachi and Nichia, notably Shuji Nakamura, invented high-brightness blue LEDs. This was a major breakthrough using gallium nitride (GaN) materials. The invention of blue LEDs made full-color displays and white LEDs possible.
2014: Shuji Nakamura, Isamu Akasaki, and Hiroshi Amano were awarded the Nobel Prize in Physics for their work on blue LEDs.
Development of White LEDs:
White LEDs are typically created by combining blue LEDs with phosphors. The blue light from the blue LED excites the phosphor, which then emits yellow light, and the combination of the two produces white light.
Advances in LED technology have resulted in a wide range of LED colors not only in the visible range, but also in the ultraviolet and infrared ranges. Today, LEDs are used in a variety of applications, including displays, lighting, indicator lights, and communications.
The following introduces the basic classification and application of LED
●Classification by output power: 0.4W, 1.28W, 1.4W, 3W, 4.2W, 5W, 8W, 10.5W, 12W, 15W, 18W, 20W, 23W, 25W, 30W, 45W, 60W, 100W, 120W, 150W, 200W, 300W, etc.
●Classification by output voltage: DC4V, 6V, 9V, 12V, 18V, 24V, 36V, 42V, 48V, 54V, 63V, 81V, 105V, 135V, etc.
●Classification by appearance structure: two types: PCBA bare board and with shell.
●Classification by safety structure: two types: isolated and non-isolated.
●Classification by power factor: with power factor correction and without power factor.
●Classification by waterproof performance: waterproof and non-waterproof.
●Classification by excitation method: self-excitation and external excitation.
●Classification by circuit topology: RCC, Flyback, Forward, Half-Bridge, Full-Bridge, Push-PLL, LLC, etc.
●Classification by conversion method: AC-DC and DC-DC.
●Classification by output performance: constant current, constant voltage and both constant current and constant voltage.
Application of LED driver power supply:
Used for spotlights, cabinet lights, night lights, eye protection lights, LED ceiling lights, lamp cups, buried lights, underwater lights, wall washers, floodlights, street lights, signboard light boxes, string lights, downlights, special-shaped lights, star lights, guardrail lights, rainbow lights, curtain wall lights, flexible lights, strip lights, belt lights, piranha lights, fluorescent lights, high pole lights, bridge lights, mining lights, flashlights, emergency lights, table lamps, lighting, traffic lights, energy-saving lamps, car taillights, lawn lights, colored lights, crystal lamps, grille lights, tunnel lights, etc.
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Post time: Aug-03-2024