(Phys.org)—Currently, all light-emitting diodes (LEDs) emit light of only one color, which is predefined during fabrication. So far, tuning the color of light produced by a single LED has never been realized, despite numerous ...
(Phys.org) —Quantum dot LEDs (QLEDs) are a promising technology for creating large-area displays that could have applications for TVs, cell phones, and digital cameras. So far, however, the highest efficiencies of QLEDs ...
(Phys.org) —Using an ink containing tiny graphene flakes, scientists have inkjet-printed graphene patterns that can be used for printing finely detailed, highly conductive electrodes. Although inkjet-printed graphene has ...
(Phys.org)—Many researchers have reported improvements in LED technology by enhancing the properties of the LED itself. But the packaging that secures and protects the LED also impacts its overall performance. In a new ...
(PhysOrg.com) -- For the first time, researchers have demonstrated that an LED can emit more optical power than the electrical power it consumes. Although scientifically intriguing, the results won’t immediately result ...
(PhysOrg.com) -- Physicists from Taiwan have designed and fabricated nano-sized light-emitting diodes (LEDs) that emit light spanning the entire visible spectrum. Although the tiny full-color LEDs aren't intended for commercial ...
(PhysOrg.com) -- Researchers from the Nichia Corporation in Tokushima, Japan, have set an ambitious goal: to develop a white LED that can replace every interior and exterior light bulb currently used in homes and offices. ...
(PhysOrg.com) -- Scientists have developed a lighting device that can change its color temperature throughout the day, matching the natural daylight chromaticities produced by the sun. Currently, no other type of lighting ...
(PhysOrg.com) -- Organic semiconductors are promising building blocks for many devices, from LEDs to transistors, offering potential advantages such as cost-effectiveness, flexibility, and high performance. Currently, most ...
The invention of the printing press revolutionized duplication of the written word, giving the hands of tired scribes a break and making written material more accessible. A similar breakthrough has happened in reverse in ...
Optics & Photonics
Aug 10, 2023
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A light-emitting diode (LED) (pronounced /ˌɛliːˈdiː/, or just /lɛd/), is an electronic light source. The LED was first invented in Russia in the 1920s, and introduced in America as a practical electronic component in 1962. Oleg Vladimirovich Losev was a radio technician who noticed that diodes used in radio receivers emitted light when current was passed through them. In 1927, he published details in a Russian journal of the first ever LED.
All early devices emitted low-intensity red light, but modern LEDs are available across the visible, ultraviolet and infra red wavelengths, with very high brightness.
LEDs are based on the semiconductor diode. When the diode is forward biased (switched on), electrons are able to recombine with holes and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor. The LED is usually small in area (less than 1 mm2) with integrated optical components to shape its radiation pattern and assist in reflection.
LEDs present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching. However, they are relatively expensive and require more precise current and heat management than traditional light sources.
Applications of LEDs are diverse. They are used as low-energy indicators but also for replacements for traditional light sources in general lighting and automotive lighting. The compact size of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are useful in communications technology.
This text uses material from Wikipedia, licensed under CC BY-SA
