Related topics: light

The science behind varying performance of different colored LEDs

Researchers from the Low Energy Electronic Systems (LEES) Interdisciplinary Research Group (IRG) at Singapore-MIT Alliance for Research and Technology (SMART), MIT's research enterprise in Singapore, together with Massachusetts ...

New perovskite LED emits a circularly polarized glow

Light-emitting diodes (LEDs) have revolutionized the displays industry. LEDs use electric current to produce visible light without the excess heat found in traditional light bulbs, a glow called electroluminescence. This ...

Blue light means big progress for perovskite-based LEDs

Researchers at Linköping University, Sweden, have developed efficient blue light-emitting diodes based on halide perovskites. "We are very excited about this breakthrough," says Feng Gao, professor at Linköping University. ...

Optoelectronic devices that emit warm and cool white light

The advantages of light-emitting diodes (LEDs), such as their tiny size, low cost and excellent power efficiency, mean they are found everywhere in modern life. A KAUST team has recently developed a way of producing a white-light ...

Sol 2931: Mars Hand Lens Imager instrument acquires image

NASA's Mars rover Curiosity acquired this image using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover's robotic arm, on November 3, 2020, Sol 2931 of the Mars Science Laboratory Mission, at ...

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Light-emitting diode

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