Related topics: light

A light bright and tiny: Scientists build a better nanoscale LED

A new design for light-emitting diodes (LEDs) developed by a team including scientists at the National Institute of Standards and Technology (NIST) may hold the key to overcoming a long-standing limitation in the light sources' ...

Faster LEDs for wireless communications from invisible light

Researchers have solved a major problem for optical wireless communications—the process by which light carries information between cell phones and other devices. Light-emitting diodes (LEDs) pulse their light in a coded ...

Organic spacers improve LED performance

Light-emitting diodes (LEDs) release energy in the form of light when electrons and "holes" (electron vacancies) recombine in response to an applied voltage. Over the past few years, scientists have turned their attention ...

Pure red LEDs fulfill a primary goal

Making pure red LEDs from nitride crystals is a goal that has so far frustrated engineers. However, these LEDs are vital for building the next generation of energy-efficient micro-LED displays to follow OLED displays and ...

Stable perovskite LEDs one step closer

Researchers at Linköping University, working with colleagues in Great Britain, China and the Czech Republic, have developed a perovskite light-emitting diode (LED) with both high efficiency and long operational stability. ...

Hot OLEDs can 'switch back'

It is well-known that LEDs and transistors should not be connected in parallel as slight differences in resistance can lead to imbalanced current flow. This effect gets even stronger if the devices heat up as their resistance ...

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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