An Introduction to Light-emitting Diodes
By C. Bourget. 2008
276 citations recorded by the source corpus.
Light-emitting diodes (LEDs) are semiconductor devices that produce noncoherent, narrow-spectrum light when forward voltage is applied. LEDs range in wavelength from the UVC band to infrared (IR) and are available in packages ranging from milliwatts to more than 10 W. The first LED was an IR-emitting device and was patented in 1961. In 1962, the first practical visible spectrum LED was developed. The first high-power (1-W) LEDs were developed in the late 1990s. LEDs create light through a semiconductor process rather than with a superheated element, ionized gas, or an arc discharge as in traditional light sources. The wavelength of the light emitted is determined by the materials used to form the semiconductor junction. LEDs produce more light per electrical watt than incandescent lamps with the latest devices rivaling fluorescent tubes in energy efficiency. They are solid-state devices, which are much more robust than any glass-envelope lamp and contain no hazardous materials like fluorescent lamps. LEDs also have a much longer lifetime than incandescent, fluorescent, and high-density discharge lamps (U.S. Dept. of Energy). Although LEDs possess many advantages over traditional light sources, a total system approach must be considered when designing an LED-based lighting system. LEDs do not radiate heat directly, but do produce heat that must be removed to ensure maximum performance and lifetime. LEDs require a constant-current DC power source rather than a standard AC line voltage. Finally, because LEDs are directional light sources, external optics may be necessary to produce the desired light distribution. A properly designed LED light system is capable of providing performance and a lifetime well beyond any traditional lighting source.
Subfields: Condensed Matter Physics, Electrical and Electronic Engineering
View Paper: https://www.semanticscholar.org/paper/614728b30c22ee7a6abd3a43e9223bbfe406467f
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Condensed Matter Physics
In Electrical and Electronic Engineering
Citations in the corpus
- A Moderate to High Red to Far-red Light Ratio from Light-emitting Diodes Controls Flowering of Short-day Plants (2013, background): “Compared with conventional lamps, LEDs have many desirable characteristics including a very long operating life, narrow bandwidth capability, full instantaneous irradiance when powered, and continually improving electrical efficiencies (Bourget, 2008; Morrow, 2008).”
- Growth, Photosynthetic Characteristics, Antioxidant Capacity and Biomass Yield and Quality of Wheat (Triticum aestivum L.) Exposed to LED Light Sources with Different Spectra Combinations (2014, background): “As a result, crop yields, physiological characteristics and metabolic components are under control (Bourget 2008, Massa et al. 2008, Morrow 2008).”
- LEDs for Energy Efficient Greenhouse Lighting (2014, background): “A properly designed LED light system can provide highly efficient performance and longevity well beyond any traditional lighting source [11].”
- The effects of light-emitting diode lighting on greenhouse plant growth and quality (2013, background): “The lifetime of LEDs is about 50000 h and still rising (Bourget 2008).”
- Effect of light-emitting diodes on growth and morphogenesis of upland cotton (Gossypium hirsutum L.) plantlets in vitro (2010, background): “These solid-state light sources are therefore ideal for use in plant lighting designs, and they allow wavelengths to be matched to plant photoreceptors to provide more optimal production and to influence plant morphology and metabolism (Bourget 2008; Massa et al. 2008; Morrow 2008).”
- Comparison of Supplemental Lighting from High-pressure Sodium Lamps and Light-emitting Diodes during Bedding Plant Seedling Production (2014, background): “…energy causing the surface of HPS lamps to reach LEDs are solid-state, semiconducting diodes that can emit narrow spectra of light from 250 nm to 1000 nm or greater and have been considered for use as sole source and SL (Barta et al., 1992; Bourget, 2008; Bula et al., 1991; Massa et al., 2008).”