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Encyclopedia > LED lamp
LED Lamp with GU10 twist lock fitting, intended to replace halogen reflector lamps.
LED Lamp with E27 Edison screw.

A LED lamp is a type of solid state lighting (SSL) that utilizes light-emitting diodes (LEDs) as a source of illumination rather than electrical filaments or gas. Image File history File links Ampoules à LED, composé de 20 LED, puissance 1 Watt. ... Image File history File links Ampoules à LED, composé de 20 LED, puissance 1 Watt. ... GU10 is a triple CD 10th anniversary release from Boxed celebrating their Global Underground series. ... The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ... Image File history File linksMetadata Size of this preview: 800 × 600 pixel Image in higher resolution (2592 × 1944 pixel, file size: 1. ... Image File history File linksMetadata Size of this preview: 800 × 600 pixel Image in higher resolution (2592 × 1944 pixel, file size: 1. ... A 230/240 V AC incandescent light bulb with Edison E27 (27 mm) Male screw base. ... Solid State Lighting (SSL) refers to a type of lighting that utilizes light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes as sources of illumination rather than electrical filaments or gas. ... LED redirects here. ... An electrical filament is a thread of metal, usually tungsten, which is used to convert electricity into light in incandescent light bulbs (as developed in 1878 by Joseph Wilson Swan, among others), and into heat in vacuum tube devices. ... For other uses, see Gas (disambiguation). ...


LED lamps (also called LED bars or Illuminators) are usually clusters of LEDs in a suitable housing. They come in different shapes, including the standard light bulb shape with a large E27 Edison screw and MR16 shape with a bi-pin base. Other models might have a small Edison E14 fitting, GU5.3 (Bipin cap) or GU10 (bayonet socket). This includes low voltage (typically 12 V halogen-like) varieties and replacements for regular AC mains (120-240 V AC) lighting. Currently the latter are less widely available but this is changing rapidly. The light bulb is one of the most significant inventions in the history of the human race, illuminating the darkness of the evening and bringing light indoors at all times in order focus on the task at hand. ... A 230/240 V AC incandescent light bulb with Edison E27 (27 mm) Male screw base. ... A typical MR16 lamp MR16 (sometimes referred to as MR-16) is a standard format for halogen reflector lamps made by a variety of manufactures. ... A 230/240 V AC incandescent light bulb with Edison E27 (27 mm) Male screw base. ... A halogen lamp with a bipin cap. ... A bayonet mount A bayonet mount before and after insertion A bayonet mount or bayonet connector is a fastening mechanism that relies on mated surfaces; a male side with one or more pins or slots, and a female receptor with matching slots and a spring that maintains a clamping force. ...

Contents

History

The phenomenon of solid state junctions producing light was discovered in the crystal detector era. In the 1960s commercial red LEDs became available, and by the 1970s these were in widespread use as indicators in a very wide range of equipment. These early LEDs had much too small an output to be useful as lighting. They replaced the previously widely used indicator types of filament lamps and neons. Compared to neons, indicator LEDs have longer lifetimes and run on lower voltage; compared to underrun miniature filament lamps, indicator LEDs have much longer lifetimes, such that they do not require replacement, and consume less power. The lack of need for replacement also eliminates the need for bulb sockets and a user access port.


Commercial amber (yellow) and orange LEDs followed, and were used where differentiation of multiple LEDs was required. For many years LEDs came in infra-red, red, orange, yellow, and green. Blue, cyan, and violet LEDs finally appeared in the 1990s.


To produce a white SSL device, a blue LED was needed. In 1993, Shuji Nakamura of Nichia Corporation came up with a blue LED using gallium nitride (GaN). With this invention, it was now possible to create white light by combining the light of separate LEDs (red, green, and blue), or by placing a blue LED in a package with an internal light converting phosphor. With the phosphor type, some of the blue output becomes either yellow or red and green with the result that the LED light emission appears white to the human eye. Shuji Nakamura (中村 修二 Nakamura Shūji, born in May 22, 1954, Ikata, Ehime, Japan) is a professor at the University of California, Santa Barbara (UCSB). ... The Nichia Corporation is a Japanese chemical manufacturing company that is most widely known for producing phosphors. ... Gallium nitride (GaN) is a wide bandgap semiconductor material used in optoelectronic, high-power and high-frequency devices. ... Green screen A phosphor is a substance that exhibits the phenomenon of phosphorescence (sustained glowing after exposure to light or energised particles such as electrons). ...


Technology overview

A single LED die can produce only a limited amount of light, and only a single color at a time. To produce the white light necessary for SSL, light spanning the visible spectrum (red, green, and blue) must be generated in approximately correct proportions. To achieve this, three approaches are used for generating white light with LEDs: wavelength conversion, color mixing, and most recently Homoepitaxial ZnSe. External links LEd Category: TeX ... Visible light redirects here. ... For other uses, see Wavelength (disambiguation). ... Zinc selenide (ZnSe), is a light yellow binary solid compound. ...


Wavelength conversion involves converting some or all of the LED’s output into visible wavelengths. Methods used to accomplish this feat include:

  • Blue LED & yellow phosphor – Considered the least expensive method for producing white light. Blue light from an LED is used to excite a phosphor which then re-emits yellow light. This balanced mixing of yellow and blue lights results in the appearance of white light, but produces poor color rendition (i.e., has low CRI).
  • Blue LED & several phosphors – Similar to the process involved with yellow phosphors, except that each excited phosphor re-emits a different color. Similarly, the resulting light is combined with the originating blue light to create white light. The resulting light, however, has a richer and broader wavelength spectrum and produces a higher color-quality light, albeit at an increased cost.
  • Ultraviolet (UV) LED & red, green, & blue phosphors – The UV light is used to excite the different phosphors, which are doped at measured amounts. The colors are mixed resulting in a white light with the richest and broadest wavelength spectrum.
  • Blue LED & quantum dots – A process by which a thin layer of nanocrystal particles containing 33 or 34 pairs of atoms, primarily cadmium and selenium, are coated on top of the LED. The blue light excites the quantum dots, resulting in a white light with a wavelength spectrum similar to UV LEDs.

Color mixing involves using multiple colors of LEDs in a lamp to produce white light. Such lamps contain a minimum of two LEDs (blue and yellow), but can also have three (red, blue, and green) or four (red, blue, green, and yellow). As no phosphors are used, there is no energy lost in the conversion process, thereby exhibiting the potential for higher efficiency. External links LEd Category: TeX ... Green screen A phosphor is a substance that exhibits the phenomenon of phosphorescence (sustained glowing after exposure to light or energised particles such as electrons). ... External links LEd Category: TeX ... Green screen A phosphor is a substance that exhibits the phenomenon of phosphorescence (sustained glowing after exposure to light or energised particles such as electrons). ... For other uses, see Ultraviolet (disambiguation). ... A quantum dot is a potential well that confines electrons in three dimensions to a region of the order of the electrons de Broglie wavelength in size, a few nanometers in a semiconductor. ... General Name, Symbol, Number cadmium, Cd, 48 Chemical series transition metals Group, Period, Block 12, 5, d Appearance silvery gray metallic Standard atomic weight 112. ... For other uses, see Selenium (disambiguation). ... A phosphor is a substance that can exhibit the phenomenon of fluorescence (glowing during absorption of radiation of another kind) or phosphorescence (sustained glowing without further stimulus). ...


Homoepitaxial ZnSe is a technology developed by Sumomito Electric where a LED is grown on a ZnSe substrate, which simultaneously produces blue light from the active region and yellow emission from the substrate. The resulting white light has a wavelength spectrum on par with UV LEDs. No phosphors are used, resulting in a higher efficiency white LED. It has been suggested that Wafer prober be merged into this article or section. ...


To be considered SSL, however, a multitude of LEDs must be placed close together in a lamp to add their illuminating effects. This is because an individual LED produces only a small amount of light, thereby limiting its effectiveness as a replacement light source. In the case where white LEDs are utilized in SSL, this is a relatively simple task, as all LEDs are of the same color and can be arranged in any fashion. When using the color-mixing method, however, it is more difficult to generate equivalent brightness when compared to using white LEDs in a similar lamp size. Furthermore, degradation of different LEDs at various times in a color-mixed lamp can lead to an uneven color output. Because of the inherent benefits and greater number of applications for white LED based SSL, most designs focus on utilizing them exclusively. External links LEd Category: TeX ... External links LEd Category: TeX ...


Driving LEDs

LEDs have very low dynamic resistance, with the same voltage drop for widely varying currents. Consequently they can not connect direct to most power sources without causing self destruction. A current control ballast is normally used, which is sometimes constant current.


Indicator LEDs

Miniature indicator LEDs are normally driven from low voltage DC via a current limiting resistor. Currents of 2mA, 10mA and 20mA are common. Some low current indicators are only rated to 2mA, and should not be driven at higher current. Resistor symbols (American) Resistor symbols (Europe, IEC) Axial-lead resistors on tape. ...


Sub-mA indicators may be made by driving ultrabright LEDs at very low current. Efficacy tends to reduce at low currents, but indicators running on 100uA are still practical. The cost of ultrabrights is higher than 2mA indicator LEDs.


LEDs have a low max repeat reverse voltage rating, ranging from apx 2v to 5v, and this can be a problem in some apps. Back to back LEDs are immune to this problem. These are available in single color as well as bicolor types. There are various strategies for reverse voltage handling.


In niche applications such as IR therapy, LEDs are often driven at far above rated current. This causes high failure rate and occasional LED explosions. Thus many parallel strings are used, and a safety screen and ongoing maintenance are required.


Alphanumeric LEDs

These use the same drive strategy as indicator LEDs, the only difference being the larger number of channels, each with its own resistor. 7 segment and starburst LED arrays are available in both common anode or common cathode forms.


Lighting LEDs on mains

A CR dropper (capacitor & resistor) followed by full wave rectification is the usual ballast with mains driven series-parallel LED clusters.


A single series string would minimise dropper losses, but one LED failure would extinguish the whole string. Parallelled strings increase reliability. In practice usually 3 strings or more are used.


Operation on square wave and modified sine wave (MSW) sources, such as many inverters, causes heavily increased resistor dissipation in CR droppers, and LED ballasts designed for sine wave use tend to burn on non-sine waveforms. The non-sine waveform also causes high peak LED currents, heavily shortening LED life. An inductor & rectifier makes a more suitable ballast for such use, and other options are also possible. A square wave is a kind of basic waveform. ... An inverter may be: inverter (electrical), which converts direct current (DC) to alternating current (AC) inverter (logic gate), also called a NOT gate. ... An inverter may be: inverter (electrical), which converts direct current (DC) to alternating current (AC) inverter (logic gate), also called a NOT gate. ... A wave that loses amplitude is said to dissipate. ... In trigonometry, an ideal sine wave is a waveform whose graph is identical to the generalized sine function y = Asin[ω(x − α)] + C, where A is the amplitude, ω is the angular frequency (2π/P where P is the wavelength), α is the phase shift, and C is the... Look up burn, burning, burned in Wiktionary, the free dictionary. ... Waveform quite literally means the shape and form of a signal, such as a wave moving across the surface of water, or the vibration of a plucked string. ... Look up current in Wiktionary, the free dictionary. ... An inductor is a passive electrical device employed in electrical circuits for its property of inductance. ... AC, half-wave and full wave rectified signals A rectifier is an electrical device, comprising one or more semiconductive devices (such as diodes) or vacuum tubes arranged for converting alternating current to direct current. ...


Lighting LEDs on low voltage

LEDs are normally operated in parallel strings of series LEDs, with the total LED voltage typically adding up to around 2/3 of the supply voltage, and resistor current control for each string. A broad metal chain made of torus-shaped links. ... In a general sense, a series is a related set of things that occur one after the other or are otherwise connected one after the other. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Resistor symbols (American) Resistor symbols (Europe, IEC) Axial-lead resistors on tape. ... Look up current in Wiktionary, the free dictionary. ...


In resistor-drive devices, LED current is then proportional to power supply (PSU) voltage minus total LED string voltage. Where battery sources are used, the PSU voltage can vary widely, causing large changes in LED current and therefore color and light output. For such applications, a constant current regulator is preferred to resistor control. Low drop-out (LDO) constant current regs also allow the total LED string voltage to be a higher percentage of PSU voltage, resulting in improved efficiency and reduced power use. A wall wart style variable DC power supply with its cover removed. ... For other uses, see Battery. ... For other uses, see Light (disambiguation). ... Look up efficiency in Wiktionary, the free dictionary. ...


Torches run 1 or more lighting LEDs on a low voltage battery. These usually use a resistor ballast. This article is about portable open fires. ... For other uses, see Battery. ... Resistor symbols (American) Resistor symbols (Europe, IEC) Axial-lead resistors on tape. ...


In disposable coin cell powered keyring type LED lights, the resistance of the cell itself is usually the only current limiting device. The cell should not therefore be replaced with a lower resistance type, such as one using a different battery chemistry. For other uses, see Battery. ...


Finally, an LED can be run from a single cell by use of a constant current switched mode invertor. While adding additional expense, this method provides a high level of color and brightness control, and ensures longer LED lifetime.


Comparison to other lighting technologies

  • Incandescent lamps (light bulbs) create light by running electricity through a thin filament, thereby heating the filament to a very high temperature and producing visible light. The incandescing process, however, is highly inefficient, as over 98% of its energy input is emitted as heat.[citation needed] Incandescent lamps, however, are relatively inexpensive to produce. The typical lifespan of a mains incandescent lamp is around 1,000 hours.[citation needed]
  • Fluorescent lamps (light bulbs) work by passing electricity through mercury vapor, which in turn produces ultraviolet light. The ultraviolet light is then absorbed by a phosphor coating inside the lamp, causing it to glow, or fluoresce. While the heat generated by fluorescent lamps is much less than its incandescent counterpart, energy is still lost in generating the ultraviolet light and converting this light into visible light. In addition, and should the lamp break, exposure to mercury can occur, though the levels involved are not considered hazardous. Linear fluorescent lamps are typically five to six times the cost of incandescent lamps[citation needed], but have life spans around 10,000 and 20,000 hours. Lifetime varies from 1,200 hours to 20,000 hours for compact fluorescent lamps.
  • SSL/LEDs LEDs come in multiple colors, which are produced without the need for filters. A white SSL can be comprised of a single high-power LED, multiple white LEDs, or from LEDs of different colors mixed to produce white light. The inherent advantages and disadvantages of SSL are currently the same as those of a LED. Advantages include:
    • High efficiency - LEDs are now available that reliably offer over 100 lumens from a one-watt device, or much higher outputs at higher drive currents
    • Small size - provides design flexibility, arranged in rows, rings, clusters, or individual points
    • High durability - no filament or tube to break
    • Life span - in properly engineered lamps, LEDs can last 50,000 - 60,000 hours
    • Full dimmability – unlike fluorescent lamps, LEDs can be dimmed using pulse-width modulation (PWM - turning the light on and off very quickly at varying intervals). This also allows full color mixing in lamps with LEDs of different colors.[1],[2].
    • Mercury-free - unlike fluorescent and most HID technologies, LEDs contain no hazardous mercury or halogen gases

An example of PWM: the supply voltage (blue) modulated as a series of pulses results in a sine-like flux density waveform (red) in a magnetic circuit of electromagnetic actuator. ...

Applications

This garden light can use stored solar energy due to the low power consumption of its LED

Image File history File links Size of this preview: 450 × 600 pixelsFull resolution (1536 × 2048 pixel, file size: 1. ... Image File history File links Size of this preview: 450 × 600 pixelsFull resolution (1536 × 2048 pixel, file size: 1. ... Ultraviolet image of the Sun. ... This article is about a traffic control device. ... Blinker redirects here. ... This is a current Stagecraft collaboration! Please help improve it to good article standard. ... Bicycle lighting has two purposes: seeing and being seen. ... For the Parliament song, see Flash Light (song). ... Billboard can refer to: Billboard magazine Billboard (advertising) Billboard antenna In 3D computer graphics, to billboard is to rotate an object so that it faces the viewer. ... This is a current Stagecraft collaboration! Please help improve it to good article standard. ... Art exhibitions are traditionally the space in which art objects (in the most general sense) meet an audience. ...

Challenges

The current manufacturing process of white LEDs has not matured enough for them to be produced at low enough cost for widespread use. There are multiple manufacturing hurdles that must be overcome. The process used to deposit the active semiconductor layers of the LED must be improved to increase yields and manufacturing throughput. Problems with phosphors, which are needed for their ability to emit a broader wavelength spectrum of light, have also been an issue. In particular, the inability to tune the absorption and emission, and inflexibility of form have been issues in taking advantage of the phosphors spectral capabilities. A semiconductor is a solid material that has electrical conductivity in between that of a conductor and that of an insulator; it can vary over that wide range either permanently or dynamically. ... For other uses, see Wavelength (disambiguation). ...


More apparent to the end user, however, is the low Color Rendering Index (CRI) of current LEDs. The current generation of LEDs, which employs mostly blue LED chip + yellow phosphor, has a CRI around 70, which is much too low for widespread use in indoor lighting. (CRI is used to measure how accurately a lighting source renders the color of objects. Sunlight and some incandescent lamps have a perfect CRI of 100, while white fluorescent lamps have CRI varying from the 50s to 95.) Better CRI LEDs are more expensive, and more research & development is needed to reduce costs. End user costs are still too high to make it a viable option, for instance, Maplin's website quotes comparable LED spots at £9.99 GBP[3] against the standard Halogen lamp twin pack which comes in at £6.49 GBP[4] (or roughly £3.25 GBP each). Colour rendering index, or CRI, is a measure of the quality of colour light, devised by the International Commission on Illumination (CIE). ... The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ...


Variations of CCT (color correlated temperature) at different viewing angles present another obstacle against widespread use of white LED. It has been shown, that CCT variations can exceed 500 K, which is clearly noticeable by human observer, who is normally capable of distinguishing CCT differences of 50 to 100 K in range from 2000 K to 6000 K, which is the range of CCT variations of daylight. The CIE 1931 x,y chromaticity space, also showing the chromaticities of black-body light sources of various temperatures, and lines of constant correlated color temperature Color temperature is a characteristic of visible light that has important applications in photography, videography, publishing and other fields. ...


LEDs also have limited temperature tolerance and falling efficiency as temperature rises. This limits the total LED power that can practically be fitted into lamps that physically replace existing filament & compact fluorescent types. R&D is needed to improve thermal characteristics.


Research and development

Bilkent University (In Turkish: Bilkent Üniversitesi) was founded on October 20, 1984 by İhsan Doğramacı through the resolution of the foundations which had earlier been established by him. ... A nanocrystal is a crystalline material with dimensions measured in nanometers; a nanoparticle with a structure that is mostly crystalline. ...

Future

The performance of digital solid state electronics roughly doubles every 18 months (Moore's Law). Hence it is hoped by many that LED development may follow a similar course. This is only physically possible up to a point. LEDs have shown relatively rapid development recently, but the technology is still well behind some other light sources, primarily due to the many issues with LEDs and their high cost. Gordon Moores original graph from 1965 Growth of transistor counts for Intel processors (dots) and Moores Law (upper line=18 months; lower line=24 months) For the observation regarding information retrieval, see Mooers Law. ...


If Moore's Law keeps applying to LEDs' luminous intensity, and all other issues are somehow quickly solved, LEDs may soon become more common than fluorescent lamps.


See also

Energy Portal

Image File history File links Portal. ... Simple LED circuit diagram In electronics, an LED circuit is an electrical circuit used to power a light-emitting diode, or LED. The LED being used usually has a forward voltage specified. ... Photopic (black) and scotopic [1] (green) luminosity functions. ... The lux (symbol: lx) is the SI derived unit of illuminance or illumination. ... A Common Household Light bulb This is a list of sources of light, including both natural and artificial sources, and both processes and devices. ... Spectrometer A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. ... Luminous flux is a measure of the energy emitted by a light source in all directions. ... The CIE 1931 x,y chromaticity space, also showing the chromaticities of black-body light sources of various temperatures, and lines of constant correlated color temperature Color temperature is a characteristic of visible light that has important applications in photography, videography, publishing and other fields. ... Radiation angle: In fiber optics, half the vertex angle of the cone of light emitted at the exit face of an optical fiber. ...

References

  1. ^ Warm light and high efficiency

Further reading

External links

News

Delta electronics to ship 5W bulb for $12 in July 2008 [5]

For devices such as table lamps and reading lamps, see Light fixture. ... Not to be confused with lightning. ... Molten glassy material glows orange with incandescence in a vitrification experiment. ... Light bulb redirects here. ... The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ... Nernst lamp, complete, model B with cloche, DC-lamp 0. ... A Parabolic Aluminized Reflector light, or PAR light, is a type of light commonly used in motion picture production when a substantial amount of light is required for a scene. ... The Centennial Light hanging in the Livermore, California Firehouse. ... Image File history File links Size of this preview: 361 × 600 pixelsFull resolution (768 × 1276 pixel, file size: 757 KB, MIME type: image/png) Other versions Original at Image:Gluehlampe 01 KMJ.jpg File historyClick on a date/time to view the file as it appeared at that time. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized Cadmium selenide (CdSe) quantum dots. ... Low-energy light-bulb redirects here. ... Fluorescent lamps Assorted types of fluorescent lamps. ... In contrast with all other electrical lamps that use electrical connections through the lamp envelope to transfer power to the lamp, in electrodeless lamps the power needed to generate light is transferred from the outside of the lamp envelope by means of (electro)magnetic fields. ... Germicidal lamps are simple low pressure mercury vapor discharges in a fused quartz envelope. ... 15 kW Xenon short-arc lamp used in IMAX projectors High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium (Son), low-pressure sodium (Sox) and less common, xenon short-arc lamps. ... A Mercury-vapor lamp is a gas discharge lamp which uses mercury in an excited state to produce light. ... Example of a light source using a broad spectrum metal halide lamp pointing upward towards the sky. ... Lighting neon lamp, two 220/230 volt and 110 V neon lamps and a screwdriver with neon lamp inside A neon lamp is a gas discharge lamp containing primarily neon gas at low pressure. ... A low pressure sodium/sodium oxide (LPS/SOX) streetlamp at full power A low pressure sodium/sodium oxide (LPS/SOX) streetlamp at full power (detail) A sodium vapor lamp is a gas discharge lamp which uses sodium in an excited state to produce light. ... This section may require cleanup to meet Wikipedias quality standards. ... Xenon flash lamp being fired. ... A 3000 volt electricity arc between two nails Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc can melt calcium oxide An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current... The 300,000-watt Plasma Arc Lamp in the Infrared Processing Center (IPC) at Oak Ridge National Laboratory An arc lamp is a device that produces light by the sparking (or arcing, from voltaic arc) of a high current between two carbon rod electrodes. ... A Yablochkov candle (sometimes electric candle) is a type of electric carbon arc lamp, invented in 1876 by Pavel Yablochkov. ... This article is about the chemical reaction combustion. ... Lit carbide lamp A French manufactured Carbide of Calcium lamp on a bicycle Carbide of Calcium lamp in a coal mine Carbide lamps also known as Acetylene Gas lamps are simple lamps that produce and burn acetylene gas (C2H2) which is created by the reaction of calcium carbide (CaC2) with... The Argand lamp was invented and patented in 1780 by Aimé Argand . ... For other uses, see Candle (disambiguation). ... The Indian light festival Diwali is traditionally lit up by huge numbers of Diya (plural diyas). Diya is a contracted form of deep or light given by small earthen pots (also known as Pradeep), with wick made of cotton and dipped in ghee. ... Gas lighting is the process of burning piped natural gas or coal gas for illumination. ... Swiss kerosene lamp. ... For other uses, see Lantern (disambiguation). ... This article does not cite any references or sources. ... Antique bronze oil lamp with Christian symbol (replica) A terra-cotta oil lamp, Antique oil lamp (replica) An oil lamp is a simple vessel used to produce light continuously for a period of time from a fuel source. ... Safety lamp is the name of a variety of lamps for safety in coal-mines against coal dust, methane, or firedamp, a highly explosive mixture of natural gas apt to accumulate in them. ... It has been suggested that this article or section be merged into Kerosene lamp. ... A Rushlight is a type of candle formed using the dried pith of the rush plant as its wick. ... Tilley Lamp TL10 from 1922-1946 The Tilley Lamp derives from John Tilley’s invention of the hydro-pneumatic blowpipe in 1813. ... This article is about portable open fires. ... LBNL researcher examines prototype sulfur lamp. ... LED redirects here. ... Solid State Lighting (SSL) refers to a type of lighting that utilizes light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes as sources of illumination rather than electrical filaments or gas. ... This article or section does not cite its references or sources. ... Electroluminescent wire (often abbreviated to EL wire) is a thin copper wire coated in a phosphor which glows when an AC voltage is applied to it. ... A chemoluminescent reaction carried out in an erlenmeyer flask producing a large amount of light. ... Emission spectrum of an ultraviolet deuterium arc lamp clearly showing characteristic hydrogen emission lines (sharp peaks at 656 nm and 486 nm) and continuum emission in the ~160-400 nm region. ... Radioluminescence is the phenomenon by which luminescence is produced in a material by the bombardment of ionizing radiation such as beta particles. ...

 
 

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