By the way, a few lines of this are direct quotes from pages I found on the web, I'm not claiming that everything here is my own writing.
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(1) GAS DISCHARGE LIGHTING
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(-)General Information
* Plasma physics is the study of ionized gases.
* Plasma = a gas composed largely of ions and free electrons, all moving freely (creates a path for an electrical current)
* Discharge types: glow discharge, arc discharge, dielectric barrier discharge, high impact discharge
* In a gas discharge, such as a fluorescent lamp, current causes resistance to decrease (negative impedance).
(-) CFL
(=) Compact flourescent lamp
* Meant to replace incandescent bulbs of same size, screws into standard socket and includes built-in ballast
(-) CCFL / CCFT
(=) Cold cathode flourescent lamp / tube
* cold cathode lamp's electrodes operate at 400 degrees F
* The interior surface of the cathodes are capable of producing secondary electrons at a ratio greater than unity (amplification) upon electron impact. Initially, a high voltage is applied across the tube, which accelerates a small number of naturally existing electrons and ions to the cathode, where they collide and release more electrons, causing an avalanche effect, and introducing plasma into the tube. The voltage can be turned down once a current through the tube is established, and the above-unity electron generation of the cathode will sustain the current.
* Operating principle is known as "Glow Discharge": In its simplest form, it consists of two electrodes in a cell held at low pressure. The cell is typically filled with argon. A potential of several hundred volts is applied between the two electrodes. A small population of atoms within the cell is initially ionized through random processes (collisions between atoms or with alpha particles, for example). The ions (which are positively charged) are driven towards the cathode by the electric potential, and the electrons are driven towards the anode by the same potential. The initial population of ions and electrons collides with other atoms, ionizing them. As long as the potential is maintained, a population of ions and electrons remains.
* If using multiple lamps in parallel, driving current of all lamps must be in sync (usually done by having one single inverter designed for driving multiple outputs)
* ignition electrodes NOT made of filaments (ie tungsten etc); high striking voltage overcomes need for "hot" cathode
* moderately good efficiency (about 15% less than HCFL's), moderately low heat
* about 15% longer life than HCFL's (under CORRECT operation conditions); but dim over time
* lower max luminance than HCFT's, due to less max tolerable current
* may flicker when cold + low life when hot
* require high running voltage, higher ignition voltage (task of inverter)
(-) HCFT / HCFL
(=) Hot cathode flourescent tube / lamp
* "Standard" / "household" flourescent tubes
* Hot cathode flourescent lamp's electrodes operate at over 1500 degrees F
* current running through the electrodes "boils off" electrons (technically, thermionic emission), ....
* Note: Instant start fluorescent lamps start as cold-cathode devices but soon localized heating of the fine tungsten wire cathodes causes them to operate as ordinary hot cathode lamps. (very high initial voltage on the electrode causes an excess of electrons, leading to a corona discharge; this isn't completely the same mechanism used in CCFL's, but it doesn't involve heating a filament, so it is still "cold")
(-) EEFL
(=) External/Exterior electrode flourescent lamp
* Electrodes are completely outside of lamp
* Most Asian companies provide very poorly written descriptions of EEFL operation: "This lamp has its electrode outside of the lamp. It's quite opposite from that of general fluorescent lamp. The light source of this lamp is Plasma which is derived by External electrode of electric field inside the lamp." -- WTF?
* First of all, the operation IS quite different from both hot and cold cathode, BUT NOT in that its "light source is plasma" -- all the major gas discharge lamps employ a tube filled with an ionized gas and free electrons (ie, a plasma) to excite atoms (usually mercury for our purposes) which then emit UV light. Second, "by External electrode of electric field..." is just plain nonsensical and bad english, the electric field doesn't "possess" an electrode. Then, they are mixing in "external electric field of... inside the ..."; what is inside, and what is out? My (completely guessing !!) view is that perhaps it works similarly to a MOSFET (in a basic way, don't push the analogy too far): applying an electric field across the capacitances (ext electrode, glass dielectric, gasses) at each end frees up charge carriers (maybe by accumulating them on the surface, then a corona discharge?), and there is a DC offset between the sides which causes the free carriers to flow through a "channel".
* electrode is placed outside glass tube, but when a high voltage is placed on the electrode, capacitive coupling causes dielectric barrier discharge, introducing plasma into the tube and exciting mercury atoms, etc.
(-) Dielectric barrier discharge is then defined as:
* Dielectric-barrier discharges (DBD’s) comprise a specific class of high-voltage, ac, gaseous discharges that typically operate in the near-atmospheric pressure range. Their defining feature is the presence of dielectric layers that make it impossible for charges generated in the gas to reach the conducting electrode surfaces. With each half-cycle of the driving oscillation, the voltage applied across the gas exceeds that required for breakdown, and the formation of narrow discharge filaments initiates the conduction of electrons toward the more positive electrode. As charge accumulates on the dielectric layer(s) at the end(s) of each filament, the voltage drop across the filament is reduced until it falls below the discharge-sustaining level, whereupon the discharge is extinguished.
* Also known as "silent discharge"
(-) EIFL
(=) External Internal Fluorescent Lamp (hybrid)
* See US Patent application 0050127839
(-) FFL
(=) Flat Fluorescent Lamp
* See, for example, US Patent 5850122 "Planar flourescent lamp"
* See Osram Planon, 1,850 lm @ 68 Watts, about £200 for 18.1" model in 2003, this is a DBD device
*
http://www.osram.com/products/genera...nt/planon.html
(-) CCFFL
(=) Cold Cathode Flat Fluorescent Lamp
* similar to above...
(-) Induction lamp
* Changing magnetic field induces an electric field in the gas... etc
(-) HID
(=) High impact discharge
* mercury vapor and sodium vapor lights are frequently used as street lamps and as outdoor lighting for stadiums
* usually slow startup time
* xenon can improve startup time
* Metal halides - Chemicals categorized as metal-halides (such as lithium iodide) are added inside the bulb envelope to improve the color of the light. For example, lithium adds a strong red color to the mix of colors produced by the light bulb.
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(2) SEMICONDUCTOR LIGHTING
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(-) EL lamp
(=) Electroluminescent lamp
* The EL lamp is essentially a capacitor structure with phosphor sandwiched between the electrodes. Application of an AC voltage generates a changing field within the phosphor which causes the phosphor to emit light.
(-) LED
(=) Light emitting diode
* lower than average efficiency, but technology is improving
* high output LEDs may require significant cooling
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(3) OTHER LIGHTING
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(-) OLED
(=) Organic light emitting diode
* developing technology
(-) LEP
(=) Light emitting polymer
(-) PES
(=) Photo-enforced stratification
* "painted on" LCDs, future technology
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(4) CONVENTIONAL LIGHTING
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(-) Incadescent / Filament
* Tungsten filament inside glass bulb
(-) Halogen
* Tungsten filament inside small quartz enclosure/bulb
* Bulb filled with halogen gas, which can combine with tungsten vapor as the tungsten "evaporates" off the filament, and later redeposit the tungsten (ie, recycles it for long life)
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MISC LIGHTING
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(-) Inverter / Ballast
* The term "ballast" used in fluorescent lighting applies to the device that controls the lamp current at the proper operating parameter for the lamp, provides proper open circuit voltage to start the lamp reliably without excessively damaging the cathodes, and, if applicable, provides the proper cathode heating voltage for rapid start lamps
* For conventional "hot cathode" fluorescent lamps, there are three main categories: Magnetic -- energy efficient (core-coil capacitor), Electronic - solid state high frequency, Hybrid -- magnetic with electronic cathode cutout.
* Most common design types for CCFL inverters: Royer (cheap), full bridge (almost all laptops, good for varying DC input), half bridge, push-pull (many advantages for TV's w/ stable DC input)
(-) Light measurement terms:
* Luminous intensity (candela / cd) - energy emitted by light in a given direction (non-infinitesimal...?)
* Luminosity - DENSITY of luminous intensity in a given direction (cd/m^2), independent of distance (surface area increases w/ distance)
* Luminous flux / luminous power = flux through a surface of luminous intensity (lumen = lm)
* Light temperature - The Kelvin temperature equivalent is used to describe the lamp's colour (has to due with spectrum of light radiated by a "blackbody", see any stat mech / thermodynamics book). Lamps generally vary from about 2500K, which is quite yellow through to 7000K, which is considerably bluish. The temperature of balanced white is about 5500K.
Linear Mode
