Electric protection of the luminaries
The electric classification of the luminaries is carried out according to the type of protection offered against the electric shocks.
Classification Electric requirements Consequence of a possible defect of insulation
Classify 0 Prohibited in Belgium as in the majority of the European countries.
Separation of the parts under tension by only one insulation, known as principal insulation.
In the event of defect of insulation, the protection of the person touching the apparatus rests on the environment.
Classify I Separation of the parts under tension by only one insulation, known as principal insulation.
The accessible metal parts are connected on a ground terminal.
Recommended in the traditional buildings.
In the event of defect of insulation, the protection of the person who touches the apparatus rests primarily on the quality of the circuit of grounding and on a differential circuit breaker
Classify II An additional or reinforced insulation is added to the principal insulation.
Materials with greater isolation resistance are used.
Recommended in the wet buildings or when one cannot connect the luminary to a driver of protection.
Because of double insulation, a defect of insulation cannot occur and the person who touches the apparatus is not in danger.
Classify III The food is carried out in very low working stress
the circuit is isolated from the network and the tension is smaller than 50V.
In theory, this apparatus does not pose electric risks.
Protection fire of the luminaries
The luminaries are electricals appliance which transform into heat 60 to 90% of electrical energy that they absorb.
The temperature on the bulb out of glass of an incandescent lamp of 100 W is about 250°C. It thus goes from oneself that the incandescent lamps must be gone up at a sufficient distance from any flammable surface.
One tends to believe that the fluorescent lamps are less dangerous than the incandescent lamps because of their energy distribution. The practice shows however that it is by no means the case. Indeed, the temperature of service of the electromagnetic ballasts can exceed 100°C. In the event of abnormal service the temperature can reach close to 350°C. And such a temperature represents a real fire hazard when the regulations of assembly are not respected.
One thus makes a distinction between normally flammable surfaces of assembly and immediately flammable surfaces.
The luminaries assembled on a normally and not easily flammable" surface must carry a marking:
These luminaries are built so that the temperature on the bearing surfaces does not exceed 130°C in abnormal service and 180°C in the event of defects of the ballast.
No luminary can be gone up on an immediately flammable surface. In the case of such a ceiling, the luminaries must obligatorily be suspended.
The luminaries not carrying marking can be gone up only on said surfaces not fuels.
Current markings
Assembly allowed on flammable with difficulty or normally materials.
Assembly allowed in workshops presenting of the fire hazards (dusty environment).
Assembly allowed in pieces of furniture flammable with difficulty or normally.
Assembly in pieces of furniture of nonknown characteristics.
Luminous distribution of a luminary
The form of the reflectors and the positions of the lamp make it possible to obtain various models of luminous distributions:
extensive distribution : give a uniform illumination, allows a more important spacing of the luminaries and accentuates contrasts on the level of the scheme of work
intensive distribution : concentrate the beam of light downwards. This mode of lighting is interesting for the lighting of the spans great height or for work on screen
asymmetrical distribution : allows to light, for example, vertical surfaces such as tables or walls.
In the catalogs, the luminous distribution of a luminary is represented by a polar diagram taking again in continuous feature the distribution perpendicular to the lamps and into dotted the distribution in the axis of the lamps.
Plans of cut of a luminary
To describe the photometric characteristics of a luminary, the manufacturers define various plans "C" and angles "Y" following which one can observe a luminary.
Longitudinal plan Transverse plan Diagonal plans
C90, C270 C0, C180 C30, C45, C60
 
 
Dazzling of discomfort (factor UGR)
The dazzling of discomfort coming directly from the luminaries must be quantified by the author of the project by using the tabular method of evaluation of the rate of dazzling unified UGR of the Co.
Without returning in the details, factor UGR gives an idea of the dazzling of discomfort in the field of vision of the observer compared to basic brightness (dazzling caused by the association of several luminaries in an environment considered). This factor UGR varies from 10 to 30. The higher the value of the factor is, the more the probability of dazzling of discomfort is important.
Values of reference define quality grades:
28 Zone of circulation
25 Room of files, staircases, elevator
22 Space reception
19 Normal activities of office
16 Technical designs, work stations CAD
The following factors play a big role in the determination of value UGR :
the shape and dimensions of the room,
the clearness of the surface (brightness) of the walls, the ceilings, the grounds and other extended surfaces,
the type of luminary and protection,
the brightness of the lamp,
the distribution of the luminaries in the room,
positions of the observer.
The values of the UGR given in the standard INTO 12464-1 are maximum values not to exceed.
formulate calculation of the UGR: 8 log (0.25/lb X Σ L² ω/P²)
LP is the basic brightness expressed in candela ⁄ m ² and represents indirect vertical illumination on the eye-level of the observer.
L is brightness containing the luminous parts of each luminary in the direction of the observer in candela ⁄ m².
ω is the solid angle (steradian) luminous parts of each luminary on the eye-level of the observer.
P is an indication of position of Guth provided in specific tables and represents the position of a luminary compared to the vertical axis.
Color of the light
The color of the artificial light has an direct action on the feeling of comfort of the luminous environment of a space. A light of hot color is mainly made up of red radiations and oranges. It is the case of the normal incandescent lamps.
The standard fluorescent tubes generate a cold light made up mainly of radiations violets and blue. The table below illustrates the variation of the feeling of comfort of the luminous environment of a room according to the level of illumination which is provided to him.
The coloured radiations emitted by the objects and the environment can also produce certain psychophysiological effects on the nervous system. Thus the colors big wavelengths (red, orange) have a stimulating effect while those short wavelengths (blue, purple) have a calming effect.
The intermediate colors (yellow, green) have, just as the white, an effect tonic and favorable to the concentration. The dark colors and the gray have a depressing action on the other hand. Finally the colors can contribute on the whole modifying the apparent dimension of surfaces and volumes. The hot colors will preferably be used in buildings of exaggerated size while the cold colors will be selected for the buildings of reduced size.
Output
One evaluates the energy quality of a lamp by his apparent brightness (in lm ⁄ W) definite like the report ⁄ ratio of luminous flow (in lumen) by the absorptive electric output (in Watt). From the catalogs of suppliers, it is possible to know exactly the apparent brightness of a lamp.
Cut-off angle of a lighting fitting
Definition
The cut-off angle of a lighting fitting is the angle under which the naked source cannot be seen by the observer. It is expressed in degrees.
One speaks about cut-off angle in the transverse direction and the longitudinal direction.
Measure level of illumination
The levels of illumination are measured thanks to a lux-meter.
The price of such an apparatus varies between 25 and 125 € according to its its possibility, measurement bracket, degree of accuracy of connecting a separate electric eye, possibility of recording values and of calculating the average, of measuring a discontinuous illumination or of integrating in time a variable illumination of it
Calculation of interior average illumination
To determine the level of average illumination of a room using a lux-meter, it is necessary to take various measurements of specific illumination according to the methodology defined by standard NBN L 14-002 and to establish an arithmetic mean of it.
The surface of the room is divided into a certain number of elementary rectangles of equal size.
Specific illuminations are measured in the center of each rectangle.
Average illumination on the whole of surface considered is the arithmetic mean of the measured values.
Emoy = E1 + E2 +... + In) ⁄ N
K Minimum no.
points of measurement
 
less than 1 4 index of the room K
K = (has X b) ⁄ h (has + b)
with
has and B = width and length
room, H = height
useful of the installation.
1. 1,9 9
2. 2,9 16
3 and more 25
Calculation of external average illumination
To determine, for a lux-meter, the level of average illumination of an external space, it is necessary to carry out, on a reproducible zone, various measurements of specific illumination and to establish an arithmetic mean of it.
The site and the number of points of measurement are given according to a regular squaring whose size of the meshs is obligatorily lower or equal to the height of fire of the luminaries divided by 2.
Imperative conditions of measurement
the measuring cell must be perfectly horizontal
the measuring cell must be safe from any shadow
time must be dry (the droplets can distort measurement).

Comparative of power

Helps with the choice of the power

Incandescent Halogen LED Consumption ⁄ year Incand. ⁄ LED
25W 15W 1,5W 64 KW ⁄ 3,83 KW
30W 20W 3W 77 KW ⁄ 7,66 KW
50W 35W 4W 127 KW ⁄ 10,22 KW
65W 45W 5W 166 KW ⁄ 12,77 KW
75W 50W 6W 192 KW ⁄ 15,33 KW
100W 65W 9W 255 KW ⁄ 23 KW
120W 75W 12W 307 KW ⁄ 30,66 KW
150W 100W 14W 383 KW ⁄ 35,77 KW
180W 120W 20W 460 KW ⁄ 51,1 KW

Equivalence bulb sphere with LED

Earth LED Incandescent equivalent Form  
6W 40W  
8W 60W  
14W 80W  

Equivalence spots with LED (white)

White spot LED Incandescent equivalent Form  
2,5W
Culot : G4 et EZ10
12 à 25V
20W halogène  
DICHRO 6W
Culot : GU5.3 et EZ10
12 à 25V
50W halogène  
9W
Culots : GU10, E11, E14, E17,
B22 (Baïonnette), E26, E27
100 à 240V
65W halogène  
12W AR111
Culot : G5.3 et Screw Terminal
12 à 25V
75W halogène  
14W
Culots : E26, E27
100 à 240V
100W halogène  
16W
Culots : E27
100 à 240V
120W halogène  
20W
Culots : E26, E27
100 à 240V
150W halogène  

Equivalence tubes fluorescent with LED

for the replacement of a fluorescent tube by its equivalent with LED, it is necessary to disconnect the ballast and to withdraw the choke of the small rule before connecting the new tube to LED.
Tube LED Fluorescent equivalent Form  
9W 600mm T8 18W 600mm  
22W 1200mm T8 36W 1200mm  
24W 1500mm T8 58W 1500mm  

Equivalence halogenous lamp

Projector LED Halogenous equivalent Form  
20W 150W  
40W 250W  
70W 500W  
140W 1000W  

Luminous classification

Source of light Luminous intensity (Lumens) Apparent brightness (Lumens ⁄ Watt)
Candle   12 lm
Bulb incandescence 60 W "normal" 600 lm with 750 lm 10 lm/W with 12,5
Bulb incandescence 60 W "quality" 1000 lm 15 lm ⁄ W with 20
Bulb incandescence 100 1370 lm 13,3
Halogenous lamp 25 500 lm 20
Halogenous lamp 63 1260 lm 20
Halogenous lamp 125 2500 lm 20
Fluorescent tube 8 520 lm 65
Fluorescent tube 18 to 21 W (60cm) 1340 lm 65
Fluorescent tube 36 ⁄ 37 W (120cm) 2400 lm 65
Mercury discharge lamps high pressure - 60
Sodium vapour lamps low pressure - 160
Sodium vapour lamps high pressure - 120
Leds of power current (2007) 50 lm with 100 lm 600 lm planned for 2010 1500 lm planned for 2020 35 lm ⁄ W with 60 lm ⁄ W 150 lm ⁄ W planned for 2010
Led XLamp XR-E 80 lm under 350 my 175 lm under 1000 my 70 lm ⁄ W (to 350 my) 48 lm ⁄ W (at 1000 my)
Led Luxeon K2 140 lm under 1500 my xx lm ⁄ W (at 1500 my)
Led Luxeon Starlight 0,5 - 24
Led Luxeon Starlight 1 - 30 to 40
Led Luxeon 3 - 25
Led xxx (Lumiled ⁄ Philips) 1,2 W/8,3 136 lm under 350 my 502 lm under 2000 my 115 lm ⁄ W (under 350 my, 1,2W) 61 lm ⁄ W (under 2000 my, 8,3W)
Led Jupiter 50 lm with 100 lm -
Led Golden delicious Osram Dragon) 50 lm with 100 lm -
Led ASMT 1W (Avago) 45 lm under 350 my ⁄ 3, 6V -
Led CMDA (CML) 1W, 2,5W or 5W 100 lm under 350 my -
Led Ostar Lighting (Osram) 200 to 400 lm -
Led SPNovaLed (Dominating) 55 lm -
Led NanoXED (Lexedis) 30 lm -
Led LedCup 1 W (Optek) - -
Led Orion 1,24 W (Citizen) 57 lm under 350 my ⁄ 3, 55V 85 lm under 700 my ⁄ 3,55V 68,4 lm ⁄ W (under 350mA) 45,9 lm ⁄ W (under 700 my)
NSPWR70 (Nichia) 9.4 lm under 20 my 150
Led STAR LED 3000 °K 3 100 lm under 700 my ⁄ 3,5V 33
Led STAR LED 7000 °K 5 220 lm under 1300 my ⁄ 3,6 44
Led Xeon 1 50 lm under 350 my 50
Led Xeon 3 130 lm under 700 my 43

Luminous Equivalensce

Lux W ⁄ m Comment
0,5 Luxes - Harms of full moon
10 Luxes - Half-light, or lighting candle
20 to 80 Luxes - Enlightened city
100 Luxes - Minimal luminosity to read a text
100 to 200 Luxes - Domestic lighting
300 to 500 Luxes - Public places
1000 Luxes - Room really very quite enlightened
5000 Luxes 50 W ⁄ m Outside in covered weather
10000 Luxes 100 W ⁄ m Outside in average weather
20000 Luxes - Intense illumination (in the vicinity direct of a halogenous lamp 50W)
50000 to 100000 Luxes 1000 W ⁄ m Outside in sunny weather

Traditional incandescent lamp

Type Total apparent brightness Total apparent brightness (lm ⁄ W)
Tungsten of 40 W incandescent 1.9% 12.6
Tungsten of 60 W incandescent 2.1% 14.5
Tungsten of 100 W incandescent 2.6% 17.5
halogen of glass 2.3% 16
quartz halogen 3.5% 24
incandescent with high temperatures 5.1% 35
ideal black body radiator to 4000 7.0% 47.5
radiator of ideal black body to 7000 14% 95
ideal white source of light 35.5% 242.5
source (green) monochromatic ideal of 555 nanometers 100% 683
old lamp with carbon filament.
The incandescent lamp traditional, invented in 1879 per Joseph Swan and improved by work of Thomas Edison, product of the light while carrying to incandescence a tungsten filament, the metal which has the most melting point (3430° celcius). in the beginning, a carbon filament was used, this last while being sublimated then while condensing on the lamp glass, opacified glass rather quickly.
incandescent lamp
Bulb of glass, also called sphere, bulb or envelope
Inert gas
Tungsten filament
Discussion thread (contact with the central stud)
Discussion thread (contact with the base)
Wire of support of the filament
Mounting or drinking glass holder
Base (electrical contact)
Base (not of screw or bayonnette)
Insulator
Central stud (electrical contact)
 
halogenous, transparent incandescent lamp with the Xenon 70W
lamp out of translucent glass.
In the presence of dioxygene, the filament carried to high temperature would burn instantaneously, this is why, right from the start, this type of lamp was provided with an envelope of glass isolating a medium without dioxygene, the bulb, which gave its popular name to the device, then by extension to any system, protected by an envelope out of glass, intended to manufacture light starting from electricity.
inside the bulb, one finds is a gas characteristic of the type of bulb: rare gas often of krypton or argon is the vacuum.
Ineluctably the overheated filament vaporises and loses matter by sublimation, then this metal vapour condenses on the colder envelope. The bulb becomes increasingly opaque and the filament becomes more fragile. The filament ends up breaking at the end of several hundred hours: 1000 hours for a traditional lamp, up to 8 times more for certain lamps of special use.
In the current lamps, the tungsten filament is rolled up helical, in order to increase the length of the filament, and thus the visible quantity of produced light.

Halogenous incandescent lamp

The lamp (with incandescence) halogenous produces the light, like a traditional incandescent lamp, while carrying to incandescence a tungsten filament, only of halogenous gases iodises And brominates with high pressure were introduced into a bulb out of quartz glass supporting the high temperatures.

Operation

This process limits the sublimation of the tungsten filament (undesirable transfer of the tungsten atoms of the filament towards the internal wall of the bulb):
under the action of heat the filament loses by sublimation of the tungsten atoms,
the latter while cooling combine with halogenous gas instead of settling on quartz glass,
then by natural convection, the gas approaches the hot spot and the tungsten atoms settle again on the filament under the effect of heat.
That makes it possible to make function the filament with more high temperature that in a traditional lamp and obtain despite everything one more important lifespan, typically 2000 H instead of 1000 h.
While functioning with more high temperature, (approximately 3000°K instead of 2700°K) the colour temperature of the filament approaches that of the Sun (6000°K), which gets a brighter light and more in adequacy with the human vision. Consequently, the apparent brightness of the lamps with halogens is higher approximately 30% than that of the traditional bulbs.

Disadvantages and advantages

The lamps with halogens have however the reputation to be large consumers of energy. That comes owing to the fact that the models of show, on foot, are equipped with lamp of 150,300 even 500 W according to the models and, that these standard lamps generally replace systems of less power.
But a halogenous lamp of 100W lights as much as a traditional bulb of 150W, therefore consumes less for the same rendered service.
The difference in apparent output is due to the fact that these luminaries light the ceiling, therefore luminous flow is indirect, but generally more homogeneous.
Moreover, these standard lamps are provided with a variator of power to decrease illumination. This technique makes fall considerably the output, since, by lowering the average tension of feeding, it decreases the temperature of the filament and thus, its apparent brightness.
One will prefer as much as possible using a lower loudspeaker tube and, to multiply if need be the number of luminaries to obtain a greater luminosity.
In addition, an higher temperature and bulbs definitely smaller than those of the traditional lamps induce a temperature of surface of the very important bulb and base. It is generally disadvised touching with the fingers the bulbs: indeed micro the traces of greases left by the fingers return in the long term porous quartz glass, when this one reached the operating temperature, which compromises the lifespan of the lamp.

Uses and diversifications

These last years, the lamps with halogen multiplied in the hearths:
Lamps functioning with the tension of the sector, that is to say in low tension (230 volts), but using a traditional casing screw or bayonet). They are often equipped with an external bulb of traditional form, out of glass, which protects the tube from quartz glass, smaller.
Lamp very low tension, that is to say lower than 50 volts (generally 12) in D.C. current, functioning with a specific, transformer feeding or electronic convertor, intended to feed from small spots or desk lamps (these lamps often incorporate reflectors dichroic). These lamps very low tension have a better luminous output (lm ⁄ W) that the lamps functioning with the tension of the sector because the shorter filament and of more important section can be carried higher in temperature.
The lamps with halogens also are very much used in the field of the car and the motor cycle. Their denomination starts with the letter H:
H1, H2, H3, H7 : lamp of 55W to a filament
H4 : Lamp with two filaments (approved version 55 and 60W for lighting road/crossing
H4 : Lamp with two filaments (version not approved for road 90 and 100W for lighting on circuit.

Fluorescent tube

A fluorescent tube is a particular type of flashlight, which produces light, thanks to an electric shock in a tube. Their light can be white (for lighting) or coloured (as on the illustrations, for the manufacture of signs).

Beginnings

The idea to employ fluorescence for lighting goes back to second half of the XIX e century with Becquerel which covered the interior of the tubes with discharge with various fluorescent powders. These primitive fluorescent lamps will not find an application practical because of their insufficient luminous intensity.
It is only into 1895 that Thomas Edison will invent a fluorescent lamp starting from a tube with X-ray whose internal surface of the bulb is coated with calcium tungstate. This substance converts part of the X-radiations into bluish white light with an apparent brightness three times higher than that of the carbon filament lamps of the time, it for one lifespan much longer. These performances could have propelled this lamp on the market of lighting but the X-radiation produced by this lamp will send to the cemetery an employee of Edison.
The technology of the fluorescent tubes thus developed according to the diagram of Becquerel, starting from tubes with discharge under low pressure.

The tube neon of Georges Claude

The invention of the neon tube by Georges Claude at the beginning of the XX esiècle marked the beginning of the commercial use of tubes of colour (pink and yellow) employing a fluorescent coating. The saturated hues obtained did not certainly allow the use of these sources for lighting domestic or other than advertising. However, it was discovered that the simultaneous use of tubes with mercury vapour, emitting a blue light (invented by Cooper-Hewitt in 1901), with tubes of Claude allowed obtaining a white light of relatively poor quality. Moreover, these lamps used mercury baths like electrodes, which gives place, as one knows it today, with very poor yield of the source because of considerable energy which it is necessary to extract the electrons from the electrodes

New electrodes

1927 will have to be waited until, and work of Ruttenauer and Pirani Osram for the development of oxide electrodes the alkaline ones. This innovation made it possible to reduce the losses of energy to the level of the electrodes for the extraction of the electrons. This thus enormously increases the output of the lamps. It is only in years 1930 that tubes with mercury vapour under low pressure will be used in conjunction with a fluorescent coating in order to generate a white light. The design of these tubes was similar to the tubes of Claude, with cold hollow cathodes and a feeding under high voltage. In spite of an effectiveness of about 15-20 lm ⁄ W, of many installations of tubes with high voltage will be done in the stores, restaurants and other public places.
The real availability of the fluorescent tubes started only with the introduction in 1936, by Osram, with the specialised Exposure of 1937 of Paris, tubes with hot cathode whose apparent brightness is carried to 30-40 lm ⁄ W because of use of less wasteful electrodes in energy. General Electric in the United States, GEC in England and Philips in the Netherlands will follow in 1937-1938. Always at Osram, the development of the adequate fluorescent powders allowed the launching of the first fluorescent tube in 1936 the World Fair of Paris (Osram), followed in 1938 by GE to New York then by Philips (1938) and GEC (the U.K.). If this crucial change in the design allowed more raised outputs, the lifespan of these sources was however limited to 2000 hours because of fast deterioration of the electrodes and the fluorescent powder. It will be necessary to await the end of the Second world war to see the introduction, by GEC, of binary mixtures of bismuth and strontium halophosphates propelling the apparent brightness towards the 50-60 lm ⁄ W while improving quality of the emitted light. Since the years 1950, the improvement of the quality of the components also allowed the increase in the lifespan of these sources and a better maintenance of the apparent brightness. In this respect, the diameter of the tubes was not lower than 38mm in order to limit the damage caused by the mercury plasma on the fluorescent coating.

New fluorescent powders

A major innovation will be born in 1973 with the introduction by Philips of ternary mixtures of silicates and aluminates whose general properties are quite higher than those of the halophosphates. In addition to one apparent brightness being able to exceed the 80lm ⁄ W with a quality of largely increased light, the resistance of this type of materials to the electric shock allowed the reduction of the diameter of the tubes of 38mm 26mm (T8) then 16mm (T5) and even less. This reduction of dimensions of the lamps allowed the design of more compact luminaries with a better sight check of the emitted light.

Techniques

The fluorescent lamps contain a mixture of mercury argon and vapour with low pressure and not inevitably of neon as the popular speech would let it believe. The visible light is produced by two successive processes:
The ionisation of the gas mixture under the effect of an electric current generates a light in the range of the ultraviolet rays, therefore invisible but very energy. The conditions of discharges are optimised so that a maximum (60-70%) of the consumption is radiated in the two lines of resonance of mercury with 184,9nm and 253,7nm.
This first radiation is then converted into visible light, energy (the difference giving of heat), on the internal surface of the tube by a binary or ternary mixture of fluorescent powders.
The colour of the produced light thus comes primarily from the specific composition of this internal coating. Neon is a rare gas, like argon, sometimes used but producing a red light. It is thus seen that this use is very particular and that it is by abusive simplification and metonymy that the name of this gas became synonymous, today of fluorescent lamp.
The geometry of these lamps as well as the means of excitation of the mercury plasma can take various forms according to the needs.

Linear tubes

The linear tubes are, by far, the most used fluorescent lamps. The length of these tubes varies few centimetres with more than two metres according to the power. Each end is equipped with an electrode made up of a tungsten filament doubly or three times over wound and coated of a barium-strontium-calcium oxide coating for an optimal injection of the current of electrons in the electric shock. These electrodes function alternatively like a cathode or an anode according to the direction of the current (alternate). The geometry of these electrodes varies from a model of lamp with another and those whose power exceeds the 100W have electrodes designed with two additional probes in order to be able to collect the ionic fort running at the time of the anodic phase.
Two classes of lamps of general use are distinguished. On the one hand, there are the lamps with very good colour fidelity employing a fluorescent powder containing silicates and of aluminates, often named lamps with three standard tapes to their emission spectrum. In addition to one very good quality of light IRC from 80 to 95, the apparent brightness is raised, about 80 with 105lm ⁄ W. In addition, there exists on the market of the lamps at low prices still employing halophosphates. These last have a less effectiveness (60 to 75 lm ⁄ W) and a quality of light (IRC 55-70) too weak for an employment apart from industrial lighting.
Except this traditional range of lamps, there exist sources with ultraviolet radiation (UV) of which the tubes black light employing a fluorescent powder radiating around 365nm, tubes UVA and UVB for the bronzing and the processing of certain materials, then tubes UVC for sterilisation. These last lamps are not equipped with fluorescent powder and their bulb is manufactured either out of quartz, or out of glass with low content iron oxide in order to ensure a good transmission of UV generated by the mercury plasma.
The power of the linear tubes is standardised.
Length Power
1,5 58
1,2 36
0,9 30
0,6 18

lamp fluocompactes

Fluorescent lamp.
As their name indicates it, these lamps are compact thanks to folding into two, three, four or six of a fluorescent tube whose diameter lies between 7 and 20 Misters Because of the low diameter of the tube, only of the fluorescent powders with three tapes are used. The compact shape of the tube with discharge poses also a problem of thermal dissipation and several means are employed to limit the steam pressure saturating with mercury in order to remain with the optimum mode of operation. Certain lamps employ amalgams of mercury-tin or mercury-bismuth, whereas others are equipped with cold appendices where mercury condenses.
The first was created by Philips (announced in 1976, introduced in 1980), then Osram (1981) followed by the other manufacturers. The design of this new generation of lamps was justified by the increase in the energy costs following the two oil crises of the years 1970. Thus, the first lamps fluocompactes introduced by Philips were designed to replace the lamps with filament directly in their luminaries. However, the integration of the ferromagnetic ballast posed an serious issue of weight and volume which limited the applications of these lamps to energy saving. It is only about the middle of years 1980 that the first lamps fluocompactes with electronic feeding will be marketing. With a better output and reduced dimensions, these lamps were integrated more and more in the landscape of domestic lighting.
As for the rumour of emission of UV, this one is false because the fluorescent layer of the lamp absorbs UV and re-emits visible light (pieces of continuous spectrum).

Toxicity

mercury: Because the lamps fluocompactes contain mercury, a toxic metal, they require to be treated separately other household waste. Mercury represents an important danger to the expectant mothers, the new-born babies and the children in general. The refuse tips often refuse this type of lamps because they contain mercury. The mercury contents of the lamps fluocompactes can vary from 3 with 46mg. If a lamp fluocompacte breaks, it is recommended to block its breathing, to open a window and to air part 10 or 15mn before collecting the remains to avoid breathing of the mercury vapours.
Beryllium: beryllium powder was used as internal layer of the tube. It is a very toxic product which can induce a disease known as berylliosis in the workmen who handled it.

Lamp with induction

The factor limiting the lifespan of the fluorescent lamps is the consumption of the electrodes. The lamp cannot function any more correctly if the electrodes cannot sufficient provide any more electrons necessary to the maintenance of the electric shock. There exists a class of lamp which does not have electrodes, but an antenna radio frequency which generates and excites a argon-mercury plasma thanks to an alternate magnetic field.
There exist two kinds of lamp with induction, the lamp with high frequency induction and the lamp with low frequency induction.

Emitted light and spectral characteristics

The fluorescent tubes intended for lighting can emit coloured light or white light. (tubes UV are not used for lighting, except special effects)
One finds tubes coloured emitting the following colours: blue, green, red (low intensity), amber and pink.
The tubes emitting of the white light can produce different strong white, one speaks about hue, heat to very cold. They are characterised according to 2 criteria: their colour temperature and their index of returned colour (IRC).
For memory, a white light includes/understands all the wavelengths of the spectrum, it is a continuous spectrum. The fluorescent tubes emit a discontinuous spectrum, one thus speaks about colour temperature proximale. The index of returned colour makes it possible to assess the quality of made visual and the risk of metamerism.

Colour temperature

The fluorescent tubes intended for lighting are available in the following colour temperatures:
2700 K : near to the incandescent light, domestic use and hotel trade (OSRAM: Interned)
3000 K : near to the halogenous light, use in hotel trade, shops, museums (OSRAM: hot white/cool white)
3500 K : (not very frequent) compromise between halogenous light and light of office
4000 K : "neutral" white, very much used in the offices and industrial environments; this intermediate colour temperature with the advantage of not appearing neither too yellow the day, nor too cold night (OSRAM: white of luxury)
5000 K : near to light of day (but attention with the IRC), used in museums, photography and in graphic arts
6500 K : near to the light to an overcast sky (but attention with the IRC), used in the hospitals (what gives this so typical light cold) (OSRAM: light of day/daylight)
8000 K : (not very frequent) near to the light to a blue sky (light of north), special uses.

Index of colour fidelity (IRC)

For the same colour temperature, the IRC can vary. This difference is not perceptible by looking at the tube directly, or when its light reaches a white surface, because the brain compensates for a uniform lighting automatically, but becomes obvious when coloured objects are lit, which appear then with dominant: fruits, clothing, photographs (very visible differences), nuanciers dental, etc
The tubes available in three big families of are returned colour:
IRC 55 to 70%: made colour poor, use in workshop, industry, public places of circulation. In photography, they produce dominant a green characteristic. Average apparent brightness.
IRC 85%: returned colour correct, use in office, school, hotel trade, domestic (alas). The hues flesh are deformed, the yellow draws towards the green, the blue ones draw towards the purple one, and generally all the hues seem more saturated, a little artificial. It is, for example, very difficult to appreciate the colour of a clothing in a shop lit with this IRC. In photography, they also produce dominant green. Very good apparent brightness.
IRC with 90%. : higher colour fidelity, use in graphic arts, museums, dentistry, photography, luminous boxes, very desirable use in domestic lighting. Used in photography, they do not show dominant green the so characteristic one. Good apparent brightness.
In parallel, each IRC is available in a range of colour temperatures, but all the combinations are not available and certain families of fluorescent lamps offer less choice. Vastest is offered by the tubes of 26mm of diameter, whereas the lamps fluocompactes exist only in three or four hues, and almost exclusively in IRC 85%.
The choice of a tube (or a lamp fluocompacte) must thus be carried out imperatively according to the two criteria, the IRC being too often ignored.
In order to facilitate the choice, the manufacturers adopted all the Philips nomenclature, in addition to the trade descriptions.

Standardised marking of fluorescent tubes

The code, with three digits, gathers at the same time the index of returned colour and colour temperature. The first figure indicates the IRC, of tens of %, the two figures following indicate the colour temperature, in hundreds of K. One can note that this marking is also used for certain gas-discharge lamps, in particular those with metal halides.
code 640 indicates a tube of an IRC of 60 and a colour temperature of 4.000K (white industrialist), lighting of workshop, hollow, etc
code 840 indicates a tube of an IRC of 85 and a colour temperature of 4.000K (ex: White Osram deluxe), typical lighting in office.
code 827 indicates a tube of an IRC of 85 and a colour temperature of 2.700K (ex: Osram interned), typical lighting of the fluocompactes.
If one wishes to simulate light of day (phototherapy for example) one imperatively needs an IRC 90% and one colour temperature of 5000K or 6500K, that is to say a hue 950 or 965. Hue 950 asserts an IRC going up to 98, which in fact a hue privileged for the accurate check of the colours, in particular in printing works.
If one wishes to imitate the incandescent light (lighting domesticates), one would need 2700K and an IRC 90. The lamps fluocompactes could make more important great strides if it were available in this quality, because with hue 827 suggested, the majority of users perceives a difference compared to the incandescence. Such a hue existed at Philips out of tube of ø 26 mm, but was removed.
Summary table of the hues of fluorescent lamps (a dash indicates that this combination does not exist)
  2700K 3000K 3500K 4000K 5000K 6500K 8000K
IRC 50-76 - 530 - 640 ⁄ 740 - 765 -
IRC 85 827 830 835 840 - 860 ⁄ 865 880
IRC>90 - 930 - 940 950 ⁄ 954 965 -

Sodium vapour lamp

History

Use of the sodium vapour as source of light goes back to the use of peat combustible, or the orange light of the flame was wrongfully allotted to sulphur. It is only in the middle of the XIX e century, with the advent of the tubes with discharge under low pressure and of the arcs to the carbon, which one studies the use of sodium and his salts for lighting. It is however only about years 1930 that the first sodium metal vapour lamps will be born gràçce with the development by Arthur Compton of glass with borate resistant to alkaline but as the steam pressure and the temperature of discharge are increased, the lamp worsened irremediably at the end of a few seconds.
In 1932, Philips and Osram, respectively in the Netherlands and in Germany, market the first lamps of this type which will be used immediately for road lighting. With an apparent brightness of 55 lm ⁄ W, these sources were most economic at the time. The technology of these lamps enormously evolved/moved until in the years 1950, or their morphology changed then little. Their very bad colour fidelity and their rather high dimensions limit their applications to the lighting of public motorways. So it was very early planned to increase the steam pressure in order to dissipate more power per unit of length, and to enrich the spectrum emitted in order to make the light more pleasant to the eye.
A crucial aspect of these sources, which was the subject of considerable efforts of research and development, is the thermo isolation of the tube with discharge. The first lamps used a tube with discharge coupled with a vase of Dewar transparent, similar to those present in the Thermos bottles. Although the satisfactory thermo isolation fàt at the time, these external bottles had the disadvantage of dirtying interior quickly. This problem was solved in the middle of the years 1950 with a design monopièce or the tube with discharge is enclosed in a vacuum drawn enclosure. The thermo isolation was improved with the use of sheaths of glasses which made these lamps rather heavy and fragile.
An major improvement was the replacement of these sheaths by a transparent bismuth or money, gold film deposited on the internal surface of the external bulb, thinking the infra-red radiation towards the tube of discharge. It is only at the end of years 1950 that one discovers that synthetic sapphire is resistant to the sodium vapours.
Thus a first lamp with high pressure is manufactured in 1958 in the laboratories of Thorn, into Large-Bretagne.Cependant, it is only with development of the polycrystalline aluminiums tubes, and adequate sealings, that a commercial lamp will be born in 1964. Although the barrier of the 100 lm ⁄ W fàt reached with this technology, the use of these thin films posed the problem of the absorption of the light emitted by the electric shock. This problem was partly solved with the use of tin oxide for film, then of tin and indium oxide which made it possible to reach with the beginning of the year the 1980 200 lm ⁄ W, a limit which to date was not exceeded.
The first lamps made in laboratory had a sodium and xenon filling, but for practical reasons of mercury was added.

Technology

Low pressure

Bulb of a lamp LSP
The sodium vapour lamps under low pressure (LPS) are made up of a tube with discharge folded U-shaped and enclosed in a vacuum drawn external bulb. The tube with discharge is filled with a mixture neon (99%) argon (1%) under low pressure allowing the starting of the discharge and the heating of sodium until 260°C. The tube is manufactured containing glass sodocalcic covered with a thin layer of glass to borate, resistant to the vapour of alkaline metal. This tube is equipped at its ends with electrodes covered with rare earth oxides for a good electron emission.
The external bulb has a vacuum whose quality is maintained gràçce with barium mirrors located close to the casing. A zirconium pellet is often employed to crack the hydrocarbon vapours which can be present. Tin and an indium oxide film, a thickness of 0,3 micrometer recovers the interior of the external bulb. This coating is designed to think the infra-red radiations towards the tube of discharge.

High pressure

The sodium vapour lamps under high pressure (SHP) use others chemical compounds like mercury for practical reasons; however, only sodium is responsible for the light output, the xenon and mercury being used only to make it possible the lamp to start, and to fix the good electric properties of the arc.
The sources under low pressure are characterised by a radiation quasi monochromatic orange, which is not the case of the lamps under high pressure or the interaction between the various elements gives a superimposed spectrum of tapes and discrete lines. Thus, the light of these lamps has a better quality, because it contains other colours that the orange. However, the IRC remains poor owing to the fact that the prevalent hue relatively remains an yellow-orange saturated. It is this characteristic which gives to these lamps an excellent apparent brightness, the eye being more sensitive to the emitted wavelengths. For these two reasons, these sources light the vast majority of the roads and industries of the world.
Two types of lamps whose light is whiter were developed in the years 1980. The first type of lamp has a CRY of Ra65, compared with Ra20 for the traditional lamps, and a colour temperature of 2200K instead of 2000K. These changes are obtained by the increase in the temperature and the steam pressure, of which the side effects are a less good output and a fall lifespan. In spite of this change, the quality of the light is still not sufficient with a regular commercial practise. These lamps find their employment of centre town and in the residential districts.
The second type of lamp has a pressure and a temperature more raised even, giving a light to which the colour is close to that of an incandescent lamp. It is thus quite naturally, with a CRY of Ra80 and a colour temperature of 2500-2700 K, that these white lamps with sodium found an application in the commercial lighting, there or one seeks to obtain a cordial environment. However, their output and their less lifespan do not give them a reliability for urban lighting.
The family of the lamps sodium vapour standard extends from 35watts until 1000W, with an apparent brightness of 90lux· W-1 until 140lux·W-1, which makes of it a source of choice for an economic lighting.
Powers standards of clear tubular lamps can be:
50 W
70 W
100 W
150 W
250 W
400 W
600 W
1000 W

Power supplies

except for the lamps of 18 Watt, all the models up to 180 Watt have a tension of starting higher than 250 Volt. So the majority of these lamps are fed by an auto-transformer with dispersion whose tension with the secondary in open circuit is of 450 V.
Since the years 1980, there exist feeding systems known as hybrid composed of a self inductance and an igniter high voltage. The coil is designed in such a way that the third harmonic of current is important. The resulting wave of current is squarer than sinusoidal, property which increases the output of these lamps.
The lamps with metal iodides (MH or metal halide) produce a white light which supports the growth of the plants. The produced light is close to light of day. The strong proportion of blue in the spectrum of colours emitted by lamps MH is well adapted for the vegetative period (pushes plants)
The lamps with sodium with high pressure (HPS) emit an orange light and their spectrum of colours is adapted better for flowering or fructification. "Special" lamps HPS horticultural integrate in their spectrum of "the extreme red" particularly appreciated at the time of flowering. One can only use them or in complement of a white lamp (MH) to succeed of superb flowerings.
These lamps are a point source of preferable light for the plants with a linear source like the fluorescent tubes.

Theory of operation

The operating process proceeds in 3 stages:
Initially, there is ionisation of neon (Ne) what produces a red light and a progressive heating
at the temperature of 98°C, there is vaporization of sodium (Na), is followed from there its ionisation and the production of a yellow light
After surroundings 10 minutes, the temperature is of approximately 200°C then there is a stabilisation around the 270°C.

Lamp with electroluminescent diode

Lamp with white LED

The lamp with electroluminescent diode, or lamp with LED, is a type of flashlight which uses diodes electroluminescences (in summary LED, or English LED).
They were especially used to produce luminous indicators because of their supply voltage adapted to the electronics and their long life of life (pilot of day before or operation electricals appliance, indication), but with recent technological advances, they can be now also used to light.
Lamps with white LED GUI10
Lamp with LED with screwed lamp-socket Edison E27 (27 mm)

Presentation

A lamp made up of LED produces light by electroluminescence of a semiconductor, the output is much more interesting without however reaching that of the phenomena of fluorescence (fluorescent tube, bulb fluocompacte). The lifespan of the LED is much more important than for these the last two mechanisms with an unquestionable advantage, the LED do not suffer in any way of alternations lighting ⁄ extinction (attention however, it is not inevitably the case of electronics accompanying it in the bulb).
The output of the bulbs with LED is often indicated to the tension of use (low tension) and, not with the tension of the network (110-120 or 220-250 volts).

Strong points and weaknesses

Advantages:
weak electricity consumption due to a correct output
lifespan much longer than a fluorescence or incandescent lamp (50000 hours), end-of-life declaring itself by a progressive fall of output and not by a brutal breakdown
security of an operation in low tension
heat proportionally less than the incandescence because of the best output
D does not produce? ’ultraviolet
contrary to a fluorescent lamp (fluocompacte), a lamp with LED does not emit a radiation with average or low frequency, likely to be harmful at short distance
can produce a large variety of colours by simple composition, with manufacture, of the various electroluminescent diodes constituting it, or in dynamics by modification of the currents feeding the various LED.
Disadvantages :
in 2006, the price with purchase of the lamps with LED remains two to four times higher than that of a traditional lamp, with equal luminosity but should drop quickly taking into account the fast development of the sales
the LED known as white produce this white by mixture of some basic colours and thus do not have a continuous spectrum like the incandescent lamps
the temperature of the white often produces car towards blue (white cold), perceived by the users like giving a cold atmosphere to the interiors, it exists however white lamps drawing more towards the yellow (white heat)
the IRC is him also generally poor (it is definitely better with the LED appeared in 2009)
the LED do not support the high temperatures: the thermal dissipation of the bulbs with LED is a factor limiting the rise to power of these last
the blue LED as well as the white LED contain a blue spectrum of strong dangerous intensity for the retina if they enter the field of view, even peripheral. This is of course proportional to their power, and becomes increasingly alarming whereas LED increasingly more powerful are marketing. However recently appeared of the LED with tons hot, with the spectrum impoverished of blue light.

Organic electroluminescent diode

An organic electroluminescent diode (OLED) Organic Light-Emitting Diode) is component which makes it possible to produce light. The structure of the diode is relatively simple since it consists in superimposing several organic semiconductor layers between two electrodes of which one (at least) is transparent.
Technology OLED is used for the display in the field of the flat panel displays and its use as panel of lighting is another potential application. Because of the properties of materials used to design these diodes, technology OLED has interesting advantages compared to the dominant technology of the displays with liquid crystals (LCD). Indeed the electroluminescent property of the OLED does not require the introduction a retro-lighting what confers on the screen major levels of gray and a less thickness. The flexibility of these materials makes it possible also to produce a flexible screen and thus to integrate it on supports very varied like the plastics.

History

The first patent is deposited in 1987 by the company Kodak and the first commercial application appeared about 1997.
Andre Bernanose and his team produced light containing organic materials, by subjecting thin layers of crystal of orange acridine and quinacrine to a AC current of high tension. In 1960, researchers of the Chemical laboratory developed doped electroluminescent cells with anthracene, supplied with a AC current.
The low electric conductivity of these materials limited the quantity of emitted light, until the appearance of new materials like the polycetylene, the polypyrrole and the blackened polyaniline. In 1963, in a series of publications, the team directed by Weiss indicates that the polypyrrole oxidized and doped with iodine has a very good conductivity : 1S ⁄ cm. Unfortunately, this discovery was forgotten, just like the ratio of 1974 on the bistable switches containing mélanine, which have a great conductivity when they are with the state one. These switches had the characteristic to emit light when they changed state.
In a publication of 1977, the team of Shirakawa indicates a high conductivity in a similar material, the polycetylene oxidized and doped with iodine. This search will be worth with these researchers the Nobel Prize of Chemistry for the discovery and the development of conducting organic polymers.
More recent work was undertaken since, with large projections, like the publication of the team of Burroughs which, in 1990, brings back the very great effectiveness of polymers emitting in the wavelength of the green

Operation

Principle
The basic structure of a component OLED consists in superimposing several layers of organic materials between a cathode and an anode, which often transparent is made of indium-tin oxide (ITO). The organic thin layers typically comprise a layer of transport of holes (HTL), a layer of emission (EML) and a layer of transport of electrons (LTE). By applying an adapted electric tension, the electrons and the holes are injected into layer EML starting from cathode and of the anode. The electrons and the holes combine in layer EML to form excite then electroluminescence appears. The materials of transfer of charge, the layer of emission and the choice of the electrodes are fundamental parameters which determine the performances and the effectiveness of component OLED.

Details

The principle of operation of the OLED is based on electroluminescence. The source of light is in fact due to the recombination of a exciton (even electron-positron pair), inside the transmitting layer. At the time of this recombination, a photon is emitted. The goal of the researchers is to optimise this recombination. For that, it is necessary that the transmitting layer has a number of holes equal to the number of electrons. This balance is however difficult to reach in an organic material. Indeed, the mobility of an electron is approximately three times larger than that of a hole.
The exciton has two states (singulet or triplet). Only a exciton on four is of singulet type. The materials used in the luminous layer often contain fluorophores. However, these fluorophores emits light only in the presence of a exciton with the state of singulet, of or a notorious loss of output.
Fortunately, by incorporating metals of transition in a OLED in small molecules, it appears a quantum phenomenon, the coupling of spin. This coupling allows a kind of fusion between the states of singulet and triplet. Thus, same with the state triplet, the exciton can be source of light. However, this phenomenon implies a shift of the emission spectrum towards the red, thus making the wavelengths short (blue-purple) more difficult to reach starting from a exciton with the state of triplet. But this technique quadruples the effectiveness of the OLED.
In order to create let us excite them in the transmitting layer, it is necessary to tear off electrons of with dimensions and to add other of it. This is why the luminous layer is taken in sandwich by two electrodes:
an anode (+) which creates holes (tears off electrons with material),
a cathode (-) which brings the electrons.
The holes (positive) and the electrons (negative) attracting, they will migrate through luminescent material and will meet to form a exciton.
The luminophores (elements of the layers luminous) used in a OLED are mainly derived from the statement poly [phenylene vinylene] and from the poly [fluorene]. The anode remains traditional, made up of indium-tin oxide (ITO), just like cathode, out of aluminium or calcium. the interface between luminescent material and the electrodes, of specific materials are intercalated, in order to improve the injection of electrons or holes and thus to improve the effectiveness of the OLED.

Derived technologies

Small molecules
Technique OLED with small molecules was developed by Eastman-Kodak. The production uses a system of vacuum deposit, which makes the process more expensive than of other techniques of manufacture. Moreover, as this process uses a substrate out of glass, it makes the screen rigid (although this limitation is not due to the small molecules). Term OLED refers by defect with this type of technique (sometimes under the term of SM-OLED, for Small Molecules).
The molecules mainly used for the OLED include organometallic chelates (example: Alq3, used in the first organic electroluminescent device) and of the combined dendrimères.
There exists now a hybrid electroluminescent layer which employs nonconducting polymers, coatings of conducting electroluminescent molecules (small molecules). This polymer is used for its mechanical advantages (resistance) and to facilitate the production, without being concerned with its optical properties. The longevity of the cell remains unchanged.

PLED

The electroluminescent diodes with polymer (DELP or its Anglicism PLED for Polymer Light-Emitting Diodes, also known under the name of PEL for electroluminescent Polymers or, in English, LEP for Polymer Light-Emitting) derive from the OLED screens but the latter use polymers taken between two flexible sheets to emit light. These polymers can be liquid, which would support a fast industrialisation. Moreover, the rate of cooling of these screens would be much higher than those of the traditional LCD displays.
Screens PLED result from search relating to polymers able to emit light, initially by the technical department of display of the university Cavendish Laboratory off Cambridge in 1989.
The principle of manufacture is the deposit in thin layer, and makes it possible to create colour displays recovering all the visible spectrum, while consuming little electricity. Their manufacture does not use the vacuum deposit, and the active molecules can be deposited on the substrate by a process similar to the inkjet printers. Moreover, the substrate can be flexible (as in the FART), making the production less expensive.

PHOLED

PHOLED is the acronym of Phosphorescent Organic Light-Emitting Diode. This technique is patented by the American company Universal Display Corporation. Little information is currently accessible (operation, characteristics) because of youth from this technique. However, one can quote like asset a better output than the traditional OLED, and like defect one lifespan limited in the blue ones (like often in technique LED).

Use

The OLED are used currently more and more on products at short or average lifespan (mobile phones, Digicams, wandering mp3, and same a keyboard of computer, etc). The use for products at longer lifespan (monitors of computers and television sets in particular) should spend a little more time. They are also under development for the use of lighting with a performance similar to fluo compact CFL, and an IRC similar to the incandescent one.

Advantages

Technique OLED has many advantages compared to the LCD:
Better colour fidelity (100% of diagram NTSC)
Better contrast (until 1000000:1)
More diffuse light (less directing): angle of wider comfort of vision
Thinness and flexibility of the support
Manufacturing process more accessible
Response time 0,1ms
The manufacturing process of the OLED screens is radically different from the current flat panel displays. The fact of using techniques close to the inkjet printers makes it possible to consider very advantageous production costs, compared with the LCD or the plasma displays.
Moreover, the OLED emit the light directly, which induces on the one hand a diffusion close to 90° compared to the normal of the screen and on the other hand a better restitution of the colours.
Lastly, the black of the OLED is true, that is to say it does not correspond to any emission of light, contrary to the LCD using a retro-lighting which tends to filter through the flagstone in the blacks. The LCD also lose half of their luminous power to the polarisation of the light more still 2 ⁄ 3 of their power to the passage of the filters of colour: finally, one loses 89% of the luminous power. In comparison, technique OLED is much more sparing.

Disadvantages

The OLED have three main drawbacks:
The principal defect of the OLED is their lifespan (approximately 14000heures), in particular for the blue OLED. It is estimated that it would take one lifespan of approximately 50000heures so that a flagstone OLED can play the role of television set. This weak lifespan compared with the LCD displays and the plasma displays slows down the business development of this technology. However, of tech news emergent, like the PHOLED, which use a phosphorescent material. The variations of energy thus created make it possible to reach one lifespan close to 20000heures for the blue PHOLED.
Toshiba and Displaylink however would have succeeded in mitigating this problem by using a technique based on a metal membrane in order to optimise the diffusion of the luminosity. Gràce with this technique, the two firms affirm to have succeeded in designing a prototype OLED of 20,8pouces one lifespan higher than that of traditional screens LCD, that is to say more 50000heures.
It now remains to solve the problems of design and production of broad flagstones OLED; indeed, televisions OLED could replace the LCD displays and plasma.
Moreover, the organic materials of the OLED are sensitive to moisture, of or the importance of the conditions of manufacture and their containment in the screen (in particular for the flexible screens).
Lastly, the OLED are a technique owner, held by several companies of which Eastman Kodak, which could constitute a brake with the development of the technique until the patents fall into the public domain.

incandescent bulb has carbon nanotube

If the bulb in question deserves our attention, it is because the diameter of its filament measures only 100 atoms (yes, you read well, they are atoms). This filament is indeed carried out by means of a carbon nanotube.
Its two ends are connected in their turn with two nano gold filaments which allow its connexion a chip containing more traditional silicon; the whole being placed vacuum. There one finds the principle of the first bulb with incandescence carried out by Edison: a filament of carbon placed vacuum but with dimensions without common measurement since the diameter of the filament is approximately 100.000 times weaker and the size of "the bulb" about 10.000 times smaller. But the analogy does not stop there. Indeed, if one runs a variable current in the carbon nanotube, one can control his heating and, starting from a certain temperature, this one emits light visible with the naked eye in spite of its microscopic size
The researchers of the UCLA then used a series of filters equipping an optical microscope to study the luminous intensity of the lamp to various wavelengths. To their surprise, since that the 107 carbon atoms of the nanotube remain largely under the thermodynamic limit of 1023 atoms approximately, the distribution of luminous energy according to the studied wavelength follows indeed, with the precision of current measurements, the law of the black body at a temperature T

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