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4. Incandescent and Halogen LampsContents
4 1 History4.1 History4.2 Physical Fundamentals4.3 Construction3 Co s uc o4.4 Lifetime4.5 Halogen Incandescent Lamp4.6 Interference Filter 4.7 Types of Halogen Lamps4 8 New Developments4.8 New Developments
Chapter Incandescent and Halogen LampsSlide 1
Incoherent Light SourcesProf. Dr. T. Jüstel
1820 A th d l Ri b l i Pt i i
4.1 History1820 Arthur de la Rive observes a glowing Pt-wire in vacuum1840 Joseph Wilson Swan experiments with carbonised paper wires1854 Heinrich Goebel constructs the first incandescent lamp with a bamboo fiber, which
finally leads to the carbon filament lampy pProblem: still not sufficiently well evacuated C + O2 CO2
1868 First fabrication of incandescent lamps by Swan (low lifetime)1879 Patent of Thomas Alva Edison
Edison improves incandescent lamps by better evacuation of the lamp bulbEdison improves incandescent lamps by better evacuation of the lamp bulb higher lifetime
1881 Demonstration (Presentation) of Edison Lamp at the World Exhibition in Paris Coil still made from CS hi f hi h lti t l T W R OSearching for high melting metals Ta, W, Re, OsWinner: Tungsten because of the lowest vapour pressure lowest blackening
1900 Max Planck: Theoretical basis (Planck's law) 1902 Osmium wire (Auer and Welsbach)( )1911 Ar/N2 filling1912 Tungsten wire1936 First lamp with a double coiled filament1958 First application of Xenon as a filling gas1958 First application of Xenon as a filling gas1960 Halogen cycle (Zubler and Mosby, GE)1971 First H4 automotive lamp (today also H7) 1973 First halogen lamp with interference filter2010 I d t l k t d h t b ll
Chapter Incandescent and Halogen LampsSlide 2
Incoherent Light SourcesProf. Dr. T. Jüstel
2010 Incandescent lamps marketed as heat balls
4.2 Physical Fundamentals
Input Power
Energy balance of an incandescent lamp
Electromagnetic radiation Conductivity losses Gas losses
Electric current I IR Visible UV
1
1.2
Tungsten filament with the electrical
resistance R
0.5
I ( )
V z( )
V() S t l iti it
resistance R
Electric loss for current I
P = U*I = R*I2
500 1000 1500 200000.
2000.200
nmz
nmWavelength [nm]
V() = Spectral sensitivity curveSpectrum of a glowing filament at about
T = 2700 K (incandescence)
Chapter Incandescent and Halogen LampsSlide 3
Incoherent Light SourcesProf. Dr. T. Jüstel
Wellenlänge in nmnm nmWavelength [nm]380 780
4.2 Physical FundamentalsTh bl k b d di ti b d fi d th li ht i i i th lThe black body radiation can be defined as the light emission in thermalequilibrium (thermal radiation)
3
Spectrum of a black body radiatorPlanck's radiation law (1900)
3x103
3x103
4x103
3000K
1cL T/c51
e
c1 = 2hc2 = 3.741832.10-16 Wm2 2x103
2x103
2500K
L e [W
m-2
nm-1
]1eλ T/c5e 2
c2 = hc/k = 1.438786.10-2 Km = Wavelength [m]Le = Spectral irradiance (radiation density)
5x102
1x103
2000K
L
T = Temperature [K]
Light source Color temperatureS 5800 K
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Wavelength [nm]
Sun 5800 KStudio halogen lamp 3400 KHalogen lamp 3000 K Incandescent lamp (b lb) 2700 K
Wien's displacement law
K]μm2880Tλmax [
Chapter Incandescent and Halogen LampsSlide 4
Incoherent Light SourcesProf. Dr. T. Jüstel
Incandescent lamp (bulb) 2700 K
4.2 Physical FundamentalsIncandescent and halogen lamps are spatially and temporally incoherent lightsources
Incoherence Temporally coherence Spatially and temporallyIncoherence Temporally coherence Spatially and temporally coherence
Through color filter and pinhole a small-area, t ll d ti ll
A color filter allows only light of a certain wavelength to
A light bulb radiates incoherent: the wavelengths of the individual
temporally and spatially coherent light source of very low intensity is created
pass through: the radiation is temporally coherent (monochromatic)
waves are different or between the various points of the radiating surface, there is no fixed phase relationship
Chapter Incandescent and Halogen LampsSlide 5
Incoherent Light SourcesProf. Dr. T. Jüstel
relationship
4.3 ConstructionFilament is double coiledTungsten filament
Fill gas = noble gas (Ar Kr Xe) + N2
(Mo)
noble gas (Ar, Kr, Xe) + N2(pressure = 1 bar) Typical: 80% N2 + 20% Ar
It is coiled initially on Mo, then Mo is removedthen Mo is removed
Ar 39,9 g/molKr 83,8 g/molX 131 3 / l
Screw thread = Edison-TypeBajonett-TypeC t t
Xe 131,3 g/mol
Bajonett-TypeDiameter in mm
Europe E10 E14 E27 E40USA E12 E17 E26 E39
Contact
Chapter Incandescent and Halogen LampsSlide 6
Incoherent Light SourcesProf. Dr. T. Jüstel
USA E12 E17 E26 E39
4.3 ConstructionFrom a glass bulb to an incandescent lamp
Chapter Incandescent and Halogen LampsSlide 7
Incoherent Light SourcesProf. Dr. T. Jüstel
4.3 ConstructionProduction of tungsten filament
Tungsten production Filament productionOres: CaWO4 or (Fe,Mn)WO4
“Scheelite” “Wolframite”W-staves
Hammering, rollingDi ti ith HCl
MeCl2 + WO3.H2O “Tungstite”
W-plates
Pulling
Digestion with HCl
(NH4)10[H2W12O42] “Paratungstate”W-wires
g
Winding/coiling
Leaching with NH3
WO3
W-filament
Winding/coiling600 °C
-W-metal powder
Doping, H2, 450 °C
Pressing + sintering to W-staves
Chapter Incandescent and Halogen LampsSlide 8
Incoherent Light SourcesProf. Dr. T. Jüstel
4.4 LifetimeBlackening of incandescent lamps
Tungsten which evaporates from the filament condenses i id f th l b lbinside of the glas bulb
WasserT OsWasserT OsReTaW
Tungsten has the lowest vapour pressure of all metals and the highest melting point of all metals (Tm 3410 °C) Carbon (graphite) melts at 3550 °C
Chapter Incandescent and Halogen LampsSlide 9
Incoherent Light SourcesProf. Dr. T. Jüstel
of all metals (Tm = 3410 °C), Carbon (graphite) melts at 3550 °C
4.4 LifetimeThe hotter is the filament, the more efficient is an incandescent lamp, however blackening is then also stronger
Operating conditions of an incandescent lamprepresent a compromise between the energy efficiency and lifetime t.efficiency and lifetime t.
Typical values for operation at nominal voltage: = 13 lm/W and t = 1000 h
in K = 13 lm/W and t = 1000 h
„Hot spot“- mechanismW i b thi
W
W-wire becomes thinner Resistance increases Local output and temperature increase Vapour pressure increases Burning-out at „hot spot“
Chapter Incandescent and Halogen LampsSlide 10
Incoherent Light SourcesProf. Dr. T. Jüstel
4.5 Halogen Incandescent LampFunctional principle
In halogen incandescent lamp tungsten is transported Wback to the filament from glass bulb via chemical transport Glass bulb remains clear
Filling gas = nobel gas + O2 + X2 (X = Br, I)
= Solubility curve = p + p + p += pW+ pWO+ pWBr+ .....
Chapter Incandescent and Halogen LampsSlide 11
Incoherent Light SourcesProf. Dr. T. Jüstel
4.5 Halogen Incandescent LampChemical transport in halogen incandescent lamps
The position of the chemical equilibrium ΔSΔHl K00
is temperature dependent: W + O2 + X2 ⇌WO2X2 van‘t HoffRΔS
TRΔHlnK
Halogen-cycle
lnK
W + O2 + X2 ⇌ WO2X2 Chemical transport
lnK2 > 0 T2 = Wall WO2X2(g)
WBrO
lnK = 0
lnK1 < 0 T1 = Filament
Wendel
1/T
1
1/T1/T
1 W(s) + O2(g) + X2(g)
Chapter Incandescent and Halogen LampsSlide 12
Incoherent Light SourcesProf. Dr. T. Jüstel
1/T21/T1
4.5 Halogen Incandescent LampLimitation of the W-Recycling
• Although W back transport is efficient, no curing of the W-filament occursg p g• Gaseous W condenses at the cold spot (thickest section due to lowest resistance)
W + ½ O2 ⇌ WOW ½ O2 ⇌ WO
WO + ½ O2 ⇌WO2
WO2 + ½ O2 ⇌WO3
2 W + 3 O ⇌ 2 WO ΔH 764 kJ/ lTungsten crystals
2 W(s) + 3 O2(g) ⇌ 2 WO3(s) ΔH = -764 kJ/mol
Chapter Incandescent and Halogen LampsSlide 13
Incoherent Light SourcesProf. Dr. T. Jüstel
4.5 Halogen Incandescent LampSet of problems with UV-radiation
Due to the higher filament’s temperature halogen incandescent lamps emit alsoDue to the higher filament s temperature, halogen incandescent lamps emit also some of UV-A and UV-B radiation, since the quartz bulb is transparent to UV radiation.
T i i t
Transmission and emission spectrum of Ce3+ doped silica glass
Transmission spectrum of quartz glass
100
0,8
1,0 Transmission spectrum Emission spectrum
ty [a
.u.]
60
80
on (%
)
0,4
0,6
mis
sion
inte
nsit
40
60
Tran
smis
sio
300 400 500 600 700 8000,0
0,2Em
W l th [ ]120 140 160 180 200
0
20
W l th
Chapter Incandescent and Halogen LampsSlide 14
Incoherent Light SourcesProf. Dr. T. Jüstel
Wavelength [nm]Wavelength nm
4.5 Halogen Incandescent LampAdvantages over incandescent lamps
In halogen incandescent lamp remains the (bulb) wall, during the chemical g p gtransport, clear Reduction of bulb size Increase the noble gas pressure Increase the noble gas pressure Lower evaporation rate of tungsten gives a higher lifetime, what gives partly higher efficiency (higher filament temperature)
T [K] [lm/W] [%]
2700 13 10 Incandescent lamp2800 16 113000 22 13 Typical halogen lamp3200 29 163400 36 20
Special halogen lamp (Projectors, TV-studios)
Chapter Incandescent and Halogen LampsSlide 15
Incoherent Light SourcesProf. Dr. T. Jüstel
( j
4.6 Interference FilterSince incandescent lamps and halogen incandescent lamps emit substantially IR-radiation, even higher efficiencies can be achieved by IR filter
Principle on the example of the halogen lamp
Visible light is transmitted
IR light is reflected back to the filament = 20 lm/W 40 lm/W
Selective mirror
IR light is reflected back to the filament
ctan
ce
Interference filter
Ref
lec Interference filter
Chapter Incandescent and Halogen LampsSlide 16
Incoherent Light SourcesProf. Dr. T. Jüstel
UV 380 Visible 780 IR [nm]
4.6 Interference Filter Interference filters consist of a sequence of low-and highly refractive inorganic layers
m. Constructive interferencem Constructive interferenceHigh reflectance
Path difference = 2nd - /2
Glass (n = 1.5) TiO2, ZnS, ... (n = 2.3 – 2.7)(k+1/2) Destructive interference
Low reflectance
dd
Example: 2nd = 500 nmLow reflectance
k=0 = 500 nm n
Visible IR
k=0 = 500 nmk=1 = 500/2 = 250 nmk=2 = 500/3 = 167 nm......
High reflectance
Ref
lect
ion
1 Layer
U t 40 lHigh reflectancem=0 = 500/0.5 = 1000 nmm=1 = 500/1.5 = 333 nmm=2 = 500/2.5 = 200 nm 200 400 600 800 1000 [nm]
Up to 40 layers
Chapter Incandescent and Halogen LampsSlide 17
Incoherent Light SourcesProf. Dr. T. Jüstel
......
4.6 Interference FilterEnergy saving filter
IRVIS
C ld li ht i i i i filtCold light mirror Cold light mirror is an inverse energy saving filter: It reflects visible light and let IR radiation pass through.
IR
VIS
C ld li ht fl t t f t i d d d d bl i ibl b hi d th l
VIS
Chapter Incandescent and Halogen LampsSlide 18
Incoherent Light SourcesProf. Dr. T. Jüstel
Cold light reflector are not perfect, i.e. deep red and deep blue are visible behind the lamp
4.6 Interference FilterInterference filter as colour filter
Application in light sources and spectrometersfle
xion
Ref
380 780 IR [nm]
Lack of blue in emission spectrum yellow filter
Chapter Incandescent and Halogen LampsSlide 19
Incoherent Light SourcesProf. Dr. T. Jüstel
4.7 Types of Halogen LampsHalogen lamps for general lighting P = 200 - 500 W
U = 230 VP = U2/R, i. e. U R, R = *l/A Longer and thinner filament Filament is less stable Filament is less stable Tfilament is lowered decreases in comparison with
low voltage lampsLow-voltage halogen lamps High-voltage halogen lamps
low voltage lamps
Outer envelope PAR = Parabolic U = 12, 24 V (Transformator is required)
Chapter Incandescent and Halogen LampsSlide 20
Incoherent Light SourcesProf. Dr. T. Jüstel
(hot & fingerprints) reflector lampP = 20 - 50 W
4.7 Types of Halogen LampsLow Voltage vs. High Voltage Halogen Lamps
Lamp type Low voltage High voltageVoltage U [V] 12 230
Power P [W] 20 20Power P [W] 20 20
Filament length l [cm]
2,21 15,81[ ]Diameter d [μm] 54,1 7,558
Chapter Incandescent and Halogen LampsSlide 21
Incoherent Light SourcesProf. Dr. T. Jüstel
4.7 Types of Halogen LampsCar head lights
Di d h d li ht (l b )Drive light (high beam)
Dimmed head lights (low beam)Drive light (high beam)
Dimmed head lights (low beam) Dimmed head lights (low beam)
Low beamHigh beam Low beamHigh beam
H7-Lamps(1 Filament)
H4-Lamps(2 Filaments)
Chapter Incandescent and Halogen LampsSlide 22
Incoherent Light SourcesProf. Dr. T. Jüstel
(1 Filament) (2 Filaments)
4.7 Types of Halogen LampsHalogen lamps SSTV Market (Stage-Studio-TV)
Headlamp
Sphericalmirror f
Fresnel lensFresnel lens
Original filament Picture of a filament
Chapter Incandescent and Halogen LampsSlide 23
Incoherent Light SourcesProf. Dr. T. Jüstel
4.8 New DevelopmentsWhite LEDs are becoming strong competition for halogen incandescent lamp
Light source Luminous flux Efficiency Brightness CRI Lifetime CostsLight source Luminous flux Efficiency Brightness CRI Lifetime Costs[lm] [lm/W] [Mcd/m2] [kh] [$/Mlm.h]
Incandescent 60 W 900 15 10 100 1 7.2Halogen 50 W 1000 20 20 100 2 6 3Halogen 50 W 1000 20 20 100 2 6.3LED 2002 125 25 3 75 60 6.0LED 2013 1000 250 10 90 60 < 1.0
Further development of incandescent and halogen bulbs
Tungsten filament with photonic band structure via 3D-structuring.Aim: Reduction of the IR-emission and therefore increasing gthe light efficiency.
Chapter Incandescent and Halogen LampsSlide 24
Incoherent Light SourcesProf. Dr. T. Jüstel
4.8 New DevelopmentsSpecialties
High performance lamps Colored incandescent lampHigh performance lamps Colored incandescent lamp(up to 20 kW) (coated with inorganic metal oxides )
i h C Al O i h F OChapter Incandescent and Halogen LampsSlide 25
Incoherent Light SourcesProf. Dr. T. Jüstel
with CoAl2O4 with Fe2O3
4.8 New DevelopmentsSpecialties
Doping of the lamp glass, e.g. by Nd2O3 (GE Lighting: Reveal®)op g o e p g ss, e.g. by Nd2O3 (G g g: eve )Aim: Increase of the color temperature without loss of color rendering
Enhancement of the contrast between red and green
Chapter Incandescent and Halogen LampsSlide 26
Incoherent Light SourcesProf. Dr. T. Jüstel
4.8 New DevelopmentsSpecialties
2010: Marketing of incandescent lamps as heatballs as a reaction on the ban2010: Marketing of incandescent lamps as heatballs, as a reaction on the ban of incandescent lamps driven by the EU
2016: Ban of halogen lamps implemented
Chapter Incandescent and Halogen LampsSlide 27
Incoherent Light SourcesProf. Dr. T. Jüstel