6. high pressure discharge lamps - fh münster · 6. high pressure discharge lamps content 6.1...

6. High Pressure Discharge LampsContent

6.1 Overview of Low- and High-Pressure Discharge Lamps6.1 Overview of Low and High Pressure Discharge Lamps6.2 Spectrum of a Hg Discharge6.3 The High-Pressure Mercury Lamp (HP)6 4 Phosphors for High-Pressure Mercury Lamps6.4 Phosphors for High-Pressure Mercury Lamps6.5 The Electrode6.6 The Electrode Feed Through6 7 T f R fl t6.7 Types of Reflectors6.8 Application of HP-Lamps6.9 The High-Pressure Sodium Lamp (HPS)6.10 Application of HPS Lamps6.11 Metal-Halide Lamps (MH)6.12 Photometric Data in Comparison6.13 Applications of MH Lamps6.14 UHP-Lamps6.15 New Developments

Chapter High Pressure Discharge LampsSlide 1

Incoherent Light SourcesProf. Dr. T. Jüstel

p

6.1 Overview of Low- and High-Pressure Discharge Lamps

Hg low-pressure (TL) Hg high-pressure (HPMV = high pressuremetal vapour)

HID = High Intensity Discharge

metal vapour)

Na high-pressure (HPS = high pressure sod.)Hg low-pressure (CFL)

Na low-pressure (SOX) Metal-halide high-pressure (MH)



Emissionsspektrum von Hg6.2 Spectrum of Hg Discharges

Energy level scheme of Hg Schematic emission spectrum of a Hg-discharge at a low pressure [~ mbar]Ionization level (~ 10.4 eV)

254

7( S )3 1

6( D )3 1

7( S )1 0

10

185

76683 66( P )

7( S )1 0

6( P )1 1

y[e

V]

200 300 400 500 600

1

577

546

436

408

313

366

6( P )3 0

6( P )3 1

6( P )3 2

Leve

lene

rgy

185

nm

5

[nm]

1

06( S )1 0

0



6.2 Spectrum of Hg Discharges

254

577

546

436

8

366

Pressure increase

185

577

546

436

408

313

366

85

254

40

313

Pressure increase

in nm200 300 400 500 600

55443 3

in nm200 300 400 500 600

18 3

Pressure dependence of the lumen output

in nm in nm

]

100

60 lm/W Why is this of interest for lamps?

100 lm/W

P

[lm

/W]

60

60 lm/W Why is this of interest for lamps?

Good imaging properties

High luminance

Phosphor High luminance

20 lm/W20



Pressure10 bar 1 bar

6.2 Spectrum of Hg DischargesMeasured spectra of water-cooledcapillary mercury discharge lamps

P = 25 P = 25 atmatm..

P = 30 P = 30 atmatm..

P = 100 P = 100 atmatm..

P = 150 P = 150 atmatm..Source: W. Elenbaas,Quecksilberdampf-Hochdrucklampen (1966)



Hochdrucklampen (1966)

6.3 The High-Pressure Mercury Lamp (HP)Evacuated outer bulb

Melting

Electrode

Melting

Burner (Hg, noble gas = startingGas, mostly Xe)Gas, mostly Xe)

Ballast



6.4 Phosphors for High-Pressure Mercury Lamps5

4

5

2

3

ensi

ty [a

.u.]

1

Inte

400 500 600 700 8000

Wavelength [nm]

Blue-white light due to theBlue white light due to the lack of red radiation in the emission spectrumSolution: Phosphor!

= 60 lm/WRa = 20 Lifetime = 20.000 h



Solution: Phosphor!

6.4 Phosphors for High-Pressure Mercury Lamps5

4

5

Plasma

.u.]

2

3Phosphor

ve In

tens

ity [a

.

1Rel

ativ

Suitable phosphors(Sr,Mg)3(PO4)2:Sn 620 nm Broadband emission

400 500 600 700 8000

Wavelength [nm]

Mg4GeO5.5F:Mn 660 nm Line emissionYVO4:Eu 620 nm Line emissionY(V,P)O4:Eu 620 nm Line emission = 60 lm/WRa = 50Lifetime = 20.000 h



6.4 Phosphors for High-Pressure Mercury LampsSn2+ , Mn4+ phosphorsas UV Red converter

Luminescence spectra of (Sr,Mg)3(PO4)2:Sn

0,8

1,0

max = 620 nmQE254 = 79 %

0,4

0,6

RQ254 = 5%x = 0.549y = 0.426LE = 150 lm/W

elat

ive

inte

nsity

ity

100 200 300 400 500 600 700 8000,0

0,2 Emission spectrum Excitation spectrum Reflection spectrum

Re

Sample U2024W l th [ ]

Luminescence spectra of Mg4GeO5.5F:Mn

Inte

nsi

1,0

Emission spectrum Excitation spectrumReflection spectrum

Wavelength [nm]

0

0,6

0,8 max = 658 nmQE254 = 81 %RQ254 = 7%x = 0.713y = 0.287

Reflection spectrum

ive

inte

nsity

i f

[nm]

0,0

0,2

0,4 y 0.287LE = 80 lm/W

Rel

at



Problem: Low lumen equivalent of these phosphors 100 200 300 400 500 600 700 800Sample U601

Wavelength [nm]

6.4 Phosphors for High-Pressure Mercury LampsYVO4:Eu3+ phosphors - Thermal behavior

Excitation spectra of YVO4:Eu0,30

U737025CU737075C

Luminescence intensity as a function of t t d it ti l th

0,15

0,20

0,25U737075C

U737150C U737200C U737250C U737300C U737330C

nten

sity

[a.u

.]

6

7

8 integral 254 nm exc. Integral 300 nm exc. Integral 350 nm exc.

sity

temperature and excitation wavelength

0 00

0,05

0,10

monitored at 619 nm

Em

issi

on in

4

5

6

mis

sion

inte

n

250 300 350 4000,00

Wavelength [nm]

80000 U737025CU737075C

1

2

3

Rel

ativ

e em

Emission spectra of YVO4:Eu

Th l i ffi d UV A it ti i40000

60000

80000

excitation at 300 nm

U737075C U737150C U737200C U737250C U737300C U737330C

inte

nsity

[a.u

.]

0 50 100 150 200 250 300 3500

Temperature [°C]

The luminous efficacy under UV-A excitation increasesup to about 300 °CReason: Increase in spectral overlap

0

20000

40000

Em

issi

on



550 600 650 700 750

Wavelength [nm]

6.5 The ElectrodeHg low-pressure Hg high-pressure

36 W 400 W

0.5 cm1.0 cm

36 W 400 WI = 0.36 A I = 4 A

Tungsten + emitter Tungsten + emitterBaO / SrO / CaO BaO / SrO / Y2O3 / ThO2

T = 1350 K T = 2000 - 3000 K



6.6 The Electrode Feedthrough

Plasma

Problem: Different thermal expansion coefficients SiO2 = 0.5*10-6 K-1

W = 4.3*10-6 K-1

Mo = 2.8*10-6 K-1Quartz (1000 °C)Plasma

Tungsten Very thinMo- or Nb-foil

Molybdenum



6.7 Types of ReflectorsParabolic reflectors Elliptical reflectors

y = x2

Focal point (light source) An ellipse has two focal points

Only when the light source is point like

HID-lampsHID lamps



6.8 Application of HP-LampsIn street lighting (outdoor lighting)

= 60 lm/WRa = 50Lifetime = 20.000 hP = 100 W - 2000 W



P 100 W 2000 W

6.9 The High-Pressure Sodium Lamp (HPS)

589

nmNa low-pressureLamp (0.01 mbar)

Na high-pressureLamp (100 mbar)Pressure increase 58

9 nm

300 400 500 600 700 300 400 500 600 700 in nm

300 400 500 600 700

in lm/W200 in nm

300 400 500 600 700

Pressure dependence of the lumen output

120

Na-pressure



Na pressure10 bar 1 bar

6.9 The High-Pressure Sodium Lamp (HPS)Problem: Na reacts at high temperatures with the quartz glass wall

4 Na + SiO2 2 Na2O + Si2 2

Solution: Transparent, high temperature resistant material, which does not react with Na

Crystalmaterial, which does not react with Na

Al2O3-ceramics (corundum): MgO, CaO, B2O3-Additives(DSA = densely sintered alumina)(DSA = densely sintered alumina)

20 mPolycrystalline structure

Pressure, 1200 °C

Nb or Mo



Nb or Mo

6.9 The High-Pressure Sodium Lamp (HPS)

Widening of the Na-line and self-absorption leads to a spectral hole in the emission spectrum at around 589 nmpNa = 150 mbar (saturated)pHg = 1000 mbar (buffer gas)HgpXe = 100 mbar (start gas) = 90 - 120 lm/WRa = 20 – 50 (pressure dependent)589 nm a (p p )Tc = 1930 K

n=2

n=3

n=1(589 + x) nm (red-shift)(589 - x) nm (blue-shift)



6.10 Application of HPS LampsArchitectural and street lighting



6.11 Metal-Halide High-Pressure Lamps

In Tl Na451 535 589

Filling: NaI - TlI - InISnBr2 - SnI2 NaI - DyI3 (SSTV)NaI - ScI3 (automobile headlight)

Goal: High & color rendering

SnBr/SnI-molecule emitters

DyI-molecule emitters



6.11 Metal-Halide High-Pressure LampsHPI (High Pressure Iodide) lamps

451 nm(In)(In)

535 nm

589 nm

(Tl)

589 nm(Na)



6.11 Metal-Halide High-Pressure Lamps

Hg / NaI / TlI / DyI3 / ArP = 75 W

Tl0.30

Spectrum of a MH lamp

P = 75 WNaV Prad / P 60 %

Prad vis / P 33 %0 20

0.25

NaHg

Prad,vis / P 33 %

0.15

0.20

W/n

m]

Hg0.10

I [W

Hg0.05

atomic line and molecular radiation0.00

350 400 450 500 550 600 650 700 750 800

[nm]



[nm]

6.11 Metal-Halide High-Pressure LampsFilling of metal halide lamps

Lamp starting (starting gas) p g g gNoble gases: Ar or Xe (xenon lamps) → Penning-effectRadioactive substances: 85Kr, 147Pm

Operating voltage• Hg• Hg • Trend towards the substitution of Hg (environmental aspect) → Zn

Light emission• Hg• Me-halides (Me = Na, In, Tl, Sc, Sn, Dy, ...)



6.12 Photometric Data in ComparisonImprovement (lm/W) Ra Color temperature Tc [K]

HP (Hg) - 60 20 6000

+ phosphor 60 50 3800+ phosphor 60 50 3800

HPS (Na) - 60 - 130 20 2000Xe-pressure 80 - 150 20 2000

Na-pressure 60 - 90 60 2200

MH HPI (NaI-TlI-InI) 70 - 80 70 3800 - 4200SnBr2-SnI2 70 902 2

NaI-DyI3 75 - 80 90 3800 - 5600

NaI-ScI3 80 - 90 75 3600 - 4200



6.13 Applications of MH LampsHPI Street lighting(NaI-TlI-InI) Architectural lighting

Sports field lighting

Tin Older type of lampis replaced by MHis replaced by MH

NaI-DyI3 Sports field lightingNaI ScI Shop lightingNaI-ScI3 Shop lighting

Studio-stage-TV (SSTV)Automotive headlights

NaI ScI + Hg + Xe (blue)NaI-ScI3 + Hg + Xe (blue)



SSTV k t St St di TV

6.13 Applications of MH LampsSSTV market = Stage-Studio-TV

Reflector

Spherical mirror f Fresnel-lens

Farbtemperatur = 5600 K



6.13 Applications of MH LampsIn the „beamer“



6.13 Applications of MH LampsConstruction of a beamer

A projector is actually a slide projector (diascope)!

Lamp at the focal point Collecting SlideLamp at the focal point in a parabolic reflector

Collectinglens

Slide

In a beamer the slide ProjectionIn a beamer the slide is replaced by a small

LCD screen or by a DMD(Digital Mirror Device)

Projectionscreen



( g )

6.13 Applications of MH Lamps

LCDs are based on liquid crystals, which rotate the polarization plane of polarised light by a

Operating principle of a LCD (Liquid Crystal Display)

the polarization plane of polarised light by a rotational angle ά

Polarizer-foil P

Liquid crystal cell (with ITO)

Analyzer foil (perpendicular to P)

U

Analyzer foil (perpendicular to P)

Pixel on for U = 0

Pi l ff f U > 0Chapter High Pressure Discharge LampsSlide 28


Pixel off for U > 0

6.14 UHP-LampsRequirements for light sources for projectors

• If possible punctual A lot of light from a small volume• High luminance (light density ) High Hg-pressure

UHP = Ultra High Pressure (Performance)Approx. 200 bar Hg, electrode separation ~ 1 mm Strong pressure-broadened lines of Hg

m nm

m

408

nm 436

n m

546

n

577

nm

400 500 600 700 800



400 500 600 700 800

6.14 UHP-LampsComponents of UHP-Lamps



6.14 UHP-LampsDesign of UHP-lamps

Description of UHP-lamp by• Chemical equations

Vapor pressure of metal halidesVapor pressure of metal halidesDisintegration of the metal halides in the plasma

•Temperature distribution in the plasmaEnergy balanceLoss via radiationLoss via radiationLoss due to chemical energyLoss due to heat

Convection (flow) Heat conduction

• Convection equation = Navier-Stokes-Equation

wuzh:Potential0

yh

xh

2

2

2

2



• Energy balance of the electrodes and the wall

6.14 UHP-Lamps



6.15 New DevelopmentsSulfur lamp: In 1990 the first discharge lamp based on a molecular sulfurdischarge (S4 – S8) was develop

The energy coupling into the discharge takes place by means of a microwavegenerator (magnetron), because electrodes can not be used



g ( g ),

6.15 New DevelopmentsS lf l T t l l i flSulfur lamp: To generate a very large luminous flux

Typical operating parametersInput power: 1.400 W Ball diameter: approx. 30 mm Luminous flux: 135000 lmLuminous flux: 135000 lmColor temperature: 5700 KStarting time: 25 s Lifetime (lamp): 60.000 hLifetime (lamp): 60.000 h Lifetime (magnetron): 20.000 h Light output: 95 lm/W

Light source with extremely high light output, about 140000 lm (~ 40 fluorescenttubes) and (almost) pure-white light (emission band of S8, …. , S2 molecules)

Efficiency: Similar to fluorescent lights (thus 90 - 100 lm/W)Problems: EMC and lifetime of the microwave generator



6.15 New DevelopmentsS lf l M h i f li ht ti E i i f l l SSulfur lamp: Mechanism of light generation Emission from molecules , e.g. S2

C. W. Johnston, Transport and equilibrium in molecular plasmas: The sulfur lamp, Technische Universiteit Eindhoven 2003



Technische Universiteit Eindhoven, 2003

6.15 New DevelopmentsSubstitution of Hg by Zn (e.g. in automotive headlamps)

Zn/Ar Discharge Zn/Ar/metal halide Discharge

0,8

1,0

481

472

Wel = 75 WLE = 114 lm/Wx = 0.228, y = 0.227Tc = 34000 KEfficacy = 20 lm/W[a

.u.]

0 20

0,25

0,30Wel = 75 WLE = 280 lm/Wx = 0.436, y = 0.387Tc = 3000 KEfficacy = 85 lm/W[a

.u.]

0,4

0,6

636

468

y = 0.174 Wopt/Welektr

Ra8 = 0

ssio

n in

tens

ity

0,10

0,15

0,20 Efficacy = 85 lm/W = 0.33 Wopt/Welektr

Ra8 = 80

ssio

n in

tens

ity

400 500 600 700 8000,0

0,2

Ce3+ Luminescence

Em

is

300 400 500 600 700 8000,00

0,05

Em

is

Zn-Ar Zn-Ar-metal halide20 l /W 85 l /W

400 500 600 700 800File: Zn discharge lamp (60-75-90W)

Wavelength [nm]300 400 500 600 700 800

File: Zn discharge lamp (60-75-90W)Wavelength [nm]

20 lm/W 85 lm/WEnergy efficiency 17% 33%R 0 80



Ra 0 80

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