Chapter High Pressure Discharge Lamps Slide 1 Incoherent Light Sources Prof. Dr. T. Jüstel 6. High Pressure Discharge Lamps Content 6.1 Overview of Low- and High-Pressure Discharge Lamps 6.2 Spectrum of a Hg Discharge 6.3 The High-Pressure Mercury Lamp (HP) 6.4 Phosphors for High-Pressure Mercury Lamps 6.5 The Electrode 6.6 The Electrode Feed Through 6.7 Types of Reflectors 6.8 Application of HP-Lamps 6.9 The High-Pressure Sodium Lamp (HPS) 6.10 Application of HPS Lamps 6.11 Metal-Halide Lamps (MH) 6.12 Photometric Data in Comparison 6.13 Applications of MH Lamps 6.14 UHP-Lamps 6.15 New Developments
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Chapter High Pressure Discharge Lamps
Slide 1
Incoherent Light Sources
Prof. Dr. T. Jüstel
6. High Pressure Discharge Lamps
Content
6.1 Overview of Low- and High-Pressure Discharge Lamps
6.2 Spectrum of a Hg Discharge
6.3 The High-Pressure Mercury Lamp (HP)
6.4 Phosphors for High-Pressure Mercury Lamps
6.5 The Electrode
6.6 The Electrode Feed Through
6.7 Types of Reflectors
6.8 Application of HP-Lamps
6.9 The High-Pressure Sodium Lamp (HPS)
6.10 Application of HPS Lamps
6.11 Metal-Halide Lamps (MH)
6.12 Photometric Data in Comparison
6.13 Applications of MH Lamps
6.14 UHP-Lamps
6.15 New Developments
Chapter High Pressure Discharge Lamps
Slide 2
Incoherent Light Sources
Prof. Dr. T. Jüstel
Hg low-pressure (TL)
Na low-pressure (SOX)
Hg high-pressure (HPMV = high pressure
metal vapour)
Na high-pressure (HPS = high pressure sod.)
Metal-halide high-pressure (MH)
HID = High Intensity Discharge
6.1 Overview of Low- and High-Pressure Discharge Lamps
Hg low-pressure (CFL, PL)
Chapter High Pressure Discharge Lamps
Slide 3
Incoherent Light Sources
Prof. Dr. T. Jüstel
Emissionsspektrum von Hg
l [nm]
200 300 400 500 600
18
5
25
4
57
7
54
6
43
6
40
8
31
3
36
6
Energy level scheme of Hg Schematic emission spectrum of a
Hg-discharge at a low pressure [~ mbar]
6.2 Spectrum of Hg Discharges
Ionization level (~ 10.4 eV)
6 ( S ) 1 0
6 ( P ) 3 0
6 ( P ) 3 1
6 ( P ) 3 2
7 ( S ) 3 1
6 ( D ) 3 1
7 ( S ) 1 0
6 ( P ) 1 1
L e v
e l e
n e r g
y [ e
V ]
1 8 5
n m
0
1 0
5
Chapter High Pressure Discharge Lamps
Slide 4
Incoherent Light Sources
Prof. Dr. T. Jüstel
Pressure dependence of the lumen output
l in nm 200 300 400 500 600
18
5
25
4
57
7
54
6
43
6
40
8
31
3
36
6
l in nm 200 300 400 500 600
18
5 25
4
57
7
54
6
43
6
40
8
31
3
36
6
Pressure
h [
lm/W
]
100
60
10 mbar 1 bar
6.2 Spectrum of Hg Discharges
Pressure increase
60 lm/W Why is this of interest for lamps?
Good imaging properties
High luminance
100 lm/W
20 lm/W 20
Ph
osp
hor
Chapter High Pressure Discharge Lamps
Slide 5
Incoherent Light Sources
Prof. Dr. T. Jüstel
6.2 Spectrum of Hg Discharges
Measured spectra of water-cooled
capillary mercury discharge lamps
P = 25 atm.
P = 30 atm.
P = 100 atm.
P = 150 atm.
Source: W. Elenbaas,
Quecksilberdampf-
Hochdrucklampen (1966)
Chapter High Pressure Discharge Lamps
Slide 6
Incoherent Light Sources
Prof. Dr. T. Jüstel
Evacuated outer bulb
Burner (Hg, noble gas = starting
Gas, mostly Xe)
Ballast
6.3 The High-Pressure Mercury Lamp (HP)
Electrode
Melting
Chapter High Pressure Discharge Lamps
Slide 7
Incoherent Light Sources
Prof. Dr. T. Jüstel
Blue-white light due to the
lack of red radiation in the
emission spectrum
Solution: Phosphor!
h = 60 lm/W
Ra = 20
Lifetime = 20.000 h
6.4 Phosphors for High-Pressure Mercury Lamps
400 500 600 700 800
0
1
2
3
4
5
Inte
nsity [
a.u
.]
Wavelength [nm]
Chapter High Pressure Discharge Lamps
Slide 8
Incoherent Light Sources
Prof. Dr. T. Jüstel
Suitable phosphors
(Sr,Mg)3(PO4)2:Sn 620 nm Broadband emission
Mg4GeO5.5F:Mn 660 nm Line emission
YVO4:Eu 620 nm Line emission
Y(V,P)O4:Eu 620 nm Line emission
h = 60 lm/W
Ra = 50
Lifetime = 20.000 h
6.4 Phosphors for High-Pressure Mercury Lamps
400 500 600 700 800
0
1
2
3
4
5
Phosphor
Plasma
Re
lative
In
ten
sity [
a.u
.]
Wavelength [nm]
Chapter High Pressure Discharge Lamps
Slide 9
Incoherent Light Sources
Prof. Dr. T. Jüstel
Sn2+ or Mn4+ phosphors
as UV Red converter
Problem: Low lumen equivalent of these phosphors
6.4 Phosphors for High-Pressure Mercury Lamps
Luminescence spectra of (Sr,Mg)3(PO4)2:Sn
Luminescence spectra of Mg4GeO5.5F:Mn
l [nm]
Inte
nsi
ty
100 200 300 400 500 600 700 8000,0
0,2
0,4
0,6
0,8
1,0
lmax = 658 nm
QE254 = 81 %
RQ254 = 7%
x = 0.713
y = 0.287
LE = 80 lm/W
Emission spectrum
Excitation spectrum
Reflection spectrum
Re
lative
in
ten
sity
Sample U601Wavelength [nm]
100 200 300 400 500 600 700 8000,0
0,2
0,4
0,6
0,8
1,0
lmax = 620 nm
QE254 = 79 %
RQ254 = 5%
x = 0.549
y = 0.426
LE = 150 lm/W
Emission spectrum
Excitation spectrum
Reflection spectrum
Re
lative
in
ten
sity
Sample U2024Wavelength [nm]
Chapter High Pressure Discharge Lamps
Slide 10
Incoherent Light Sources
Prof. Dr. T. Jüstel
YVO4:Eu3+ phosphors - Thermal behavior
The luminous efficacy under UV-A excitation increases
up to about 300 °C
Cause: Increase in spectral overlap with Hg
high-pressure discharge spectrum
6.4 Phosphors for High-Pressure Mercury Lamps
Excitation spectra of YVO4:Eu
250 300 350 4000,00
0,05
0,10
0,15
0,20
0,25
0,30
monitored at 619 nm
U737025C
U737075C
U737150C
U737200C
U737250C
U737300C
U737330C
Em
issio
n in
ten
sity [a
.u.]
Wavelength [nm]
550 600 650 700 7500
20000
40000
60000
80000
excitation at 300 nm
U737025C
U737075C
U737150C
U737200C
U737250C
U737300C
U737330C
Em
issio
n in
ten
sity [
a.u
.]
Wavelength [nm]
0 50 100 150 200 250 300 350
0
1
2
3
4
5
6
7
8 integral 254 nm exc.
Integral 300 nm exc.
Integral 350 nm exc.
Rela
tive e
mis
sio
n inte
nsity
Temperature [°C]
Emission spectra of YVO4:Eu
Luminescence intensity as a function of
temperature and excitation wavelength
Chapter High Pressure Discharge Lamps
Slide 11
Incoherent Light Sources
Prof. Dr. T. Jüstel
Hg low-pressure Hg high-pressure
36 W 400 W
I = 0.36 A I = 4 A
Tungsten + emitter Tungsten + emitter
BaO / SrO / CaO BaO / SrO / Y2O3 / ThO2
T = 1350 K T = 2000 - 3000 K
0.5 cm 1.0 cm
6.5 The Electrode
Chapter High Pressure Discharge Lamps
Slide 12
Incoherent Light Sources
Prof. Dr. T. Jüstel
Tungsten Very thin
Mo- or Nb-foil
Molybdenum
Plasma
Problem: Different thermal expansion coefficients SiO2 a = 0.5*10-6 K-1
W a = 4.3*10-6 K-1
Mo a = 2.8*10-6 K-1
Quartz (1000 °C)
6.6 The Electrode Feedthrough
Chapter High Pressure Discharge Lamps
Slide 13
Incoherent Light Sources
Prof. Dr. T. Jüstel
Parabolic reflectors Elliptical reflectors
y = x2
Focal point (light source)
Only possible if the light source is point like
An ellipse has two focal points
HID-lamps
6.7 Types of Reflectors
Chapter High Pressure Discharge Lamps
Slide 14
Incoherent Light Sources
Prof. Dr. T. Jüstel
In street lighting (outdoor lighting)
h = 60 lm/W
Ra = 50
Lifetime = 20.000 h
P = 100 W - 2000 W
6.8 Application of HP-Lamps
Chapter High Pressure Discharge Lamps
Slide 15
Incoherent Light Sources
Prof. Dr. T. Jüstel
6.9 The High-Pressure Sodium Lamp (HPS)
l in nm
300 400 500 600 700
58
9 n
m
Na-pressure
h in lm/W 200
120
10 mbar 1 bar
Na low-pressure
Lamp (0.01 mbar)
l in nm
300 400 500 600 700
Na high-pressure
Lamp (100 mbar) Pressure increase
Pressure dependence of the lumen output
58
9 n
m
Chapter High Pressure Discharge Lamps
Slide 16
Incoherent Light Sources
Prof. Dr. T. Jüstel
Problem: Na reacts at high temperatures with the quartz glass wall