11. gas discharge displays - fh-muenster.de. gas discharge displays content 11.1 technologies for...

Chapter Gas Discharge Displays

Slide 1

Incoherent light sources

Prof. Dr. T. Jüstel

11. Gas Discharge Displays

Content

11.1 Technologies for Flat Displays

11.2 Construction of Gas Discharge Displays

11.3 Manufacturing Process

11.4 Light Generation in Plasma Displays

11.5 Operation of the Gas Discharge

11.6 Selection Criteria for Display Phosphors

11.7 Phosphors in CRTs and PDPs

11.8 Red PDP Phosphors

11.9 Green PDP Phosphors

11.10 Blue PDP Phosphors

11.11 Status and Outlook


Slide 2




Technology Efficiency Max. size Areas of application

Organic EL 2 lm/W 10„„ Automobiles, mobile phones

Inorg. EL 1 lm/W 17„„ Instrument displays

FED 5 lm/W 17„„

LCD 4 lm/W 65„„ Laptops, monitors, LCD TV

PALC 4 lm/W 40 - 50„„ -

LED Array 8 - 10 lm/W > 100„„ Billboards

Projection TV 5 lm/W 50 - 60„„ TV

PDP 5 lm/W ~ 152„„ TV, scoreboards

CRT 3 lm/W 36„„ TV, monitors

Remark: Theoretical limit for white light ~ 300 lm/Wopt.

Energy efficiency of displays ~ 1 - 5%


Slide 3




Properties

Flat and large

(32 - 300 inch)

Thin ~ 100 mm

Lightweight

~ 20 - 30 kg for 42-inch

Large viewing angle

~ 170°

No distortion

Unaffected by external

magnetic fields

Gas Discharge Displays

152" HDTV-PDP


Slide 4




Emissive Display Types

Technology CRT PDP

Excitation source Electron beam Gas discharge

Excitation energy 20 - 30 keV 6 - 10 eV

Gas pressure < 10-3 mbar 200 - 300 mbar Xe/Ne

Phosphors Sulfides Oxides

Viewing angle > 160° > 160°

Resolution EDTV UHTV

720 x 480 pixel 3840 x 2160 pixel (4K)


Slide 5



11.1 Technologien für flache Bildschirme 11.1 Technologies for Flat Displays

Plasma displays 1929


Slide 6




Rear

glass plate (PD200)

Address electrodes (Ag)

RGB phosphor

Bus electrode (ITO)

Front glass plate

R G B

Dielectric

MgO protective layer

Dielectric

Gas filling ~ 500 Torr Ne with 3 - 5 % Xe

Simplified layer structure


Slide 7




Conical structure

U-shaped structure

Structure of a plasma cell

Glass back panel

Structuring by barrier ribs

TiO2-film as a reflector

Phosphor layer (with

additives)


Slide 8




Preparation of the front plate


Slide 9




Preparation of the back plate


Slide 10




Front glass plate

Gas discharge

VUV VUV

Visible

light

Rear glass plate

~ 200 µm

Noble gas discharge

VUV light

Phosphor

Visible light

Functional principle


Slide 11



PDP-cell Xe2 * - lamp Hg - lamp

h Plasma 24 % 70 % 75 %

h UV 40 % 90 % 98 %

h Phosphor

20 % 25 % 44 %

h Coupling out 50 % 90 % 98 %

h Display 1.0 % 14 % 30 %

Typ. light output 3 lm/W 40 lm/W 90 lm/W


Efficiency of light generation

hdisplay = hdischarge . hUV

. hphosphor . h out-coupling


Slide 12




400 500 600 700 800

0,0

0,2

0,4

0,6

0,8

1,0

Em

issio

n in

ten

sity [

a.u

.]

Wavelength [nm]

Light generation in Ne discharges

Ne + e- Ne* + e-

Ne* Ne + h(74 nm + vis.)

Ne* + Ar Ne + Ar+ + e-

Ne* + Xe Ne + Xe+ + e-

(Penning ionization)

- Monochrome PDPs

- Neon discharge lamps

- Hg-discharge lamps with Ne-filling "neon lamps"

Gas mixtures of Ne/Ar or Ne/Xe thus cause a reduction of the ignition voltage by

the so-called “Penning effect”


Slide 13




Light generation in Xe/Ne discharge

Xe(1S0) + e- Xe(3P1) + e-

Xe(3P2) + e-

Xe**

Xe** Xe(3P1) + h(828 nm)

Xe(3P2) + h(823 nm)

Xe(3P2) Xe(1S0) + h(147 nm)

Xe(3P1) + Xe(1S0) + M Xe2*(1u+) + M / Xe(3P2) + Xe(1S0) + M Xe2*(3u

+) + M

Xe2*(3u+) Xe2*(1g

+) + h(150 nm) 2 Xe(1S0)

Xe2*(1u+) Xe2*(1g

+) + h(172 nm) 2 Xe(1S0)

Internuclear Distance (Å)

2 3 4 5 6 7

Ene

rgy

Resonance Line

1st2nd

Continuum

1u

3P1 + 1S0

3P2 + 1S0

B

A

1S0 + 1S0 X

3u+

1u+

1g+

Wa

ve

len

gth

/ n

m147

172

Resonance Line

Low Pressure

High Pressure

2nd Continuum

1st Continuum


Slide 14




50% Xe2*-excimer and 50% Xe* resonance emission at 25 mbar Xe partial pressure

PDPs 2005: Xe percentage at 10 - 15% and 300 mbar total pressure, i.e., Xe2*-excimer

radiation predominates

0,001

0,010

0,100

1,000

0 50 100 150 200

Re

lati

ve

pro

po

rtio

n o

f ra

dia

tio

n

Xenon partial pressure / mbar

150 nm

147 nm

172 nm

140 150 160 170 180 190

0,0

0,2

0,4

0,6

0,8

1,0

10% Xe

20% Xe

1% Xe

Em

issio

n in

ten

sity [

a.u

.]

Wavelength [nm]

Light generation in Xe/Ne discharge


Slide 15



With the Xe pressure the efficiency and the ignition voltage increases


Influence of Xe partial pressure

0

100

200

300

400

500

600

0 5 10 15 20

Xe-content (%)

Su

sta

invo

ltag

e (

V)

Vsm

Vf

660 mbar, 500 V, 50 kHz

0

1000

2000

3000

4000

0 5 10 15 20

Xe-content (%)

Lu

min

an

ce (

cd/m

2)

0

1

2

3

4

5

6

Effi

cacy

(lm

/W)


Slide 16



100% Ne Ne/Xe 100% Xe

High ignition voltage

~ 2 kV

No visible emission

(color is defined by the

phosphor)

VUV emission

147, 150, 172 nm

Low ignition voltage

~ 300 V

Visible emissions

580 - 720 nm

(Monochrome red)

VUV emission

74 nm


Dependence on the Xe/Ne partial pressure


Slide 17




0

V

0

I

t

Dielectric barrier discharges

Schematic operation of a PDP-cell Course of voltage and current

V 0

Dielectric

negative glow

negative glow


Slide 18




Addressing the pixel

Each pixel has 2n brightness levels

By 8-bit addressing one obtains 28 = 256 brightness levels

In a RGB-display there is therefore 2563 = 16.7 million colors available

1 2 4 8 16 32

1 Frame: Will be specified by the refresh rate (100 Hz)

erasing/priming addressing sustaining


Slide 19




Influence of the surface on the plasma ignition by ion induced emission of

secondary electrons

i =

MgO is the material with the highest Ne ~ 0.5

Number of emitted electrons

Number of ions on the surface

Plasma MgO

Front glass

2

2

)1/1ln(ln

i

f

dpC

dpDV


Slide 20




MgO protective layer causes

• a protection against sputtering

• a reduction of the ignition voltage

0 10 20 30

100

150

200

250

300

350

400

450

Glas, i = 0.06

MgO, i = 0.5

Ne

Ign

itio

n v

olta

ge

(V

)

p x d (Torr cm)

10 10010

-2

10-1

100

Ne

MgO; i = 0.5

Glas; i = 0.06

Eff

ective

s g

am

ma

E / p (V Torr-1 cm

-1)

Tasks of the MgO protective layer


Slide 21



11.6 Selection Criteria for Display Phosphors Stability

Temperature stability Sensitivity to oxidation

Stability in suspension Solubility, surface potential

Plasma stability Resistance to sputtering

Color point stability Photo-oxidation, reduction

Light output

Linearity Saturation

Efficiency Quantum yield QA, absorption A

Image quality

Image artifacts Decay time

Color space Color point x, y

Environmental compatibility

Energy efficiency Quantum yield QA, absorption A

Toxicity Chemical composition


Slide 22




Plasma Display

• High absorption A under VUV excitation, i.e., band gap EG ~ 6 – 8 eV

• High quantum yield QY under VUV excitation, i.e., Eu2+, Tb3+, Mn2+, Eu3+

• High light output LO = QY*A

• VUV stability

1 µm

VUV (PDPs) or electrons (CRTs) Visible light


Slide 23




Light output

LO = QE* (1-R)

Energy efficiency

= LO *N(hem)/N(habs)

~ 20%

400 450 500 550 600 650 700 7500,0

0,2

0,4

0,6

0,8

1,0

Re

lative

in

ten

sity

(Y,Gd)BO3:Eu

Zn2SiO

4:Mn

BaMgAl10 O

17 :Eu

Wavelength [nm]

Energy efficiency

= (1-rb)*t* hem /Eg

~ 15 - 20%

PDP phosphors (oxides) CRT phosphors (sulphides)

400 450 500 550 600 650 700 7500,0

0,2

0,4

0,6

0,8

1,0

Re

lative

in

ten

sity

Wavelength [nm]

Y2O2S:EuZnS:Cu,Al,AuZnS:Ag


Slide 24




Commercial CRT and PDP phosphors

Color Chemical composition x y Problem areas

Blue ZnS:Ag 0.15 0.08

Green ZnS:Cu 0.29 0.61

Y3(Al,Ga)5O12:Tb 0.37 0.55

Y2SiO5:Tb 0.33 0.58

Gd2O2S:Tb 0.36 0.57

Red YVO4:Eu 0.66 0.33

Y2O2S:Eu 0.66 0.33

Blue (Y,Gd)(V,P)O4 0.16 0.13 Burn-in

BaMgAl10O17:Eu 0.15 0.06 (stability)

Green Zn2SiO4:Mn 0.25 0.70 Motion artifacts

BaMgAl10O17:Eu,Mn 0.15 0.72 (decay time)

BaAl12O19:Mn 0.19 0.73

(Y,Gd)BO3:Tb 0.34 0.62

Red (Y,Gd)BO3:Eu 0.64 0.35 Color gamut

(Y,Gd)2O3:Eu 0.65 0.34 (color point)

(Y,Gd)(V,P)O4:Eu 0.66 0.33

CRT

PDP


Slide 25




Cathode ray tube (CRTs)

Color space is defined by the color points

of the phosphor

x y

ZnS:Ag 0.15 0.08

ZnS:Cu,Al, Au 0.29 0.61

Y2O2S:Eu 0.66 0.33

Plasma displays (PDPs)

Gas filling: Ne, 3 - 15% Xe

Red neon lines reduce color purity of

blue and green phosphor

x y

BaMgAl10O17:Eu 0.15 0.06

Zn2SiO4:Mn 0.25 0.70

(Y,Gd)BO3:Eu 0.65 0.35

Color space


Slide 26




Eu2+ phosphors

Transition: 4f65d1 4f7 (bands)

Position depends on the crystal field

~ 1 µs

Eu3+ phosphors

Transition: 5D0 7FJ (lines)

Inversion symmetry (S6, D3d)

Magnetic dipole transition 5D0 - 7F1

J = 0, ± 1 (J = 0 J = 0 forbidden)

MeBO3:Eu (calcite, vaterite)

~ 8 - 16 ms

No inversion symmetry

Electric dipole transition 5D0 -7F2,4

J 6 (Jbeginning = 0 J = 2, 4, 6)

Y2O3:Eu (bixbyite), Y(V,P)O4:Eu (xenotime)

~ 2 - 5 ms


Slide 27



Color saturation: Y2O2S:Eu > YVO4:Eu > Y2O3:Eu > (Y,Gd)BO3:Eu

600 650 700 750

5D

0 -

7F

3

5D

0 -

7F

4

5D

0 -

7F

2

5D

0 -

7F

1

(Y,Gd)BO3:Eu

Y2O

3:Eu

YVO4:Eu

Y2O

2S:Eu

Inte

nsity

Wavelength [nm]

Phopshor Color point x, y (Y,Gd)BO3:Eu 0.640 0.360 Y2O3:Eu 0.641 0.344 YVO4:Eu 0.645 0.343 Y2O2S:Eu 0.650 0.342


Emission spectra and color points


Slide 28



Phosphor (Y,Gd)BO3:Eu Y2O3:Eu YVO4:Eu Y2O2S:Eu

Band gap EG 7.5 eV 5.6 eV 5.0 eV 4.4 eV

150 200 250 300

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

(Y,Gd)BO3:Eu

YVO4:Eu

Y2O

3:Eu

Y2O

2S:Eu

Lig

ht outp

ut

Wavelength [nm]

Phosphor Light output LO

147 nm 172 nm

(Y,Gd)BO3:Eu 0.78 0.75 Y2O3:Eu 0.60 0.69 YVO4:Eu 0.41 0.50 Y2O2S:Eu 0.26 0.32


Efficiency

Excitation spectra and VUV light output of Eu3+-phosphors


Slide 29




Phosphor Decay time 1/10 [ms]

(254 nm excitation)

Y2O2S:Eu 1.0

Y2O3:Eu 2.5

YVO4:Eu 3.5

(Y,Gd)BO3:Eu 8.5

0 5 10 15 20 25 30 35 401E-5

1E-4

1E-3

0,01

0,1

1 GDBO3:Eu

(Y,Gd)BO3:Eu

(Y,Lu)BO3:Eu

Y(V,P)O4:Eu

(Y,Gd)2O3:Eu

No

rma

lise

d e

mis

sio

n inte

nsity

t [ms]

Decay time decreases with increasing deviation of the inversion symmetry of the

lattice site of Eu3+

Relaxation of selection rules!

Decay time of Eu3+-phosphors


Slide 30




(J. Solid State Chem. 128 (1997) 261-266)

• Location A: Slight deviation from the S6 symmetry (C3)

• Location B: Strong deviation from the S6 symmetry ( (C3)

5D0 - 7F2,4 emission is observed due to the deviation of the S6 symmetry

Local symmetry of Y3+ and Eu3+ in YBO3 (vaterite)

Platz A Platz B


Slide 31




Color point shifts from orange to red in the series Gd3+, Y3+, Lu3+

Distortion depends on r[(Eu3+) - r(Me3+)]

550 600 650 700 7500,0

0,2

0,4

0,6

0,8

1,0

GdBO3:Eu

YBO3:Eu

LuBO3:Eu

Em

issio

n in

ten

sity [

a.u

.]

Wavelength [nm]

585 nm 5D0 - 7F0

594 nm 5D0 - 7F1

612, 627 nm 5D0 - 7F2

650 - 680 nm 5D0 - 7F3

690 - 720 nm 5D0 - 7F4

Cation Radius* [Å]

Lu 1.00

Y 1.04

Gd 1.08

Eu 1.09

*for CN= 6

Emission spectra of LnBO3:Eu (vaterite)


Slide 32




Color point as a function of excitation energy

• Charge-transfer excitation 254 nm x = 0.638, y = 0.360

• Band excitation 147 nm x = 0.646, y = 0.349

Feldman equation:

R = 0.046*U5/3/ [µm]

(Y,Gd)BO3:Eu = 5.2 g/cm3

10 kV R~ 500 nm

2 kV R ~ 30 nm

0,60 0,61 0,62 0,63 0,64 0,65 0,66

0,32

0,33

0,34

0,35

0,36

0,37

254 nm

172 nm

147 nm

10 kV

2 kVy

x

Color point of (Y,Gd)BO3:Eu3+


Slide 33




Small excitation volume

PDP phosphors are highly charged:

• Saturation

• Strong aging

• Surface layer of the particles must be pure phase and highly crystalline

254 nm corresponds ~ 10 kV

147 nm corresponds ~ 1 kV

R ~ 1.5 µm

R < 0.1 µm

Penetration depth of VUV radiation in matter


Slide 34




Emission spectrum = f(excitation energy)

Photoluminescence Cathodoluminescence

500 600 7000,0

0,5

1,0 2 kV

10 kV

Inte

nsitä

t

Wellenlänge [nm]

500 600 7000,0

0,5

1,0 254 nm

172 nm

147 nm

Inte

nsitä

t

Wellenlänge [nm]

Emission spectra of (Y,Gd)BO3:Eu


Slide 35




Trigonal, D3d symmetry

x = 0.61, y = 0.38

Cubic, Oh symmetry

Cation vacancies

x = 0.64 , y = 0.33

CaO:Eu LuBO3:Eu

200 300 400 500 600 700 8000,0

0,2

0,4

0,6

0,8

1,0

7F

2

7F

4

Em

issio

n in

ten

sity [

a.u

.]Wavelength [nm]

200 300 400 500 600 700 8000,0

0,2

0,4

0,6

0,8

1,0

7F

2

7F

4

7F

1

Em

issio

n in

ten

sity [

a.u

.]

Wavelength [nm]

Color points of Eu3+-phosphors


Slide 36




Host lattice 1/10 [ms]

LaPO4 5.5

CeMgAl11O19 7.0

YBO3 8.5

1/10 = f(host lattice)

400 450 500 550 600 650 7000,0

0,2

0,4

0,6

0,8

1,0

Wavelength [nm]

BaAl12

O19

:Mn x = 0.204, y = 0.717

Zn2SiO

4:Mn x = 0.249, y = 0.700

Em

issio

n inte

nsity [

a.u

.]

Mn2+-phosphors

0,0

0,2

0,4

0,6

0,8

1,0

YBO3:Tb x = 0.338, y = 0.615

LaPO4:Tb x = 0.352, y = 0.580

Em

issio

n inte

nsity [

a.u

.]

Host lattice 1/10 [ms]

Zn2SiO4 5 - 40

BaAl12O19 5 - 40

BaMgAl10O17 5 - 40

1/10 = f(Mn2+-concentration)

Tb3+-phosphors

Emission spectra and decay times of Mn2+- and Tb3+-phosphors


Slide 37




Color saturation

Mn2+-phosphors

y- coordinate: 0.69 - 0.73

Tb3+-phosphors

y- coordinate : 0.58 - 0.62

Tb3+ has emission-line

multiplets at 590 and 620 nm

Zn2SiO4:Mn

YBO3:Tb


Slide 38




Zn2SiO4:Mn CIE1931 color point x, y

• as a powder 0.25, 0.70

• in PDP 10% Xe 0.23, 0.69

• in PDP 3.5% Xe 0.34, 0.62 similar to CRT

400 500 600 700 8000,0

0,2

0,4

0,6

0,8

1,0

File: ColourPoints of green PDPs

P116 3.5% Xe, ZSM

x=0.338, y=0.619

Em

issio

n inte

nsity [

a.u

.]

Wavelength [nm]

400 500 600 700 8000,0

0,2

0,4

0,6

0,8

1,0


P183 10 % Xe, ZSM

x=0.233, y=0.686

Em

issio

n inte

nsity [

a.u

.]

Wavelength [nm]

3.5% Xe 10% Xe

Spectra of the green PDP-pixels with Zn2SiO4:Mn


Slide 39



3.5 % Xe 10 % Xe


(Y,Gd)BO3:Tb CIE 1931 color point x. y

• as a powder 0.34, 0.62

• in PDP 10% Xe 0.35, 0.60 similar to CRT

• in PDP 3.5% Xe 0.39, 0.53

400 500 600 700 8000,0

0,2

0,4

0,6

0,8

1,0


P249 10% Xe, YGBT

x=0.346 , y=0.595

Em

issio

n inte

nsity [

a.u

.]

Wavelength [nm]

400 500 600 700 8000,0

0,2

0,4

0,6

0,8

1,0 P206 3.5% Xe, YBT

x=0.391 , y=0.534

Em

issio

n in

ten

sity [

a.u

.]

Wavelength [nm]

Spectra of the green PDP-pixels with (Y,Gd)BO3:Tb


Slide 40




Me = Ba (1.34 Å) BAM

• BaMgAl10O17 -alumina

• BaMg3Al14O25 -alumina

Me = Sr (1.12 Å) SAM

• SrMgAl10O17 -alumina

• Sr2MgAl22O36 = SrMgAl10O17 + SrAl12O19

(-alumina + magnetoplumbite)

Me = Ca (0.99 Å) CAM

• CaMgAl14O23 magnetoplumbite

• CaMg2Al16O27 magnetoplumbite

• CaMgAl10O17 -alumina

(unstable magnetoplumbite)

magnetoplumbite -alumina

Construction of the intermediate layer

Phosphors in the system MeO-MgO-Al2O3


Slide 41



11.10 Blue PDP Phosphors Structure of BaMgAl10O17

Localization of the europium

• Eu2+ Intermediate layers

• Eu3+ Spinel blocks

Potential secondary phases

• Al2O3

• BaAl2O4

• MgAl2O4

• EuAl11O18

• EuAlO3

• EuMgAl11O19

• Ba0.75Al11O17.25

• ….

Isostructural to -alumina NaAl11O17

Spinel block MgAl10O16

Intermediate layer BaO


Intermediate layer BaO


Unit cell


Slide 42




Ba2+(Eu2+) is nine-coordinate (tri-capped trigonal prism D3h)

Relative small crystal field splitting Blue emission band

Ba2+ environment Layer structure

Structure of BaMgAl10O17


Slide 43




Stability limit of -alumina phase lies at M12k > 4.6 Å

Eu2+ (r9 = 1.17 Å) is smaller than Sr2+ (r9 = 1.26 Å)

Thus: Eu2+-ion incorporation destabilizes the ß-alumina phase

Incorporation of large cations stabilizes the ß-alumina phase (Rb+, K+)

Structural influence of the cations

in the interlayer

1,1 1,2 1,3 1,4 1,5 1,6

4,3

4,4

4,5

4,6

4,7

4,8

4,9

NdCa

La

Sr

Pb

Rb

K

Ba

AgNa

Co

nd

uctio

n la

ye

r th

ickn

ess M

12k

Ionic radius [A]

ß-alumina

magnetoplumbite

Thermodynamic stability of -alumina


Slide 44




150 200 250 3000,0

0,2

0,4

0,6

0,8

1,0

Quantum yield QE

Light output LO = QE(1-R)

Reflection R

Wavelength [nm]

400 450 500 5500,0

0,2

0,4

0,6

0,8

1,0

E

mis

sio

n in

ten

sity

Excitation at 172 nm



Wavelength [nm]

VUV absorption and high quantum yield close to 100 %

Half-width of the emission band increases with the excitation energy

Luminescence spectra of BaMgAl10O17:Eu2+

Efficiency and reflection Emission spectra as a

function of excitation energy


Slide 45




Color point: Influence of the Eu2+-concentration

Cation Radius [Å]

• Ba2+ 1.34

• Sr2+ 1.12

• Ca2+ 0.99

• Eu2+ 1.09

BAM:x%Eu2+ x, y

• 1% 0.152, 0.052

• 10% 0.151, 0.060

• 15% 0.151, 0.067

• 50% 0.144, 0.111

Green shift of the color point by increasing the Eu2+ concentration Incorporation of Eu2+

destabilizes the BAM phase and leads to the formation of BaAl2O4:Eu

0,14 0,15 0,160,05

0,06

0,07

0,08

0,09

0,10

0,11

0,12

BAM:50% Eu

BAM:15% Eu

BAM:1% Eu

BAM:10% Eu

y

x

Color coordinates


Slide 46




254 nm exc. x = 0.146, y = 0.068 ~ 10 kV electron (400 nm)

Activator excitation high penetration depth

147 nm exc. x = 0.140, y = 0.098 ~ 2 kV electron (30 nm)

Band excitation low penetration depth

Feldman equation

R = 0.046*U5/3/ [µm]

0,14 0,15 0,160,05

0,06

0,07

0,08

0,09

0,10

147 nm

172 nm

254 nm

10 kV

2 kVy

x

Color point: Influence of the excitation energy


Slide 47



2 kV excitation (surface) 10 kV excitation (volume)

The secondary phase BaAl2O4:Eu makes itself noticeable in the emission spectrum

400 500 6000,0

0,2

0,4

0,6

0,8

1,0

Ba0.75

Al11

O17.25

:Eu2+

Wavelength [nm]400 500 600

0,0

0,2

0,4

0,6

0,8

1,0

BaAl2O

4:Eu

2+

Wavelength [nm]


Cathodoluminescence of BaMgAl10O17:Eu2+


Slide 48




400 500 6000,0

0,2

0,4

0,6

0,8

1,0

BaAl2O

4:Eu

2+

Wavelength [nm]

400 500 6000,0

0,2

0,4

0,6

0,8

1,0

BaAl2O

4:Eu

2+

Wavelength [nm]

147 nm excitation (surface) 254 nm excitation (volume)

Photoluminescence of BaMgAl10O17:Eu2+


Slide 49




150 200 250 300 3500,0

0,2

0,4

0,6

0,8

1,0

BAM uncoated, 2h 500°C, air

uncoated

Lig

ht

ou

tpu

t L

O =

QE

*(1

-R)

Wavelength [nm]

Particle coating consists of an inert material that acts as a barrier for

a) Oxygen No thermal degradation

b) 74 nm (147 nm) radiation Reduced photodegradation

Materials: Al2O3, AlPO4, Ca2P2O7, SiO2, MgO

150 200 250 300 3500,0

0,2

0,4

0,6

0,8

1,0

Lig

ht

ou

tpu

t L

O =

QE

*(1

-R) BAM coated

BAM coated, 2h 500°C, air

Wavelength [nm]

BaMgAl10O17:Eu2+: Stability enhancement by particle coating

Excitation spectra of

uncoated powderer

Excitation spectra of

coated powder


Slide 50




Comparison of CRTs and PDPs (Stand 2008)

PDP-TV CRT-TV

Display diagonal 80 cm - 750 cm

(32" - 300")

max. 90 cm

(max. 36")

Luminance

(1% white display)

100 - 150 Cd/m2 100 - 130 Cd/m2

Peak luminance

(white display)

1000 Cd/m 2 500 Cd/m 2

Efficiency 3 – 5 lm/W 2 - 3 lm/W

Power consumption in typical TV operation

150 - 300 W 200 - 300 W

Lifetime > 30000 h > 30000 h

Weight 20 - 30 kg (42‟‟) 80 kg (36")

Thickness < 10 cm 60 cm (36")


Slide 51




Future measures to improve the image quality of PDPs

Gas discharge

• Higher Xe partial pressure (higher driving voltage)

• Optimization of the surfaces (materials with a high -coefficient)

Cell geometry and optics

• Improving the conversion of generated VUV photons

• Improving the light out-coupling to the front plate (reflector layers)

• Increasing the contrast: doping of screen‟s glass, color filters, black matrix

Phosphors

• Improving the photostability of the blue phosphors

• Shortening of the decay of the green phosphors

• Improvement of the color point and shortening of the decay of the red phosphor

• Increasing the contrast of colored phosphors

11. gas discharge displays - fh-muenster.de. gas discharge displays content 11.1 technologies for...

Documents