Lecture 9 6.976 Flat Panel Display Devices
Photoluminescence Case Study: Plasma Display Panels
Outline • • • • • • •
Overview Physical Principles Plasma Discharge Physics Photoluminescence Addressing Fabrication Processes How well do they work
6.976 Flat Panel Display Devices - Spring 2001
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References • Larry Weber, Color Plasma Displays, Seminar M-6, SID Seminar Lecture Notes, 1996 • Shigeo Mikoshiba, Color Plasma Displays, Seminar M-6, SID Seminar Lecture Notes, 1999 • Shigeo Mikoshiba, Color Plasma Displays, Seminar M-2, SID Seminar Lecture Notes, 2000 • G. Blasse et al. Luminescent Materials, Spinger-Verlag, 1994. • T. N. Criscimagna, “AC Plasma Display,” Chapter 3 in Display Devices, J. I. Pankove, ed., Spinger-Verlag, 1980.
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Summary of Today’s Lecture • Color Plasma Display Panels (PDPs) are photoluminescent flat panel displays which generate UV using two dimensional array of miniplasma discharge cells • PDPs have inherent memory • PDPs are passive matrix addressed. • Energy consumed by the addressing circuit of PDPs could be reduced by using energy recovery techniques www.pctechguide.com
6.976 Flat Panel Display Devices - Spring 2001
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60” Diagonal Plama Display Panel
Weber, SID ‘00 6.976 Flat Panel Display Devices - Spring 2001
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LG Electronics Plasma Display Panel
Park, SID ’00, p. 475 6.976 Flat Panel Display Devices - Spring 2001
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Mikoshiba, SID Seminar Notes, 2000 6.976 Flat Panel Display Devices - Spring 2001
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Color Plama Display Fundamentals • Ultra-Violet light is generated by a gas discharge • Ultraviolet light excites a phosphor layer • Phosphor fluoresces visible light • Different phosphors are used for Red, Green and Blue • Each phosphor sub-pixel has 256 possible intensity levels www.pctechguide.com
6.976 Flat Panel Display Devices - Spring 2001
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What is a Plasma? Low Temperature
Solid
atom
Liquid
atom
6.976 Flat Panel Display Devices - Spring 2001
High Temperature Gas
electron ion
Lecture 8
Plasma
electron
ion
8
Where does the UV Come From?
nucleus
electron
Ground State 6.976 Flat Panel Display Devices - Spring 2001
Spontaneous Emission of Light
Excited State Lecture 8
Ground State 9
Visible-Light Emission Process PDP
CRT
1
Secondary electron emission
Thermionic electron emission
2
Multiplication of electrons by ionization
-
3
Electronic excitation of gas
-
4
VUV radiation from excited gas
-
5
Photoluminescence
6.976 Flat Panel Display Devices - Spring 2001
Cathodoluminescence
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Basic Device Structure
Weber, SID ’00 Digest p. 402 6.976 Flat Panel Display Devices - Spring 2001
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Basic Structure and Glow Formation Anode Phosphor V0
Positive Column
R Negative Glow Cathode
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Penning Ionization Direct ionization ( higher breakdown voltage)
Ar + e − → Ar + + 2e − Penning ionization ( lower breakdown voltage) (16.6 eV)
Ne + e
−
→
Ne + Ar → *
Ne + 2e *
+
Ne + Ar + e
(16.6 eV)
6.976 Flat Panel Display Devices - Spring 2001
− −
(15.8 eV)
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I-V Characteristics
Mikoshiba, SID Seminar Notes, 2000
Vd = data line voltage Vs = scan voltage 6.976 Flat Panel Display Devices - Spring 2001
Vd < VBD and Vs < VBD but Vd + Vs > VBD Lecture 8
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Current Limiting Techniques
Weber, SID Seminar Notes, 1996 6.976 Flat Panel Display Devices - Spring 2001
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Luminous Regions
Weber, SID Seminar Notes, 1996 6.976 Flat Panel Display Devices - Spring 2001
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Model of Important Gas Discharge Reactions
Weber, SID Seminar Notes, 1996 6.976 Flat Panel Display Devices - Spring 2001
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Feedback Model
Weber, SID Seminar Notes, 1996 6.976 Flat Panel Display Devices - Spring 2001
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Basic Cell Model for AC PDP
Pleshko 6.976 Flat Panel Display Devices - Spring 2001
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Basic Cell Operation of AC PDP
Pleshko 6.976 Flat Panel Display Devices - Spring 2001
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Wall Charges in an AC PDP Cell electrode
+++
excited atom
+++++ -
+ +
+++++
---
---
- -
+ +
+ +
- +- + + - + + +++
+++
---
(e)
(f)
---
-----
-----
(a)
(b)
(c)
dielectric layer
+
ion
6.976 Flat Panel Display Devices - Spring 2001
-
electrode charge
(d) wall charge
electron
- -
+++ + + + -
- +- + -
excited atom Lecture 8
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Simple Write and Erase
Pleshko 6.976 Flat Panel Display Devices - Spring 2001
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VUV Output in On- and Off States
Weber, SID Seminar Notes, 1996 6.976 Flat Panel Display Devices - Spring 2001
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Photoluminescence • The ground state has equilibrium distance Ro with vibrational states are as shown • The excited state has equilibrium distance Ro’ with vibrational states are as shown • The parabola offset is ∆R • The absorption transistion is – g→e
• The emission transition is – e→g
Blasse 6.976 Flat Panel Display Devices - Spring 2001
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Excitation and Emission
Blasse
• Emission and Excitation spectral different. • Phosphors are excited with 147 nm radiation • Red, green and blue phosphors emit at their corresponding wavelength 6.976 Flat Panel Display Devices - Spring 2001
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RED Phosphor for 147 nm Excitation CIE chr. Diagram Phosphor
Relative Efficiency
(NTSC)
x
y
0.67
0.33
1/10 decay
Y2O3:Eu3+
1
0.64
0.34
4 ms
(Y,Gd)BO3:Eu3+
1.3
.64
.36
11 ms
.51
.34
Y.96P.60V.40O4:Eu.0 4
Mikoshiba, SID Seminar Notes, 2000 6.976 Flat Panel Display Devices - Spring 2001
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GREEN Phosphor for 147 nm Excitation CIE chr. Diagram Phosphor
Relative Efficiency
x
y
.21
.71
0.18
0.73
14 ms
(Ba,Sr,Mg)O•Al2O3:Mn2+ 1.2
.15
.75
14 ms
Zn2SiO4: Mn2+
.23
.70
(NTSC) BaAl 12O19:Mn2+
1
1.2
1/10 decay
Mikoshiba, SID Seminar Notes, 2000 6.976 Flat Panel Display Devices - Spring 2001
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BLUE Phosphor for 147 nm Excitation CIE chr. Diagram Phosphor
Relative Efficiency
x
y
(NTSC)
.14
..08
BaMgAl10O17: Eu2+
.15
.077
YP.85V.15O4
.19
.21
1/10 decay
