oled 구조 및 구동원리 -...

[email protected]

OLED Business TeamDigital Display Company

LG Electronics Inc.

OLED

2006. 02. 08

20.1, 1280X800, AMOLEDLPL/LGE, 2004

(2006 2 FPD )

Great Company Great People 2/54All contents remain the property of Displaybank and the author

- OLED - OLED Display - (Panel Module) -

Contents


from IEC/TC 110/PT 62341, Terminology and letter symbols

Terminology

3.1.28organic electroluminescenceemission of light from organic materials by injecting current 3.1.29organic electroluminescent displaydisplay showing visual information in which organic electroluminescence occurs3.1.30organic light emitting diodelight emitting device in which light is emitted from organic materials, possessing properties of diode3.1.31organic light emitting diode displaydisplay showing visual information in which organic light emitting diode is applied3.1.32organic light emitting diode display devicegeneric term for organic light emitting diode display panel and organic light emitting diode display module3.1.33organic light emitting diode display moduleorganic light emitting diode display panel and its driving electronics3.1.34organic light emitting diode (display) paneldisplay panel of an organic light emitting diode display without external drivers


OLED


ITO

HIL

HTL

ETL

EIL

EML

Al

Exciton

+

(ITO)

(HIL)

(HTL)

(EML)

(ETL)

(EIL)

OLED Mechanism

Conduction Band (LUMO)

Valence Band (HOMO)

LUMO : Lowest Unoccupied Molecular OrbitalHOMO : Highest Occupied Molecular Orbital

ITO : Indium Tin OxideHIL : Hole Injection LayerHTL : Hole Transport LayerEML : Emitting LayerETL : Electron Transport LayerEIL : Electron Injection Layer


exciton

or

Triplets

Singlet

>>>( >+ )

>( >- )

hole electron

21 21

Charge

transfer

&


Emission Mechanism

Singlet Exciton

Electron - hole

Triplet Exciton

h Phosphorescence(, ~1sec)Fluorescence(, ~nsec)

Charg

e sep

aratio

nCh

arge r

ecom

binati

on

Charge separation(Photoconductivity)

Charge injection

Intersystemcrossing

Thermaldeactivation

Ground State

25% 75%

Thermaldeactivation

h


Emission Mechanism


Power efficiency (unit: /W)

power = r PL V() ext

where : charge balancing factor (~100%)r : fraction of neutral excited states formed as singlet

excitons via the electrical current ( 25%, 100%)

PL : photoluminescence (PL) quantum efficiency, the fraction of energy released from fluorescent or phosphorescent material as light (~100%)

V() : eye response curve (At peak visual response 555nm, 1W=683lm)

ext : the fraction of emitted photons that are coupled out of the device. ~1/ (2n2) (


( : n =1.46 )

( ITO: n = 1.8 ~ 2.1)

( n ~ 1.7)

cathode51% waveguided

31.5% waveguided or emitted from sides

17.5% coupled out

Out-coupling

Internal QE

External QE


Emission Efficiency of OLED

External quantum efficiency(ext)Max. ext = rs qf coupling = 5%

Charge injection & transfer

e-h Pair(Exciton) formation()Max. = 100%

Singlet Exciton formation(rs)Max. rs = 25%

Triplet Exciton formation (rt) Max. rt + Max. rs = 75% + 25% = 100%

Fluorescence Emission(qf)Max. qf = 100%

Phosphorescence Emission (qp)Max. qp = 100%

Optical Coupling(coupling)coupling = 20%

Optical Coupling(coupling)coupling = 20%

External quantum efficiency(ext)Max. ext = rt qpcoupling = 20%

O

X

Flourescence

G: 19%R: 7%B: 5~6%

Phosphorescence


OLED Display


OLED Panel Structure : PM, Bottom Emission

Anode(ITO)

Cathode(metal)

(Cathode

Separator)

Glass Substrate

(Insulator)

Getter

(ETL)

(EML)

(HTL)

(HIL)

(EIL)

Sealant

RGB(Full Color)

Encap-sulation

Cathode

Separator

Organic EL

ITO

Glass

Polarizer


(ETL)

(EML)

(HTL)

Anode

Cathode

-

+

-+

: 100 ~ 200 nm

Exciton

Lightoutput

OLED Device Materials

(from KETI, 2005)


N

O

N

OAl

O

N

NN

DNTPD(HIL) Alq3(ETL)-NPD(HTL)

mQD (Green)DCJTB(Red) DPVBi(Blue)

N

N

N

N

O

N

CNNC

N O

S

N

O

Organic Materials

UV UV UV


25%

100%

Fluorescence & Phosphorescence Emitter

Singlet Exciton Max. s = 25%

( & )

- Pair(Exciton) ()Max. = 100%

Singlet/Triplet Exciton Max. (s + t)=25% +75% =100%

(Fluorescence) (Phosphorescence)

4 R, G .

GroundState

S0

S1

SingletExcitedState

T1

TripletExcitedState

SingletExciton

h()

S0

S1T1

TripletExciton

h()

h()

SingletExciton

ThermalDecay

Radiative Non-radiative Radiative Radiative


()( & )

Fast decay time(


Efficiency(lm/W)

RedPh. 6.6

Green

Ph. 15.5

BluePh.

Life time(hr)(@ Full White 100 nit)

13,000(@ 520 nit/pixel)

4,000(@ 960 nit/pixel)

Comparison of power consumption in Ph. & Fl.

2.0Fl. 46,700(@ 520 nit/pixel)

5.9Fl. 32,000(@ 960 nit/pixel)

Fl.

300(@ 390 nit./pixel)

11,000(@ 390 nit./pixel)

3.1

2.6


- EML Dopant : Ir based metal complex- Hole Blocking Layer(HBL) - Identical charge transfer layer with flourescence emiier

NIr

3

Ir(ppy)3

NN

HIL(CuPc)

NNCH3H3C

Device ITO/CuPc/NPD/CBP+Dopant/BAlq/Alq3/Cathode(B:MgAg, RG:LiF/Al) -

HBLBCP Data . BAlq

NO

AlN

O

NO

NCu

N

N

NNN

N

N

N N

CBP

BAlq

Green Ir(ppy)3 (ppy)2Ir(acac) Red HTL, ETL Codep. Red PtOEP(x=0.71, y=0.29, ext=2.2%, 70 cd/m2) (btp)2Ir(acac) Blue

(btp)2Ir (acac) Firpic

N

Ir

NO O

N

F

F

F

F2

N

IrO

O

(ppy)2Ir (acac)

NOAl

ON O

S

N

IrO

O

2

HTL(NPD) HBL ETL(Alq3)

BCP

Host G Dopant R Dopant B Dopant

Phosphorescence Emitter


(Panel Module)


OLED Process(PM)

R/G/B source

Evaporation Loading

PLASMA

O2

Plasma

Seal Sealing Canister Getter

TAB Pol Cell Cell Aging

Encap.

PHOTO&

ETCHINGITO sputtering ITO patterning Metal patterning

UV

AM AM


ModuleFactory

INPUTAM TFT

EL HIL, HTL, RGB EML

ETL (shadow mask)

Al Encapsulation

sealing

SCRIBE &BREAKING

Cutting the combined glassinto screen units

FINALINSPECTION

Inspecting the TFT panel while regular display signal is applied

OLED Process (AM)


ITO Strip(anode)

Buffer Layer

Metal Strip(Cathode)

Separator()

Patterning

Photo Encap.

Cathode(Al) Patterning ,


PRINCIPLE O2, Ar Gas RF Power Plasma , .

RAW MATERIALO2, Ar Gas

TARGETITO Work Function OELD Device .

Plasma Treatment

PLASMA

Gas RF

Pre-treatment

PRINCIPLEO2 Gas UV Ozone ().

RAW MATERIALO2, UV Lamp

TARGET Device .

UV Cleaning

O2

UV

Photo Encap.


Evaporation

PRINCIPLE Termally Heating .

RAW MATERIALAlq3, R/G/B dopant, CuPc, -NPD, LiF, Al

APPLYING PROCESS, Metal .

Thermal Evaporation

Organicmaterial

Crucible

Cold trap

Shutter

GlassSubstrate

PRINCIPLEMagnetic Field Electron Beam .

RAW MATERIALLiF, Al

APPLYING PROCESS, Metal .

E-beam Evaporation

Vacuum Pump

GlassSubstrate

ElectronBeam

ElectronBeam Source

Crucible

Ingot Rod

MoltenPool

FluxProfile

Photo Encap.


OLED Pixellation : Full Color

CCM C/F ,CCM

Color filter white 1/3

Differential degra., R,G,B

, display

, display

, display

Application

,R,G,B shadow mask

R,G,B shadow mask ,

()

(C/F )

( )

(Color Satu.)

Color ChangeMedium (CCM)

White + Color Filter

Side-by-SideDeposition

GR

B B B

B

R G B

GR B

Photo Encap.


--

--- Patterning

- 370x400mm - 550x650 for C/F

LITI

--

- Shadow mask * 730x920 Glass 100~130 ppi(Max. 40 inch Wide)* < 23m

--

- OLED -

- 370x470mm - 2,000x2,000 (for C/F)

Ink-Jet

- 370x470mm (Max. 20.1 inch Display)

- 730x920

Thermal Evaporation(Shadow Mask)

OLED Photo Encap.

(LITI: Laser Induced Thermal Imaging)


SDI, KDC 2005

Photo Encap.


Thin Film Encapsulation

TFT- LCD

GlassTFT GlassBack Light

20 grams

5 mm

10%

$18.00

20 grams

5 mm

10%

WeightThicknessBreakage

Cost

OLED

GlassTFT Glass

Flexible OLED

Flexible TFT Glass

2010

OLED

TFT Glass

2005

5mm

0.2mm

Photo Encap.


Encapsulation Panel , Panel .

Aging

O/S

Probe TEST

Cleaning

Breaking

Pol.

Cell .

Panel .

Glass Cell Crack .

Scribing Glass

Polarizer Chip .

, Film .

Scribing

Panel Pad , Line, Open/ Short .

Photo Encap.


Line Fail?

Pixel - Short Panel .

- Pixel (Anode, ITO) : Data Line

- Pixel (Cathode, Al) : Scan Line

Line Fail Aging

Data Line ( m )

Scan Line (n-1)

Scan Line ( n )

Scan Line (n+1)

Line Fail Short PixelH

H

L

Driver IC Short Pixel Scan Line High Voltage

Scan Line n+1 Select

Scan Line n Select

Line Fail


Glass View Polarizer .

Panel Polarizer Align .

* Protecting Film

* Polarizer Panel AttachingAttaching

Alignment Alignment

Function of PolarizerFunction

of Polarizer

Polarizer ,

.

Light Source

InterceptTransmit

polarizer

Polarizer Attachment

SUCTION BLOCK

Pol

Photo Encap.


Circular Polarizer Photo Encap. : Contrast Ratio

: Panel (50% )


TAB

Panel Module ACF PanelPAD

Panel ACF COF Panel Pad .

ACF

Panel module Pattern .

Seal/Tape TAB Seal Tape .

Case Set EL , Case Panel .

// , .

Photo Encap.


Module Process

1. Module

; SET .

) LCD Monitor LCD Module. Hand Phone STN LCD Module

2. OLED Module

OEL Panel

Driver/ControllerIC

FPC

FPC : Driver/Controller IC Panel PCB

Driver IC : Panel IC( Scan Data )

Controller IC : Driver IC MPU Data IC


OLED PanelOLED Panel

Data IC

Data IC

Scan IC

Inter-face

&DC/DC

Conv-erter

Controller

R,G,B Data

R,G,B Data

Synch./ Control Signal/ Power

Synch./ Control Signal/ Power

Synch./ControlSignal

R,G,BData

Memory

Data

Power

CPU

Data/Synch.

---- General Module -------- Extended Module ----

:::

:::

Frame, CLK..

Module Block Diagram


1. Module

1) TAB (Tape automatic bonding) : Film Interface Drive IC .

2) COG (Chip On Glass) : LCD Glass IC .

3) COF (Chip On FPC) : LCD Interface FPC IC .

4) COB (Chip On Board) : Main Board Control PCB PCB

5) OLB(Out Lead Bonding)

; FPC TCP Panel ACF

6) SMT(Soldering Mount Technique)

; FPC PCB

7) Module Assembly (Module )

; COF, OLB, SMT Module

2. Module

OLED Module

COF or TCP

OLED PanelOLB FOB

PCB


FOG

Sub-Unit Sub-KIT

++ FOB

OLED Product Assembly Process

+

ILB

+

SMT

Bare PCB


(PM, AM)


OLED Display

I [A/cm2]

L [Cd/m2]

Approximate linear relationship between light intensity vs. current density.

Easy gray scale realization with current control. Vmin

Voltage

Current

Imax

IminVmax

I-V characteristics like a diode

OELCPIXEL

Circuit model

Opto-Electrical characteristics


OLED


Cathode

Organicfilm

AnodeGlasssubstrate

Glasssubstrate

TFT

OLED

Matrix EL device

Line Emission

Passive Matrix (PM) Active Matrix (AM)

Matrix EL TFT

Frame time Emission

1)

1) TFT : Thin Film Transistor


Passive Matrix

Scan 1

Scan 2

Scan 3

Scan 4

Data 1

Data 2

Data 3

Data 4

t1 t2 t3 t4 t5

Data 5

Data 6

Scan Line , Data Line Pixel

Data

1 2 3 4 5 6

Scan

1

2

3

4


Passive Matrix OLEDs Requires cathode patterning High pulsed drive currents (proportional to row counts) Higher drive voltage than active matrix display Higher power consumption Shorted pixels result in cross-talk or line defects Simple structure/fabrication (low fabrication cost) Small sized panel

+ + + + + +

Data Lines (Anodes)

Scan L

ines (

Cath

odes)

Programmable current source

OEL Cpara

PMOLED


Scan 1

Scan 2

Scan 3

Scan 4

Data 1

Data 2

Data 3

Data 4

t1 t2 t3 t4 t5

Data 5

Data 6

Scan Line , Data Line Pixel (( Frame)Frame)

Data

1 2 3 4 5 6

Scan

1

2

3

4

Active Matrix


Active Matrix OLEDs Common cathode, Display during frame time Low pixel drive voltage/current Low power consumption Full color capability Medium/large sized panel

AMOLED


PM & AM Active MatrixPassive Matrix

LTPS(TFT) + OLED

Simple Process Low Cost

Cost

& Symmetry

Driving method

Panel IC

= Scan Line

Scan Line

Scan Line

Duty Driving(Scan )

Scan Line

Static Driving( )

Size Display (Mobile, CNS, Notebook, TV )

2 Mobile Display - Car Audio, ,

Display

1) PM (Lp) .Lp = Lo Scan Line PM 1 Pixel ,

tp = 1 Frame / Scan Line AM 1 Pixel = 1 Frame

1 Frame (AM)

LoTime

Lp

tp


a-Si TFT 100 poly-Si TFT , TFT compact TFT-LCD .

poly-Si TFT LCD

Controller, Interface Controller, Interface circuit,circuit,--source, source, Amp, DCAmp, DC--DCDC

data driver

gate

dri

ver

Gate

PCB

(DC-DC con

vert, Vc

om)

Source PCB (Controller, -source )

D-IC

a-Si TFT LCD

Excimer Laser

Scan

poly-Si

: depo. (poly-Si)film .

a-Si:H poly-Si Single-Si

(cm2/Vsec)

0.5 ~ 1 50 ~ 200 ~ 600

NMOS NMOS,PMOS NMOS,PMOS

LTPS (Low Temperature Poly-Si) TFT


AMOLED

Conventional 2T-1C Pixel Structure

(from Professor Jin Jang, 2005)


IR-Drop of VDD Line

PixelCircuit

PixelCurrent

PixelCircuit

PixelCircuit

PixelCircuit

VDD

( n ) IPixel

IPixel

IPixel

IPixel

IPixel

( n-1 ) IPixel

ParasticResistance of

Pixel VDD Line

RPixel

RPixel

IPixelRPixel

2 IPixelRPixel

Worst Case Pixel

VDD - Vdrop

2)1(

))1(.....21(

)1(...

........2

+=

++++=

+

++=

nnRI

nnRI

RnIRIn

RIRIV

pixelpixel

pixelpixel

pixelpixelpixelpixel

pixelpixelpixelpixeldrop

AMOLED


Pixel to Pixel Non-uniformity

17, 500cd/m2, SXGA, 6bit-gray T1 : 20um/20um , T2 : 5um/10um Pixel Current : 20nA ~ 5.8uA VDD 12V VTH variation +/- 0.3V Mobility variation 10%

7VDD Line IR Drop

5Mobility Variation

25VTH Variation

Maximum Error (gray)Error Factors

AMOLED


Bottom Emission OLED Top Emission OLED

Passivation Layer

Glass Substrate

getterSealant

Glass cap or Film type cap

Driving TR

Planarization layer

Glass Substrate

GetterMetal cap

Driving TR

Planarization layer

Inert gasMetal cathode

Anode

Semitransparentcathode

OrganicLayer

Pixel

High aperture ratio No Limitation circuit complexity

High integral density High resolution

Low Aperture Ratio Limitation circuit complexity

AMOLED


Consideration for Driving Scheme Decision

Target Resolution(Line Time)

Aperture Ratio(# of Pixel Circuit TFT& Control Signal Line)

Pixel to Pixel Luminance Uniformity

Data Programming Time Pre-charge Scheme

(Driver LSI)

OLED Pixel Current Power, OLED Life time

IR-Drop of VDD lineTFT Threshold Voltage& Mobility Variations

Panel Size(Data Line

Capacitance)

PanelBrightness

AMOLED


AMOLED History (2005. 2 )

(from Professor Jin Jang, 2005)

oled 구조 및 구동원리 -...

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