EEFL Backlight Technology

Confidential

EEFL-Backlight Technology(End-Cap Type External Electrode Fluorescent Lamp)

EEFL-Backlight Technology(End-Cap Type External Electrode Fluorescent Lamp)

KDT m&s Co.,Ltd., Korea

ConfidentialBasic Characteristics of CCFL & EEFL Basic Characteristics of CCFL & EEFL

I-V Characteristics 19″ Lamp(2.6 mm / 393 mm)

0 1 2 3 4 5 6 7 80

10000

20000

30000

40000

50000

Brig

htne

ss [c

d/m

2 ]

Power [W]

CCFLEEFL

EEFL

CCFLOperation

0 500 1000 1500 20000

5

10

15

20CCFLEEFL

Starting

CCFL

Cur

rent

[m

A] (

RM

S)

Cathode

fall Voltage

CCFLOperation

EEFL Operation

EEFL

Voltage [V] (RMS)

ConfidentialBasic Characteristics Basic Characteristics

Multi-EEFLsMulti-CCFLs

Co

• Co : Ballast Capacitor

for the Uniformity

• Good Uniformity

ConfidentialEEFLs EEFLs for the High Brightness & High Efficiencyfor the High Brightness & High Efficiency

Key Issues ;

1st. Switching Inverter generating AC-Square Pulses

2nd. Driving Methods of Self-Discharge Synchronizing

3rd. New External Electrode Formation Scheme : Metal-Glass Melt-Bonding Technology provides

High Capacitance

ConfidentialLamp Operation Lamp Operation CCFL (LC-Resonance Inverter) EEFL (Switching Inverter)

- V-I Phase Synchronized (Zero Crossing)(i) Rising Voltage

[+] [-]Current

(ii) Sustaining Voltage Wall Charge

[G] [G]

Self-Discharge Current

[+] [-]

Current

(iii) Falling Voltage

V

I

tV

t

[+] [-]Current

Direct

v

I

t

- Self-Discharge Synchronized for high Efficiency

t

Current

Direct

v

[-] [+]

ConfidentialSwitching Inverter Switching Inverter

A

B

C

D

Multi lamps

Vcc

A

B

C

C

Multi lamps

Vcc

• Full-Bridge Circuit • Half - Bridge Circuit

• Push-Pull Circuit • AStable Multi - Vibrator

Vcc

amp amp

Multi lampsMulti lamps

A BVcc

ConfidentialEEFL Driven by a Switching Inverter EEFL Driven by a Switching Inverter

- 19″Lamp - EEFL(Switching Inverter)

25µs(40 kHz) 12.5µs

5µs

DUty = 50%

ii) Current (100mA/Div.)

iii) Optical Signal

Main & Self Discharge

Overlapped

i) Voltage (2kV/Div.)

Vp

0 1 2 3 4 5 6 7 8 9 100

10000

20000

30000

40000

50000

Power [W]

EEFL(Switching

Inverter)

EEFL(LC-Resonance

Inverter)

Brig

htne

ss [

cd/m

2 ] CCFL(LC-Resonance

Inverter)


25µs(40 kHz)

Main Discharge

Self Discharge

10µs

Duty = 40%


iii) Optical Signal


10µsVp



iii) Optical Signal

Duty = 24%

25µs(40 kHz)

6µs

Main Discharge

Self Discharge

12.5µs

Vp


a) Rising Voltage

+-

Main-discharge Current

VoltageVP

tr

tPtf

Vp

(+) (-)

(+)

Wall charge Vw

++++++----- - (-)

Wall charge Wall charge

Vw

b) Sustaining Voltage

c) Falling Voltage

+++

---

++

--

Self-discharge Current

t

Current(Synchronize)

Current(Delayed)

t

t

Current(Over Current)

Self-discharge Synchronizing Point

Delayed

Over Current

t


Self-Dischage Synchronized Wave Formulas

b) Over-ShotSynchronizing Point

a) Rounded Wave

t

t

V

I

Synchronizing PointV

t

I

t

C) Sloped d) Sawtooth

Synchronizing Point Synchronizing PointV VVP

t t

II

tt

ConfidentialEEFL Electrode Structure EEFL Electrode Structure

ℓ

L

Electrode Length

• Optimum Electrode Length

0 2 4 6 8 100

5000

10000

15000

20000

25000

30000

35000

40000

45000

Brig

htne

ss [

cd/m

2 ]

Power [w]

1cm1.5cm2cm2.5cm3cm3.5cm

ℓ =ℓ =ℓ =ℓ =ℓ =ℓ =

ℓ=3.5cm

ℓ = 3cm

ℓ = 2.5cm

ℓ = 2cm

Lamp length : 375mm

0 20 40 60 80 1000

1

2

3

4

5

Opt

imum

Len

gth

[cm

]

Lamp Length [cm]

1.8

4.0

3.0

ℓ = 1.5cm

ℓ = 1cm

ConfidentialEEFL Electrode StructureEEFL Electrode Structure▶ Electrode Formation Methods

1) Metal Cap ( Copper Cap )2) Metal Foil Taping3) Metal Plating4) Metal–Glass Melt-Bonding

Al-PasteCopper Cap Cu-Taping

Metal-Bonding Metal-Bonding

ConfidentialEEFL Electrode StructureEEFL Electrode Structure

0 1 2 3 4 5 6 70

5000

10000

15000

20000

25000

30000

35000

40000

45000 Ag melt-bondingAl melt-bondingAl-tapingCu-taping

2 4 6 8 100

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

Effic

ienc

y [l

m/w

]

Brig

htne

ss [c

d/m

2 ]

0

10

20

30

40

50

60

EEFL (Ag melt-bonding)conventional CCFL

Brig

htne

ss [

cd/m

2 ]

Bonding

Taping

Power [W]Power [W]

ConfidentialMetalMetal––Glass MeltGlass Melt––Bonding Technology Bonding Technology

• Metal–taping (Low Capacitance)

• Metal–glass melt–bonding(High Capacitance)

(+)

Glasspolarization

metal

Wall charge

(+)

Wall charge

+

Metal-tape

Wall charge

Glasspolarization

Irregular space (high field)

Wall charge

+

ConfidentialVarious EEFLVarious EEFL--Lamps Lamps

-Color EEFL Lamps



450 mm

393 mm

355 mm

314 mm

291 mm

1000 mm

ConfidentialEEFLEEFL––Edge Lighting Backlight Edge Lighting Backlight 2) Bended Electrode1) Elongated Bottom Electrode

Dead Zone(~0.8cm)

Lamp

ReflectorLGP

Lamp

ReflectorLGP

ConfidentialEEFLEEFL––Backlight ( EdgeBacklight ( Edge––Lighting ) Lighting )

19″Panel17″Panel

Reflector

Multi-Vibrator Switching InverterFull-Bridge Switching Inverter

( 15 * 3 * 1 ) (cm)( 12 * 3 * 1 ) (cm)

ConfidentialEEFLEEFL––Direct Lighting Backlight Direct Lighting Backlight

Type1 : Electrodeless Lamps Type2 : Elongated EEFLs Type3:Bended EEFLs

- Simple Connection- Low Efficiency ~50 lm/W

- Narrow Dead Zone- High Efficiency ~ 60 lm/W

- Narrow Dead Zone- High Efficiency ~ 60 lm/W

Electrodeless Lamp ElongatedLampHole

LampHole

LampHole

Lamp Connector(Copper Inside hole)

Lamp Connector(Copper Inside Hole)

Lamp Connector(Conductive Lubber Inside Hole)

ConfidentialEEFLEEFL––Backlight ( DirectBacklight ( Direct––Lighting ) Lighting )

20.1″ Panel Diffusion Plate Opened

( 12 * 3 * 1 ) (cm)( 9.5 * 4.8 * 1 ) (cm)

ConfidentialEEFLEEFL––Backlight ( DirectBacklight ( Direct––Lighting ) Lighting )

Full bridge Switching Inverter

12 - EEFLsi) Voltage (2kV/Div.)


iii) Optical Signal

( 12 * 3 * 1 ) (cm)

Multi-Vibrator Switching Inverter

12 - EEFLs



iii) Optical Signal

( 15 * 3 * 1 ) (cm)

ConfidentialEEFLEEFL--Backlight ( Direct Backlight ( Direct ––Lighting ) Lighting )

Cu-Taping Electrode

40 45 50 55 60 65 70

50

52

54

56

58

60

62

64

Brightness

Efficiency

Brightness [ cd/ m

2]

20 Inch panel

Effi

cien

cy [

lm/W

]6500

7000

7500

8000

40 45 50 55 60 65 7045

48

51

54

57

60

63

Effi

cien

cy [l

m/W

]

Efficiency

5000

6000

7000

8000

9000

10000

11000

1200017 Inch panel

Brightness

Brightness [ cd/ m

2]

Frequency [kHz] Frequency [kHz]


20.1 Inch 20.1 Inch ((InputInput : 12: 12VV)) : Metal-Bonding Electrode

9 10 11 12 13 14

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

Inpu

t Cur

rent

[A]

Input Voltage [V]

Frequency

Maximum

12V

Efficiency

12V

Brightnes

s

20 30 40 50 60 70 80 903000

4000

5000

6000

7000

8000

9000

10000

11000

Power [w]

52545658606264666870727476788082

Effi

cien

cy [l

m/W

]

Brig

htne

ss [c

d/m

2]


20.1 Inch 20.1 Inch (Input(Input : 24 : 24 VV)) : Metal-Bonding Electrode

Frequency

Maximum84

Efficiency

Brightne

ss

24V

35 40 45 50 55 60 65

7000

7500

8000

8500

9000

9500

10000

1050082

Effi

cien

cy [l

m/W

]

74

76

78

80

Brig

htne

ss [c

d/m

2]

20 21 22 23 24 25

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

Inpu

t Cur

rent

[A]

Input Voltage [V ]

24V

72

70

Power [W]


17 Inch (17 Inch (Input :12Input :12VV))

9 10 11 12 13 142.0

2.5

3.0

3.5

4.0

4.5

Inpu

t Cur

rent

[A]

Input Voltage [V]

Frequency

Maximum

: Metal-Bonding Electrode

Effi

cien

cy [l

m/W

]

Brightnes

sEfficiency

20 30 40 50 604000

6000

8000

10000

12000

14000

Brig

htne

ss [c

d/m

2]

Power [W]

58

60

62

64

66

68

70

72

74

12V

12V

ConfidentialEEFLEEFL––Backlight specificationBacklight specification

- Metal Bonding External Electrode

Conventional Edge-Lighting

Direct Lighting

panel 17 inch38.4*28*2(cm)

17 inch38.4*28*2(cm)

20.1 inch44.5*31*2(cm)

Tubes 4- lamps 12 - lamps 14 - lamps

Invertersize

LC-Resonance16*4.5*1 (cm)

Full Bridge12*2.8*1(cm)

Full Bridge9.5*4.8*1(cm)

Input 12V/ 1.7A 12V/ 3.61A 12V/ 4.68A 24V/ 2.48A

Input Power 20 W 43 W 56 W 59 W

Frequency 50 KHz 56 KHz 53 KHz 59 KHz

Brightness 3,500 cd/m2 11,000 cd/m2 8,650 cd/m2 10,300 cd/m2

Efficiency 50 lm/W 70 lm/W 64 lm/W 73 lm/W

ConfidentialA large Area Backlight about 40 inch in diagonalA large Area Backlight about 40 inch in diagonal

Phase SynchronizedGate Signal Generator

A Section

B Section

C Section

ConfidentialMultiMulti--CCFLsCCFLs Driven by a Switching Inverter Driven by a Switching Inverter

- Self Discharge Synchronizing provides a high Efficiencya) Rising Voltage : Charging Capacitor

Co

b) Rising & Sustaining : Main discharge ( Vr – VC 〉Vf )

c) Falling Voltage : Charging Lamp

++

--

++

--

VpVr

Vr-VcVc

Q=CoVcQ=Cℓ(Vr-Vc)

++ --- -- +++ -

VP→0

d) Falling Voltage ( Vℓ〉Vf ) : Self-discharge

Q/Cℓ=Vℓ

+

++++---- + +

--

Vp

Q=CoVP

VP

Main-discharge Current

-

VP→0

- -+ +

Self-discharge current+

• Co : Synchronizing Capacitorfor the Uniformity

ConfidentialMultiMulti--CCFLsCCFLs Driven by a Switching Inverter Driven by a Switching Inverter

- Self-discharge in Multi-CCFLswith an optimum Ballast Capacitor

(b) Co = 18 pF (a) Co = 47 pF (Without Self-discharge) (With Self-discharge)



iii) Optical Signal

Main Discharge

Duty = 24 % i) Voltage (2kV/Div.)


iii) Optical Signal

Main Discharge

Self Discharge

Duty = 24 %

ConfidentialCCFL Backlight ( DirectCCFL Backlight ( Direct––Lighting ) Lighting )

2) Multi-Vibrator Switching Inverter1) Full bridge Switching Inverter

( 15 * 3 * 1 ) (cm)( 12 * 3 * 1 ) (cm)

• 12 – CCFLs : 17inch Panel• 12 – CCFLs : 17 inch Paneli) Voltage (2kV/Div.)


iii) Optical Signal



iii) Optical Signal

ConfidentialConclusions

1. High Brightness & High Efficiency EEFLs ;- External Electrode Formulated by Metal-Glass Melt-Bonding- A Self-Discharge Synchronizing Operation- By a Switching Inverter

2. Edge-Lighting EEFLs-Backlight Panels ;- A good Uniformity obtained with single Transformer

on a single Stage Inverter.

3. Direct-Light EEFLs-Backlight Panels of 17 & 20.1 inch in Diagonal- High Luminance of 7,000 ~ 10,000 cd/m2

- High Efficiency of 70 ~ 80 lm/w(With single Transformer on a single Stage Inverter.)

Confidential

EEFLEEFL--Backlight & Switching Inverter promiseBacklight & Switching Inverter promisea new generation of LCD Backlight & Operationa new generation of LCD Backlight & Operation

- Low Power consumption- Long Life Time- High Brightness Backlight Up to ~ 10,000 cd/m2

- Low Cost

- High Efficiency Up to ~ 70 lm/W

- Simple Assembly

- Application to a Large Size Backlight Up to 1m×1m inch LCD

< Ref from Presentation at SID’02 Boston by KDT >

Documents

EEFL Backlight Technology