ACETITE ADHESIVES in LCD Applications

Toshiharu Noguchi Technical Manager

Asec Co., Ltd.

November 30, 2003

Types Of Adhesives in LCD Application

Mother Glass Bonding : UV (Temporary) Main Sealing : Heat-cure Epoxy → UV End Sealing : UV/Visible Light Cure Terminal Sealing (Reinforcement)

TAB : Silicone → UV Clip Pin : UV FPC : UV

Terminal Bonding (ACP): Heat-cure Epoxy → UV COG/ITO Coating : Silicone → UV

End-Seal

COG Overcoat

IC Chip

FPC Lead

Main Seal

(ITO Pattern)ACF

(LC)

Adhesives in LCD Application

Major Advantages of UV or UV/Visible Light Curable Adhesives:

Fast Cure → Reduction of Assembly Time Solvent Free → Environmental friendly One Component → Production Efficiency

↓

Total Cost Saving

MOTHER GLASS BONDING - 1Processes:1) Apply Main-Sealing Adhesive2) Apply Mother Glass Bonding Adhesive3) Align and mate Glasses4) UV Light Exposure5) Pressing and Heat curing

400~1,000mm

400~1,000mm

Main Sealing

Glass Bonding

MOTHER GLASS BONDING - 2

Requirements for Adhesive:

Non-Flow Viscosity

Easy Spread in Small Gap

Hot Strength (No movement during Heating)

AS-6954 (20,000mPa-s, Thixo 4)

END SEALING - 1

End Sealing Processes

1) Suck LC into Cell

2) Wipe excess LC around the Charging Port

3) Apply and Suck-In Adhesive

(by Cooling Method or Press Method)

4) UV Light Exposure

Sealing Process Details

COOLING MethodSTEP 1: Filling LC into Cell

STEP 2: WIPING OFF Excess LC

STEP 3: Applying UV Adhesive

STEP 4: Cooling Cell down to 10-15deg.C

STEP 5: Curing by UV Radiation

PRESS MethodSTEP 1: Filling LC into Cell

STEP 2: Stacking 20-60 Cells

STEP 3: Pressing

STEP 4: WIPING OFF

Excess LC

STEP 5: Applying UV Adhesive

STEP 6: Releasing Press slightly

STEP 7: Curing by UV Radiation

END SEALING - 2

Main Problems In End Seal:1) LC Disordering: Color difference / Contrast

2) Occurrence of Irregular shapes (“HIKE”) at Neck

Region: Poor Appearance & LC Leakage

3) Gaps between End Seal & Main Seal: LC Leakage

4) Debonding of End Seal: LC Leakage

LC

4)2)

3)

1)

END SEALING - 3

Requirements of End Sealant Good Compatibility with LC (Low Extractive Ionic Compounds) Good Adhesion to substrates (LC wetted) Low UV Energy Curability (500~1,000mJ/cm2) (High CTV → Visible Light Curability) Resistance to Washing agent Durability Appropriate Viscosity

END SEALING - 4

AS-1202 (6,000mPa-s)AS-1010 (10,000mPa-s)AS-1203 (20,000mPa-s)

TERMINAL SEALING - 1

Application Clip Pin: TN (Segment Type) FPC, TAB: STN, TFT

Process

1) Dispensing Process:

One-sided or Two-sided

a) Roller Method b) Syringe Method

2) UV Light Curing Process

UV Adhesive

ACF TAB

ACF

FPCUV Adhesive

Terminal Sealing - 2Requirements of Terminal Sealant

• Good Adhesion to Glass, ITO, Sn, PI• Flexibility (Low Stress)• Moisture Resistance• Durability to withstand Thermal Shock &

Thermal Aging• High Temp. resistance (Pin Clip)• Cure Depth > 1.0mm (Pin Clip)• Appropriate Viscosity

AS-2002 (5,000mPa-s)AS-1057 (9,000mPa-s)AS-1204 (20,000mPa-s)

TERMINAL BONDING - 1

Application FPC to Glass (ITO, Conductive)

Process

1) Apply ACP on ITO Terminal Pattern

2) Put FPC on the ITO Terminals

3) UV Light Exposure with Pressing

Glass

Cu PatternAu coated sphere

ITO Pattern

FPC

ACP

TERMINAL BONDING - 2ACP UV Adhesive + Conductive Particles Particles

Au coated Sphere Resin Diameter: 3 ~ 5μm

Requirements of UV Adhesive Good Adhesion to Glass, ITO, FPC Appropriate Flexibility Appropriate Cure Shrinkage (Pressing Force) Moisture Resistance and Durability Appropriate Viscosity

AS-2002 (5,000mPa-s)

COG/ITO OVERCOATING - 1Processes: 1) Mount IC Chip on Glass (ITO Circuit)

2) Heat-Pressing

3) FPC Bonding with ACF or ACP

4) Apply COG Overcoat Resin over IC and ITO Pattern

5) UV Light Exposure

IC ChipOvercoat Resin

ACF or ACP FPC

CURRENT PROCESS Bottle Neck

1) Insufficient Moisture Protection capability

with RTV Silicone

2) Low Productivity due to Long Curing Time

with RTV Silicone

COG/ITO OVERCOATING - 2

UV Curing Adhesives

Requirements of COG OVERCOATING RESIN Low Water Permeability Not Corrosive Low Stress (Low Shrinkage or High Flexibility) Toughness Good Wettability (Glass, ITO, PI, Si) Adequate Low Viscosity (< 1,000mPa-s) Fast Cure (< 1,000mJ/cm2) Durability (Thermal Shock, Heat Aging)

COG/ITO OVERCOATING - 3

AS-2008 (600mPa-s)

LIGHT SHIELD RESIN - 1Application 1) Protect IC of COG from Malfunction by Light

2) Apply the opposite side of Glass IC mounted

3) Current Process: Al or Black Adhesive Tape

IC ChipOvercoat Resin

ACF or ACPFPC

Appendix

Light Shield Tape or Resin

Requirements of LIGHT SHIELD RESIN UV/Visible Light Opaque (Black, White or Silver) Screen Printable (High Productivity) Good Adhesion to Glass Adequate Low Viscosity (< 1,000mPa-s) Fast Cure (< 1,000mJ/cm2) Durability

EX03-133 (6,000mPa-s)

LIGHT SHIELD RESIN - 2

We can support you everywhere and every time

directly!

文字の記入Thank you !