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

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 - 1 Processes: 1) Apply Main-Sealing Adhesive 2) Apply Mother Glass Bonding Adhesive 3) Align and mate Glasses 4) UV Light Exposure 5) Pressing and Heat curing 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 Method STEP 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 Method STEP 1: Filling LC into Cell STEP 2: Stacking 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/cm 2 ) (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 FPC UV Adhesive

Terminal Sealing - 2 Requirements 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 - 2 ACP  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 - 1 Processes: 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 Chip Overcoat 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/cm 2 )  Durability (Thermal Shock, Heat Aging) COG/ITO OVERCOATING - 3 AS-2008 (600mPa-s)

LIGHT SHIELD RESIN - 1 Application 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 Chip Overcoat Resin ACF or ACP FPC 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/cm 2 )  Durability EX (6,000mPa-s) LIGHT SHIELD RESIN - 2

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