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LCD (Liquid Crystal Display). Edited by Chi Hun, Kim. History of LCD. Liquid Crystal. Liquid Crystal Disply. Operation Mechanism ( TN-LCD & STN-LCD ). 2) STN-LCD. 1) TN-LCD. Operation Mechanism (TFT-LCD). 3) TFT-LCD. Structure of LCD. Glass substrate. Color filter. Polarizers.
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LCD (Liquid Crystal Display) Edited by Chi Hun, Kim
Operation Mechanism ( TN-LCD & STN-LCD ) 2) STN-LCD 1) TN-LCD
Operation Mechanism (TFT-LCD) 3) TFT-LCD
Structure of LCD Glass substrate Color filter Polarizers Liquid crystal Signal lines Transparent common electrode Scan line Thin film transistor Transparent display electrode Glass substrate Back light
Black Matrix Role - Isolation of light source from adjacent pixel - Effect of increase in contrast - Prevention of inaccurateoperation
Two Types of Spacer It can be expected that the demand of column spacer increase according to increasing of market of LCD-TV.
Organic insulator - VGA 80 ~ 82% Black Matrix type - VGA 60% Organic Insulating Layer
Materials of Organic Insulating Layer • Photosensitive resin • PAC
Structure Structure of polarizer in LCD - PVA (Poly vinyl alcohol) - TAC (Tri-acetyl cellulose) - Protection Film - AR(Anti-reflection) AG(Anti-Glare)
BLU : Optical Sheets & LGP • Optical Sheets • LGP
The Functional of Alignment Layer • LC Alignment by Rubbed Alignment Layer • Regulation of LC Movement
Steric Effect ⇒ 2.4° ⇒ 6.2° ⇒ 13.3°
Polysiloxane cinnamate: PSCN Photo-dimerized monolayer : PDML 6FD-HAB-CI polyimide Poly(ω(4-chalconyloxy) alkoxyphenylmaleimide) Ultra Violet Arrangement
Voltage Holding Ratio (VHR) VHR(%) PI-1 : 99% PI-2 : 90% PI-3 : 80% PI-4 : 60% PI-5 : 50%
Liquid Crystal Themotropic LC, Lyotropic LC Nematic, Smectic, Cholesteric, Ferroelectric Anti-ferroelectric, Discotic, Polymer LC
Molecular Structure of Liquid Crystal Compounds Terminal group(Alkyl, Alkoxy, CN, Halogen atm etc. Central Groups: Benzene or cyclohexane ring Lateral Substituted group : H, Halogen atom, CN, OH, NO2etc.) Linkage Groups: Ester, Ethylene, Methyloxy, Acetylene,
R O / R C N R C N 1972/3 : BDH R C O O C N 1973 : Halle D.D.R N R O / R C N N 1973/4 Hoffmann -La Roche R C N R C N 1976/77 R C N : Merck, F.R.G O R C N O 1980 : Halle , D.D.R R C H C H C N 2 2 1983 Hull, BDH R C H C H C N 2 2 History of Liquid Crystal Compounds
R R ' R R ' F R C H C H R ' 2 2 C H C H R ' R 2 2 R C H C H R ' F 2 2 R R ' R R ' R C H C H R ' 2 2 R C H C H R ' 2 2 Components for Use in Wide Working Range TN Mixtures Low viscosity High clearing point Wide range, low viscosity
Current Materials in TFT-LCD Item Function Materials • Color Filter PR • Black Matrix • Liquid Crystal • Alignment Layer • Polarizer • Prism Film • Retardation Film • Substrates • Full Color • Pixel • Light Valve • LC Aligning • Polarization of Light • Light Pass • Phase Compensation • Panel substrate • Acrylic Polymer, Pigment • Cr/CrOx, Resin • Organic • Polyimide • PVA, TAC, Adhesives • PET film, UV-Curing resin • Polycarbonate,LC film • Glass, Plastic
Target Application Polymer Materials Photopolymers Photo-Polyacrylates Polyimides UV-Alignment Layer - IPS* Mode - VA** Mode Wide Viewing Angle High Aperture Tech - Organic Passivation Layer - TFT on CF Array (TOC) Dielectric Polymers Hybrid Polymers Brightness Enhancing Plastic Substrate Organic TFT Organic Gate Insulator Optical Polymers Conducting Polymers Flexible Display Novel PDPR for TV Ink - Jet Technology New Color Technology New Polymer Binders Fast Response Time TV Application (~6 msec) New type LC New TFT-LCD Technology with (New) Polymer Materials * : In Plane Switching **: Vertical Alignment