LCD (Liquid Crystal Display)

ICML Hanyang University

Polymeric Materials for Information & Communication

LCD (Liquid Crystal Display)

Edited by Chi Hun, Kim



History of LCD

시기 발명자 ( )형태 종류

1854년 R.C Virchow 농도 전이형 액정 발견

1888년 F. Reinitzer 온도 전이형 액정 발견

1930년 V. Freedericksz Freedericksz 전이 발견

1962년 Wiiliams DSM- LCD 특허 출원

1971년 Schadj, Helfrich TN- LCD

1972년 P. Brody Activ- Matrix 제안

1980~1983년 N.Clark, S. longerwall, K.Yoshino LCD강유전성 액정

1984년 Scheffer, Nehring STN- LCD



Liquid Crystal



Liquid Crystal Disply



Operation Mechanism ( TN-LCD & STN-LCD )

1) TN-LCD 2) STN-LCD



Operation Mechanism (TFT-LCD)

3) TFT-LCD



Structure of LCD

Back light

Liquid crystal

Glass substrate

Glass substrate

Color filter

Polarizers

Signal lines

Transparent display electrode

Thin film transistor

Scan lineTransparent commonelectrode



Process – Color Filter



Process – TFT



Process – LCD Panel



Black Matrix

Role- Isolation of light source from adjacent pixel- Effect of increase in contrast- Prevention of inaccurate operation



Component - Black Matrix



Color in LCD



Pigment Type



Function of Components



Color Filter Material

구 분 재 료

Binder Polymer (Copolymer or Terpolymer)아크릴계 수지

Photoinitiator and Sensitizer Triazine, I369, DETX

Functional Monome Polyfunctional Acrylates

Solvents PGMEA(Methoxypropylacetate)EEP(Ethyl- 3- ethoxypropionate)Cyclohexanone

Pigments ( 0.15μm ) 평균입경 이하

Red: Dianthraquinone(CI Pigment R177)Green: Halo- Cu- phthalocyanine(CI Pigment G36)Blue: Cu- phthalocyanine(CI Pigment B15:6)Yellow: Isoindoline(CI Pigment Y139)Violet: Dioxazine(CI Pigment V23)



Over Coat



PVA Mode



ITO Etching Margin in PVA Mode



Over Coat



Spacer



Two Types of Spacer



Two Types of Spacer

It can be expected that the demand of column spacer increase according to increasing of market of LCD-TV.



Organic Insulating Layer

Black Matrix type - VGA 60%

Organic insulator - VGA 80 ~ 82%



Materials of Organic Insulating Layer

• Photosensitive resin

• PAC



Polarizer



Structure

Structure of polarizer in LCD- PVA (Poly vinyl alcohol)- TAC (Tri-acetyl cellulose)- Protection Film- AR(Anti-reflection) AG(Anti-Glare)



Backlight Unit



BLU : Light Source



BLU : Optical Sheets & LGP

• Optical Sheets • LGP



The Functional of Alignment Layer

• LC Alignment by Rubbed Alignment Layer • Regulation of LC Movement



What is Pretilt Angle (θp)?



Necessity of Pretilt Angle



Polyimide (Alignment Layer)



Steric Effect

⇒ 2.4°

⇒ 6.2°

⇒ 13.3°



Substitution Effect



Ultra Violet Arrangement

Polysiloxane cinnamate: PSCN

Photo-dimerized monolayer : PDML

Poly(ω(4-chalconyloxy) alkoxyphenylmaleimide) 6FD-HAB-CI polyimide



Voltage Holding Ratio (VHR)

VHR(%)PI-1 : 99%PI-2 : 90%PI-3 : 80%PI-4 : 60%PI-5 : 50%



Liquid Crystal

Nematic, Smectic, Cholesteric, FerroelectricAnti-ferroelectric, Discotic, Polymer LC

Themotropic LC, Lyotropic 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,



History of Liquid Crystal Compounds

C NR O/ R C NR

C O OR C N

N

N

C NR O /R

C NR

C NR

C NR

C N

O

O

R

C H 2C H 2 C NR

C H 2C H 2R C N

1972/3

1973

1973/4

1976/77

1980

1983

: BDH

: Halle D.D.R

Hoffmann -La Roche

: Merck, F.R.G

: Halle , D.D.R

Hull, BDH



Fluorine Substituted Liquid Crystal Compounds



Components for Use in Wide Working Range TN Mixtures

R R '

R C H2

C H2

R '

C H2

C H2

R 'R

R 'R

F

R '

F

C H2

C H2

R

Low viscosity

Wide range, low viscosity

R 'R

R 'R

C H2

C H2

R 'R

C H2

C H2

R 'R

High clearing point



Chiral Liquid Crystal Compound



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

Item Function Materials

Current Materials in TFT-LCD



* : In Plane Switching** : Vertical Alignment

Wide Viewing Angle

Brightness Enhancing

UV-Alignment Layer- IPS* Mode- VA** Mode

High Aperture Tech- Organic Passivation Layer- TFT on CF Array (TOC)

PhotopolymersPhoto-PolyacrylatesPolyimides

Dielectric PolymersHybrid Polymers

Flexible DisplayPlastic SubstrateOrganic TFTOrganic Gate Insulator

Optical PolymersConducting Polymers

Target Application Polymer Materials

New Color TechnologyNovel PDPR for TVInk - Jet Technology

New Polymer Binders

Fast Response Time TV Application (~6 msec) New type LC

New TFT-LCD Technology with (New) Polymer Materials



Large Area TFT-LCD Market (Quantity)



Large Area TFT-LCD Market (Revenue)



Mobile TFT-LCD Applications & Market Size



Reference

1) Chem. Rev. 2000, 100, 1847-1873

2) J. R. Park, G. Ryu, J. Byun, H. Hwang S. T. Kim, and I. Kim, Optical review, 9, 207 (2002)

3) http://smdl.snu.ac.kr/lecture/dis/ybkim/kyb.ppt

4) Polymer Science and Technology Vol. 15, No. 6, pp.674-682 December 2004

5) Polymer Science and Technology Vol. 14 No. 2, pp.174-180 April 2003

6) Polymer Science and Technology Vol. 12, No. 3, pp.674-682 June 2001

7) B. O. Myrvold, H. Yokokura, Y. Iwakabe, K. Kondo and S. Ohhara, Japan display, 827 (1992)

8) http://en.wikipedia.org/wiki/LCD

9) http://www.webopedia.com/TERM/L/LCD.html

10) http://web.media.mit.edu/~stefan/liquid-crystals/liquid-crystals.html

11) http://en.wikipedia.org/wiki/Liquid_crystal_display

LCD (Liquid Crystal Display)

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