Technology for LCD TV Current and Future LCD

Technology for LCD TV -Current and Future 趙治宇 教授 台灣大學物理系

LCD Performance vs. CRT and Plasma -Based on 32” CRT, 30” LCD and 32” PDP Contrast Brightness (cd/m 2) 600 Living Room (200 -300 lx) 1000 500 400 300 500 450 200 14 12 0 CRT LCD PDP Reflection Ratio (%) 10 PDP 10 1000 Weight (kg) 60 40 8 6 CRT 250 100 0 LCD 59 11. 5 4 20 1. 5 2 7. 5 0 0 CRT LCD PDP CRT 21. 8 32. 7 LCD PDP Courtesy by Sharp’s displaysearch 2003 conference talk

Key factors to boost LCD TV Green earth: -60% of CRT TV power consumption -EU will prohibit CRT TV import from the middle of 2006 -Montreal -California state government legislate restrict using CRT DTV broadcasting -DTV will be prevailing after 2006

Requirements of LCD TV Viewing angle -176/176(170/170) -no color shift with angle -technology: IPS, MVA, OCB etc. Response time -12 ms (GTG) -technology: OSC, OCB, scanning B/L Low cost -large substrate -market expansion -technology: production, component

Current High Performance LCD Technology -Wide viewing angle In-Plane Switching mode: IPS A P LC molecules Black White Rubbing direction Off state On state

Current High Performance LCD Technology -Wide viewing angle Multi-domain Vertical Alignment Mode: MVA Black White/Gray Protrusion/bump Protrusions produce multi-domain

Performance Comparsion IPS has better performance in general viewing angle and faster intergray response time MVA has better peak (not average) contrast ratio GTG: gray to gray ☉: high ○: average △: low

Characteristic of IPS mode Inherent wide viewing angle -small retardation change with viewing direction -without compensation film White color -yellow shift from 45 o diagonal -blue shift from 135 o diagonal Black Luminance -off angle need improvement

Cont’d Relatively low aperture ratio -complex inter-digitized electrodes -nonlinear behaviour with pixel pitch Black level -sensitive to rubbing condition -Light leakage due to electrode edge taper angle variation Imaging sticking -charge trapped in Si. Nx layer -weak alignment anchoring energy

Performance Improvement Technology -IPS mode Dual Domain: white color at 45 o and 135 o diagonal angle Novel Array structure for high transmittance Rubbing-free alignment technology

Characteristic of MVA mode Inherent wide viewing angle -small retardation change with viewing direction (IPS has better performance on WVA) White color -shift from gray to gray Black Luminance -off angle need improvement Rubbing-free -less mura defects appear

Other Performance Improvement Technologies • Rubbing free alignment technology • Color filter on Array(COA)/ Array on Color Filter technology(AOC) • Photo spacer technology • Low resistance bus line technology

Performance Improvement Technology -Super-MVA mode Improvement aperture ratio by slit ITO Optimal compensated film for off angle performance protrusion Multi-domain are formed by protrusions Slit ITO Multi-domain are formed by slit ITO

Future Requirements Technologies Innovation New Technology • High performance • Low cost • High yield • High throughput

Potential Technologies for Next Gen. LCD Production Softlithography -Microcontacting Printing -Microreplication Nanolithography -Dip-pen lithography Size reduction lithography etc. . .