BY CLOVER DISPLAY LTD.

(HONG KONG S.A.R, CHINA)AN LCD MANUFACTURER SINCE 1983

URL http://www.cloverdisplay.com &  

DATE :Sept 29, 2005

 SPEAKER

Mr. JOHNNY C. L. CHOU

<Topics>1. FLAT PANEL DISPLAY    2. INTRODUCTION TO LCD TECHNOLOGY.3.    HOW LCDs ARE MADE.4.    COLOR LCD5. TODAY’S LCD6.    CUSTOM DESIGN LCD & LCM (MODULES).7.    TOUCH PANEL, Bi-STABLE LCD & ORGANIC LED.8.    QUESTION & ANSWER. Edition #7 (2005)

SEMINAR ON LCD & FLAT PANEL DISPLAYS

1.0. FLAT PANEL DISPLAYS

Display Types

( commonly used Display )

Emits

Light

Voltage Current Patterning

Flexibility

CRT ( Cathode Ray Tube ) Yes High DC Low ( scanning )

VFD ( Vacuum Florescent Displays )

Yes High DC Low Medium

LED ( Light Emitting Diode ) Yes Low DC Medium Low

Plasma Displays Yes High DC Low Low

EL ( Electro Luminescent Displays )

Yes High DC Low High

LCD ( Liquid Crystal Display ) NO Low AC Low High

OLED (Organic LED) Yes Low DC Low-medium

High

P.1.

2.1. Three major characteristics of Liquid Crystal

2.1.1. The Thermal Nature

High Temp

Clearing PointMelting Point

Liquid State

Liquid Crystaline State

Solid State (Crystal)

2.1.2. The Optical Nature of a LC molecule

LightNO light passing through

Light passing through

Low Temp

2.1.3. The Electrical Nature of the LC molecules

AC potentialNo potential field

Electrodes

P.2.

2.0. LIQUID CRYSTAL

XXX

 Smectic Phase Nematic Phase Cholesteric phase

2.2. COMMON STRUCTURAL PHASES in the Liquid Crystal State

P.3.

2.3. Two other components to make a Liquid Crystal Display Panel 2.3.1. Transparent Electrodes ---- Glass with conductive ITO layer which is

etched to form a pattern. 2.3.2. The Polarizer Film

Light wave& its axis

Polarizer &its light axis

Outgoing light& its axis

2.4. A TYPICAL TN TYPE LCD CELL

With AC Voltsconnected

NO powersupply

Polarizer(Axis 0 degree)

Polarizer(Axis 90 degrees)

Glass with electrodes

Glass with electrodes

Light

Cell Gap =The separationbetween two glasses

Positive Mode = Black digit on the grey backgroundNegative Mode =Clear digits on the dark background

P.4.

2.5. THREE COMMON TYPES OF LCD

Light(Back Light)

2.5.1. TRANSMISSIVE TYPE

2.5.2. REFLECTIVE TYPE

POLARIZER ON THE FRONT SIDE REFLECTOR ON THE BACK SIDE

Incident Light

2.5.3. TRANSFLECTIVE TYPE

Day LightNight Light(Back Light)

TRANSFLECTOR ON THE BACK SIDE

POLARIZER ON BOTH SIDES

POLARIZER ON THE FRONT SIDE

LCD

LCD

LCD

Eyes

P.5.

2.6. CHARACTERISTIC CURVES

% LIGHT ABSORPTION(or TRANSMISSION)

VOLTS

Vs (Saturation Voltage)

Vth (Threshold Voltage)

10% change

90% changesAt higherTemp.

Time

% LightAbsorption

Ton 5ms to 100ms Toff 20ms to 300ms

Depending on how the LCD fluid is formulated.The smaller the cell gap, the faster response.

0 volt

Vth of LC

-40 deg C +80 deg C

5 v4 v

-40 deg C +80 deg C

LC FluidViscosity

10,000

100

mm2/sec

At a lowerTemp.

P.6.

2.7. TN & STN (Super Twisted Nematic)

mid-plane tilt angleVth Vs

The LC molecule

90 degTwisted

180 deg 240 deg

Volts

% Light Absorption

0

% Light Absorption

0

% Light Absorption

0

Twisted Twisted

V V

Narrow View Angle

TN LCD STN LCD

Wide View Angle

Grey Backgroundin the positive mode

Yellow Green background colorIn the positive mode P.7.

2.8. HTN (Highly Twisted Nematic) & FSTN (Film STN)

TN90 deg Twisted

STN180 deg or higher degTwisted

HTN110 degTwisted

Narrow View AngleWide View Angle BUT with Darker Color Background &Blue or dark blue patterns.

Wider View Angle than TNbut narrower than STN

FSTN240 deg or higher degTwisted

View angle same as 240 deg STN BUT in Grey Background Color& Black patterns.

LCD Cell

Retardation Films on Polarizersto correct the color phase

DSTN (Double STN Cells)

1st Cell with patterns Same as usual STN

2nd Cell without patternBut in reverse twisting

Old waywhen NORetardationfilm

1st Minimum TN

Little wider View Angle than TN(see later pages)

Polarizer

P.8.

2.9. COMPARISON AMONG TN, HTN, STN & FSTN 2.9.1. Positive Mode (Pattern on a Clear Background)

Either TN HTN STN STN FSTN

Deg Twisted 90 110 180 240 240

Background

Color

Grey Grey Yellow Green

or Grey

Grey or

Yellow Green

Grey

Pattern Color

Black Black Dark Blue

or Blue

Blue or

Dark Blue

Black

Temp Range

-40C to +85C -20C to +40C -20C to +70C -20C to +70C -20C to +70C

Multiplex Ratio

=< 1/8 duty =<1/16 duty =<1/32 duty =<1/240 duty =<1/240 duty

View Angle 60 deg 80 deg 120 deg 120 deg 110 deg

View Direction

At 6 or 12 O’clock ONLY

At 6 or

12 O’clock ONLY

May specify

6 or 12 O’clock

May specify

6 or 12 O’clock

All

Voltage 2.5v min

5v typical

3v min

5v typical

3v min

5v typical

5v typical, (higher duty, higher volts)

5v typical, (higher duty, higher volts)

P.9.

2.9.2. Negative Mode (Clear Pattern on a Color Background)

TN HTN STN STN FSTN

Degree Twisted 90 deg 110 deg 180 deg 240 deg 240 deg

Background

Color

Black Black (Seldom used) Dark Blue Black

Pattern Color Clear Clear (Seldom used) Clear Clear

Other natures same as the Positive Mode.

2.10. Gooch-Tarry Curve --- The 1st Minimum TN LCD% Transmission

12%

0%

4%

8%

d n(um)0.48 (1st Min* ) 1.05 (2nd Min) 1.64 (3rd Min)

n : Birefringence (reflective indices ofLight transmitted in parallel & perpendicularTo the director of LC molecules.

d : the cell gap

P.10.*The 1st Min process is patented by E. Merck.

2.11. THE STATIC & MULTIPLEX DESIGN OF ELECTRODES

4 pairs of electrodes8 connectors needed.

No time sharing for the input signals –The STATIC Design

5 electrodes5 connectors needed.

1/4 time sharing for the input signals to each of the top electrode.No time sharing for the bottom glass.We call the top electrodes the SEGMENT while the bottom electrodes the COMMON.

4 electrodes in matrix4 connectors needed.

1/2 time sharing for the input signals to both the top and bottom electrodes----The MULTIPLEX Design.

We call it 1/2 duty if the 1/2 time sharing is used on the Common.

The higher the duty ratio, the shorter time the power signal goes into each electrode pair. Finally the power rms value may NOT be enough to fully drive the LC twisting properly.

PROBLEM:

P.11.

2.12. THE PASSIVE AND ACTIVE LCD

Signal

Signal

Time

Time

X1

X2

Y1 Y2

An ACTIVE Component ;MIM (metal insulator metal) DiodeOrTFT (thin film transistor)

The LCD Pixel

The TFT method is commonly used today on the large DOT MATRIX LCD,we call it the ACTIVE MATRIX LCD, or AMLCD

The LCD built together with the Active Component is not only the TFT LCD. The LCOSis also an LCD built on a silicon wafer with active components to control the LCD.

In general, the duty ratio over 1/256 may not give a good contrast in the Passive design.But there are still some special design to work in the Passive way, such as;Dual Scan STN (DSTN), High Performance Addressing (HPA), …. etc

P.12.

2.13. THE HISTORY OF LC & LCD

Application Approx Year Major Development

1888 Liquid Crystalline initially described by an Austrian Scientist,Mr. Friedrich Reinitzer.

1904 E. Merck sold the first Liquid Crystal substrates to the research market.

1960 Westinghouse used the cholesteric LC as a temperature indicator.

1965 RCA demonstrated a dynamic scattering LCD to show numeric symbols.Kent State Univ. in Ohio USA presented an LCD operated at room temp.

1970 Rockwell (USA) and Sharp (Japan) made LCD Calculators.Hull Univ. in England synthesised new biphenyls with excellent physicalproperties for display use.

Higher Contrast Twisted Nematic Mode in use.OCLI (USA) coated ITO on glass as electrodes.BDH (UK) sold LC to LCD manufacturers.

1975Hamlin Inc (USA) in TN LCD mass production.E. Merck introduced Biphenylcyclohexanes LC for higher multiplex.

Motorola built LCD on 4 ½”x 4 ½” glass substratesMicroma (USA) further improved the mass production technique andFairchild Semiconductor Inc. moved LCD production to Hong Kong.Timex (USA) bought RCA LCD facility and merged with Fairchild.

The Japanese developed a Chemical Sealing process for cost reduction.

Thermometer

Calculator

Time pieces

Instruments

Data bank & PDA

P.13.

Application Approx Year Major Development

2.13. THE HISTORY (continued)

The first LCD scriber made by Villa Precision Inc. (USA)

1980 Roche, BDH, E.Merck improve LC mixtures for TN, STN

Fairchild scaled up to 14x14” substrates5x7 Character

Dot Matrix GraphicWord Processor

Clover Display Ltd established in May 1983

MIM & TFT AMLCD inventedFull Dot Matrix &TV Panels 1985

PDA, Laptop & Notebook PC

Brewer Science Inc. & OIS of Troy, USA developed colourAMLCD for space shuttle use.

Full color TFT panel for Notebook PC

1990

1995

2000

Bi-stable Cholesteric LCD

E Books

Mobile phones

New Display to replace LCD ?---- OLED, PLED

P.14.

3.0. HOW LCDs ARE MADE 3.1. THE FRONT END PROCESS

ITO Glass ITO = Indium Tin Oxide, a transparent conductive layer coated on the Sodium Lime Glass. Its resistance is from 10 Ohms to 120 Ohms/square.Glass area usually in 14x16”. Thickness in 1.1, 0.7, 0.5, 0.4, 0.3mm

Clean Glasswith DI water

Patterning theElectrodes on ITO

Artwork & Mask Design

Methods: Photo Masking, Resist Ink Printing, ITO Ink direct Printing, Laser Cutting.

Alignment Layer

Sealing Frame &Silver Dot Printing

Top/bottom GlassAlignment and Seal

To form the cell and the inter-connections between the top and bottom glasses

To form a rough surface to hold the LC molecule chains

The Laminated pairs

P.15.

3.2. THE BACK END PROCESS

Laminated PairCutting into cells

Liquid Crystal Filling

Liquid Crystal MixtureFormulation

End Sealing & Cleaning

Testing & Inspection

Polarizer Fixing

Polarizer Cutting

Cosmetic Check

ShipmentsOptional Process

Metal Pin or Heat Seal Connector fixing

LCD Module Assembly (COB, TAB, COG, COF)

P.16.

4.0. THE COLOR LCD

Black and White LCD Full Color LCD

Slice ITO into narrowsections

RGB ColorFilter

Segments

Common

Common

The color LCD can be built as a Passive LCD. But most large size Dot Matrix Color LCDs are built in the Active design.

P.17.

In order to give a better color mixing,the RGB line widths are usually lessthan 30 micron in width per color. Hence the same for the ITO electrodes.

4.1. THE FULL COLOR LCD

4.0. THE COLOR LCD (continued)

4.2. THE ECB (ELECTRICALLY CONTROLLED BIREFRINGENCE) COLOR LCD

Clear DarkGrey

Y O R P B GColor around2.4v to 3.7v

DarkV

% LightAbsorption

0

V

Various ECB Types;

1) Homogeneous TypeRed->Yellow->Green->Blue

2) Deformation of Vert Aligned Plane (DAP) TypeBlue->Green->Yellow->Red

3) Hybrid Aligned Nematic (HAN) TypeGreen->Red->Blue

4) Vertical Aligned Nematic(VAN) Type

P.18.

No pure color, 50% Green + 25% Red + 25% Blue at this point

4.3. DOUBLE CELL COLOR LCDThere are two kinds of double cell can generate colors;A) With Color Polarizer B) With usual Polarizers at certain angles (Only working in Transmissive Mode) (Reflective Mode is also possible)

4.4. GUEST HOST LCD (Single fixed color)Mixing color dye in the LC fluid and build LCD in Negative Mode.It will show clear pattern on a color background.Such method was used in the early date.

4.5. LCD WITH COLOR POLARIZER, COLOR FILM OR COLOR REFLECTOR IN CERTAIN AREA (fixed color)

4.6. COLOR INK PRINTING ON THE BOTTOM GLASS SURFACE (fixed color)

Pre-printed color polarizer is expensive.

This is the cheapest way to make LCD with fixed colors.The LC image & color area may not coincide well due to the glass thickness.

P.19.

5.0. TODAY’S LCD

Duty Ratio

Panel Size

1/1Static

1/2

1/3

1/4

1/8

1/16

1/32

1/64

1/256

10 mm2 100 1,000 10,000 100,000 mm2

Time piecesHand Held Games

Film Camera

Calculator

Data Bank

Mobile Phone Digital Instruments

PDA

Digital CameraOffice Equipment

Notebook PanelsProjector Portable TV

Active LCD

Passive LCD

STN

TN

1M+ Pixels

100K Pixels

10K Pixels

1K Pixels

100 Pixels

P.20.

LCD TV & Monitors

1/128

6.0. CUSTOM DESIGN LCD & LCM --- The factors to consider6.1. LCD PANEL DIMENSIONS

Outer Dimensions (Be economical size)

View Area (normally 2mm from the edges)

End Seal (0.5mm thick)

Active Area (Area with patterns)

Pinout or Connection Area (2 to 2.5mm)

Glass Thickness (1.1, 0.7, 0.5, 0.4 or 0.3mm/one side)

Economical Panel Size: The outer dimension may use up most the raw glass sheet area.

14x16 inches(355x406 mm)

7x8 inches(178x203mm)

For small order size or pilot run,7x8 inches sheets are used to boostup the yield and save the tool cost.

(The usable area is 7mm off the edge)

( Glass Material: Sodium Lime Glass with SiO2 barrier, surface polished for STN use )

P.21.

Raw Glass Sheetor

6.2. PANEL CONFIGURATIONS

Eyes

A B C D

Connectors suitable:Zebra (Silicone Rubber) – A, B,Heat Seal or TAB – A, B, C, D,Metal Pins – C, D,

All the above 4 models required Ag (silver) connections inside the LCD cell.If such Ag connection not to be used or unable to be used, the configurations will be as follows;

The thick lines representingthe pinout areas.

E F G

Models E, F & G are good for combination use of Zebra and Heat Seal connectors together.Most TAB connections are also applying on such models.

P.22.

For TN LCD, don’t forget to specify the View Direction

12 O’clock 6 O’clock

45+deg 15+deg40+deg 40+deg

15+deg 45+deg

6.3. PATTERN LAYOUT

C S1 S2 S3 S4 S5 S6 S6 S3 C S1 S2 S4 S5

GoodLayout

BadLayout

Too Long Trace Cross Over Narrow down trace

+

P.23.

6.4. ZEBRA CONNECTORS

Side Wall Insulators

Conductive Layers

Insulation Layers

Pitch: (Conductor/Insulator Layers)Low Cost Type --- 0.25+-0.05mmGeneral Type ----- 0.18+-0.04 mmDot Matrix Type – 0.10+-0.03 mmGraphic Type ------0.05+-0.025 mm

Contact Resistance: 1000 –1500 ohms at 10%-15% compression

Metal Mounting Bezel

PCB

LCD

Zebra

Assembly

Mis-aligned Good A safer way(wider contact on PCB)

LCD

Zebra

•Pre-clean Zebra•Three or more conductors in contact•PCB wraping <0.375mm / 50 mm•Bezel has opening gaps with PCB•0.3mm or 10%-15% compression•Dummy zebra use with single side contact LCD. •Insulation side wall quality.

Precautions in Assembly

P.24.

Three kinds of Rubber

1. Sponge Rubber

2. Silicon Rubber

3. Super Soft Rubber

6.5. HEAT SEAL CONNECTORSConductors (~20 um particles) printed on a Polyester (PET) Film of 20 -25um

Contact Resistance & PitchGraphite Type --- 35 to 100 ohms/sq 0.40, 0.60, 2.80 mmSilver Graphite Type ---- 0.5 ohm/sq 0.23, 0.35, 2.80 mmSilver Type ------ 0.05 ohm/sq 0.23 mm

Choose proper LCD configuration:

PET side

Conductor sideLCD

PCB

LCD

PCB

PET side

PET side

Hot Press

PCB

PET film

Welded

Precautions in Assembly

•The Hot Press head temperature 120-140 deg C at joint•32 Kg/sq cm pressure is recommended•Leveling the press for even pressure along the joint.•Properly select the sealing time to prevent uneven flow or wash away the conductor particles.•100pcs/mm2 particles at contact area is suggested.•Peeling off strength be >200gm (Vertical) & >500gm (Horizontal)

P.25.

6.6. METAL PIN CONNECTORS ( for 0.7 & 1.1mm glass )

LCD

Standard Pitch: 1.27mm, 1.8mm, 2.0mm, 2.54mmPin Length: 20mm, 30mm, & 45mm max

Contact Resistance: <0.05 ohm

Precautions in Assembly:• Prolong soldering may damage the Pin contact to glass ---- A good LCD will add carbon cushion between pin clip and glass contact area.• Care on bending the pins ---- LCD maker provides pin lead forming.• Pin length under 4.0mm is not recommended.• Wave solder is not recommended ---- Polarizer is weak• Mechanical stress on pin or temperature changes may cause LCD background color changed.

6.7. TAB (TCP IC BONDING)

IC on a flexible filmwith conductors.The Film is heat sealedonto the LCD pinout area

LCD

P.26.TAB = Tape Automation BondingTCP = Tape Carrier Package

All the above connections may have IC on PCB by SMT, Wire Bonding (COB) or Insert & Solder.

Epoxy enforcementWider seal area isrequired.

Clip Depth 2.0mm to 2.4mm max

6.8. CHIP ON FILM (COF)

Same as TAB, but with morecomponents on the film likea circuitry on PCB

LCD

6.9. CHIP ON GLASS (COG)

LCD

IC Chip

Glass withFine tracesFan-in &Fan-out

Same as anusual LCD

Most panels with Metal Pins

The IC Chipfor COG isdifferent fromthose for usualwire bondingon PCB.

P.27.

ACF* film is used to fix theCOG chip onto the glass.The ACF film is similar to Heat Seal but with much finer Pitch and conductive particles. * ACF=Anisotropic Conductive Film

6.10. TRICKS ON THE LCD PANEL DESIGN6.10.1. THE BIAS VOLTAGE

% LIGHT ABSORPTION

10%

90%

0 volt

Volts

VoltsVth

The Bias Voltage

Time

The drivingVoltage

Theoretical Driving Waveform

Applied toSegment

Applied toCommon

ResultingWaveformto LCD

Off On

Practical Design Waveform

(Example: Waveform to LCD at 1/3 Bias)

Off OffOnV

2/3V1/3V

0-1/3V-2/3V

-VP.28.

Recommended Driving Freq60 Hz to 120 Hz

6.10.1. THE BIAS VOLTAGE (continued)

P.29.

The formula and design facts;N: Multiplex Rate. Example: N=3 for 1/3 dutyS: Bias The ideal design S=1+ NVd: The supply voltage to the panel.

Von = ( Vd / S ) x ( N-1+S ) / N

Voff = ( Vd / S ) x [ N – 1 + ( S – 2 ) ] / N

2

2

N 2 3 4 8 16

S 2 2 3 4 5

Vd 3 volts 3 volts 3 volts 3 volts 5 volts

Voff 1.06 v 1.22 v 1.00 v 0.88 v 1.22 v

Von 2.37 v 2.12 v 1.73 v 1.27 v 1.58 v

Von – Voff 1.31 v 0.90 v 0.73 v 0.39 v 0.36 v

Less than 1 volt !Beware the drifting under temp changes

6.10.2. CROSS OVER LAYOUT

C2

S1 S2 S3 S4

C1

C1

2 cross over points

Hided under Frame

Epoxy Sealing Frame

Ag DotConnection

6.10.3. THE POLARIZER SELECTION•The Glue Type or Non-glue Type polarizer. •The Polarizer with the UV Barrier may extend the LCD Life under strong UV exposure.•The Anti Glare Polarizer may improve the contrast.•The high durability polarizer may stand for wider temperature environment.•The slightly orientation of Polarizer axis may change the background color.

P.30.

6.11. THE THERMAL COMPENSATIONIt is recommended to use the thermal compensation circuit when a LCD will be operated undera wide temperature range.

6.12. TEMPERATURE RANGE

TempDeg C

0 deg-20-30 +50 +60 +75 deg

General purpose

Low Temp Type

Wide Temp Type

OperatingTemp.

StorageTemp 10 deg C lower 10 deg C higher

Problemwhen exceedsrated temp.

Black SpotsSlow response

Background blackenedCross Talk

The STN temp is 10 deg narrower than TN

All the above defects are reversible at room temp

Temp

-40 deg +10 +30 deg +100

Possible design

Specific for Low TempSpecific for High Temp

P.31.

Clearing point

Melting point

6.13. BACK LIGHTS

Choice of

Back Light

Descriptions Common

Color

Side LED Type

( Fig. 1 )

Wedge diffuser (Light Guide) and reflector are needed.

Poor illumination for large panel

Yellow Green,

Blue, White

Array LED Type

( Fig. 2 )

Consuming more power and generating more heat.

Beware the difference in supply voltages of each model. Easy assembly

Yellow Green,

Red.

EL (Electro-

Luminescent)

The best in even brightness and light weight. But less brighter than LED Backlight. High voltage and EMC consideration.

Green, Blue,

White.

CCFL (Cold Cathode Fluorescent Lamp)

The strongest illumination.

High voltage and EMC consideration.

White.

Important: The Transmissive and the Transflective Type LCD absorb the different light intensity.

Diffuser Paper

Reflector PaperReflector domes

LEDs

Light Guide

Fig. 1. Fig. 2.

Light Light

P. 32.

LED wiring

+

-

7.0. BI-STABLE LCDBi-stable Cholesteric Display, orSSCT – Surface Stabilised Cholestric Texture Display, orMulti-stable Chiral Nematic Display, orE-Book Display

This is a new technology in LCD making use of the Cholesteric Liquid Crystal. Mr. John West and Mr. D. K. Yang of Kent State University, Ohio, USA filed the patent in 1995. The display image is retentive in the absence of an electric field. It has a excellent readability and wide view angle under the daylight or strong ambient light. No Polarizer is required on this kind of display panels.

The Liquid Crystal is switchable and stable in two kinds of texture.(a) The Twisted Planar Texture, which has the LC layers parallel to the display surface, reflects the incident light.(b) The Focal Conic Texture, whose LC is in fragmentary, scatters the incident light.

Switch-able

The above two textures are switch-able under 30V to 180V pulse of 10ms to 100ms, and stable in zero electric field. By properly adjust the pitch of the Twisted Planar Texture, it can reflect R, G, B lights.

P.33.

(a) (b)

8.0. ORGANIC LEDThe Organic Electro Luminescent Displays (OELD) , or The Organic Light Emitting Devices (OLED)

The EL ( Electro-luminescence ) Back Light for LCD has been used for many years. It operatesat high voltage (>100V). In 1987, Tang and Van Slyke in Kodak, USA reported a low voltage (<10V)Organic EL. It comes a new display ---- the OELD.

8.1. THE BASIC STRUCTURE Metal CathodeElectron Transport LayerRe-combination and Emission Layer

Hole Transport Layer

ITO Layer (Anode)Glass Substrate

Light emits

8.2. THE DIFFERENCE BETWEEN LCD & OLED LCD OLEDNo Light emission Emits light in colours (100cd/sqm)Narrow view angle Wide view angle (>150 degrees)Slow response Fast response (<10 microsec)

OLED has most the advantage of LCD such as; Easy patterningLow operating voltage but at high current ( 20ma/cm2)Low manufacturing costThin and light weight P.34.

DCvolt

8.0. ORGANIC LED (continued)8.3. THE OLED & PLED

There are two major ways to build the OLED;a. The small molecule process ---- by spluttering the organic materials onto the ITO patterns. Kodak uses such way.b. The large molecule process, or the polymer process ---- by spin coating, dip coating or screen

printing the organic pastes layer by layer. Cavendish Lab in Cambridge, UK and DowCorning, USA developed such process and materials in ’90s.

Some people now call the OLED made under polymer process the PLED.The small molecule process is also applying to making the ACTIVE OLED.Pioneer, Japan seems the first one in mass production for the OLED.It is expected the OLED will replace the LCD step by step from 2005.

CLOVER DISPLAY GROUP has started a joint venture with the University of Hong Kong to researchand develop the materials and process for OLED. The newly formed joint venture company is named COLED DISPLAY LTD., established Sept 2002.

P.35.

9.0. TOUCH PANELS9.1. ANALOG TYPE

PE FilmWith ITO

Glass withITO

SilverConductors

Pin outArea

Epoxy dots As Spacer

Ra Rb

Rc

Rd

A PE film with ITO layer is sealedonto an ITO Glass with epoxy dots asSpacer to maintain a gap. When the external pressure of touching makes contact of two ITOlayers, the sensing IC circuit with givean analog reading corresponding to thetouch position.

9.2. DIGITAL TYPE

PE FilmWith ITO

Glass withITO Pin out

Area

Epoxy dots As Spacer

The ITO on the PE Film and theITO Glass are etched out into sectors.When touched, the correspondingsectors are shorted circuit and reflectedto the pins concerned.

P.36.

10.0. CUSTOM LCD/LCM DEVELOPMENT GUIDE.Enquiry from Customer

Feasibility Study & NRE Charge / Unit Price Quoted

Free quote in 2-4 working days

NRE Order Confirmation NRE payment in advance

LCD Panel PCB & Circuit External Casing

Panel Drawingfor Approval

Circuit diagram& PCB Layout

Case Drawing

1 week 1 week 1-3 weeks

Mask Design& Samples**for Approval

PCB Tool Design& Samples** forApproval

Hand mould up sample

3-6 weeks

3-4 weeks 3-10 weeks

Primary Sample

Final CaseMould

Final Sample

3-9 weeks

Total development time;LCD Panels 4-7 weeks, LCM Modules 4-10 weeks; With External Case 7-18 weeks

** normally 10-20 LCDor 3-5 LCM sampleswill be free. For more qty,please notice us in advancewhen confirm the NRE order.

P.37.

11.0. ACKNOWLEDGEMENT & DECLAIMER

We have tried our best to present up-to-date and correct information here. Some of them to beexplained together with photographs and demonstration samples to form a complete part of theIntroduction. We wish that the information discussed in this seminar may help the design engineers to makea cost effective and quality custom design in an easier and logical way. However, this is not an academic seminar that we have used a simply way in the presentation.All information here is provided in good faith without any expressed or implied warranty. The readershould seek for more detail advice from the industry.

The information in above are partly referring to the following documents;1. Proceedings of the Liquid Crystal Seminar HK by E. Merck, Darmstadt, Germany.2. Various articles in the SID International Symposium and Information Display by the Society for

Information Display, Inc. USA3. LCD Displays, the leading edge in flat panel displays, by Sharp Technical Library, Vol. 1, of

Sharp Corporation, Osaka, Japan.

Prepared by;Johnny C. L. Chou, Clover Display Ltd. Room 1006, 26 Hung To Road, 10/F, Kwun Tong, Hong Kong Tel: 23428228, 23413238 Fax: 23418785, 23574237 email: cdl@cloverdisplay,com URL: http://www.cloverdisplay.com (in English) http://www.cloverdisplay.com.hk (in Japanese) http://www.cloverchina.com (in Chinese)

Editions: 7th edition Sept 29, 2005 6th edition Mar 13, 2003. 5th edition Sept 19, 2001. 4th edition Apr 16, 2000. 3rd edition Sept 6, 1999. 2nd edition Sept 1, 1998. 1st edition May 19,1997.All copy rights reservedClover Display Ltd. H.K.

P.38.