LCM Introduction

Excel Technology International Corporation

LCM Applications

LCD & LCM Differences

Liquid Crystal Display - User must decide what kind of driver to use.

LCD Module – Provides a PC Board. The driver chips are on the board ready to be used.

Construction of LCD The LCD (Liquid Crystal Display) is formed with 6~10µm thick nematicliquid crystal sandwiched between two glass plates with transparent electrodepatterns, and polarizers stationed on the outside of the two glass plate.

6. Edge Sealing Glue7. Conductive Dot Between 2 Glass8. ITO Electrode

1. Front Polarizer2. Front Glass3. Rear Glass4. Rear Polarizer with Reflector5. Sealing Glue

Construction of LCDThe LCD (Liquid Crystal Display) is formed with 6~10µm thick nematicliquid crystal sandwiched between two glass plates with transparent electrodepatterns, and polarizers stationed on the outside of the two glass plate.

6. Edge Sealing Glue 8. ITO Electrode 9. Sio2 Film

10. Alignment Film11. Spacer12. Liquid Crystal

Viewing Direction

Top12 12 O’ClockO’Clock

Bottom6 6 O’ClockO’Clock

Right3 3 O’ClockO’Clock

Left

9 9 O’ClockO’Clock

2

Definition of viewing angleThe LCD changes in contrast depending on the direction of viewing and the rangewithin which the display can be recognized is limited. Taking this recognizable range as the viewing angle, it is defined as below:

Away from viewer Towards viewer

Vertical area of definition

Left Right

Horizontal area of definition

1

Definition of viewing angle

For TN Type LCDFor TN Type LCDFor TN Type LCDFor TN Type LCD For STN Type LCDFor STN Type LCDFor STN Type LCDFor STN Type LCD

Top = 2 (12 O’Clock)

2

Bottom = 1 (6 O’Clock)

1 1

Bottom = 1 (6 O’Clock)

Top = 2 (12 O’Clock)

2

Dot configuration and dimensions

B

F

D

G

AC

B

H

E

A

I

C

D

F

Dot Size = A x BCharacter pitch = ECharacter size = H x I

Size of display area = F x GDot pitch (1) = CDot pitch (2) = D

Character Type Graphic Type

Twisted Nematic. This is the abbreviation of Twisted Nematic field effect

mode. This is the mode which arranges the liquid crystal molecules by controlling their movement with electric voltage (electric field) so as to twist them by 90o in the through the polarizer placed on the two upper lower plate of LCD by controlling the movement of the liquid crystal molecules.

Almost all of medium and small type segment-display LCDs are in this mode, which is therefore this is the most common mode.

What is a TN (Twisted Nematic) Mode LCD

90o

Super Twisted Nematic

This is the abbreviation of Super Twisted Nematic field effect mode. While the TN mode arrange the liquid crystal molecules by twisting them by 90o ,the STN mode arrange them by giving a still larger twist and provides display by birefringence effect of liquid crystal.The LCD structure in the STN mode is the same as that in liquid crystal, adopting birefringence effect, there is a color in the display and also a background color. In this STN mode, a wide-viewing angle view is obtained, and the STN offers a high-contrast display compared with the TN mode. Specially, it is widely used in large size full-dot matrix LCD module.For colors, it has two modes depending on the combination of polarizer, namely, yellow mode and gray mode.

What is a STN (Super Twisted Nematic) Mode LCD ?

120240oBirefringence=

LCD

Form

of

Dis

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DFo

rm o

f D

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Neg

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D-TN ModeTransmissive Type

Reflective Type

Transflective Type

Transmissive Type

TN Mode

TN Mode

Transflective Type

Transmissive TypeShutter Type Color

Colored Polarizer

D-TN Color

Transmissive TypeTransflective TypeReflective Type

LCM Construction

Bezel (Metal Frame)

LCD PCB1. TAB2. COF3. COG

Backlighting1. LED2. EL3. C.C.F.L.

LCD Driver I.C.1. Package2. Die Form3. TAB Type

Connector1.Rubber Connector2.Pin Connector3.Flexible Connector

How to drive the LCD Com. & Seg.

How to drive the LCD Com. & Seg.

Products Numbering SystemCharacter Type

Display Format Character LCM

Series number

T=TNY= Yellow green STNG= Silver gray STN

R: ReflectiveF: TransflectiveM: TransmissiveN: Negative

E=ELL=LEDC=CCFL

Columns (C) x Lines (H) H= High Temp.N= Normal Temp.

A= Amber B= Blue greenR= RedW= WhiteY= Yellow green

B=Bottom view 6HT=Top view 12H

E X 1 6 2 0 0 Y F N L BY1

LCD series No.

Products Numbering SystemGraphic Type LCM

Display Format Graphic LCM

T=TNY= Yellow green STNG= Silver gray STN

Dot number C x R

E X 2 4 1 2 8 Y H L YF1 B

LCD series No.

R: ReflectiveF: TransflectiveM: TransmissiveN: Negative

H= High Temp.N= Normal Temp.

E=ELL=LEDC=CCFL

A= Amber B= Blue greenR= RedW= WhiteY= Yellow green

B=Bottom view 6HT=Top view 12H