Introductions1

I. Materials Preparing

LCD materials include ITO Glass, Polarizer, Spacers, Seals, LCD Fluid, and other chemical solutions.

(I) ITO Glasses

1. The makeup of ITO glass：

Ca-Na glass （Bi-Si glass ）mother glass coated with SiO2 (to prevent the Na expanding into the LC fluid in the cell, thickness: 200~250 Å（1 Å =0.0001mm）

) and then, ITO layer (thickness:250~2000 Å). The reason to coat ITO, namely Indium Tin Oxide, is because the Indium Oxide is highly transimissive, while the Tin Oxide is highly conductive.

2. Categories of ITO Glasses

(1) Dimensions:

∙ 14*14

∙ 14*16

∙ 20*24

Basically RIFDA uses 14x16 glasses.

(2) Surface Resistance

∙ High Resistance: 150 ~ 500 Ω

∙ Regular: 60 ~ 150 Ω

∙ Low Resistance: < 60 Ω

STN products usually use low resistance polished glass, and COG products normally adopt 15Ω polished glass.

The transparency of glass (∆n) is different as well.

(3) Thickness

∙ 1.1mm

∙ 0.7mm

∙ 0.55mm

∙ 0.4mm

Normally the 0.55 and 0.4mm glasses are used in STN/FSTN/CSTN applications. The thinner the glass is, the higher its cost.

3. Precautions for handling and storing ITO glasses

∙ The ITO layer can easily absorb the water in the air, and thus cause moist change. Therefore, don’t expose the ITO glass to the humidity for a long time.

∙ Put in the activated positively charged ionic 活性正介离子solvent，ITO can easily have ion exchange (离子置换) reactions, and generate less conductive and transmissive substances. Therefore, do not saturate it into the activated positively charged ionic (活性正介离子) solvent for a long time.

∙ ITO is consisted of lots of tiny substances, which can dissociate (裂变) because of rise of temperature. That would increase the crystal edge 晶界and therefore increase the ITO resistance. This is why the display effects would be affected by the temperature.

(II) Polarizer

Different functions of polarizer:

∙ UV-resistant、

∙ Glitter-resistant、

∙ Hard membrane 、

∙ reflection-resistant、

∙ high transmissive film

偏光片性能

偏振度：普通偏光片的偏光效率要>85%，彩色片的偏光效率相对较低，一般在80%以下。目前最好的偏振片偏振度可达99%以上

透过率：实际偏光片的透光率值都略低于50%。

色相：指偏光片颜色所对应的色坐标值

有效厚度：偏光板的总厚度，包括基板厚度，胶厚度及保护膜厚度。

Storing and Handling of polarizer

∙ The storage condition of polarizer is:temperature-20℃±15℃、humidity- 65%±20%RH，far away from progeny。

∙ Be care for the usage of polarizer, avoiding rubbing, bending and striking。

∙ The surface of polarizer should be clean, do not touch the surface, and protect from smudginess (without protecting coat）。

∙ Carefully peel off the protective film before assembling the LCD.

∙

(III) LC Fluid

液晶分类

1. 物理条件分：热致液晶、溶致液晶

2. According to structure, there are four categories of Liquid Crystal Fluids: Neumatic, Cholesteric、Smectic、Disk

液晶的主要技术参数：

*相变温度特性：熔点至清亮点之间的温度区间

*粘度：响应时间

*介电各向异性∆ع：阈值电压和响应速度

*光学各向异性∆n ：Δn•d≧λ/2 Δn小则视角大

*弹性常数：陡度

*液晶电阻率：液晶纯度

*扭曲能力

Liquid Fluid is very sensitive to the humidity and luminance, therefore it should be stored in where there is facilitated with dehydrating system and blue lighting.

(IV) Other Materials

光刻胶、PI材料、钝化膜、黑膜、紫外硬化性树脂（封边胶、封口胶、封PIN胶）、导电胶（丝印用、上PIN用）、玻璃纤维、垫片、金粉、镍粉、全息膜、匀光片、金属引线

LCD上游材料日本厂商

II. Manufacturing of ITO glass

(I) Surface and PI handling

1. Cleaning & Curing

1) Clean with alkaline cleaner (碱性清洗液)and super sonic disposal

2) Clean with DI (De-ionize 去离子) water

3) Super sonic + spraying/showing clean

4) Dehydrated with wind blade

5) Dehydrated with curing

6) UV cure to get rid of bacteria

2. PR Coating

PR (photo-resistant) glues will be coated onto the clean surface of the ITO glass. We use the rolling tubes to evenly apply the glue, which is already missed with dilution solvents.

There are 2 kinds of PR glues, positive and negative. Negative glues can be dissolved in some oxide solvents, such as acetone (丙酮), ether (乙醚), diethyl ether (环乙醚); but would not be dissolved in the alkaline (碱性) solvents. When exposed, it then would have photo-synthesis reactions (光聚作用), which would make it not dissolvent in those oxide solvent, but dissolvent in the alkaline solvents. During the etching process, the layers of glues would have an image exactly reverse to that of the etching model. This is why it is called Negative. Vise versa is positive glues. 2 characteristics would be critical here:

(1) Distinctiveness rate: It symbolizes the accuracy of etching. If the pitch wide is W, then the Distinctiveness ratio is 1/W; for example, if W=0.5um, the D/R = 2000lines/mm.

(2) Sensitization Rate: Is indicates the sensitiveness of the PR glue to the lights. The higher the S/R is, the shorter the exposure time will be.

3. PR Curve

Basically its functions are to evaporate the dilutions in the glue, and to enhance the adhesiveness of the glue to the surface of glass.

4. Exposure

∙ Covered with exposure covering plate, the ITO glass coated with PR glue would be placed under the UV lights to selectively expose the PR glue. Those parts of exposed glues would thus become not dissolvable by oxide solvents; while those which are not exposed would still be dissolvable.

∙ The exposure plate is designed by the Designing Dept., in accordance with customer’s requirements.

∙ Normally the exposure timing for TN glass is 1 ~ 2 seconds, while that for STN is at least 5 second.

5. Development

Use developing solvent (which has 4% base碱) to take off those exposed parts of PI, and reserve those unexposed parts. It would protect the ITO during etching process.

* There is another step called Top Coating, which would apply the SiO2 onto the surface of ITO glass, after the developed process. Its function is to fill into the dents between the developed and non-developed parts, thereby not only increasing the insulation, but also improving the viewing angles by efficiently removal of the electro shape under non display situation. For ordinary TN and STN LCD products, it is not required.

6. Main Curve

The ITO glass would be cured under high temperature of 140ºC in order to enhance the strength of PI coating, and meanwhile evaporate the leftover of the diluting solvents.

7. Etch

Using appropriate proportioned etching solvents to wear away the ITO coating of those parts whose PR coating is removed during development process. Those which still have PR coating would not react, and thus would shape as the ITO electro circuits.

8. Stripping

Use high concentration NaOH solution as stripping solvent, erode the leftover of the PI glue, and structure the ITO outline which is exactly the same as the design of the exposure plate.

9. Cleaning and curing

(1) Use highly pure water wears away the leftover of base碱solvents, PI glues, and other foreign substances.

(2) Dry out the ITO glass

So far the first step of ITO glass manufacturing process, surface and PI handling, is accomplished. Next we will go into PI buffing and alignment process.

(II) PI Buffing

1. PI Printing

Apply the organic polymeric material (有机高分子材料), polyimide (聚酰亚胺, PI ) onto the surface of glass. PI is not conductive, and can stand high temperature.

2. Pre-Cure

Since the PI have some diluting solvents, so curing process would evaporate those solvent when it make the PI coating more even. But the major function would solidify the PI layer, whose hardness would affect the rubbing dents and angle.

Thus its temperature is critical here. Normally TN required a curing temperature of 230°C, while STN asks for 210°C, and FSTN, 180°C.

3. PI Rubbing

The PI layer would be rubbed at a specific angle by fine-hair brush, and thus consist dents which the liquid crystal 分子 would ally to. This procedure would thus determine the twisting angle of LCD: TN 90 Degree, while STN 210 Degree.

4. Cleaning

Specific procedure would remove the contaminations, such as leftover of the brush etc.

(III) Alignment

1. Seal Printing & Pre-curing

1) Seal Printing

Use the tech of silk printing, the sealing glue would be applied to both upper and lower glass, along the edges of the LCD cell as designed. There are 2 kinds of sealing glue, heat-curing glue and UV-curing glue. Even the curing conditions are different, both are made of epoxy resin环氧树脂，环氧胶. It is highly non-conductive, but we can connect the electrode of upper and lower glass by adding some silver particles.

2) Pre-curing:

Based on the characteristics of the materials of glue, we use heat or UV to cure the glue and the silver particles.

2. Ag(Cross-order) Printing & Spacer Spray

1) Ag (cross-order) Printing

Apply the cross order onto the surface of the glass.

2) Spacer Spray

Spacer is made ball-shaped powder made of resin 树脂. The evenly spread spacer (several um Ø) would support the cell thickness. Normally we use 5.2um, 6.2um, 6.75um and 7.75um spacers.

To prevent the pollution inside the LCD cell, the spacer cannot have 水分or other foreign substances.

Spacers Spraying

Spacers under Microscope

3. Aligning (Glass Assembly)

Assemble the upper and lower glass in accordance with the positioning requirements of the design. The positioning marks and the direction of glass cannot be messed up.

4. Curing

Under high temperature of 160ºC, cure the glue of the sealing line to improve adhesiveness. Meanwhile, apply pressure onto the cell would make the cell thickness more even. But over-curing be UV would

The cell thickness would directly affect the product display effects, especially for STN products. If the evenness of the cell thickness exceeds the tolerance of ±0.2um, the elect-optical characteristics and color of display would have huge difference. Thus, cell thickness is critical for LCD product’s quality, and it is determined in this process.

We now have walked through so-called front processes, and would introduce the backside process, which include fluid injection, end sealing, testing and polarizer assembling, etc.

(IV) Backside Process 1

1. Cell scribing

There are scribing symbols on 4 corners of the single LCD cell.

Cut the whole glass into several strips of glass; expose the opening where the LC fluid will be injected into the cell.

2. LC Injection

LC injection Steps:

(1) Place the empty cells into the hermetically sealed chamber, vacuum the air. Then pose the LC fluid to the opening. There are 2 ways of posing the fluid, one is needling for smaller openings, the other is saturating for either larger or small openings.

(2) Instill dry noble gas (惰性气体) into the chamber to press the LC fluid into the cell.

This process has high requirements on the circumstances since it easily can be contaminated by steam, grease or particles.

3. End Sealing

Seal the opening of the fluid-filled cell with sealing resin 树脂glue, to avoid external contaminations and to prevent fluid leakage.

4. Curing

The sealing glues can be cured by either heat or UV disposal.

5. Break-off

The strips of the LCD cells have to be broken off into individual LCD cells.

6. Cleaning

Use cleaning solutions to wash away the liquid crystal fluid and other particles attached to the exterior of the cells; then use water to wear away the cleaning solutions, and the use DI water (去离子水) and super-sonic waves to clean.

7. Heating

By heating up for a period of time (80ºC for 30 seconds), we force the liquid crystalline molecules to follow the directions of the rubbing

8. Edge Grinding

Grind the cracks of the edge of the glass

(V) Backside Process 2

1. Cleaning

Wipe off the dust left over from the Edge Grinding process with 酒精， 异丙醇, 氟利昂溶剂; don’t use 丙酮或芳香族熔剂(如甲苯).

2. Visual Inspection

Visual Inspection is accomplished under 2 pieces of polarizer. When the 光轴 of polarizer parallel to each other, they consist a transparent area; under which you can observe the possible foreign defects caused in the prior manufacturing process.

Possible defects detected in this process:

1) Inside contaminations: foreign substances attached onto the surface of glass before cell-assembly; or the spacers not spread evenly.

2) Finger prints: Operator’s finger touched the ITO surface or the PI layers.

3) Directing defaults: the clear/dark situation can not observed, or part of some characters appears; or the rubbing traces can be seen. The causes is the PI layer is not applied (or not stubbornly attached); or the rubbing force is not appropriate

4) Seal-frame out of shape: the line is not even

5) Rainbow: the unevenness of the cell thickness cause the circle/strips color differences.

6) Bubbles: inappropriate fluid injection causes that the cell is not fully filled.

7) Gas intruded: gas intrudes into the cell due to the not fully sealed opening.

8) Scribe defects: the scribing process cause some cut into the seal line, or cracks.

9) Scratches: scratches on the surface of the screen

10) Seal-opening contaminations: seal-opening glue interfere into the seal-frame; cause the pasty opening.

11) Cracks

3. Electrical Inspection

Apply the voltage signals onto the LCD to test the actual display effects. The signal from the tester includes COM signals and SEG signals. COM signals would go through the silver point to the back electros, and SEG would go directly to the front electros. So, if a cross voltage applied onto a cross point of back electros and front electros (driving voltage) is higher than LCD’s 阀值voltage, the character or graphics corresponding would show up. In this sense, the tester can also be used to judge and alert the big current (大电流) caused by shortcut or contaminations.

Defects detected in this process:

1) Line Missing

2) Short Cut

3) Non-Display

4) Blurred wording

5) “Fat” characters

6) Half Characters

7) Disrupting wording

8) Black strip

9) Whit dots

10) Large power consumption

4. Cleaning

Before applying the polarizer, the surface of the glass should be clean again.

5. Polarizer assembly

- Cut the whole piece of polarizer in accordance with the directions of the long side (the 光轴’s direction)

- Assembly: assemble the well-cut polarizer onto the glass in accordance with the drawings’ positions.

- 消泡: 碾压apply 4~6 kgs pressure onto the LCD cell to press out the bubbles between polarizer and the screen.

- Inspectation: Possible defects includes:

1) Assembly defaults: assembly in wrong directions, no-assembling, or wrongly assembled.

2) Size is not in accordance with that of the drawings

3) Deviated

4) Contamination

5) No protective film

6) Damaged polarizer or scratches

7) Bubbles between the screen and polarizer

- Adjust the color difference, normally adjust the face polarizer for Y/G STN displays; adjust the bottom polarizer for FSTN displays.

6. Pin assembly

Pins would connect the electrodes of LCD to the driving circuits, which would apply the driving signals (COM and SEG) onto the corresponding LCD electrodes for display.

- 点碳浆 highly conductive

- Assemble the pins using UV glue

- Cut the pins

7. Electrical Inspection

Testing, including visual and electrical inspects.

8. Final Inspection

QC final inspects

9. Packaging

Packaging the LCD screen into the box made of foam plastic泡沫塑料 , which is highly elastic 弹性, buffering capacitive, 缓冲性好，pressure resistant and shock-proof. 耐压力强防震。

10. Stocking

Stock into the warehouse.

(VI) Silk-Printing

Some products need silk-printing either on the top front of the screen, or onto the inside of the cell.

III. LCM Manufacturing Process

⏹ 液晶显示模组(Liquid Crystal Display Module)，缩写为LCM或LCDM。

⏹ 模块结构分类

∙ 普通模块的核心部件就是LCD与集成板，故液晶显示器件的安装需要依靠其它的元件来连接。

∙ 故按显示器件（LCD）与驱动器板的连接方式与固定方式不同来区分。

∙ 连接方式：

∙ 导电胶条，是一种普通的连接方式。

∙ 热压连接（如FPC/导电纸等）。

∙ 直接集成连接（如金属PIN脚的连接）。

∙ 固定方式：

∙ 铁架（铁架扭脚嵌入PCB）。

∙ 胶架（用螺丝，定位销固定）。

⏹

⏹ 结构流程：

⏹ 常用的接口连接方式:

∙ 导电胶条:导电胶条是一层薄的导电橡胶与一层薄的绝缘橡胶热压成。其结构如下 :

o PITCH有：0.04、0.05、0.10、0.18（单位：mm）。 LCD外引线至少与2~3条导电条正位接触。故LCD外引线PITCH及脚步宽越小则所需的电胶条的PITCH越小，LCD与PCB的对位越困难

o 常用的类型：a）YS型、b）YP型、c）YL型、d）YI型；

▪ YS型两侧是较厚的绝缘层，其弹性与当中的导电橡胶样可以支撑较大的压力

▪ YP型两侧是软多孔的绝缘胶，既能保护导电橡胶，又不会增加其硬度，弹性减小不会造成接触不良。当导电胶条的高度小于或等于宽度时，一般用此种

∙ 插座连接（Connecter）通常都是标准件, 选购的供应商如下：

NAIS、MOLEX、HIROSE、 SAMTEC 、ELCO

∙ 排线（FFC） FFC（Flexible Flat Cable）为镀锡软铜箔夹于两层绝缘材料（PVC\PET）之间的扁平线。尺寸及公差的定义和要求见《参照图样》

规范的的术语表达：

o 导通\接触面（Conductor）

o 绝缘体（Insulation）

o 补强板（Stiffener）

o 导体厚（Conductor Thickness)有0.1、0.05、0.035mm

o 此材料同FFC的柔韧性有关，0.1的较硬。

o 尽量不要采用Pitch小于0.50mm设计用于焊接。

∙ 柔性线路板（FPC）FPC（Flexible Printed Circuits) 为一种铜质线路印制在PI聚酰亚胺（Polyimide） 或PE聚脂（Polyester）薄膜基材上, 具有

o 可自由弯曲和可挠性

o 纤薄轻巧、精密度高

o 可以有多层线路，并于板上贴芯片或SMT 晶片

o 装配方式：插接、焊接、ACF热压。

o Materials:

▪ 基层 Base film： 12.5、25、50、75、125um（PI\PE)

▪ 铜薄分Copper Foil：电解铜和压延铜

▪ 料厚有：18、35、70um

▪ 覆盖层Coverlay Film： 12.5、25、50、75、125um（PI\PE)

▪ 补强板Stiffener ：0.2mm （PI\PE)

o 连接ZIF的接插件（Connecting with ZIF connectors）

o 热压异方性的导电胶膜（Bonding by ACF）

o 焊接（Bonding by Soldering）

∙ 导电纸（Heat Seal）一般开发新模块，在选用导电纸时，应尽可能采用现成已开模的或标准产品。COG的LCD以后所加的Silver Heatseal首选应选用JS-KN 型的导电纸。其作用是heatseal有粘性方便对位，也使LCD＋heatseal后容易电测。

o 标准产品导电纸的编号：脚 数（N）中心距（PITCH）纸 宽（W） ——长 度（L）42 1.0 48.4 58 60 0.5 34.2 60分别表达为 : 4210484—58, 6005342—60

∙ 电缆线（Flex Cable）

∙ 金属插脚连接, 这种方式主要适合反版LCD，如LCD外引线图所示金属插脚（即PIN脚），其PITCH常用的有1.27，1.50，1.80、 2.0、 2.54（单位：mm）。

o 使用时注意：

▪ 垂直插入插座，不能摇动着插入，还应避免反复插拔。

▪ 焊接时，应用低溶点焊锡，快速焊好，且不能反复多次 拆焊，以免因过热而使插脚与LCD导电膜接触受损

▪ 固定LCD的方式

∙ 铁架：

o 一 材 料

种类：1．不锈钢; 2．锑片(不常用)

厚度：1．0.3mm ２．0.4mm

３．0.5mm ４．0.6mm

铁架基本结构示意图

LCD—Designing Codes

 一 LCD Technology: TN (HTN) Products; STN Products ;COG;TAB;ECB Products

 二 Graphics: TN产品的最小线宽/间距为0.05/0.04mm;

STN（含COG、TAB）产品：

最小线宽为0.03mm;

最小线距为0.01mm.

 三 Glass Spec:

⏹ 最小尺寸玻璃出脚0.40&0.55mm0.70mm1.10mm

⏹ 单面5.5×76×86×8.2

⏹ 双面6×9 6×96×9.4

⏹ 带PIN /7×209×20

⏹ COG产品的最小尺寸为12.2mm×12mm

⏹ 最大尺寸TN产品的最大尺寸为356mm×392mm

⏹ STN产品的最大尺寸为356mm×392mm

⏹ COG产品的最大尺寸为120mm×165mm

⏹ TAB产品的最大尺寸为250mm×200mm

⏹ 带PIN的引脚PITCH规格为:1.27 1.50 1.80 2.00 2.54(mm).

⏹ 带PIN的产品其引脚边距玻璃边≥0.50mm.

⏹ 不带PIN的引脚PITCH规格为:TN≥0.08mm ；STN≥0.08mm ；COG≥0.05mm ；TAB≥0.08mm。

⏹ 引脚长度范围为：2.0~3.0mm

⏹ LCD外形尺寸公差范围：1.10mm的玻璃为±0.20mm

⏹ 0.40mm; 0.55mm; 0.70mm的玻璃为±0.15mm。

⏹ 使用导电胶条连接和铁架固定结构时：

⏹ LCD的厚度必须为≥0.70mm;

⏹ 在两侧ITO引脚边增加ITO对位块,其宽度等于引脚宽度的倍数,与引脚的距离等于引脚步PITCH值的倍数。如图(1)所示

图(1)

⏹ LCD视窗比铁架视窗单边大0.5mm,下限为等于铁架视窗宽度。

⏹ LCD与铁架、胶架的装配间隙为0.20mm。如图(2)所示

⏹ Display Mode

⏹ LCD-TN分为: 正像．负像和BLACK MASK

⏹ CD-STN分为: 黄模． 蓝模． 灰模． 黑白FSTN）．

⏹ 彩色． ECB（４色）

⏹ Polarizer

⏹ LCD下偏光分为: 透射；反射；半透射；

⏹ LCD上偏光分为:　磨沙．耐高温．防ＵＶ

⏹ Driving Mode

⏹ LCD的视窗距离小玻璃边不小于1.50mm

⏹ TCP类型的LCD引脚排列顺序必须按IC资料所指定的顺序排列 。

⏹ 注意IC面的朝向。啤TCP的LCD引脚高应≥2.5mm,反啤的应≥4.0mm

⏹ LCD的点距≥0.01mm,正常的保持在0.02mm以上。

⏹ LCD的基本参数 占空比 偏压 驱动电压的关系首先要根据所选取IC 所提供的参数来定

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