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interactive touch screen
Jun 01, 2018

What is LCM?


LCM (LCD Module) that is LCD display module, LCD module, refers to the liquid crystal display device, connectors, control and drive and other peripheral circuits, PCB circuit board, backlight source, structural components and other components together.


LCM manufacturing process commonly used terms


TFT-----Thin Film Transistor: Thin Film Transistor


CF-------Color Filter: Color Filter


LCD-----Liquid Crystal Display: LCD screen


TAB-----Tape Automatic Bonding: With Load Package IC


PCB-----Printed Circuit Board: Printed Circuit Board


ACF-----Anisotropic ConductiveFilm: Anisotropic Conductive Film


B/L------Back Light: backlight module


Assy---Assembly : Assembling


B/Z------Bazel : Iron Frame


Bonding: Pressing


TFT-LCD manufacturing "front, middle and rear" three segments



touch screen.jpg

As shown in the above figure, the rear module process is mainly the integration of the driver IC and the printed circuit board of the liquid crystal substrate. This part can transfer the display signal received from the main control circuit to the driver IC, and drive the liquid crystal molecules to rotate to display the image. In addition, the backlight portion is integrated with the liquid crystal substrate at this stage, and the complete liquid crystal panel is completed.


Front Array:


1, film 2, yellow 3, etching 4, stripping film


Mid Cell:


5, alignment film printing 6, sealant coating 7, spray spacers 8, into the liquid crystal 9, sealed combination 10, polarizer attached


After the Module Assembly:


11, COG process 12, flexible circuit board lamination 13, printed circuit board lamination 14, backlight module assembly 15, aging test


The main structure of the liquid crystal module (LCM)


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Liquid Crystal Module (LCM) Structure (Profile)


touch screen panel.jpg


Liquid Crystal Module (LCM) constitutes the main components and material applications


1. Polarizer: The most important as a grating, allowing only a single direction of light through, but also can protect the CF layer and TFT layer


2. CF layer and TFT layer: one by one to form an electric field, so that the liquid crystal is arranged under this electric field.


3. Alignment (PI) film: The alignment film has directional properties to allow liquid crystals to align on the alignment film.


4. Transparent metal conductive layer (ITO): Let the upper and lower glass power, to control the liquid crystal direction


5. Sealing: Just like the wall of a house, it is used to block the contact of the liquid crystal with the outside world.


6. SPACER: Like a pillar of a house, used to support two substrates


7. Liquid crystal: The arrangement of the liquid crystal is controlled under different electric fields to obtain the light of different transmittance, thereby achieving the display principle.


8. Backlight module: providing a backlight to present the LCD signal changes


Three Steps in the Liquid Crystal Module (LCM) Manufacturing Process

touch panel screen.jpg

The first step (JI): The LCD LCD panel, ACF, driver IC, flexible circuit board (FPC) and PCB circuit board are pressed together by a machine.


Step 2 (MA): Next, assemble the finished product together with the backlight, light source, and iron frame;


Step 3 (FI): Aging Test


The above-mentioned heavy testing is the "TFT-LCD" we have seen.

interactive touch screen.jpg

Liquid Crystal Module (LCM) Manufacturing Flow Chart

The main purpose of the manufacturing process


According to TFT-LCD display principle and production requirements, and through the steps and manufacturing flow chart, it is mainly divided into the following two categories:


1, the drive IC and printed circuit board press-fit


2. Application of backlight system, integration of liquid crystal substrate and aging test


Driver IC and printed circuit board press-fit


1. Anisotropic Conductive Adhesive (ACF): Anisotropic conductive adhesive is laminated on two borders so that external electrons can enter the liquid crystal substrate layer, which is a bridge for electronic transmission.




2. Drive IC Bonding: The main function of the drive IC is to output the required voltage to each pixel to control the degree of twist of the liquid crystal molecules. The driver IC is divided into two types. The source driver IC located on the X axis is responsible for the input of data. The characteristic is high frequency and has the image function. The gate driver IC on the Y axis is responsible for the degree and speed of the twisting of the liquid crystal molecules. LCD monitor response time.


3. The press-fitting of the flexible circuit board can transmit data signals and act as a bridge for the electronic transmission of external printed circuits and liquid crystal panels. It can bend so it becomes a flexible or flexible circuit board.


Application of backlight system, and liquid crystal substrate integration


1. Introduction of backlight system types and legends


The liquid crystal does not emit light autonomously, so a display device using liquid crystal as a display medium needs to be additionally equipped with a backlight system. There are usually three kinds:


CCFL (Cold Cathode Fluorescent Lamp, Cold Cathode Fluorescent Lamp)


LED (Light Emitting Diode, LED)


EL (electroluminescence panel), OLED (Organic Light Emitting Diode, organic EL, also known as organic EL), inorganic EL

Samsung XL2370's side-mounted white LED backlight in the unlit (left) and glowing (right) states


Whether it is a CCFL backlight or a variety of LED backlighting methods, the light source properties of the backlight can not be surface light sources, but line light or point light source, so it needs other components to even out the entire surface of the light, this task by the diffusion plate and Diffusion film to complete.

Diffusion plate (light guide plate) of side-mounted LED backlight system

LED backlight lighter


Backlight system and liquid crystal substrate integration and aging test


  1. The liquid crystal substrate and the backlight system are not fixed by adhesion, and need to be added to the outer layer with a metal or a plastic frame to play a role of fixing the liquid crystal substrate and the backlight system.

  2. for high temperature aging test



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