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The manufacturing process for the TFT LCD display

Views: 311     Author: Wendy     Publish Time: 2023-07-17      Origin: Site


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The manufacturing process for the TFT LCD display

These days, screens are everywhere. Do you still recall the televisions and computer monitors from two decades ago? They were enormous, hefty, and quadrate. Have you ever questioned why there is such a significant contrast between the round, thick screen and the flat, thin, and light one in front of you?

In reality, 20 years ago, monitors were CRT (Cathode Ray Tube) displays, which need a lot of room to operate the inner component. And at this point, the screen in front of you is an LCD (Liquid Crystal Display) screen.

Describe LCD.

As was already mentioned, LCD stands for liquid crystal display. It is a revolutionary display technology that makes use of liquid crystal's optical-electrical property.

A substance in the condition of liquid crystal possesses both the properties of liquid and solid crystal. Although it doesn't emit light, it may properly allow light to travel in a certain direction. A liquid crystal molecule will rotate while being affected by an electric field, which will cause the light passing through it to rotate as well. The key to display technology is liquid crystal, which may act as a light switch.

Types of LCD

LCD has been developed for decades. Basically there are TN LCD, STN LCD and TFT LCD.


Twisted Nematic stands for it. It is a dated, basic technology that can only show white and black, and it is employed in little things like calculators.


Super-twisted Nematic is referred to as STN. STN LCD can display more information since its liquid crystal rotates at more angles than TN LCD's and has a unique electrical function. DSTN LCD (double layer) and CSTN LCD (color) are two examples of upgraded STN LCDs. Many early phones, laptops, and outdoor equipment all made use of this LCD.


Thin Film Transistor stands for TFT. Its use in electronic gadgets, automobiles, industrial machinery, and other display scenarios makes it the most recent version of LCD technology. When you hear the phrase "transistor," you might realize that TFT LCDs have integrated circuits. That's true, and it's a well-kept secret that TFT LCDs benefit from having full-color, high-resolution displays.

Considering that TFT LCD now has the largest application market, let's take it a step further and examine the TFT LCD production process.

Manufacturing process of TFT LCD

TFT LCDs can be broken down into three simple sections, from bottom to top: the light system, the circuit system, and the light and color management system.Starting with the internal light and color control system, the production process will then be extended to include the entire module.

The TFT LCD manufacturing process is typically broken down into three major components: the array, cell, and module. The first two processes concern the creation of a cell, or TFT, CF (color filter), and LC (liquid crystal)-based light and color management system. The assembly of the light system, circuit, and cell is the final phase.

1. Array

In order to increase production, we will perform a number of procedures on a big glass in this phase. The glass will then be sliced into smaller pieces in the next step.

Let me start by giving you an important resource, ITO. ITO, short for indium tin oxide, is a readily depositionable thin film with the properties of optical transparency and electrical conductivity. As a result, making circuits on glass is a common practice.

Let's now discuss how TFT and CF are made. Here is a widely used technique called the PR (photoresist) method. Production of TFTs will serve as a demonstration of the PR approach in its entirety.


Place ITO and semiconductor material on the glass substrate in the designated order.

coating for photoresist.

Clean up the exposed photoresist after partial exposure.

Remove the ITO and semiconductor from the circuit without the photoresist cover.

Remove any remaining photoresist.

We frequently need to repeat the steps five times in order to build the entire circuit.


Using the PR approach, create a black matrix on the glass substrate to serve as the boundary.

Use the PR approach to individually coat the red, green, and blue materials inside the black matrix.

Apply an overcover to the layer of RGB (red, green, and blue).

ITO circuit for deposit.

2. Cell

In this phase, we'll put the TFT and CF glass together and simultaneously fill the LC.

On the ITO side of both TFT and CF glass, coat polyimide film with the intention of limiting the initial path of the LC molecule.

Create an LC boundary on both glasses using adhesive. Apply one more layer of conductive adhesive to the CF glass. This allows the LC molecules to connect to the control system.

Fill LC up to the limit.

Join two glasses together, then cut the giant glass into standard-sized pieces.

Attach polarizing film to the incised glass's two sides.

3. Module

Connect the circuit system and the cell first.

Attach the cell to the driver IC.

Connect the driver IC to the flexible printed circuit (FPC).

Printing circuit board assembly (PCBA) and FPC should be connected.

Next, set up the lighting system.

Connect the light source, typically an LED or CCFL, to the light guide plate, which is covered in reflector film.

Place the prism film on the light source before applying the diffuser film. These two films, along with reflector film, are employed to diffuse the point light from a light source and increase light intensity.

Connect the light source to the circuit for controlling the light, which is a different sort of PCBA.

Finally, we must put everything together with the screen frame and conduct an aging test.




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