What Are TFT LCD Displays and Modules?

A thin-film transistor liquid crystal display, TFT LCD display for short, is a type of LCD display that uses thin-film transistor technology to improve image quality.

TFT LCD displays have many advantages over traditional LCD displays. While traditional LCDs use a single layer of transistors, TFT LCDs use a thin film of transistors. This allows for better image quality, as well as improved response time and lower power consumption. TFT LCDs are also thinner and lighter than traditional LCDs, making them ideal for use in portable devices.

When choosing a TFT LCD, it is important to consider the viewing angle and colour reproduction. While TFT IPS displays offer better image quality, they are also more expensive.

Keep reading to learn more about TFT LCD displays, how they work, and their various applications.

How Do TFT LCDs Work?

TFT LCDs are made up of two main parts: the transistor array and the colour filter array.

The thin-film transistor array is the layer of transistors that are made of a material such as silicon. The array of transistors is connected to the control circuitry. The control circuitry contains the drivers that control the voltage applied to the transistors.

The colour filter array is the layer of the LCD that contains the colour filters. The colour filters are made of dyes or pigments and are arranged in a specific pattern. The most common patterns are RGB (red, green, blue) and CMYK (cyan, magenta, yellow, black).

When a voltage is applied to the transistor array, the transistors turn on and allow light to pass through. This light is then converted into an image by the colour filter array.

Applications of TFT LCD Displays

TFT LCDs are used in a wide variety of industries, including consumer electronics, computing, telecommunications, automotive, and medical to name a few. Specifically, they are used in:

Computers and laptop computers

Televisions

Mobile phones

Smartphones and tablets

Video game consoles

Digital cameras

Portable media players

GPS devices

Industrial and medical equipment

What Are the Key Parts of a TFT Display Module?

In addition to the thin-film transistor array and the colour filter array, a typical TFT display module includes many parts.

Liquid Crystal Layer

The liquid crystal layer is the layer of the LCD that contains the liquid crystals. The liquid crystals are made of materials such as nematic or cholesteric.

The liquid crystals are arranged in a specific pattern. The most common patterns are twist nematic (TN), super twisted nematic (STN), and in-plane switching (IPS). The liquid crystals are aligned with the electric field and are controlled by the voltage applied to the electrodes.

When an electric field is applied, the liquid crystals twist. This twisting allows light of a specific color to pass through. The light is then modulated by the liquid crystal layer.

Cover Glass

The cover glass protects the LCD from damage and provides a surface on which the user can interact with the display.

TFT LCDs use two types of cover glass. Rigid cover glass is made of either soda-lime glass or Gorilla Glass. Flexible cover glass is used in some TFT LCDs, such as those used in mobile phones. The flexible cover glass is more resistant to breakage than rigid cover glass, making it ideal for use in portable devices.

Backlight Unit

The backlight is the layer of the LCD that emits light. Backlights can be made up of light-emitting diodes (LEDs), an electroluminescent panel (ELP), cold cathode fluorescent lamps (CCFLs), and hot cathode fluorescent lamps (HCFLs), or external electrode fluorescent lamps (EEFLs).

Backlights are most often used in smaller displays to increase their readability in low light conditions.

Touchscreen

The touchscreen is an optional part of the display module that allows the user to interact with the display. A touchscreen is a layer of glass that is coated with a material that is sensitive to pressure. When the user presses on the touchscreen, the pressure is registered and converted into an electrical signal.

There are various types of touchscreens available including capacitive touchscreens, resistive touchscreens, and surface acoustic wave touchscreens.

Bezel

The bezel is another optional part of the display module. It is used to protect the display module from damage.

Driver IC

The driver IC is responsible for driving the TFT LCD panel. It converts digital signals into analog signals that can be used by the TFT LCD panel.