What is a TFT LCD screen?

TFT LCD screens are liquid crystal displays driven by thin-film transistors (TFTs). They are currently the most mainstream LCD technology, balancing resolution, color, speed, and stability, and are widely used in consumer electronics and industrial applications. TFT LCD screens are translated as Thin-Film Transistor Liquid Crystal Displays. Simply put, they are the most common and widely used type of LCD screen on the market. To understand what TFT is, we need to compare it with earlier LCD screen technologies.

Early LCD screens used passive matrix driving. This technology controlled each pixel by crossing row and column electrodes. As the number of pixels increased, this control method became inefficient, resulting in slow refresh rates, ghosting, and relatively poor color and contrast.

TFT technology completely changed this situation. It belongs to the active matrix driving technology category. Behind each pixel of a TFT LCD screen is an independent thin-film transistor (TFT). This transistor acts like an independent switch, precisely controlling the voltage of each pixel and maintaining that voltage until the next refresh.

Structural composition

A typical TFT LCD screen comprises the following layers:

Glass substrate: Supports the screen structure.

TFT array layer: Each pixel corresponds to a thin-film transistor and capacitor.

Liquid crystal layer: Controls light transmission, enabling grayscale and image variations.

Color filter: Decomposes white light into red, green, and blue sub-pixels, combining them to create a full-color image.

Polarizer: Controls the polarization direction of light.

Backlight module: Typically an LED light source, providing illumination.

Working principle

The control circuit energizes the gate signal of a pixel in a specific row, turning on the TFT transistors in that row.

Simultaneously, a column signal input voltage charges the pixel capacitor, changing the orientation of the liquid crystal molecules.

The liquid crystal molecules change their transmittance, allowing backlight to pass through or be blocked, thus displaying brightness and darkness.

The three primary colors are combined using color filters to form a color image.

Continuous row and column scanning refreshes the entire image (typically 60Hz or higher).

advantage

The display is clear and has a high resolution.

It offers excellent color reproduction, supporting up to 16.7 million colors (24-bit color).

It boasts a fast response time, making it suitable for video and dynamic images.

It consumes less power than a CRT, and is thinner and lighter.

The technology is mature, costs are gradually decreasing, and it has a wide range of applications.

shortcoming

The backlight is always on, resulting in slightly higher overall power consumption than OLED.

Black levels are not as deep as in self-emissive screens.

In extremely low temperatures, the LCD’s response time will slow down.

Application areas

Consumer Electronics: Mobile phones, tablets, laptops, televisions.

Industrial Control: Human-Machine Interfaces (HMIs), testing instruments, automation equipment.

Automotive/Motorcycle Instrument Panels: High-brightness, full-viewing-angle screens ensuring clear visibility outdoors.

Medical Equipment: High-resolution image displays, surgical monitoring.

Military and Aerospace: Wide-temperature screens, shock-resistant screens.

Why do industrial and automotive instrument panels still primarily use TFT LCD screens?

While OLED and MicroLED offer significant advantages in image quality and technical specifications, the core requirements for industrial, automotive, and medical displays are not “ultimate image quality,” but rather reliability, lifespan, cost control, and environmental adaptability.

Therefore, although OLED and MicroLED are widely popular in consumer electronics, TFT LCD screens remain the irreplaceable mainstream solution in industrial control, automotive, and medical applications due to their maturity and stability. The main reasons for the continued dominance of TFT LCD screens are as follows:

Reliability and Lifespan

Industrial and automotive equipment typically requires a stable lifespan of 5-10 years or even longer.

TFT LCD screens use inorganic liquid crystals and LED backlighting, achieving a lifespan of 50,000-100,000 hours with slow performance degradation.

OLEDs are limited by organic light-emitting materials, especially with short blue light lifespans, making them prone to burn-in. While MicroLEDs theoretically have a longer lifespan, mass production processes are not yet mature.

Wide Temperature Adaptability

Industrial and automotive environments experience large temperature differences (e.g., 30℃~85℃).

TFT screens, optimized with wide-temperature liquid crystal formulations, can maintain normal operation under extreme temperatures.

OLEDs exhibit slower response at low temperatures and are prone to material aging at high temperatures; MicroLEDs also face challenges in packaging and thermal management.

Sunlight Visibility and High Brightness Requirements

Automotive instruments and outdoor industrial equipment require clear display under strong sunlight.

TFT screens, with their high-brightness LED backlighting (up to 1000-2000 nits) and anti-reflective coating, can meet outdoor visibility requirements.

OLEDs experience significant lifespan degradation under high brightness; while MicroLEDs offer high brightness, their large-scale application costs are prohibitively high.

Cost and Mass Production

TFT-LCD technology is mature, with well-established production lines, low manufacturing costs, and offers a variety of sizes and resolutions.

OLEDs and MicroLEDs are expensive and have low yield rates, making them unsuitable for large-scale industrial/automotive applications.

For industrial projects requiring large-volume, long-term supply, TFTs offer better cost-effectiveness and sustainability.

Protection and Durability Design

Industrial and automotive TFT screens support reinforced glass, waterproof and dustproof (IP65-IP67), and vibration-resistant designs.

OLEDs and MicroLEDs are relatively fragile in terms of packaging and impact resistance, and their application has not yet been widely validated.

FAQ

What is a TFT LCD screen?

TFT stands for Thin Film Transistor Liquid Crystal Display. It’s an active-matrix LCD. Each pixel is controlled by an independent thin-film transistor, resulting in clear images, fast response times, and high color fidelity. It’s currently the most common LCD technology.

What’s the difference between a TFT LCD screen and a regular LCD?

Regular LCDs (such as TN/STN) use passive matrix driving, which is prone to slow response times, image retention, and poor contrast. TFT LCDs, on the other hand, use active matrix driving, with each pixel independently switched by a transistor, providing higher resolution, more stable images, and faster refresh rates.

How many colors can a TFT LCD screen display?

TFT screens typically offer color depths of 16-bit (65K colors), 18-bit (262K colors), and 24-bit (16.7M colors). High-end TFT screens support 24-bit true color display, allowing for richer color transitions and details.

What are the main applications of TFT LCD screens?

TFT LCD screens are widely used in consumer electronics (mobile phones, tablets, TVs), automotive instruments, industrial control equipment, medical displays, measuring instruments, and many other fields due to their stable performance and controllable cost. They are currently the most common type of display screen.

Hangzhou LEEHON Technology Co., Ltd., as a provider of LCD display driver solutions for the industrial field, has established in-depth cooperative relationships with many leading global LCD panel manufacturers such as BOE, TIANMA, IVO, AUO, Innolux, and Kyocera, and professionally supplies multi-brand, full-series industrial-grade LCD displays and customized solutions.