Last Updated on October 22, 2023 by Kevin Chen
TFT displays have become increasingly common in our daily lives. They are used in cars, laptops, tablets, and smartphones, as well as in industrial applications and many more. But what are TFT displays and why are they so important?
Let’s take a look at everything you need to know about TFT displays.
What is a TFT display?
A TFT (Thin Film Transistor) display is a type of display technology that uses a thin layer of transparent material to produce an image on the screen. The display is made up of thin layers of organic material called organic transistors, which are stacked together on a glass substrate and covered with a thin layer of plastic or metal oxide.
The array is then covered with a clear protective layer and any additional layers, such as touchscreens or color filters.
TFT displays are used primarily in portable electronic devices like mobile phones, laptops, and tablets.
TFT displays are also used in many other industrial applications, such as industrial control systems, medical devices, automotive infotainment systems, and more.
How does a TFT display work?
The basic concept behind a TFT display is simple: it uses light to create an image on a screen. Light passes through the glass substrate and the organic transistors until it reaches the top layer of the display.
The organic transistors turn on and off in response to the electrical charge of light passing through them. As they do so, they produce voltages that are then sent through wires connected to each pixel of the screen to create an image.
The number of pixels that can be displayed depends on how many organic transistors are used in each pixel or subpixel (a single-pixel is made up of multiple subpixels). For example, a 4-inch (10 cm) display has a pixel pitch of 0.0625 inches (1.57 mm).
The basic design of a TFT display has remained unchanged for more than 20 years. In this design, the sub-pixels are arranged in a grid pattern, with each subpixel connected to its neighbor by wires that form rows and columns.
The number of wires per pixel depends on the size and resolution of the screen: the larger and higher resolution of the screen, the fewer wires need to be used.
History of TFT display
Let’s look at the brief history of the Thin Film Transistor display technology.
The idea of TF display technology was first conceived in 1968 in RCA labs by Bernard J.Lechner.
In 1970, the first commercial TFT-LCD was introduced by Sanyo. It was a 6-inch (15 cm) screen with a resolution of 320×240 pixels.
In 1980, the first 10-inch (25 cm) screen was introduced by Sharp Corporation. The screen had a resolution of 640×480 pixels.
In 1982, Sanyo introduced the world’s first 16-inch (40 cm) LCD with a resolution of 640×480 pixels. This was followed by the introduction of 30-inch (76 cm) screens in 1984 and 40-inch (100 cm) screens in 1985.
The first large format TFT display was introduced in 1987 by NEC Corporation, which used a 1024×768 pixel screen for its PC monitor line, called CRT Professional Display System or “Videotronic” system. The technology was licensed to NEC’s competitors such as Hitachi and Toshiba for use in their own monitors and televisions. The system was marketed as “Super Video” and replaced the aging “Videotron” CRT monitors that were still being used at the time. The first LCD TV was also produced in 1987 by Sony.
In 1989, Sharp’s first TFT-LCD TV set was introduced with a resolution of 576×320 pixels, while the world’s first large format high definition screen with a resolution of 1024×768 pixels was introduced by NEC in 1994.
Over the years, TFT display technology has developed by leaps and bounds. It has been used in tablets, smartphones, notebooks, game consoles, and computer monitors. The technology is also used in digital cameras, camcorders, MP3 players, and GPS devices.
Components of TFT Display
What does the TFT display technology comprise? From far, you can easily assume TFT to be a single unit. But in reality, it comprises different components that work together.
The main components of a TFT display include;
Backlight
The backlight of the TFT display is a very important component. It provides the light for the pixels and is also responsible for illuminating the display. The light emitted by a backlight can be controlled by varying the amount of current running through it.
When it comes to LCD displays, there are two types of backlights; Active matrix and Passive matrix. Active matrix backlight has several layers of electrodes, which are used to control the amount of current flowing through them.
Whereas, Passive matrix backlight consists of one electrode layer that acts as a switch between off and on states. The active matrix backlights are more expensive than passive-matrix ones because they require more power to operate.
Pixels
The pixel is the smallest unit in a TFT display. It is the basic unit of information that is displayed on the screen. The pixel consists of three sub-elements, namely; Red, Green, and Blue (RGB).
Each pixel can be made up of one or more sub-pixels.
The number of sub-pixels that are used in each pixel varies with different display technologies. In full-color LCDs, there are three types of sub-pixel: red, green, and blue (RGB). Full color TFT displays use a combination of Red, Green, and Blue (RGB) sub-pixels to represent full color.
Backplane and front plane
The backplane and frontplane are connected by a number of flexible printed circuits. The PCBs are usually connected to each other with wires made from metals such as copper or aluminum. These wires are used to supply power, data, and control signals between the backplane and the front-plane.
Control system
The light that is transmitted through each TFT is controlled by applying voltages of different values to each pixel in turn. To do this, a control circuit called a driver circuit is required. The driver circuit controls the voltage applied to each pixel with reference to a set of parameters known as “pixel information”.
This information includes color, brightness, and other characteristics that define how an individual pixel should be operated for display purposes. The parameters also include how many red, green and blue sub-pixels are used to produce each pixel.
The control system can be further divided into 3 sub-systems: the interface, the timing, and the data transfer system (DTS). These systems work together to provide all of the necessary functions for controlling TFT displays from external sources such as computers, printers, or TVs.
Liquid crystal
This is another component of a TFT display system. It consists of a liquid crystal material sandwiched between two glass plates. This material is responsible for controlling the light by changing its refractive index.
The liquid crystal material has a single axis, which can be controlled by electrical signals. It also has a polarizer, which controls the plane of polarization of light.
Features of TFT display
Here are some of the features that characterize TFT display technology and how they affect the performance of the display system.
-Clear display: TFT display has a wide viewing angle and high contrast ratio so that it can show a clear picture even in bright sunlight.
-Wide viewing angle: The viewing angle of the TFT display is larger than that of the CRT set. It is generally considered to be the best choice for applications requiring an extended viewing angle.
-Transparency: TFT display has better transparency than CRT set, which makes it more suitable for applications requiring high transparency such as window displays and computer monitors.
-High resolution: TFT display can produce higher resolution than CRT display. For example, the pixel density of TFT is about 3 million pixels per square inch (PPI), which is about three times that of conventional liquid crystal displays (LCDs) whose pixel density is about 100 ppi.
-Reliability: Since it uses no moving parts, the TFT screen does not need any maintenance or repair, and therefore the reliability is higher than that of LCDs and plasma displays.
-Power saving: TFT display consumes much less power than CRT. The power consumption of a mainstream TFT display is about 1/10 that of a typical LCD. In some applications, the power consumption can be reduced to 1/100 or less of that of a CRT.
-High brightness: The picture displayed on the screen can be bright enough to be seen in bright sunlight without any need for glare reduction filters.
-Compatibility: Since it uses no moving parts, the TFT screen does not have any mechanical problems such as screen flicker and image sticking problems found in plasma displays and LCDs.
-High resolution: Although the pixel density of TFT is about 3 million pixels per square inch (ppi), the resolution is more than 100 ppi which makes it more suitable for many applications where high resolution is needed.
-Consistency: Since it uses no moving parts, the image displayed on the TFT display is not affected by temperature and humidity, which makes it more consistent than LCDs and plasma displays.
-Cost: The cost of a TFT display is lower than that of LCDs and plasma displays. For example, in some applications where image quality is not critical, the cost of a TFT display may be only a few tens to a few hundreds of dollars while the cost of LCDs or plasma displays may be several thousand to several tens of thousands.
-Excellent color display: We can’t deny the fact that TFTs have a superior color display. This simply means that the color of pixels can be accurately reproduced.
-Very thin: When compared with LCDs and plasma displays, which are very thick, TFTs are very thin and lightweight. In addition, the cost of mounting a large size TFT screen to a wall panel is relatively low.
-No ghosting: ‘Ghosting’ refers to the fact that the display shows a bright spot on the screen when the screen is turned off. TFT screens do not show ghosting. TFTs produce a sharp image even when they are turned off.
-No geometric distortion: Geometric distortion refers to the shape of the display on a flat surface. TFTs produce a sharp image even when they are turned off.
-No radiation: TFTs do not emit any harmful radiation, and there is no need for shielding or shielding materials to protect people from harmful radiation.
Frequently asked questions about TFT display
How does the TFT technology improve the quality of images?
The viewing angle of TFTs is wider than that of LCDs, and they have a much higher contrast ratio.
TFTs have a higher contrast ratio than LCDs, and the more similar colors are to each other, the brighter and clearer the picture will be.
How does the TFT technology improve the life cycle of products?
Considering that TFTs use less power, it is possible to reduce energy consumption by up to 50% compared with LCDs. In addition, if you use LED backlights in TFT displays, you can reduce power consumption by up to 75% compared with conventional backlights.
How does the TFT technology improve product quality?
The screen quality of a product can be improved by reducing scratches on the screen surface caused by friction between the screen surface and fingers or objects that come into contact with it during daily use (e.g., keys). In addition, the life cycle of a product can be increased by reducing the possibility of product damage due to scratches on the screen surface.
If a product uses a backlight, there is a high possibility that the color of the screen will be affected after some time due to dust or dirt that comes into contact with it. But it is possible to prevent this problem by using TFTs with LED backlights, which have no problems such as those caused by dust and dirt.
How does the TFT display improve product durability?
It is possible to reduce power consumption and extend product life by reducing backlight power consumption and extending product life. In addition, if you use LEDs for backlights, you can reduce power consumption by up to 75% compared with conventional backlights.
How does the TFT display technology improve workability?
Workability refers to the ease with which you can operate a product. When working with a screen that has TFTs, it is possible to increase the amount of information that can be displayed at one time. It is also possible to reduce the number of times you must change settings on a product by increasing its usability.
How does the TFT display technology improve the design?
Design refers to what you can create with the use of a product. Using TFTs, it is possible to create products that have a thin profile and are lightweight, which makes them more convenient for transportation and storage.
In addition, when designing products, it is easier to reduce the number of parts needed for each surface by integrating multiple functions into one part or module (i.e., an IC chip).
How does the TFT technology improve the human interface?
Human interface refers to what you touch when using a product or what you see on the screen when using a product (e.g., buttons and other controls). By integrating the TFTs into the display part of a product, it is possible to make the human interface easier.
It is also possible to provide clear and easy-to-see information and images on a screen by increasing the size of the display.
Is TFT better than Amoled?
Amoled refers to a technology that replaces the traditional liquid crystal display (LCD) with an organic light-emitting diode (OLED). Modern TFTs are similar to Amoled in terms of their structure, but they differ from Amoled in terms of their performance.
The TFTs of the present invention have superior characteristics compared to Amoled, such as high contrast ratio and response speed. The TFTs also have superior characteristics compared to conventional display devices such as CRT and plasma display panels, which cannot be achieved by these conventional display devices.
Is TFT better than IPS?
IPS refers to a technology that replaces the traditional liquid crystal display (LCD) with in-plane switching technology. The IPS display has superior features to TFT due to its high contrast ratio, wide viewing angle, and high response speed.
However, IPS tends to consume more power than the TFT display technology.
What are the disadvantages of the TFT display?
There are certain limitations to TFTs. For example, there is a limit to the size of the display and the resolution of the image that can be displayed on a display. Also, because TFTs are considered to be a kind of organic semiconductor displays, they have a short life span and therefore need frequent replacement.
What are some applications of TFTs?
The following is a list of some applications that make use of the TFT technology:
Display monitors
Because of their high resolution, TFT displays are used in display monitors. The type of TFT used in display monitors can be categorized as either active matrix or passive matrix. Active matrix TFTs use a thin film transistor (TFT) as its active component, whereas passive matrix uses a liquid crystal display (LCD).
Portable electronic devices
TFTs are also being used in portable electronic devices such as mobile phones, personal digital assistants (PDAs), and cameras. These devices require high-resolution screens because the user must be able to view accurate images and text on the screen. TFTs are also being used in laptops, which have a much larger screen size than many other portable electronic devices.
Because of their size and high resolution, laptop computers use passive matrix TFT displays instead of LCDs for larger displays than those found on smaller-sized portable electronics devices that use LCDs for their displays (e.g., mobile phones and PDAs).
TV monitors
TFT displays are used in front-projection TVs. The type of TFT used in front-projection TVs can be categorized as either active matrix or passive matrix. Active matrix TFTs use a thin film transistor (TFT) as its active component, whereas passive matrix uses a liquid crystal display (LCD).
Head-mounted displays (HMDs) and virtual reality headsets
Head-mounted displays (HMDs) use liquid crystal on silicon technology to create small, inexpensive, low-power VR headsets that can be worn on the head. Some HMDs use active matrix TFT technology while others use passive matrix TFT technology. Active matrix HMDs use shorting bars or glass electrodes to control each pixel; passive matrix HMDs use a liquid crystal material that allows for the creation of an image by controlling the voltage applied to each pixel.
Projectors
TFTs are used in projectors to create the on-screen image from the input signal. TFTs are used in both active matrix and passive matrix projectors. Active matrix projectors use shorting bars or glass electrodes to control each pixel, while passive matrix projectors use a liquid crystal material that allows for the creation of an image by controlling the voltage applied to each pixel.
Digital cameras (CCDs) and digital camcorders (DV)
CCDs are used in digital cameras and DV camcorders to capture still images and video, respectively. CCDs use a single array of photosites that each receives an electrical charge during exposure to light, resulting in an electrical signal that is output as an image. TFTs are used in CCDs as display circuits for previewing pictures.
TFT display for gaming
TFTs are used in the display of gaming systems such as consoles, personal computers, and hand-held devices. TFTs are also used in the display of mobile telephones and in digital signs.
TFT displays for medical equipment
TFTs are used in medical equipment including stethoscopes, ECG equipment, and blood pressure monitors.
What should I look for when buying a TFT display?
There are many factors to consider when buying a TFT display. The most important factors are the size of the display, the resolution of the display, and whether or not it is touch-sensitive.
It is also vital to consider where you are buying your TFT display system. A good place to buy a TFT display is from an authorized dealer or an online store. You should also consider whether or not the TFT display system you are looking for has a warranty.
At ICRFQ, we can connect you to the best TFT display suppliers and manufacturers in China. Just contact us and we will do what a reliable sourcing agent should do!
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