tft meaning and tft display
TFT is the abbreviation of thin film transistor, which is an important part of tft display and OLED display. What is TFT? , TFT is a semiconductor formed on a substrate using a semiconductor process, which can control the on and off of the transistor through electrical signals, and then control the on and off of the pixel.
LCD is constantly improving and developing. As the size continues to increase, the resolution continues to increase, from just displaying black and white colors to extraordinary color performance capabilities, while the passive structure is only suitable for low resolution and Monochrome display, so upgrade to active structure. The main difference between active and passive technologies is how the pixels are addressed and controlled.
Passive tft display structure
Passive tft displays use a matrix of electrodes to control each pixel on the screen. Electrodes are arranged in a grid and connected to each row and column of pixels. When a voltage is applied to a particular row and column, the corresponding pixel is activated. This method is simpler in technology and lower in cost, and graphic lcd, character lcd and segment lcd are using this technology.
Active tft display structure
Active tft displays use a matrix of thin film transistors (TFTs) to control each pixel on the screen. The GOA (Gate on array) circuit controls the opening and closing of the TFTs in each row, and at the same time applies the corresponding voltage to the required pixels, thereby controlling the amount of light passing through the pixels. Due to the precise control of each pixel, it can achieve high resolution and carry other technologies.
What is tft?
TFT is the abbreviation of Thin Film Transistor. TFT transistors are arranged in a matrix on a glass substrate and are transistors fabricated on the surface of a glass substrate through a semiconductor process. Different semiconductor materials can be used to obtain different properties, which can be divided into two types:
1.The tft using amorphous silicon material is the most commonly used tft, which is called a-Si. The electron mobility of amorphous silicon is low, so it can support the maximum FHD resolution (1080×1920)
2.The laser annealing process is carried out on the basis of amorphous silicon, so that the amorphous silicon material can be recrystallized to obtain LTPS (low temperature polysilicon), Polysilicon has high electron mobility and can support up to 8K resolution. AMOLED’s tft also uses LTPS.
what is GOA（Gate on Array）
When it comes to tft, there is another knowledge that needs to be explained, and that is GOA. GOA is the abbreviation of Gate on array. GOA technology involves placing the gate driver directly on the glass substrate of the display, rather than adding a gate driver IC. This allows for simpler and more compact designs with fewer components and lower power consumption. In terms of timing, GOA technology uses a specific sequence of signals to activate the gate lines of the display, which in turn activate individual pixels.
GOA control signal
The structure of tft display
In a TFT-LCD display, each pixel consists of three sub-pixels, one for red, one for green, and one for blue, and each sub-pixel is controlled by a separate transistor. There are GOA units at both ends of each row of sub-pixels, and the driver IC outputs signals to control the switch of the tft of each row of pixels. When the tft is turned on, the sub-pixels can be charged through the data source line. After charging, after the tft is turned off, the voltage of the sub-pixels can be held by a capacitor. Each row of pixels is turned on in turn, and different voltages are charged to each pixel when it is turned on. When all the pixels in all rows are turned on and off once, a frame of picture is formed. Usually the refresh rate of tft display is 60Hz.
How TFT controls the rotation of liquid crystal molecules
The electrical signal generated by the driver IC is used to control the opening and closing of the TFT. When it is turned on, the voltage can be charged. When the TFT is turned off, the pixel capacitor will remain charged. The electric field formed by the pixel capacitor will cause the liquid crystal to rotate. The liquid crystal will control the direction of the light, and then cooperate with the polarizer to achieve light control. By charging different voltages, the liquid crystal molecules rotate at different angles to achieve different brightness. When the brightness of the pixel needs to be changed, the TFT is turned on again and then charged with the required voltage. This achieves control of each pixel.
The state of rotation of liquid crystal molecules under different voltages
Advantages of TFT technology
1.High resolution: TFT display can achieve high resolution, 4K, or even 8K resolution, with a large number of pixels per inch to achieve delicate display effects.
2.Brightness: TFT display screen can be made very bright, and it is easy to watch under bright outdoor conditions.
3.Semi-reflective and semi-transparent technology and total reflection technology: TFT display can realize semi-reflective, semi-transparent and total reflection technology, which can realize low power consumption while having exquisite picture and rich colors.
4.Fast refresh rate: TFT display can have a fast refresh rate, 90Hz, 120Hz, 144Hz products have been developed.
5.Thin and light: TFT display is thin and light, which is very suitable for portable devices such as smartphones and tablets.
tft or thin film transistor is not only used in tft display, but also plays an important role in Mini-LED backlight. Mini-LED technology uses tens of thousands or even hundreds of thousands of micro-LED to create high-quality backlight for LCD displays. In addition to using PCB substrates as carriers, many lcd panel manufacturers also use glass substrates as carriers and use tft technology to control the display of mini-led, so that tft displays can get better display effects.