Time:2025-11-06 Browse: 1
1. a-Si (Amorphous Silicon): a-Si is the longest-standing semiconductor material used in TFT channel layers. The manufacturing process for a-Si TFT backplanes is relatively simple, offering high yield rates and low costs—qualities that give it a natural advantage in producing TFT-LCD panels on higher-generation lines. Currently, the vast majority of G8.5 and larger-generation production lines utilize a-Si TFT backplanes. However, due to a-Si's electron mobility of only 0.9–1 cm²/V·s, it’s not well-suited for creating displays with high brightness, high resolution, high PPI, or fast refresh rates. As a result, a-Si is primarily employed in entry-level display panels.
2. IGZO (Indium Gallium Zinc Oxide): Compared to a-Si semiconductor materials, IGZO TFT backplane technology offers significantly higher electron mobility. With an electron mobility of 10–25 cm²/V·s, IGZO enables faster charge-discharge rates for TFT pixel electrodes, making it possible to achieve high brightness, high resolution, high PPI, and enhanced refresh rates in large-size display panels.
3. LTPS (Low-Temperature Poly-Silicon): LTPS is a technology that transforms an amorphous silicon (a-Si) thin film deposited on glass into polycrystalline silicon (p-Si, Poly-Silicon) through a crystallization process conducted at temperatures below 600°C. Finally, thin-film processes are used to fabricate TFT devices with p-Si serving as the active layer. Among a-Si and IGZO, LTPS semiconductor material boasts the highest electron mobility, reaching over 100 cm²/V·s. This makes it ideal for producing display panels with higher brightness, greater resolution, higher PPI, and faster refresh rates. However, due to its complex manufacturing process and higher costs, LTPS is best suited for TFT backplanes on G6.0 or smaller-generation production lines.
4. LTPO (Low Temperature Polycrystalline Oxide): LTPO is a material created by combining two semiconductor technologies—LTPS and IGZO. It inherits LTPS's high electron mobility while benefiting from IGZO's exceptionally low leakage current. The superior electron mobility enables display panels to achieve features like high brightness, sharper resolutions, higher PPI, and faster refresh rates. Meanwhile, the reduced leakage current allows the panels to operate at lower refresh rates, significantly cutting power consumption. Currently, LTPO TFT backplane technology is being used in premium AMOLED products.
5. RGB CR (RGB Color Resist): The core material in the RGB color resist CF color filter substrate, typically composed of red, green, and blue primary colors. It provides chromaticity and transmittance for TFT LCD liquid crystal display panels.
6. BM (Black Matrix): On one hand, the Black Matrix BM serves to block light, preventing color mixing between adjacent red, green, and blue subpixels. It effectively stops light leakage between subpixels, thereby enhancing the contrast ratio of the display panel. 7.0c (Over Coater): Protects the red, green, and blue color-blocking layers while simultaneously flattening the CF film surface. The OC layer is made from acrylic resin and comes in two types: thermosetting and UV-curable. For products with VA and TN display modes, since the red, green, and blue color-blocking layers are covered by an ITO electrode for protection, variations in cell thickness caused by unevenness in these layers and the black matrix (BM) have minimal impact on display performance. Therefore, the OC layer can be omitted. However, IPS-display-mode products lack this protective ITO electrode layer, making precise control of cell thickness critical; hence, the OC layer is essential for these applications.
7. P/Polyimide: The alignment film is coated on both inner surfaces of the TFT array substrate and the color filter (CF) substrate. After curing, the alignment film exerts an "anchoring" effect on the liquid crystal molecules, ensuring they align at a specific pretilt angle.
8. PS (Photo Spacer): The columnar spacers are formed using photolithography and are commonly referred to as Photo Spacers. These spacers serve to support the TFT and CF glass substrates, ensuring uniform cell gap thickness. Additionally, they enhance the compression resistance of the TFT LCD while maintaining optimal transmittance and contrast ratios.
9. MPS (Main-PS): Main-PS is an elastic resin material whose primary function is to support the TFT and CF glass substrates of the LCD panel, ensuring stable and uniform thickness of the liquid crystal cell.
10.SPS (Sub-PS): Working in tandem with the Main-PS, the Sub-ps provides additional support to the liquid crystal panel. This helps enhance the panel's resistance to crushing forces—when external pressure is applied, both the Sub-PS and Main-PS work together to prevent deformation.
11.BS (Ball Spacer): The primary purpose of dispersing spherical spacers within the cell is to support the TFT and CF glass substrates while maintaining the cell's thickness. However, the dispersion process often results in uneven distribution of these spherical spacers, leading to issues such as reduced transmittance and lower contrast ratios. As a result, this technology has largely been phased out today.
12.GF Spacer (Glass Fiber Spacer): Glass fiber spacers are typically mixed into the sealing adhesive to maintain consistent cell box thickness across the cell area, ensuring uniform dispersion of liquid crystal molecules within the cell and preventing display defects around the cell perimeter.
13.LC (Liquid Crystal): Liquid crystals are an intermediate state of matter that lies between liquids and solids, exhibiting properties such as the fluidity of a liquid combined with the anisotropy of a crystal. At low temperatures around -50°C, liquid crystals typically appear as white, plastic-like crystals. As the temperature rises, the liquid crystals gradually soften, transitioning into a transparent, oily, viscous fluid. If the temperature continues to increase—typically reaching about 100°C (though the clearing point varies depending on the specific type of liquid crystal)—the material becomes a clear, flowing liquid. The temperature at which this transition to transparency occurs is known as the clearing point of the liquid crystal.
14.N+ a-Si (n+ Amorphous Silicon): N+ a-Si is commonly used in ohmic contact layers, typically positioned between the Source and Drain electrodes and the semiconductor layer. The primary function of n+ a-Si is to reduce contact resistance, enabling the Source and Drain electrodes to more efficiently extract or inject charge carriers from the semiconductor layer.
15.ITO (Indium Tin Oxide): ITO is a transparent conductive oxide, serving as one of the critical thin-film layers in TFT-LCDs. In TFT-LCDs, it is commonly used as the pixel electrode (Pixel ITO), common electrode (COM ITO), and bonding pad (PAD).
16.ATO (Antimony-Doped Tin Oxide): ATO high-resistance films are commonly used in Incell projects. The ATO is deposited on the top surface of CF glass to address issues like interference with touch signals and to enhance electrostatic conductivity.
17.Sealant: In TFT-LCDs, the border adhesive primarily serves to seal the liquid crystal cell, preventing leakage of the liquid crystal and ingress of moisture, maintaining consistent cell gap dimensions around the perimeter, and bonding the Array substrate to the CF color filter substrate.
18.Main Sealant: Typically, only one bead of border adhesive is applied around the perimeter of an LCD display panel—this is referred to as the main border adhesive.
19.Dummy Sealant: Around the perimeter of the large glass panels, an additional redundant border adhesive is applied, which helps maintain mechanical balance during the cutting process of the glass substrate. This ensures balanced forces on both the upper and lower cutting blades, while also reducing the cutting stress experienced by the primary border adhesive.
20.SiNx: Silicon nitride plays a wide variety of roles in TFT-LCDs, serving as a barrier layer, protective layer, insulating layer, and more. The SiNx film features a dense structure that effectively prevents the diffusion of impurity ions. Additionally, SiNx films are commonly used as protective coatings, safeguarding critical wiring layers. SiNx is also frequently employed as an electrical insulator, helping to prevent current short circuits by isolating different film layers.
21.G-SiNx: A silicon nitride film deposited over the gate electrode, commonly referred to as G-SiNx or, alternatively, the GI layer, primarily serves as an insulating material.
22.The silicon nitride film PA-SiNx, deposited over the Source and Drain electrodes, is commonly referred to as PA-SiNx and primarily serves as an insulating and protective layer.
23.MO/AL/MO: A combination scheme for electrode materials of the Source, Drain, and Gate electrodes—commonly used composite metal materials in AL process technology.
24.MoTi/Cu: An electrode material combination for the Source, Drain, and Gate electrodes—commonly used composite metallic materials in the CU process technology.
25.SD (Source/Drain): The Source electrode is the input electrode of the TFT, typically serving as the data input terminal, and it supplies current to the Drain electrode. The Drain electrode, on the other hand, acts as the current output terminal, receiving the current that flows through the channel from the Source electrode—and then delivering it to the pixel electrode.
26.Gate: The gate electrode is the control electrode of the TFT. By applying a voltage to it, the conductivity of the channel can be altered. The gate voltage is used to switch the transistor on and off, thereby controlling whether the pixel is lit or dark.
27.PR (Photoresist): Photoresist is a light-sensitive material used in the photolithography process. In this process, the photoresist is coated onto the surface of the film layer on the Array substrate or CF color filter substrate. After UV exposure, its chemical properties change, allowing the exposed areas to be removed by the developer solution, while the unexposed areas remain intact.
28.CLC (Capacitor of Liquid Crystal): The transition element that converts electrical input into optical output is the pixel load capacitor, which primarily consists of the liquid crystal capacitance and the storage capacitor. Its main function is to ensure the stability of the pixel voltage. The liquid crystal capacitance is a critical component in TFT LCDs, typically measuring around 0.1 pF. Due to its relatively small capacitance value, it cannot sustain the charged voltage for an extended period—only until the next frame data update occurs. For instance, at a standard 60 Hz refresh rate, each frame needs to maintain its state for approximately 16 ms. However, during this interval, the liquid crystal capacitance may fail to keep the voltage stable, leading to incorrect grayscale representation and ultimately degrading image quality.
29.Cst (Capacitor Storage): The storage capacitor was introduced to address the issues mentioned earlier. To compensate for the limitations of the liquid crystal capacitor, a storage capacitor is typically incorporated into TFT LCD designs. This storage capacitor usually has a capacitance significantly larger than that of the liquid crystal capacitor—around 0.5 pF—which enables it to effectively maintain the charge stored in the liquid crystal capacitor. The storage capacitor is generally formed between the pixel electrode and the common electrode traces, and its primary function is to ensure that the charged voltage remains stable until the next screen update occurs.
