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The main features of TFT LCD display
Release Time:2022-10-18
TFT liquid crystal display is characterized by good brightness, high contrast, strong sense of hierarchy, and bright colors, but it also has the disadvantages of relatively high power consumption and high cost. TFT liquid crystal technology has accelerated the development of mobile phone color screen. Many of the new-generation color-screen mobile phones support 65,536-color display, and some even support 160,000-color display. At this time, the high contrast ratio of TFT and the advantages of rich colors are very important.

Technical Features
TFT technology was developed in the 1990s. It is a large-scale semiconductor full integrated circuit manufacturing technology using new materials and new processes. It is the first choice for liquid crystal (LC), inorganic and organic thin film electroluminescence (EL and OEL) flat panel displays. Base. TFT is formed on non-single wafers such as glass or plastic substrates (of course also on wafers) by sputtering and chemical deposition processes to form various films necessary for the manufacture of circuits, and by processing the films to produce large-scale semiconductor integrated circuits (LSIC) . The use of non-single crystal substrates can greatly reduce costs, and is an extension of traditional large-scale integrated circuits to large-area, multi-functional, and low-cost. Fabricating TFTs that control the switching performance of pixels (LC or OLED) on large-area glass or plastic substrates is more technically difficult than fabricating large-scale ICs on silicon wafers. The requirements for the production environment (purity level 100), the requirements for the purity of raw materials (the purity of electronic special gas is 99.999985%), the requirements for production equipment and production technology all exceed the large-scale integration of semiconductors, and are the top of modern large-scale production. technology. Its main features are:
(1) Large area: the first generation of large-area glass substrate (300mm×400mm) TFT-LCD production line was put into operation in the early 1990s. Glass substrates will also be put into operation. In principle, there is no size limit.
(2) High integration: The resolution of the 1.3-inch TFT chip used for liquid crystal projection is XGA and contains millions of pixels. The film thickness of the 16.1-inch TFT array amorphous silicon with a resolution of SXGA (1280×1024) is only 50nm, as well as the TAB ON GLASS and SYSTEM ON GLASS technologies, the integration of its IC, the requirements for equipment and supply technology, and technical difficulties Both exceed conventional LSI.
(3) Powerful function: TFT was first used as a matrix address circuit to improve the light valve characteristics of liquid crystal. For high-resolution displays, precise control of object elements is achieved through voltage regulation in the 0-6V range (typically 0.2 to 4V), making it possible for LCDs to achieve high-quality high-resolution displays. TFT-LCD is the first flat panel display in human history that surpasses CRT in display quality. And people began to integrate the driver IC on the glass substrate, the function of the entire TFT will be more powerful, which is unmatched by traditional large-scale semiconductor integrated circuits.
(4) Low cost: Glass substrates and plastic substrates fundamentally solve the cost problem of large-scale semiconductor integrated circuits and open up a broad application space for the application of large-scale semiconductor integrated circuits.
(5) Flexible process: In addition to sputtering, CVD (Chemical Vapor Deposition) MCVD (Molecular Chemical Vapor Deposition) and other traditional processes for film formation, laser annealing technology has also begun to be applied, which can make amorphous films, polycrystalline films, and also Single crystal films can be produced. Not only silicon films, but also other II-VI and III-V semiconductor thin films can be made.
(6) Wide range of application fields. Liquid crystal flat panel displays based on TFT technology are the pillar industries of the information society, and the technology can also be applied to the rapidly growing thin film transistor organic electroluminescence (TFT-OLED) flat panel displays. growing.
Other key features
With the maturity of TFT technology in the early 1990s, color liquid crystal flat panel displays have developed rapidly. In less than 10 years, TFT-LCD has rapidly grown into a mainstream display, which is inseparable from its advantages. The main features are:
(1) Good use characteristics: low-voltage application, low driving voltage, improved safety and reliability of solid use; flat, thin and light, saving a lot of raw materials and use space; low power consumption, its power consumption is about CRT display. One-tenth of that of reflective TFT-LCD, and even only about one-hundredth of CRT, which saves a lot of energy; TFT-LCD products are also serialized in specifications, sizes, and varieties, which are convenient and flexible to use, maintain and update. , easy to upgrade, long service life and many other features. The display range covers the application range of all monitors in the range from 1 inch to 40 inches and the projection large plane, which is a full-size display terminal; the display quality ranges from the simplest monochrome character graphics to high resolution, high color fidelity, Video monitors of various specifications and models with high brightness, high contrast, and high response speed; display methods include direct-view, projection, see-through, and reflective.
(2) Good environmental protection characteristics: no radiation, no flicker, and no damage to the health of users. In particular, the emergence of TFT-LCD electronic books will bring mankind into the era of paperless office and paperless printing, triggering a revolution in the way of human learning, dissemination and recording of civilization.
(3) The application range is wide, and it can be used normally in the temperature range from -20℃ to 50℃. The low temperature working temperature of TFT-LCD after temperature reinforcement treatment can reach minus 80℃. It can be used as mobile terminal display, desktop terminal display, and large-screen projection TV. It is a full-size video display terminal with excellent performance.
(4) The degree of automation of manufacturing technology is high, and the characteristics of large-scale industrial production are good. The TFT-LCD industry technology is mature, and the yield of mass production is over 90%.
(5) TFT-LCD is easy to be integrated and updated. It is a perfect combination of large-scale semiconductor integrated circuit technology and light source technology, and has great potential for continued development. At present, there are amorphous, polycrystalline and monocrystalline silicon TFT-LCDs, and in the future, there will be TFTs of other materials, including glass substrates and plastic substrates.



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