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TFT LCD display
Release Time:2022-08-23
TFT LCD display is characterized by good brightness, high contrast, strong sense of layering, bright colors, but there are also relatively high power consumption and high cost deficiencies. TFT LCD technology has accelerated the development of mobile phone color screens. Many of the new generation of color screen mobile phones support 65536 color display, and some even support 160,000 color display, then the high contrast of TFT, the advantages of rich colors are very important.  
Technical features  
TFT technology is a large-scale semiconductor all-integrated circuit manufacturing technology developed in the 1990s using new materials and new processes, and is the basis for liquid crystal (LC), inorganic and organic thin film electroluminescent (EL and OEL) flat panel displays. TFT is on a non-monocrystalline chip such as a glass or plastic substrate (of course, it can also be on a wafer) by sputtering, chemical deposition process to form a variety of membranes necessary for the manufacture of circuits, through the processing of membranes to produce large-scale semiconductor integrated circuits (LSIC). The use of non-monocrystalline substrates can greatly reduce costs, which is an extension of traditional large-scale integrated circuits to large area, multi-function and low cost. Manufacturing a TFT that controls the performance of a cell (LC or OLED) switch on a large area of glass or plastic substrate is more technically difficult than manufacturing a large-scale IC on silicon wafer. The requirements for the production environment (purification degree is 100 grades), 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 are more than the large-scale integration of semiconductors, and it is the top technology of modern large-scale production. Its main features are:  
(1) Large area: In the early 1990s, the first generation of large-area glass substrate (300mm×400mm) TFT-LCD production line was put into operation, and by the first half of 2000, the area of glass substrate had been expanded to 680mm×880mm), and the glass substrate of 950mm × 1200mm would also be put into operation. In principle, there is no limit to the area.  
(2) High integration: The resolution of the 1.3-inch TFT chip for liquid crystal projection is XGA containing million pixels. The 16.1-inch TFT array amorphous silicon with a resolution of SXGA (1280×1024) has a film thickness of only 50nm, and the tab ON GLASS and SYSTEM ON GLASS technologies, the integration of their ICs, the requirements for equipment and supply technology, and the technical difficulty are more than those of traditional LSI.  
(3) Powerful: TFT was the first to improve the light valve characteristics of liquid crystal as a matrix site selection circuit. For high-resolution displays, precise control of objects 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 to surpass CRT in display quality. And people are beginning to integrate driver ICs into glass substrates, and 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 the use of sputtering, CVD (chemical vapor deposition) MCVD (molecular chemical vapor deposition) and other traditional processes such as film formation, laser annealing technology has also begun to be applied, which can make amorphous films, polycrystalline films, and can also manufacture single crystal films. Not only silicon films can be made, but other II.-VI and III.-V. semiconductor films can also be made.  
(6) A wide range of applications, TFT technology-based liquid crystal flat panel display is the pillar industry of the information society, but also technology can be applied to the rapid growth of thin-film transistor organic electroluminescent (TFT-OLED) flat panel display is also growing rapidly.  
Other main features  
With the maturity of TFT technology in the early nineties, color LCD flat panel displays developed rapidly, and in less than 10 years, TFT-LCD rapidly grew into a mainstream display, which is inseparable from its advantages. The main features are:  
(1) Good use characteristics: low voltage applications, low drive voltage, solidification use safety and reliability improvement; Flat, and light and thin, saving a lot of raw materials and use space; Low power consumption, its power consumption is about one-tenth of that of CRT displays, and reflective TFT-LCD is even only about one percent of CRT, saving a lot of energy; TFT-LCD products also have specifications, models, size series, variety, easy to use flexible, maintenance, update, easy to upgrade, long service life and many other characteristics. The display range covers the application range of all displays from 1 inch to 40 inches and the projection large plane, which is a full-size display terminal; Display quality from the simplest monochrome character graphics to video displays of various specification models with high resolution, high color fidelity, high brightness, high contrast, and high response speed; The display methods are direct view, projection, perspective, and reflection.  
(2) Good environmental protection characteristics: no radiation, no flicker, no damage to the user's health. In particular, the emergence of TFT-LCD e-books and periodicals will bring mankind into the era of paperless office and paperless printing, and trigger a revolution in the way human beings learn, disseminate and record civilization.  
(3) Wide range of application, from -20 °C to 50 °C temperature range can be used normally, after temperature reinforcement treatment of TFT-LCD low temperature can reach minus 80 °C. It can be used as a mobile terminal display, desktop terminal display, and can be used as a large-screen projection TV, which 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 technology of TFT-LCD industry is mature, and the yield of mass production reaches more than 90%.  
(5) TFT-LCD is easy to integrate and replace, is the 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-LCD, and in the future there will be TFT of other materials, both glass substrates and plastic substrates.

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