tft lcd thin film transistor liquid crystal display made in china

A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technologyactive matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven (i.e. with segments directly connected to electronics outside the LCD) LCDs with a few segments.

In February 1957, John Wallmark of RCA filed a patent for a thin film MOSFET. Paul K. Weimer, also of RCA implemented Wallmark"s ideas and developed the thin-film transistor (TFT) in 1962, a type of MOSFET distinct from the standard bulk MOSFET. It was made with thin films of cadmium selenide and cadmium sulfide. The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968. In 1971, Lechner, F. J. Marlowe, E. O. Nester and J. Tults demonstrated a 2-by-18 matrix display driven by a hybrid circuit using the dynamic scattering mode of LCDs.T. Peter Brody, J. A. Asars and G. D. Dixon at Westinghouse Research Laboratories developed a CdSe (cadmium selenide) TFT, which they used to demonstrate the first CdSe thin-film-transistor liquid-crystal display (TFT LCD).active-matrix liquid-crystal display (AM LCD) using CdSe TFTs in 1974, and then Brody coined the term "active matrix" in 1975.high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.

The liquid crystal displays used in calculators and other devices with similarly simple displays have direct-driven image elements, and therefore a voltage can be easily applied across just one segment of these types of displays without interfering with the other segments. This would be impractical for a large display, because it would have a large number of (color) picture elements (pixels), and thus it would require millions of connections, both top and bottom for each one of the three colors (red, green and blue) of every pixel. To avoid this issue, the pixels are addressed in rows and columns, reducing the connection count from millions down to thousands. The column and row wires attach to transistor switches, one for each pixel. The one-way current passing characteristic of the transistor prevents the charge that is being applied to each pixel from being drained between refreshes to a display"s image. Each pixel is a small capacitor with a layer of insulating liquid crystal sandwiched between transparent conductive ITO layers.

The circuit layout process of a TFT-LCD is very similar to that of semiconductor products. However, rather than fabricating the transistors from silicon, that is formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass panel. The silicon layer for TFT-LCDs is typically deposited using the PECVD process.

Polycrystalline silicon is sometimes used in displays requiring higher TFT performance. Examples include small high-resolution displays such as those found in projectors or viewfinders. Amorphous silicon-based TFTs are by far the most common, due to their lower production cost, whereas polycrystalline silicon TFTs are more costly and much more difficult to produce.

The twisted nematic display is one of the oldest and frequently cheapest kind of LCD display technologies available. TN displays benefit from fast pixel response times and less smearing than other LCD display technology, but suffer from poor color reproduction and limited viewing angles, especially in the vertical direction. Colors will shift, potentially to the point of completely inverting, when viewed at an angle that is not perpendicular to the display. Modern, high end consumer products have developed methods to overcome the technology"s shortcomings, such as RTC (Response Time Compensation / Overdrive) technologies. Modern TN displays can look significantly better than older TN displays from decades earlier, but overall TN has inferior viewing angles and poor color in comparison to other technology.

Most TN panels can represent colors using only six bits per RGB channel, or 18 bit in total, and are unable to display the 16.7 million color shades (24-bit truecolor) that are available using 24-bit color. Instead, these panels display interpolated 24-bit color using a dithering method that combines adjacent pixels to simulate the desired shade. They can also use a form of temporal dithering called Frame Rate Control (FRC), which cycles between different shades with each new frame to simulate an intermediate shade. Such 18 bit panels with dithering are sometimes advertised as having "16.2 million colors". These color simulation methods are noticeable to many people and highly bothersome to some.gamut (often referred to as a percentage of the NTSC 1953 color gamut) are also due to backlighting technology. It is not uncommon for older displays to range from 10% to 26% of the NTSC color gamut, whereas other kind of displays, utilizing more complicated CCFL or LED phosphor formulations or RGB LED backlights, may extend past 100% of the NTSC color gamut, a difference quite perceivable by the human eye.

The transmittance of a pixel of an LCD panel typically does not change linearly with the applied voltage,sRGB standard for computer monitors requires a specific nonlinear dependence of the amount of emitted light as a function of the RGB value.

In 2004, Hydis Technologies Co., Ltd licensed its AFFS patent to Japan"s Hitachi Displays. Hitachi is using AFFS to manufacture high end panels in their product line. In 2006, Hydis also licensed its AFFS to Sanyo Epson Imaging Devices Corporation.

Less expensive PVA panels often use dithering and FRC, whereas super-PVA (S-PVA) panels all use at least 8 bits per color component and do not use color simulation methods.BRAVIA LCD TVs offer 10-bit and xvYCC color support, for example, the Bravia X4500 series. S-PVA also offers fast response times using modern RTC technologies.

When the field is on, the liquid crystal molecules start to tilt towards the center of the sub-pixels because of the electric field; as a result, a continuous pinwheel alignment (CPA) is formed; the azimuthal angle rotates 360 degrees continuously resulting in an excellent viewing angle. The ASV mode is also called CPA mode.

A technology developed by Samsung is Super PLS, which bears similarities to IPS panels, has wider viewing angles, better image quality, increased brightness, and lower production costs. PLS technology debuted in the PC display market with the release of the Samsung S27A850 and S24A850 monitors in September 2011.

TFT dual-transistor pixel or cell technology is a reflective-display technology for use in very-low-power-consumption applications such as electronic shelf labels (ESL), digital watches, or metering. DTP involves adding a secondary transistor gate in the single TFT cell to maintain the display of a pixel during a period of 1s without loss of image or without degrading the TFT transistors over time. By slowing the refresh rate of the standard frequency from 60 Hz to 1 Hz, DTP claims to increase the power efficiency by multiple orders of magnitude.

Due to the very high cost of building TFT factories, there are few major OEM panel vendors for large display panels. The glass panel suppliers are as follows:

External consumer display devices like a TFT LCD feature one or more analog VGA, DVI, HDMI, or DisplayPort interface, with many featuring a selection of these interfaces. Inside external display devices there is a controller board that will convert the video signal using color mapping and image scaling usually employing the discrete cosine transform (DCT) in order to convert any video source like CVBS, VGA, DVI, HDMI, etc. into digital RGB at the native resolution of the display panel. In a laptop the graphics chip will directly produce a signal suitable for connection to the built-in TFT display. A control mechanism for the backlight is usually included on the same controller board.

The low level interface of STN, DSTN, or TFT display panels use either single ended TTL 5 V signal for older displays or TTL 3.3 V for slightly newer displays that transmits the pixel clock, horizontal sync, vertical sync, digital red, digital green, digital blue in parallel. Some models (for example the AT070TN92) also feature input/display enable, horizontal scan direction and vertical scan direction signals.

New and large (>15") TFT displays often use LVDS signaling that transmits the same contents as the parallel interface (Hsync, Vsync, RGB) but will put control and RGB bits into a number of serial transmission lines synchronized to a clock whose rate is equal to the pixel rate. LVDS transmits seven bits per clock per data line, with six bits being data and one bit used to signal if the other six bits need to be inverted in order to maintain DC balance. Low-cost TFT displays often have three data lines and therefore only directly support 18 bits per pixel. Upscale displays have four or five data lines to support 24 bits per pixel (truecolor) or 30 bits per pixel respectively. Panel manufacturers are slowly replacing LVDS with Internal DisplayPort and Embedded DisplayPort, which allow sixfold reduction of the number of differential pairs.

The bare display panel will only accept a digital video signal at the resolution determined by the panel pixel matrix designed at manufacture. Some screen panels will ignore the LSB bits of the color information to present a consistent interface (8 bit -> 6 bit/color x3).

With analogue signals like VGA, the display controller also needs to perform a high speed analog to digital conversion. With digital input signals like DVI or HDMI some simple reordering of the bits is needed before feeding it to the rescaler if the input resolution doesn"t match the display panel resolution.

The statements are applicable to Merck KGaA as well as its competitors JNC Corporation (formerly Chisso Corporation) and DIC (formerly Dainippon Ink & Chemicals). All three manufacturers have agreed not to introduce any acutely toxic or mutagenic liquid crystals to the market. They cover more than 90 percent of the global liquid crystal market. The remaining market share of liquid crystals, produced primarily in China, consists of older, patent-free substances from the three leading world producers and have already been tested for toxicity by them. As a result, they can also be considered non-toxic.

Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.

Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.

K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. AIP. 37 (1): 1079–82. doi:10.1889/1.2433159. S2CID 129569963.

Kim, Sae-Bom; Kim, Woong-Ki; Chounlamany, Vanseng; Seo, Jaehwan; Yoo, Jisu; Jo, Hun-Je; Jung, Jinho (15 August 2012). "Identification of multi-level toxicity of liquid crystal display wastewater toward Daphnia magna and Moina macrocopa". Journal of Hazardous Materials. Seoul, Korea; Laos, Lao. 227–228: 327–333. doi:10.1016/j.jhazmat.2012.05.059. PMID 22677053.

Fig. 1 is the plane graph of TFT-LCD array base palte of the present invention, Fig. 2 be among Fig. 1 A1-A1 to profile, Fig. 3 be among Fig. 1 B1-B1 to profile.As Fig. 1～shown in Figure 3, the agent structure of TFT-LCD array base palte of the present invention comprises the grid line 11 that is formed on the substrate 1, data wire 12, pixel electrode 13 and thin-film transistor, orthogonal grid line 11 and data wire 12 have defined pixel region, thin-film transistor and pixel electrode 13 are formed in the pixel region, grid line 11 is used for providing start signal to thin-film transistor, data wire 12 is used for providing data-signal to pixel electrode 13, the overlapping region of grid line 11 and data wire 12 is provided with cylindrical spacer 16, and cylindrical spacer 16 is used to keep the distance between array base palte behind the box and the color membrane substrates.Particularly, thin-film transistor comprises gate electrode 2, gate insulation layer 3, semiconductor layer 4, doping semiconductor layer (ohmic contact layer) 5, source electrode 6, drain electrode 7 and passivation layer 8, and gate electrode 2 is formed on the substrate 1, and is connected with grid line 11; Gate insulation layer 3 is formed on gate electrode 2 and the grid line 11 and covers whole base plate 1, and active layer (semiconductor layer 4 and doping semiconductor layer 5) is formed on the gate insulation layer 3 and is positioned at the top of gate electrode 2; One end of source electrode 6 is positioned at the top of gate electrode 2, the other end is connected with data wire 12, one end of drain electrode 7 is positioned at the top of gate electrode 2, the other end is connected with pixel electrode 13 by the passivation layer via hole of offering on the passivation layer 89, form the TFT channel region between source electrode 6 and the drain electrode 7, the doping semiconductor layer 5 of TFT channel region is etched away fully, exposes semiconductor layer 4; Passivation layer 8 is formed on data wire 12, source electrode 6 and the drain electrode 7 and covers whole base plate 1, offers the passivation layer via hole 9 that drain electrode 7 is connected with pixel electrode 13 in drain electrode 7 positions.Cylindrical spacer 16 is forming with in a composition technology with pixel electrode 13, is made up of transparent conductive film that is positioned at lower floor and the photoresist that is positioned at the upper strata, is positioned at the crossover position of grid line 11 and data wire 12.

Fig. 4～Figure 20 is the schematic diagram of TFT-LCD array base palte manufacture process of the present invention, can further specify technical scheme of the present invention, in the following description, the alleged composition technology of the present invention comprises technologies such as photoresist coating, mask, exposure, etching, photoresist lift off, and photoresist is example with the positive photoresist.

Fig. 4 is TFT-LCD array base palte of the present invention plane graph after the composition technology for the first time, Fig. 5 be among Fig. 4 A2-A2 to profile, Fig. 6 be among Fig. 4 B2-B2 to profile.At first adopt the method for magnetron sputtering or thermal evaporation, go up deposition one deck grid metallic film at substrate 1 (as glass substrate or quartz base plate), the grid metallic film can adopt metals such as Mo, Al, also can adopt the laminated film (as the Mo/Al/Mo laminated film) that is made of the multiple layer metal film.Adopt normal masks plate (also claiming dull mask plate) that the grid metallic film is carried out composition, on substrate 1, form the figure that comprises gate electrode 2 and grid line 11, as Fig. 4～shown in Figure 6.Present embodiment for the first time in the composition technology, can also be formed with public electrode wire 14 and shield bars 15 figures simultaneously in the pixel region, form storage capacitance structure of (Cs onCommon) on public electrode wire.Public electrode wire 14 is formed between two grid lines 11 with skewed, vertically the shield bars 15 of shape is positioned at the both sides of pixel region, the two ends of public electrode wire 14 are connected with two shield bars 15 respectively, form integrative-structure, make shield bars 15 also participate in forming storage capacitance.In addition, for identical pixel column, the shield bars of adjacent pixel regions 15 interconnects by intercell connector, and the public electrode wire 14 of same pixel row and shield bars 15 are linked into an integrated entity.

Fig. 7 is TFT-LCD array base palte of the present invention plane graph after the composition technology for the second time, Fig. 8 be among Fig. 7 A3-A3 to profile, Fig. 9 be among Fig. 7 B3-B3 to profile.On the substrate of finishing the said structure figure, at first using plasma strengthens chemical vapour deposition (CVD) (being called for short PECVD) method, deposit gate insulation layer 3, semiconductive thin film and doped semiconductor films successively, adopt the method for magnetron sputtering or thermal evaporation then, metallic film is leaked in deposition one deck source.Gate insulation layer 3 can adopt oxide, nitride or oxynitrides, and metallic film is leaked in the source can adopt metals such as Mo, Al, also can adopt the laminated film (as the Mo/Al/Mo laminated film) that is made of the multiple layer metal film.Adopt halftoning or gray mask plate to form data wire 12, source electrode 6, drain electrode 7 and TFT channel region figure, as Fig. 7～shown in Figure 9 by composition technology.The present invention"s composition technology for the second time is a kind of composition technology that adopts the multistep lithographic method, with form data wire in four composition technologies of prior art, the source electrode, drain electrode is identical with the process of TFT channel region figure, technical process is specially: at first leak coating one deck photoresist on the metallic film in the source, adopt halftoning or gray mask plate that photoresist is exposed, make photoresist form complete exposure area, unexposed area and half exposure area, wherein unexposed area is corresponding to data wire, source electrode and drain electrode figure region, half exposure area is corresponding to TFT channel region figure region between source electrode and the drain electrode, and complete exposure area is corresponding to the zone beyond the above-mentioned figure.After the development treatment, the photoresist thickness of unexposed area does not change, and forms the complete reserve area of photoresist, the photoresist of complete exposure area is removed fully, form photoresist and remove the zone fully, the photoresist thickness attenuation of half exposure area forms photoresist half reserve area.Leak metallic film, doped semiconductor films and semiconductive thin film by the source that the first time, etching technics etched away complete exposure area fully, form data wire, source electrode and drain electrode figure.By cineration technics, remove the photoresist of half exposure area, expose this regional source and leak metallic film.Leak metallic film and doped semiconductor films by the source that the second time, etching technics etched away half exposure area fully, and etch away the semiconductive thin film of segment thickness, expose semiconductive thin film, form TFT channel region figure.Peel off remaining photoresist at last, finish TFT-LCD array base palte of the present invention composition technology for the second time.After this composition technology, grid line 11 and data wire 12 define pixel region, data wire 12 is between two shield bars 15, one end of source electrode 6 is positioned at the top of gate electrode 2, the other end is connected with data wire 12, and an end of drain electrode 7 is positioned at the top of gate electrode 2, is oppositely arranged with source electrode 6, the doping semiconductor layer 5 of TFT channel region is etched away fully between source electrode 6 and the drain electrode 7, exposes semiconductor layer 4.In addition, the below of data wire 12, source electrode 6 and drain electrode 7 remains with doping semiconductor layer 5 and semiconductor layer 4.

Figure 10 is TFT-LCD array base palte of the present invention plane graph after the composition technology for the third time, Figure 11 be among Figure 10 A4-A4 to profile, Figure 12 be among Figure 10 B4-B4 to profile.On the substrate of finishing the said structure figure, adopt PECVD method deposition one deck passivation layer 8.Passivation layer 8 can adopt oxide, nitride or oxynitrides.Adopt the normal masks plate that passivation layer is carried out composition, form passivation layer via hole 9, passivation layer via hole 9 is positioned at the top of drain electrode 7, as Figure 10～shown in Figure 12.In this composition technology, also be formed with the grid line interface via hole in grid line interface zone (grid line PAD) and the data line interface via hole figures of data line interface zone (data wire PAD) simultaneously, the technology that forms grid line interface via hole and data line interface via pattern by composition technology has been widely used in repeating no more here in the present composition technology.

At last, on the substrate of finishing the said structure figure, adopt the method for magnetron sputtering or thermal evaporation, the deposit transparent conductive film, adopt halftoning or gray mask plate to form pixel electrode 13 and cylindrical spacer 16 figures by composition technology, pixel electrode 13 is formed in the pixel region, is connected with drain electrode 7 by passivation layer via hole 9, cylindrical spacer 16 is formed on the overlapping place of grid line 11 and data wire 12, as Fig. 1～shown in Figure 3.

The 4th composition technology of the present invention is a kind of composition technology that adopts the multistep lithographic method, and Figure 13～Figure 20 describes the process of the 4th composition technology of TFT-LCD array base palte of the present invention in detail.

Figure 13 for deposit transparent conductive film in the 4th composition technology of TFT-LCD array base palte of the present invention after A1-A1 to profile, Figure 14 for deposit transparent conductive film in the 4th composition technology of TFT-LCD array base palte of the present invention after B1-B1 to profile.On the substrate of finishing the said structure figure, adopt the method for magnetron sputtering or thermal evaporation, deposit a layer thickness and be

Transparent conductive film 18, transparent conductive film 18 can adopt materials such as tin indium oxide (ITO), indium zinc oxide (IZO) or aluminum zinc oxide, also can adopt other metal and metal oxide, as Figure 13 and shown in Figure 14.

Figure 15 for exposure imaging in the 4th composition technology of TFT-LCD array base palte of the present invention after A1-A1 to profile, Figure 16 for exposure imaging in the 4th composition technology of TFT-LCD array base palte of the present invention after B1-B1 to profile.Apply one deck photoresist 19 on transparent conductive film 18, the thickness of photoresist 19 is 3 μ m～5 μ m, can be provided with according to the design height of cylindrical spacer.Adopt the exposure of halftoning or gray mask plate, make photoresist form complete exposure area A, unexposed area B and half exposure area C.Unexposed area B is corresponding to cylindrical spacer figure region, and half exposure area C is corresponding to pixel electrode figure region, and complete exposure area A is corresponding to the zone beyond the above-mentioned figure.After the development treatment, the photoresist thickness of unexposed area B does not change, form the complete reserve area of photoresist, the photoresist of complete exposure area A is removed fully, form photoresist and remove the zone fully, the photoresist thickness attenuation of half exposure area C forms photoresist half reserve area, as Figure 15 and shown in Figure 16.

Figure 17 for etching technics in the 4th composition technology of TFT-LCD array base palte of the present invention after A1-A1 to profile, Figure 18 for etching technics in the 4th composition technology of TFT-LCD array base palte of the present invention after B1-B1 to profile.Etch away the transparent conductive film 18 of complete exposure area A fully by etching technics, form pixel electrode 13 figures, as Figure 17 and shown in Figure 180.After this technology, pixel electrode 13 tops are coated with photoresist 19.

Pass through cineration technics afterwards, remove the photoresist of half exposure area, expose this regional pixel electrode 13 figures, pixel electrode 13 is connected with drain electrode 7 by passivation layer via hole 9, form cylindrical spacer 16 figures at unexposed area, cylindrical spacer 16 is positioned at the overlapping place of grid line 11 and data wire 12, is made up of transparent conductive film that is positioned at lower floor and the photoresist that is positioned at the upper strata, as depicted in figs. 1 and 2.

Four composition technologies discussed above only are a kind of implementation methods of preparation TFT-LCD array base palte of the present invention, can also be by increasing or reduce composition technology number of times, selecting different material or combinations of materials to realize the present invention in actual the use.For example, TFT-LCD array base palte of the present invention composition technology for the second time can adopt the composition technology of normal masks plate to finish by two, promptly form active layer pattern, adopt the composition technology of normal masks plate to form data wire, source electrode, drain electrode and TFT channel region figure by another time by the composition technology that once adopts the normal masks plate.

Figure 19 is the structural representation of LCD of the present invention.LCD comprises establishes therebetween array base palte 10 and color membrane substrates 20 to box together and with liquid crystal folder, array base palte 10 adopts the structure of TFT-LCD array base palte technique scheme of the present invention, color membrane substrates 20 comprises the black matrix 21 that is formed on the substrate, color resin 22 and public electrode 23, color resin comprises redness, blue and green three chromoresins, the main purpose of black matrix 21 is to isolate color resin 22, block the light in light leak zone simultaneously, public electrode 23 is formed on black matrix 21 and the color resin 22, with respect to the higher color resin 22 of location about, the position of black matrix 21 is lower, so color membrane substrates 20 forms recess area in the position of black matrix 21.Cylindrical spacer 16 of the present invention is arranged on the overlapping place of grid line and data wire, and its top, end is located in the recess area, and end face contacts with the bottom surface of recess area.That is to say, cylindrical spacer 16 of the present invention is positioned at the position of black matrix 21, and this position is because black matrix 21 and the color resin around it 22 form recess area, so top, the end of cylindrical spacer 16 is located at lower zone, position, cylindrical spacer 16 forms a kind of metastable structure with recess area, make cylindrical spacer be in a kind of metastable state, even array base palte 10 or color membrane substrates 20 are subjected to the external force extruding or impact, the end of cylindrical spacer 16 also is difficult to move.

The invention provides a kind of TFT-LCD array base palte and LCD, cylindrical spacer is arranged on the overlapping place of grid line and data wire, and the top, end is located in the recess area that forms on the color membrane substrates, make cylindrical spacer be in a kind of metastable state, even array base palte or color membrane substrates are subjected to the external force extruding or impact, the end of cylindrical spacer also is difficult to move, and the dislocation of array base palte and color membrane substrates can not occur, has effectively avoided the generation of display defects such as light leak, contact watermark.In addition, because cylindrical spacer of the present invention and pixel electrode have effectively reduced preparation technology forming with in a composition technology, improved production efficiency.

Step 10, form the figure of grid line, gate electrode, data wire, drain electrode, source electrode, TFT raceway groove and passivation layer via hole on substrate, described passivation layer via hole is positioned at the top of drain electrode;

Step 20, on the substrate of completing steps 10 the deposit transparent conductive film, form the figure that comprises pixel electrode and cylindrical spacer by composition technology, described pixel electrode is connected with drain electrode by passivation layer via hole, and described cylindrical spacer is positioned at the overlapping place of grid line and data wire.

The invention provides a kind of TFT-LCD manufacturing method of array base plate, by cylindrical spacer being arranged on the overlapping place of grid line and data wire, after making array base palte and color membrane substrates to box, the top, end of cylindrical spacer is located in the recess area that forms on the color membrane substrates, make cylindrical spacer be in a kind of metastable state, even array base palte or color membrane substrates are subjected to the external force extruding or impact, the end of cylindrical spacer also is difficult to move, the dislocation of array base palte and color membrane substrates can not occur, effectively avoid the generation of display defects such as light leak, contact watermark.Because cylindrical spacer of the present invention and pixel electrode have effectively reduced preparation technology forming with in a composition technology, have improved production efficiency.

Step 12, on the substrate of completing steps 11, deposit gate insulation layer, semiconductive thin film, doped semiconductor films and metallic film is leaked in the source, form the figure that comprises data wire, drain electrode, source electrode and TFT raceway groove by composition technology;

Step 14, on the substrate of completing steps 13 the deposit transparent conductive film, form the figure that comprises pixel electrode and cylindrical spacer by composition technology, described pixel electrode is connected with drain electrode by passivation layer via hole, and described cylindrical spacer is positioned at the overlapping place of grid line and data wire.

In the present embodiment step 11, at first adopt the method for magnetron sputtering or thermal evaporation, go up deposition one deck grid metallic film at substrate (as glass substrate or quartz base plate), the grid metallic film can adopt metals such as Mo, Al, also can adopt the laminated film (as the Mo/Al/Mo laminated film) that is made of the multiple layer metal film.Adopt the normal masks plate that the grid metallic film is carried out composition, on substrate, form the figure that comprises gate electrode and grid line.In the practical application, can also be formed with public electrode wire and shield bars figure simultaneously in the step 11.Its preparation process is introduced in earlier figures 4～technical scheme shown in Figure 6 in detail.

In the present embodiment step 12, on the substrate of finishing the said structure figure, at first adopt the PECVD method, deposit gate insulation layer, semiconductive thin film and doped semiconductor films successively, adopt the method for magnetron sputtering or thermal evaporation then, metallic film is leaked in deposition one deck source.Gate insulation layer can adopt oxide, nitride or oxynitrides, and metallic film is leaked in the source can adopt metals such as Mo, Al, also can adopt the laminated film (as the Mo/Al/Mo laminated film) that is made of the multiple layer metal film.Adopt halftoning or gray mask plate to form data wire, source electrode, drain electrode and TFT channel region figure by composition technology.Its preparation process is introduced in earlier figures 7～technical scheme shown in Figure 9 in detail.

Figure 22 forms the flow chart of pixel electrode and cylindrical spacer for TFT-LCD manufacturing method of array base plate of the present invention.In technical scheme shown in Figure 21, described step 14 comprises:

Step 145, remove the photoresist of photoresist half reserve area by cineration technics, form pixel electrode and cylindrical spacer figure, described pixel electrode is connected with drain electrode by passivation layer via hole, described cylindrical spacer is positioned at the overlapping place of grid line and data wire, is made up of transparent conductive film that is positioned at lower floor and the photoresist that is positioned at the upper strata.

Step 22, on the substrate of completing steps 21, deposit gate insulation layer, semiconductive thin film and doped semiconductor films, form the figure that comprises active layer by composition technology;

Step 23, sedimentary origin leaks metallic film on the substrate of completing steps 22, forms the figure that comprises data wire, drain electrode, source electrode and TFT raceway groove by composition technology;

Step 25, on the substrate of completing steps 24 the deposit transparent conductive film, form the figure that comprises pixel electrode and cylindrical spacer by composition technology, described pixel electrode is connected with drain electrode by passivation layer via hole, and described cylindrical spacer is positioned at the overlapping place of grid line and data wire.

Present embodiment is a kind of composition technology that adopts the normal masks plate, main flow process and aforementioned first embodiment are basic identical, difference is, the step 12 of aforementioned first embodiment adopts the composition technology of normal masks plate to finish by two, promptly form active layer pattern, adopt the composition technology of normal masks plate to form data wire, source electrode, drain electrode and TFT channel region figure by another time by the composition technology that once adopts the normal masks plate.Adopt the composition technical process of normal masks plate to be well known to those skilled in the art, repeat no more here.

China"s first 8.5-generation TFT-LCD production line was launched in Bengbu, East China"s Anhui province, on June 18, 2019, representing a breakthrough in the production of high-definition LCD screen, Science and Technology Daily reported.

TFT-LCD, or Thin Film Transistor Liquid Crystal Display, is key strategic material of the electronic information display industry. The Gen 8.5 TFT-LCD production line, launched by the Bengbu Glass Industry Design and Research Institute of the China National Building Material Group, will produce high-definition LCD screens of 55 inches, the report said.

According to the Liquid Crystal Branch of the China Optics and Optoelectronics Manufactures Association, the demand for TFT-LCD in the Chinese mainland was about 260 million square meters in 2018, including 233 million square meters" Gen 8.5 TFT-LCD. However, the annual supply of domestically made TFT-LCD is less than 40 million square meters, with all of them Gen 6 or below, which cannot meet the demand in scale and quantity.

The association predicted that China"s market demand for Gen 8.5 TFT-LCD or above will exceed 300 million square meters by 2020, accounting for 49.6 percent of the total global demand.

The production and control precision of Gen 8.5 TFT-LCD is comparable to that of the semiconductor industry, representing a higher level of large-scale manufacturing of modern glass industry.

The institute in Bengbu, with 60 years of expertise in glass, has finally made a breakthrough in the production of Gen 8.5 TFT-LCD, and will provide key raw material guarantee for China"s LCD panel industry after it goes into mass production in September, the report said.

In ruling NY N320557 (August 4, 2021), Customs and Border Protection (CBP) discussed the country of origin of five Thin Film Transistor – Liquid Crystal Display (TFT-LCD) modules. All five modules are virtually identical in composition, as they are all composed of a TFT-LCD cell, polarizers, a backlight, a driver and control printed circuit board (PCB), and a flexible PCB for connection. TFT display technology allows for the construction of high-resolution LCD displays, and the modules – once completed – can be incorporated into a variety of consumers display applications.

The manufacturing process for the five modules is also identical. The process begins in Japan where the TFT-LCD cell is manufactured. The TFT is created by depositing transistors onto a substrate through chemical vapor deposition, while the color filter is manufactured by building a color matrix on a glass substrate. The creation process of the cells is then completed when a layer of liquid crystal is deposited between the color filter and TFT as the two part are bonded together, creating a sheet of TFT-LCD cells. As next steps, the sheet of cells is delivered to China to be cut into individual cells. The cut-up cells are then bonded to the printed circuit board assembly (PCBA) – which contains the driver and control circuity – before the polarizers, backlight, and flexible connection PCBA are attached.

In its determination, CBP notes that, as defined under 19 CFR 134.1(b), the country of origin is the “country of manufacture, production, or growth of any article of foreign origin entering the United States. Further work or material added to an article in another country must effect a substantial transformation in order to render such other country the ‘country of origin’ within the meaning of this part.”

CBP also established that “substantial transformation” takes place when a particular product “emerges from a process with a new name, character or use different from that possessed by the article prior to processing.” The agency explained that the completed TFT-LCD cell is what imparts the essential function of the module and that the manufacturing process in Japan is what renders the end-use of the product. Despite the assembly that took place in China, the process did not substantially transform the cell into a new and different article. As such, CBP determined that the country of origin of the five modules is Japan.

Optical and SEM (scanning electron microscopy) images of fabricated (a, b) CL and (c, d) CLSE pixel structures. The five white line patterns in (d) are the ITO interdigitated pixel and common electrodes. (e) Images from the normal direction and from 50 degrees to the left and right of a 2.3-inch-diagonal display incorporating the IPS TFT-LCD panel. (f) The three-black matrix (BM) patterns (top: BM covering both gate and data lines, middle: BM covering only the data lines, and bottom: without BM) and (g) optical images of pixels without BM (left: LC on and off voltages supplied to every other data line, right: LC off voltage supplied to all data lines).

Figure 3e shows images from the normal direction and from 50 degrees to the left and right of a 2.3-inch-diagonal display incorporating the IPS TFT-LCD panel fabricated in our laboratory, (f) the three black matrix (BM) patterns (top: BM covering both gate and data lines, middle: BM covering only the data lines, and bottom: without BM), and (g) optical images of panel areas without the BM (left: LC on and off voltages supplied to every other data line, right: LC off voltage supplied to all data lines). As can be seen in the image from the normal direction, the brightness and contrast of the display area with the top BM and middle BM patterns are almost the same, but the contrast of the display area without the BM is relatively lower because of the lower darkness level of the LC off pixels indicating “HITACHI”. As shown in Fig. 3g, this is due to light leaking through the aperture between the data line and adjacent common lines. Therefore, in the CL structure, the BM on the drain line is necessary to obtain a high contrast ratio by shielding light leakage. This is the same as in the conventional structure. On the contrary, there is no light leakage along the gate line through the gaps between the gate line and edges of the pixel/common electrodes, as is clearly shown in Fig. 3g. This is a unique advantage of the CL structure because the conventional structure must shield these gaps with the BM to prevent light leakage. The suppression of light leakage along the gate line in the CL structure is due to the driving scheme (see Fig. 2b,a for a comparison with the conventional structure). During the holding period (tOFF) in the conventional structure, regardless of the pixel voltage, Vp (including Vp = 0), nonzero Vgp and Vgc are always applied to keep the TFT off, and these voltages are applied to the LC layer, inducing light leakage as reported in

Figure 4a shows the gate voltage (Vg) dependence of the panel brightness, while the inset shows that of the TFT current (transfer characteristics). The gray curves are for the conventional IPS TFT-LCD with the TFT before enhancement, the common line, and the matrix BM (MBM) shown at the top of Fig. 3f. The blue curves are for the proposed CL structure with the enhanced TFT and the stripe BM (SBM) shown in the middle of Fig. 3f. In this case, enhanced TFT characteristics were obtained by using an MNOS TFT without back-channel oxidation that was enhanced by the BTS process. In both structures, the threshold voltages for panel brightness, defined by extrapolating the straight part of the brightness curves, reflect those of the TFT transfer curves defined as Vg at a drain current of 10−12 A, and they are well matched to be 4 V and 9 V, respectively. The maximum brightness for the CL structure is 137% higher than that for the conventional structure, which is due to the increase in the aperture ratio from 38 to 52% that results from the elimination of the common line and the BM covering the gate line.

(a) Dependence of panel brightness and TFT current on gate voltage for the conventional pixel structure of 38% aperture ratio (AR) with matrix black matrix (MBM) over both drain and gate lines and proposed CL pixel structure of 52% AR with strip black matrix (SBM) over only the drain lines. Transfer characteristics before and after bias temperature stress (BTS) treatment are shown in the inset. (b) Charging and (c) holding characteristics of enhanced TFT of the CL structure with gate as a common line. Vg and Vd in the TFT ON state are 30 V and +/−7 V, respectively.

To estimate the charging and holding characteristics of the MNOS-enhanced TFT in the panel, the gate TFT ON and OFF time dependences of the panel brightness were measured (Fig. 4b,c). The charging characteristics in Fig. 4b are plotted as a function of tON at tOFF = 16.6 ms, Vg = 30 V, and Vd = ± 7 V. The holding characteristics in Fig. 4c are plotted as a function of tOFF at tON = 34 μs. 95.1% charging at tON = 34 μs and 95.3% holding at tOFF = 16.6 ms indicate that the enhanced TFT has sufficient charging and holding performance to drive a standard VGA (640 × 480 pixels) panel (the number of scanning lines is estimated as tOFF/tON = 16.6/0.034 = 488).

To confirm the driving conditions for the CL structure without the BM along the gate line (with the SBM), the tOFF dependence of the contrast ratio (CR) in the CL panel was further investigated as shown in Fig. 5a, where CR is plotted as a function of tOFF for the CL panels with the matrix BM (MBM) and the strip BM (SBM). The inset shows the brightness in the bright (Vd = 7 V) and dark (Vd = 0 V) states of the CL panel with the SBM as a function of tOFF and an optical image of the panel with tOFF = 6.4 ms. The SBM and MBM panels keep CR higher than 240 with tOFF > 16.6 ms, the frame period of a display panel without flicker being noticeable to the human eye. both panels decrease CR when tOFF is less than 16.6 ms; the CR of the SBM panel decreases faster than the CR of the MBM panel. As shown in the inset, the decrease in CR was due to the increase in dark-state brightness with decreasing tOFF as light leakage increases along the gate line. This light leakage is induced by the voltage Vgp = Vgc = VgON = 30 V applied only for 34 μs during the TFT ON (charging) state, which is 1/488th the duration, tOFF = 16.6 ms, of the TFT OFF (holding) state with Vgp = Vgc = VgOFF = 0 V, but the ratio increases with decreasing tOFF and becomes effective enough to switch on LC layer and induce light leakage. However, it should be stressed again that the CL panel with the normal holding (TFT OFF) time of 16.6 ms does not suffer from the light leakage along the gate line, so the aperture ratio can be increased by removing the BM along the gate line.

Figure 6 indicates the effect of bias temperature stress (BTS) on the TFT characteristics. As the stressing time, tS, of the positive gate stress voltage, Vst =  + 77 V, increases from 0 to 3600 s, the transfer (Id-Vg) curve shifts in the positive direction (Fig. 6a). Vth is defined as Vg at which Id = 10−12 A and ΔVth is defined as the Vth shift from the initial value via BTS. As shown in Fig. 6b, ΔVth increases logarithmically with increasing tS: ΔVth = 2.17 + 4.93 × log (tS). The mechanism behind the gate-stress-induced Vth shift is electron tunnel injection from the a-Si:H semiconductor into the SiOx gate insulator. For confirmation, ΔVth of MNOS TFTs with different SiOx thicknesses is plotted as a function of the electric field applied to the SiOx layer in Fig. 6c. Here, the thickness of the SiOx was varied (5, 10, 20, 50 nm), while the SiN thickness was fixed at 200 nm. The electric field applied to SiOx, Eox, was calculated using the following equation,

Effect of bias temperature stress (BTS) on TFT characteristics. (a) The transfer (Id–Vg) curve shifts in the positive direction with positive gate bias stress of Vst =  + 77 V over the duration of 0–3600 s. (b) ΔVth, defined as the Vth shift from the initial value via BTS, increases logarithmically with increasing tS, following ΔVth = 2.17 + 4.93 × log (tS). (c) ΔVth of MNOS TFTs with different SiOx thicknesses from 5 to 50 nm as a function of the electric field applied to the SiOx layer.

Figure 7a shows the effect of back-channel oxidation (BCO) and passivation (PAS) on the Id-Vg characteristics of the MNOS TFT. The Id-Vg curve with Vth = 5.1 V is further enhanced to Vth = 10.9 V after BCO, although there is a slight degradation of the slope of the current increase in the sub-threshold region. The slope recovers after PAS without any change to the enhanced characteristics

(a) Effect of back-channel oxidation (BCO) and passivation (PAS) on Id–Vg characteristics of MNOS TFT. (b) Vth and Vth standard deviation, σVth, after BTS and after BCO without BTS treatments and (c) SiOX thickness as a function of position along gate-line, x.

The advantage of BCO over BTS is the uniformity of the enhanced characteristics; Fig. 7b shows the distribution of the enhanced Vth as a function of position along gate-line, x, for the MNOS TFTs connected with a 90-mm-long gate line in the TFT substrate after BTS and BCO treatments. The average value of Vth and the standard deviation, σVth, for pristine TFTs before BTS or BCO, are 5.1 V and 0.35 V, respectively. After BCO, Vth is uniformly enhanced, with an average Vth = 11 V and σVth = 0.4 V without increasing σVth. On the other hand, after BTS, Vth is nonuniformly enhanced with an average Vth = 9.3 V and σVth of 1.4 V. In particular, Vth increases linearly as a function of position along gate-line, x. As the gate SiOx thickness linearly decreases, from (54 nm) to (47 nm) with increasing x as shown in Fig. 7c, the increase in ΔVth after BTS with x is due to increase in the electric field applied to SiOx as shown in Fig. 6c and Eq. 1.

It has been shown that the Vth of the MNOS TFT is independent of the gate SiOx thickness when the thickness is more than 5 nm8a, Vth of the MNOS TFT with the BCO treatment becomes almost independent of the BCO SiOx thickness. As shown in the inset, the thickness of BCO SiOx composed of oxidized a-Si:H linearly increases with BCO processing time, and the Vth increase almost saturates at a BCO SiOx thickness greater than 5 nm. Therefore, the enhanced MNOS TFT after BCO has a uniformly high Vth that is robust to thickness fluctuations of the gate and BCO SiOx layers. BCO also has an advantage over BTS in terms of the stability of Vth as shown in Fig. 8b, which plots the annealing time dependence of Vth for BCO and BTS. In this experiment, the stoichiometry (x) of the gate SiOx was 1.78 for BTS and 1.78 and 1.9 for BCO. The annealing temperature in the N2 atmosphere was 200 °C. In the case of BTS, Vth decreased to the pristine value after approximately 5 h of annealing, while Vth decreased more slowly in the case of BCO. In particular, the annealing time required for Vth to fall to 7 V was 7.5 times longer than that of BTS. Increasing the stoichiometry (x) of the gate SiOx dramatically improved the BCO-enhanced Vth to as much as 11 V, which was stably maintained after 24 h of annealing at 200 °C.

(a) Dependence of Vth on thickness of back-channel oxidized (BCO) SiOX. The inset shows the SiOx thickness dependence on the BCO process time for RF powers of 200 W and 500 W. (b) Stability of Vth as a function of annealing time for three different TFTs with gate SiOx stoichiometry, x = 1.78 and bias temperature stress (BTS), x = 1.78 and BCO, and x = 1.9 and BCO. The temperature of annealing in the N2 atmosphere was 200 °C. (c) Band diagram of back-channel oxidized MNOS TFT. The red arrows show the electric dipoles at the SiOX/a-Si:H and a-Si:H/BCO SiOX interfaces.

A schematic band model for the MNOS TFT with the BCO treatment and the sectional structure of the interface between the a-Si:H and gate and BCO SiOx are shown in Fig. 8c. The uniformly high Vth that is independent of SiOx thickness is due to the dipoles generated at the channel and back-channel interfaces between a-Si:H and SiOx8 of reference

(Yicai Global) June 19 -- China National Building Material has built the country"s first production line capable of producing 8.5th-generation TFT-LCD glass substrates, making China one of few nations to master the technology.

The central state-owned firm"s Bengbu Glass Industry Design and Research built the facility after three years of research, Science and Technology Daily reported. The plant aims to obtain certifications that will allow it to manufacture for domestic display makers.

TFT-LCD, or thin-film-transistor liquid-crystal displays, are classified by the size of their glass substrate. Sixth-generation displays are now widely considered out-dated while 8.5th-gen tech is the most advanced. The newer technologies use larger substrates, which are more efficient to make and can be used in larger screens.

RE:Country of origin; Thin Film Transistor (TFT); Liquid Crystal Display (LCD); TFT/LCD module; PCB; flat panel display computer monitor; marking; outermost container; ultimate purchaser; substantial transformation; Hitachi; Japan; China; HRL 560427; 19 CFR 134.1(a); 134.32(d).

This is in reply to your letter, dated April 8, 2002. In that letter, you requested a ruling on the country of origin marking requirements for TFT- LCD modules assembled in China of Japanese components and imported into the United States to be used to make notebook computer monitors and flat panel desktop computer monitors. Our response follows.

Hitachi will produce finished thin film transistor (TFT)/liquid crystal display (LCD) modules that will be imported into the United States. The two products at issue are: 1) TFT/LCD modules for use with notebook computers; and 2) a Super IPS (In Plane Switching) TFT-LCD module to make flat panel desktop computer monitors.

The Back Light Unit is assembled in China. The process includes first adding a reflection sheet to a plastic mold case, the latter sometimes also made in China. Then, the Cold Fluorescent Lamp (CFL) unit, which is made by assembling bushing rubber, the CFL, CFL connector and CFL cable, is affixed to the reflection sheet with a doubled sided adhesive tape. A light guide is also attached to the CFL unit. Then, a diffuser sheet is attached to the top of the light guide. A lens film is then affixed on the diffuser sheet. Another lens film is attached and lastly, a diffuser sheet is placed on top of the lens film.

You state that although the Japanese-origin TFT-LCD Cell is the primary component, the Japanese components are substantially transformed in China when they are assembled into a TFT-LCD module in China. You contend that the components, which include the PCB, Back Light Unit (with CFL), tape, frame, cables, and the TFT-LCD Cell, when assembled result in a different commercial article, that is, a completed TFT-LCD module ready for use to manufacture notebook computer monitors or flat panel desktop computer monitors.

A representative of your company stated by telephone on April 24, 2002, that after importation of the finished TFT-LCD modules into the U.S., your company stores them in a warehouse as part of your company’s inventory. When a customer orders the modules, they are shipped to the customer. Your representative stated that because the imported articles are highly sensitive and fragile, your company does not normally repackage the imported articles. Your company’s customers then incorporate the TFT-LCD modules into a monitor when manufacturing their final computer product. In other words, the modules are not ready to be used as monitors when imported into the U.S. because they lack components such as the frame, power supply, driver, et cetera and must be further processed in the United States.

What are the country of origin marking requirements for finished TFT-LCD modules assembled in China from Japanese components and imported into the United States to be used for manufacturing notebook computer monitors and flat panel desktop computer monitors?

Section 134.35(a), Customs Regulations (19 C.F.R. § 134.35(a)), provides that the manufacturer or processor in the U.S. who converts or combines the imported article into a different article having a new name, character or use will be considered the ultimate purchaser of the imported article within the contemplation of 19 U.S.C. § 1304(a), and the article shall be excepted from marking. The outermost containers of the imported articles shall be marked in accord with this part.

Based on the facts provided, it is our opinion that the assembly of various components used in producing the TFT/LCD module in China, including the Back Light Unit which is made in China from approximately 12 components, effects a substantial transformation of the individual components. The individual components, most of which are made in Japan, lose their identity and become integral part of the new article – TFT/LCD module. The assembly operations are also not minimal or simple. Thus, the TFT/LCD module as imported into the United States qualifies as a product of China and therefore should be marked as such.

In HRL 560427, the LCD module was made in Japan and imported into the U.S. The LCD module was then combined with nine other U.S. components to manufacture the final Flat Panel TFT/LCD monitor for personal computers. Customs ruled that the Japanese-origin LCD module was substantially transformed in the U.S. when incorporated into the monitor in the U.S. Similarly, in the instant case, the TFT/LCD module made in China will be incorporated in the United States into flat panel desktop computer monitors and notebook computer monitors manufactured by your customers.

In the instant case, unlike the case in 560247, the importer is not the manufacturer or the processor. However, subject to the terms of 19 C.F.R. § 134.35(a) and 19 C.F.R. § 134.1(d)(1), your company’s customers, who use the imported TFT/LCD modules to produce the flat panel desktop computer monitors and notebook computer monitors in the United States would be considered the ultimate purchasers. Therefore, as in HRL 560247, the imported article in the instant case qualifies for the marking exception provided in 19 C.F.R. § 134.35(a) and 19 C.F.R. § 134.32(d). Consequently, the country of origin marking requirements may be met in the instant case by having the imported articles’ containers (i.e. boxes or other containers that hold the modules) marked with the country of origin, assuming that those containers also reach your customers.

For the foregoing reasons and based on the facts provided, the TFT/LCD modules are products of China and therefore should be so marked. However, because the TFT/LCD modules will be used by your customers to manufacture flat panel desktop computer monitors and notebook computer monitors in the United States, your customers are the ultimate purchasers. Therefore, the marking requirements may be met by marking the containers of the imported articles with their country of origin, assuming that your customers receive the articles in those containers.

China has been opened its first thin film transistor liquid crystal display (TFT LCD) production line in the Changchun Digital Science Park in Jilin Province. A joint venture between a Chinese company and a Hong Kong investor, the $160m facility will go into production by the end of the year. It claims to have already signed contracts with local computer and electronics manufacturers for the first two years’ output.

China"s first 8.5-generation TFT-LCD production line was launched in Bengbu, East China"s Anhui province, on June 18, 2019, representing a breakthrough in the production of high-definition LCD screen, Science and Technology Daily reported.

TFT-LCD, or Thin Film Transistor Liquid Crystal Display, is key strategic material of the electronic information display industry. The Gen 8.5 TFT-LCD production line, launched by the Bengbu Glass Industry Design and Research Institute of the China National Building Material Group, will produce high-definition LCD screens of 55 inches, the report said.

According to the Liquid Crystal Branch of the China Optics and Optoelectronics Manufactures Association, the demand for TFT-LCD in the Chinese mainland was about 260 million square meters in 2018, including 233 million square meters" Gen 8.5 TFT-LCD. However, the annual supply of domestically made TFT-LCD is less than 40 million square meters, with all of them Gen 6 or below, which cannot meet the demand in scale and quantity.

The association predicted that China"s market demand for Gen 8.5 TFT-LCD or above will exceed 300 million square meters by 2020, accounting for 49.6 percent of the total global demand.

The production and control precision of Gen 8.5 TFT-LCD is comparable to that of the semiconductor industry, representing a higher level of large-scale manufacturing of modern glass industry.

The institute in Bengbu, with 60 years of expertise in glass, has finally made a breakthrough in the production of Gen 8.5 TFT-LCD, and will provide key raw material guarantee for China"s LCD panel industry after it goes into mass production in September, the report said.

The most common semiconducting layer is made of amorphous silicon (a-Si). a-Si  thin film transistor - liquid crystal display (TFT-LCD) has been the dominant technology for the manufacturing of active matrix TFT-LCD for over 20 years. a-Si is a low cost material in abundant supply.

a-Si is a low cost material in abundant supply. However, the electron mobility of a-Si is very low (around 1cm2/Vs) and can’t physically support high refresh rates such as the 240Hz needed for HDTV. Due to their high electron mobility, new materials such as metal oxide (MO) and low temperature polysilicon (LTPS) are now replacing a-Si to manufacture the industry’s two main types of screens: LCD and organic light-emitting diode (OLED) displays.

SHANGHAI, Aug 26 (Reuters) - China"s BOE Technology Groupwill soon start building the country"s first eighth generation TFT-LCD (thin-film transistor liquid crystal display) production line with an investment of 28 billion yuan ($4.1 billion), a source close to the situation said on Wednesday.

The short name of TFT:Thin Film Transistor in Chinese. What is the difference between TFT and LCD? Our laptops and desktops now use relatively advanced TFT displays, which consist of LCD pixels and are powered by thin-film transistors integrated behind the pixels. Therefore, the TFT type display screen also belongs to a class of display devices with a source matrix.

TFT type display screen is currently a better LCD color display, TFT type display has many advantages: high responsiveness, high brightness, high contrast, and so on.TFT displays are closest to CRT displays. The TFT screen also often appears on the screen of each big mobile phone, there are 65536 colors, 160,000 colors, 16 million colors three, its display effect is also very good.

TFT means that every LCD pixel on an LCD is driven by a thin-film transistor integrated behind it. Thus can achieve high speed, high brightness, high contrast display screen information, TFT-LCD(thin-film transistor liquid crystal display) is one of the majority of LIQUID crystal displays.

Liquid Crystal Display (LCD). The structure of the LCD is placed in the middle of the two pieces of parallel glass liquid crystal box, the substrate glass set on TFT (thin-film transistor), set the color filter substrate glass on, on the TFT signal, and the voltage change to control the rotation direction of the liquid crystal molecules, so as to achieve control of each pixel display emergent polarized light or not and to achieve. Now THAT LCD has replaced CRT as the mainstream, the price has dropped a lot and become widely available.

The TFT(Thin Film Field-effect Transistor) is a video in which every single pixel in the liquid crystal display is actuated by a