a si tft lcd cell factory

According to LCD (Liquid Crystal Display) technology and LCD materials, mobile phone LCD assemblies can be classified into 2 types: TFT (Thin Flim Transistor) and OLED（Organic Light-Emitting Diode). TFT display needs with backlight, but OLED is light-emitting, each pixel is creating its own light.

For Original iPhone LCD, 5-8 plus and Xr, 11 is TFT, X-13 Pro Max is OLED (except XR and 11). But in mobile phone aftermarket, there are too many different types and different qualities, which makes customers confused.

What is in-cell? What is OGS or " with TP"? What is COF? What is COG? What is OEM? What is FOG? What is Original Change Glass? What is IPS? What is LTPS? What is a-Si?

HTPS with small size, high precision, and high contrast. Most used in magnified display products. Such as projectors, projection TVs, etc. And cannot be used as a mobile phone display, so we don"t talk about it here.

IGZO has 20–50 times the electron mobility than a-Sin. IGZO only has been licensed to Samsung Electronics and Sharp. However, it was Sharp who first implemented IGZO into their smartphones (Aquos Phone Zeta SH-02E), tablets, and 32-inch LCDs. IGZO for mobile phones is only Sharp. Almost all mobile phones on the market didn"t use IGZO.

Because the electrons deflect the liquid crystal molecules through the transistor. Electron mobility fundamentally determines the refresh rates of the TFT device. The smaller mobility, the slower transmission of holes and electrons, and the slower response rate. Can"t physically support high refresh rates.

In order to improve the response performance, can increase transistor size to enhance the migration, but this will lead to the extra TFT device that will occupy the display area pixel area. Therefore, the larger unit transistor area, the single-pixel occupy area is smaller(Pixel Aperture Ratio ), resulting in lower brightness.

Secondly, because the volume cannot be smaller, then the number of pixels per unit area is limited, which means the pixel density is small, which is what we call PPI is low, resulting in low resolution. The image needs to be zoomed, the original image data is lost, and resulting in the blurred image effect.

As we can see electron mobility of a-Si is very low (0.5-1cm2/Vs). But LTPS can deliver a hundred times the mobility than a-Si, and a much higher aperture ratio and PPI is much higher than a-Si resolution.

Compared with LTPS，a-si TFT have those "weakness":a-Si with so much low resolution and low definition. a-Si is 720*1280 with a very blurred display effect.

a-Si with so much bad display performance, but why are there still so many manufacturers producing phone LCDs with a-Si, or why do the customers willing to use a-Si LCD for their phone?

LCDs business has too much competition and wholesalers want to make more profit, they keep pushing suppliers to make LCDs at lower prices. So some of the suppliers start to produce aftermarket phone displays with a-Si to match customers" lower price requirements.

The customers with asymmetric information. End-Users don"t know how to distinguish LCDs qualities. Some of them just chase the price but not quality. That is another reason wholesalers want a lower price.

Now in the market a-Si LCDs for iPhone is TFT with TP but not in-cell. Our ZY a-Si will be in-cell not just TFT with TP. ZY a-Si incell for Xr and 11 ready now, please to get more details.

For more details or questions about in-cell and TFT with TP or about phone LCD display. Please click here to get more information, or Long press and scran the QR code to add me.

A not-for-profit organization, IEEE is the world"s largest technical professional organization dedicated to advancing technology for the benefit of humanity.

A not-for-profit organization, IEEE is the world"s largest technical professional organization dedicated to advancing technology for the benefit of humanity.

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-plane switching was developed by Hitachi Ltd. in 1996 to improve on the poor viewing angle and the poor color reproduction of TN panels at that time.

Initial iterations of IPS technology were characterised by slow response time and a low contrast ratio but later revisions have made marked improvements to these shortcomings. Because of its wide viewing angle and accurate color reproduction (with almost no off-angle color shift), IPS is widely employed in high-end monitors aimed at professional graphic artists, although with the recent fall in price it has been seen in the mainstream market as well. IPS technology was sold to Panasonic by Hitachi.

Most panels also support true 8-bit per channel color. These improvements came at the cost of a higher response time, initially about 50 ms. IPS panels were also extremely expensive.

IPS has since been superseded by S-IPS (Super-IPS, Hitachi Ltd. in 1998), which has all the benefits of IPS technology with the addition of improved pixel refresh timing.

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.

It achieved pixel response which was fast for its time, wide viewing angles, and high contrast at the cost of brightness and color reproduction.Response Time Compensation) technologies.

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.

Backlight intensity is usually controlled by varying a few volts DC, or generating a PWM signal, or adjusting a potentiometer or simply fixed. This in turn controls a high-voltage (1.3 kV) DC-AC inverter or a matrix of LEDs. The method to control the intensity of LED is to pulse them with PWM which can be source of harmonic flicker.

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.

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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.

TFT-LCD was invented in 1960 and successfully commercialized as a notebook computer panel in 1991 after continuous improvement, thus entering the TFT-LCD generation.

Simply put, the basic structure of the TFT-LCD panel is a layer of liquid crystal sandwiched between two glass substrates. The front TFT display panel is coated with a color filter, and the back TFT display panel is coated with a thin film transistor (TFT). When a voltage is applied to the transistor, the liquid crystal turns and light passes through the liquid crystal to create a pixel on the front panel. The backlight module is responsible for providing the light source after the TFT-Array panel. Color filters give each pigment a specific color. The combination of each different color pixel gives you an image of the front of the panel.

The TFT panel is composed of millions of TFT devices and ITO (In TI Oxide, a transparent conductive metal) regions arranged like a matrix, and the so-called Array refers to the region of millions of TFT devices arranged neatly, which is the panel display area. The figure below shows the structure of a TFT pixel.

No matter how the design of TFT display board changes or how the manufacturing process is simplified, its structure must have a TFT device and control liquid crystal region (if the light source is penetration-type LCD, the control liquid crystal region is ITO; but for reflective LCD, the metal with high reflection rate is used, such as Al).

The TFT device is a switch, whose function is to control the number of electrons flowing into the ITO region. When the number of electrons flowing into the ITO region reaches the desired value, the TFT device is turned off. At this time, the entire electrons are kept in the ITO region.

The figure above shows the time changes specified at each pixel point. G1 is continuously selected to be turned on by the driver IC from T1 to TN so that the source-driven IC charges TFT pixels on G1 in the order of D1, D2, and Dn. When TN +1, gATE-driven IC is selected G2 again, and source-driven IC is selected sequentially from D1.

The more vertical the Angle at which the LIQUID crystal stands, the more light will not be guided by the LIQUID crystal. Different liquid crystal standing angles will direct different amounts of light. From the above examples, the larger the angle at which the liquid crystal stands, the weaker the light that can be penetrated. (The direction of the upper and lower polarizer will determine the intensity of penetration, so as long as you understand the Angle of the liquid crystal standing will guide the intensity of light).

Undirected light is absorbed by the upper polarizer. Natural light is polarized in any direction. The function of the polarizer is to filter out most of the light oscillating in different directions and only allow light in a specific direction to pass through.

Many people don’t understand the differences between generations of TFT-LCD plants, but the principle is quite simple. The main difference between generations of plants is in the size of glass substrates, which are products cut from large glass substrates. Newer plants have larger glass substrates that can be cut to increase productivity and reduce costs, or to produce larger panels (such as TFT display LCD TV panels).

The TFT-LCD industry first emerged in Japan in the 1990s, when a process was designed and built in the country. The first-generation glass substrate is about 30 X 40 cm in size, about the size of a full-size magazine, and can be made into a 15-inch panel. By the time Acer Technology (which was later merged with Unioptronics to become AU Optronics) entered the industry in 1996, the technology had advanced to A 3.5 generation plant (G3.5) with glass substrate size of about 60 X 72 cm.Au Optronics has evolved to a sixth-generation factory (G6) process where the G6 glass substrate measures 150 X 185 cm, the size of a double bed. One G6 glass substrate can cut 30 15-inch panels, compared with the G3.5 which can cut 4 panels and G1 which can only cut one 15-inch panel, the production capacity of the sixth generation factory is enlarged, and the relative cost is reduced. In addition, the large size of the G6 glass substrate can be cut into large-sized panels, which can produce eight 32-inch LCD TV panels, increasing the diversity of panel applications. Therefore, the global TFT LCD manufacturers are all invested in the new generation of plant manufacturing technology.

The TRANSISTor-LCD is an acronym for thin-film TFT Display. Simply put, TFT-LCD panels can be seen as two glass substrates sandwiched between a layer of liquid crystal. The upper glass substrate is connected to a Color Filter, while the lower glass has transistors embedded in it. When the electric field changes through the transistor, the liquid crystal molecules deflect, so as to change the polarization of the light, and the polarizing film is used to determine the light and shade state of the Pixel. In addition, the upper glass is fitted to the color filter, so that each Pixel contains three colors of red, blue and green, which make up the image on the panel.

– The Array process in the front segment is similar to the semiconductor process, except that thin-film transistors are made on glass rather than silicon wafers.

– The middle Cell is based on the glass substrate of the front segment Array, which is combined with the glass substrate of the color filter, and liquid crystal (LC) is injected between the two glass substrates.

-The rear module assembly process is the production operation of assembling the glass after the Cell process with other components such as backlight plate, circuit, frame, etc.

The luminescence principle is tied to the vapor electroplating organic film between the transparent anode and the metal cathode. The electron and electric hole are injected, and the energy is converted into visible light by the composite between the organic film. And can match different organic materials, emit different colors of light, to achieve the requirements of the full-color display.

The organic light display can be divided into Passive Matrix (PMOLED) and Active Matrix (AMOLED) according to the driving mode. The so-called active driven OLED(AMOLED) can be visualized in the Thin Film Transistor (TFT) as a capacitor that stores signals to provide the ability to visualize the light in a grayscale.

Although the production cost and technical barriers of passive OLED are low, it is limited by the driving mode and the resolution cannot be improved. Therefore, the application product size is limited to about 5″, and the product will be limited to the market of low resolution and small size. For high precision and large picture, the active drive is mainly used. The so-called active drive is capacitive to store the signal, so when the scanning line is swept, the pixel can still maintain its original brightness. In the case of passive drive, only the pixels selected by the scan line are lit. Therefore, in an active-drive mode, OLED does not need to be driven to very high brightness, thus achieving better life performance and high resolution.OLED combined with TFT technology can realize active driving OLED, which can meet the current display market for the smoothness of screen playback, as well as higher and higher resolution requirements, fully display the above superior characteristics of OLED.

The technology to grow The TFT on the glass substrate can be amorphous Silicon (A-SI) manufacturing process and Low-Temperature Poly-Silicon (LTPS). The biggest difference between LTPS TFT and A-SI TFT is the difference between its electrical properties and the complicated manufacturing process. LTPS TFT has a higher carrier mobility rate, which means that TFT can provide more current, but its process is complicated.A-si TFT, on the other hand, although a-Si’s carrier movement rate is not as good as LTPS’s, it has a better competitive advantage in cost due to its simple and mature process.Au Optronics is the only company in the world that has successfully combined OLED with LTPS and A-SI TFT at the same time, making it a leader in active OLED technology.

Polysilicon is a silicon-based material about 0.1 to several um in size, composed of many silicon particles. In the semiconductor manufacturing industry, polysilicon should normally be treated by Low-Pressure Chemical Vapor Deposition. If the annealing process is higher than 900C, this method is known as SPC. Solid Phase Deposition. However, this method does not work in the flat display industry because the maximum temperature of the glass is only 650C. Therefore, LTPS technology is specifically applied to the manufacture of flat displays.

Let me suppose that it belongs to the SPC method. However, compared with traditional SPC, this method can produce polysilicon at low temperatures (about 500~600 C). This is because the thin layer of metal is coated before the formation of crystallization, and the metal composition plays an active role in reducing crystallization.

A method for direct deposition of Poly-film without vapor extraction. The sedimentation temperature may be below 300C. Growth mechanisms contain catalytic cracking reactions of SiH4-H2 mixtures.

This method is currently the most widely used. The Excimer laser is used for heating and melting A-SI. It contains low amounts of hydrogen and recrystallizes to Poly-film.

The LTPS membrane is much more complex than a-SI, yet the LTPS TFT is 100 times more mobile than A-SI TFT. And CMOS program can be carried out directly on a glass substrate. Here are some of the features that p-SI has over A-SI:

2. Vehicle for OLED: High mobility means that the OLED Device can provide a large driving current, so it is more suitable for an active OLED display substrate.

3. Compact module: As part of the drive circuit can be made on the glass substrate, the circuit on the PCB is relatively simple, thus saving the PCB area.

MVA technology not only improves the panel view but also solves most of the problems of gray-scale inversion due to the special arrangement mode of liquid crystals.

LCD screens are backlit to project images through color filters before they are reflected in our eye Windows. This mode of carrying backlit LCD screens, known as “penetrating” LCD screens, consumes most of the power through backlit devices. The brighter the backlight, the brighter it will appear in front of the screen, but the more power it will consume.

The “reflective” architecture USES an external light source to display the image via a reflector, which saves electricity but is harder to see in the absence of an external light source.

“Half penetration and half reflection” is the compromise between the two. The device USES a half mirror instead of the reflector, which can not only pass through the backlight but also use the reflection from the external light source to achieve the effect of saving electricity, increasing brightness, and reducing weight.

Different from the traditional manufacturing process, COG technology directly assumes the drive IC on the glass substrate. The advantages of this technology include:

ODF process is an epoch-making manufacturing method, which is time-consuming, low yield, and difficult to achieve in the past. Such as the production of large panels of TV products, in response to the rapid response of small Gap panels, or advanced high-quality MVA panels, using ODF process technology, the problem can be readily solved.

using the ODF process, we no longer need a vacuum tempering process, LIQUID crystal injection machine, sealing machine, and panel cleaning equipment after sealing.

Generally speaking, in the ODF process, the use efficiency of a LIQUID crystal is more than 95%, but compared with 60% of the traditional process, it can fully save more than 35% of the cost of liquid crystal materials. It can also save water, electricity, gas, and lotion when cleaning sealant and related panels.

The manufacturing process saved is originally the most time-consuming and time-consuming process in the traditional manufacturing process. Moreover, with the trend of large-scale panels, or high-quality panels of small Cell Gap, the time will be longer. Traditionally, Cell processes take at least three days to complete, but ODF processes take less than one day.

Microtech Technology Company Limitedestablished in 2001,offers professional design and manufacturing services for hundreds types of Liquid Crytal Display modules and Touch Panels-TN,FSTN,TFT,RTP,CTP.With the advantages of high contrast,fast response time,wide viewable angle and low power consumption,Microtech"s products are widely used in Industrial Equipment,Medical devices,Home Intelligent Devices,Digital cameras,Video Game Devices,Instruments etc.Since its establishment,the management has been following human-oriented strategy and developing reliance among customers.To comply with these beliefs and ISO 9001:2015 standards,Microtech keeps on recruiting capable professionals,adopting advanced technology,developing new products,improving process and enhancing quality.Based on its strong R&D capacity, outstanding product quality and professional service,Microtech has won the high reputation from both mainland and oversea customers,and established long-term strategic partner relationship with them.

Our products are not only satisfy the display individuation requirement of all the mobile phone manufacturing factories in the mainland,but also meet the highly uniformity and reliability requirement to the display effect of module for many famous brands in Europe,American and Asia pacific.In addition,our products which have reached the extent of excellent quality and reliability could be applied in Automotive,Medical,Power station,Transportation,Industrial & Equipment and Office equipment for many famous enterprises in American,France,Italy,Australia,Korea and so on.

Our company have passed theISO 9001 quality system certification and SGS, RoHS, CE certification, to ensure all of our products and services are in international standard.

In order to obtain an excellent quality management team and offer our customers professional & efficient service and satisfied products,We comprehensively carry out Zero Defect quality management,implement ISO9001:2008 standards training and organize the examination /enrollment of quality management personnel national professional qualification.Our Mission "Efficient and timely service is the key to our success.Our success is tied with our client"s success. We are dedicated to provide excellent service to our customer at the most competitive prices." To provide customer a value added LCD product by stringent quality control,comprehensive technical support,and utilization of latest technology.

With our motto "Quality and Services are vital to enterpriess",Microtech aims to produce high quality LCD module to meet the customers" specific needs in all-round way.Meanwhile we seek for continuous service improvement,increase our market share,strengthen our competitiveness,and ultimately,expand our market worldwide!

TFT LCD screen has always been the mainstream in the display industry, and its longevity is by no means accidental. It has achieved brilliant results in terms of luminous efficiency, full color, and life, and it is still being deepened. . What are the specific parts of its manufacturing process? Below, Youyi Vision will briefly introduce you:

The manufacturing process of TFT LCD screen has the following parts: forming a tft array on a tft substrate; forming a color filter pattern and an ito conductive layer on a color filter substrate; forming a liquid crystal cell with two substrates; installing peripheral circuits and assembling a backlight And other module assembly.

The process of forming a tft array on a tft substrate has realized industrialization of tft types including: amorphous silicon tft (a-si tft), polysilicon tft (p-si tft), monocrystalline silicon tft (c-si tft) ) Several kinds. Currently the most used is still a-si tft. The manufacturing process of a-si tft is to sputter the gate material film on the borosilicate glass substrate, and form the gate wiring pattern after mask exposure, development, and dry etching.

Stepper exposure machine is generally used for mask exposure. The second step is to use the pecvd method for continuous film formation to form a sinx film, an undoped a-si film, and a phosphorus-doped n+a-si film. Then mask exposure and dry etching are performed to form the a-si pattern of the tft part. The third step is to form a transparent electrode (ito film) by a sputtering film forming method, and then form a display electrode pattern through mask exposure and wet etching. The fourth step is to form the contact hole pattern of the insulating film at the gate end using mask exposure and dry etching. The fifth step is to sputter Al, etc. into a film, expose and etch with a mask to form the source, drain and signal line patterns of tft. Finally, a protective insulating film is formed by the pecvd method, and then the insulating film is etched and formed by mask exposure and dry etching (the protective film is used to protect the gate, the end of the signal line electrode and the display electrode). At this point, the entire process is completed.

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Display screen is everywhere nowadays. Do you still remember the TVs or computer monitors 20 years ago? They were quadrate, huge and heavy. Now let’s look at the flat, thin and light screen in front of you, have you ever wondered why is there such a big difference?

Actually, the monitors 20 year ago were CRT (Cathode Ray Tube) displays, which requires a large space to run the inner component. And now the screen here in your presence is the LCD (Liquid Crystal Display) screen.

As mentioned above, LCD is the abbreviation of Liquid Crystal Display. It’s a new display technology making use of the optical-electrical characteristic of liquid crystal.

Liquid crystal is a state of substance that has both the characteristics of liquid and solid crystal. It don’t emit light itself, but it can let the light pass perfectly in specific direction. Meanwhile, liquid crystal molecule will rotate under the influence of a electric field, and then the light goes through it will rotate too. That said, liquid crystal can be a switch of light, which is the key in display technology.

STN LCD: STN is for Super-twisted Nematic. The liquid crystal in STN LCD rotate more angles than that in TN LCD, and have a different electrical feature, allowing STN LCD to display more information. There are many improved version of STN LCD like DSTN LCD (double layer) and CSTN LCD (color). This LCD is used in many early phones, computers and outdoor devices.

TFT LCD: TFT is for Thin Film Transistor. It’s the latest generation of LCD technology and has been applied in all the displaying scenario including electronic devices, motor cars, industrial machines, etc. When you see the word ‘transistor’, you may realize there’s integrated circuits in TFT LCD. That’s correct and the secret that TFT LCD has the advantage of high resolution and full color display.

In a simple way, we can divide TFT LCD into three parts, from bottom to top they are: light system, circuit system and light and color control system.In manufacturing process, we’ll start from inner light and color control system and then stretch out to whole module.

It’s accustomed to divide TFT LCD manufacturing process into three main part: array, cell and module. The former two steps are about the production of light and color control system, which contains TFT, CF (color filter) and LC (liquid crystal), named a cell. And the last step is the assembly of cell, circuit and light system.

In order to enhance productivity, in this step we’ll do a series of procedure on a large glass, which will be cut into smaller pieces in the following step.

First, let me introduce a crucial material, ITO, to you. ITO, abbreviation of Indium tin oxide, has the characteristic of electrical conductivity and optical transparency, as well as can be easily deposited as a thin film. Thus it’s widely used to create circuit on glass.

Now let’s turn to the production of TFT and CF. Here is a common method called PR (photoresist) method. The whole process of PR method will be demonstrated in TFT production.

◇   Use glue to build a boundary for LC on both glass. And on CF glass, apply one more layer of conductive adhesive. This enable LC molecule link to the control circuit.

◇   Put the diffuser film and prism film on light source in turn. Together with reflector film, these two films are used to turn the point light from light source into area light and enhance light intensity.

TFT-LCD technology is based on semiconductor IC manufacturing processes, and is unique in that it uses glass substrates rather than traditional silicon wafers. For the TFT manufacturing process, thin film formation, such as CVD and PVD processes, is a very important part. The ODF process has been developed for the assembly of color filters and TFT substrates, and is used in large size LCDs.

First of all, the movement and arrangement of liquid crystal molecules need electrons to drive, so in the carrier of liquid crystal – TFT glass, there must be able to conduct the part to control the movement of liquid crystal, here will use ITO (Indium TIn Oxide, transparent conductive metal) to do this thing. ITO is transparent, also known as thin film conductive crystal so that it will not block the backlight.

The different arrangement of liquid crystal molecules and the rapid movement changes to ensure that each pixel accurately display the corresponding color, and the image changes precisely and quickly, which requires precision control of the liquid crystal molecules. ITO film requires special processing, as if printed circuitry on a PCB board, drawing conductive lines throughout the LCD board.

For array panels with back-channel etched TFT structure.The main process can be divided into 5 steps (5 lightings) according to the sequence of the layers to be made and the interrelationship between the layers.

The process includes: Gate layer metal sputtering, Gate lithography, Gate wet lithography, and other processes. After these processes, scan lines and gate electrodes are formed on the glass substrate, i.e. gate electrodes. The graphical representation of the completed process is shown in the following figure.

Photolithography is the process of copying Mask graphic structures onto the glass substrate to be etched. There are three main processes: photoresist coating, exposure, and development

Dry lithography: The chemical reaction between the process gas and the film, as well as the bombardment of the film by the plasma, is used to remove the film layer.

The process includes: PECVD triple layer continuous film formation, island lithography, island dry lithography and other processes. After these processes, the final amorphous silicon island for TFT is formed on the glass substrate. The graphics obtained after the process is completed are shown in the following figure.

PVD (Physical Vapor DeposiTIon), i.e. physical vapor deposition, is an advanced surface treatment technology widely used in the international arena. Its working principle is to use gas discharge to partially dissociate the gas or evaporated material under vacuum conditions, and to deposit the evaporated material or its reactants on the substrate while the gas ions or the evaporated material ions bombard the action. At present, the most used PVD technology on the market is mainly divided into three categories: magnetron sputtering plating, multi-arc ion plating and evaporation plating.

Specific processes include: S/D metal layer sputtering into a film, S/D lithography, S/D wet lithography, channel dry lithography and other processes. After these processes, the source, drain, channel and data lines of the TFT are finally formed on the glass substrate. At this point, the TFT has been produced. The graphics obtained after the process is completed are shown in the following figure.

The process includes PECVD, photolithography, and dry lithography of vias. After these processes, the final TFT channel protective insulation layer and guide through the hole are formed on the glass substrate. The graphics obtained after the process is completed are shown in the following figure.

Specifically, the process includes: sputtering of ITO transparent electrode layer, ITO photolithography, ITO wet lithography and other processes. After these processes, the transparent pixel electrode is finally formed on the glass substrate. The graphics obtained after the process is completed are shown in the following figure.

At this point, the whole array process is completed. In short, the array process of 5 times of light is: 5 times of film formation + 5 times of etching

Color filters can be produced by various methods; photolithography is a typical method. In photolithography, color filters are produced by exposing a glass substrate coated with a photographic color resist through a photomask. The resist is hardened to form the RGB pattern of the LCD.

The middle section of the cell is a combination of the front Array glass as the substrate and the color filter glass substrate, and the liquid crystal (LC) is injected between the two glass substrates.

Rubbing the PI film on top of the glass substrate by using the alignment cloth hairs to create grooves for liquid crystal orientation, so that the liquid crystal is neatly aligned between the upper and lower alignment films in the direction specified.

Pre-Tilt Angle (Pre-TIlt Angle or TBA: Tilt Bias Angle) characteristic refers to the arrangement of liquid crystal molecules on the mating film is not parallel to the film surface, but one end of the molecule in the friction direction relative to the film surface has a certain warp, the stilt angle is called pre-tilt angle. If there is no pre-tilt angle, under the external electric field, the liquid crystal molecules can stand up randomly from two directions, which will cause poor display.

When making LCD panels it is impossible to produce them one by one, which is too inefficient, so multiple pieces are processed at once and separated by cutting.

After that is bonding IC and FPC; assembling backlight module, the whole machine shell and other processes, relative to the front of the high-precision process to be simpler.

COG (Chip on Glass) and FPC (Flexible Printed Circuit) is a circuit connection method. Due to the many electrodes, one-to-one lining connection is very difficult. Nowadays, the common practice is to make an array of leads on the glass and a corresponding array of leads on the IC/FPC, and to connect the electrodes on the IC/FPC to the electrodes on the glass one-to-one through an anisotropic conductive film (ACF). The schematic diagram of the lead electrode array on the glass is as follows.

Assembly is the combination of backlight, screen, control circuit board, and touch screen and other components together to form a complete display module. Assembly is generally done by hand, and skilled workers are very important here.

In addition to the above main process, there are some auxiliary processes in the module section, such as: laser cutting, electrical testing after cutting, electrical testing after bonding, electrical testing after assembly, microscopic inspection after cutting, microscopic inspection or automatic optical inspection after binding, shear force peel test after IC bonding, tensile peel test after FPC bonding, electrical aging after assembly, packaging and shipping, etc.

Although we are not process processing personnel, but we still need to understand the relevant things, because in the interface with other departments or personnel in order to be more comfortable. Problems can be considered in many aspects, if you do not know the process related knowledge, encounter problems simply will not think of here, so the process of understanding or necessary.

If you want to buy a new monitor, you might wonder what kind of display technologies I should choose. In today’s market, there are two main types of computer monitors: TFT LCD monitors & IPS monitors.

The word TFT means Thin Film Transistor. It is the technology that is used in LCD displays.  We have additional resources if you would like to learn more about what is a TFT Display. This type of LCDs is also categorically referred to as an active-matrix LCD.

These LCDs can hold back some pixels while using other pixels so the LCD screen will be using a very minimum amount of energy to function (to modify the liquid crystal molecules between two electrodes). TFT LCDs have capacitors and transistors. These two elements play a key part in ensuring that the TFT display monitor functions by using a very small amount of energy while still generating vibrant, consistent images.

Industry nomenclature: TFT LCD panels or TFT screens can also be referred to as TN (Twisted Nematic) Type TFT displays or TN panels, or TN screen technology.

IPS (in-plane-switching) technology is like an improvement on the traditional TFT LCD display module in the sense that it has the same basic structure, but has more enhanced features and more widespread usability.

These LCD screens offer vibrant color, high contrast, and clear images at wide viewing angles. At a premium price. This technology is often used in high definition screens such as in gaming or entertainment.

Both TFT display and IPS display are active-matrix displays, neither can’t emit light on their own like OLED displays and have to be used with a back-light of white bright light to generate the picture. Newer panels utilize LED backlight (light-emitting diodes) to generate their light hence utilizing less power and requiring less depth by design. Neither TFT display nor IPS display can produce color, there is a layer of RGB (red, green, blue) color filter in each LCD pixels to produce the color consumers see. If you use a magnifier to inspect your monitor, you will see RGB color in each pixel. With an on/off switch and different level of brightness RGB, we can get many colors.

Wider viewing angles are not always welcome or needed. Image you work on the airplane. The person sitting next to you always looking at your screen, it can be very uncomfortable. There are more expensive technologies to narrow the viewing angle on purpose to protect the privacy.

Winner. IPS TFT screens have around 0.3 milliseconds response time while TN TFT screens responds around 10 milliseconds which makes the latter unsuitable for gaming

Winner. the images that IPS displays create are much more pristine and original than that of the TFT screen. IPS displays do this by making the pixels function in a parallel way. Because of such placing, the pixels can reflect light in a better way, and because of that, you get a better image within the display.

As the display screen made with IPS technology is mostly wide-set, it ensures that the aspect ratio of the screen would be wider. This ensures better visibility and a more realistic viewing experience with a stable effect.

Winner. While the TFT LCD has around 15% more power consumption vs IPS LCD, IPS has a lower transmittance which forces IPS displays to consume more power via backlights. TFT LCD helps battery life.

Normally, high-end products, such as Apple Mac computer monitors and Samsung mobile phones, generally use IPS panels. Some high-end TV and mobile phones even use AMOLED (Active Matrix Organic Light Emitting Diodes) displays. This cutting edge technology provides even better color reproduction, clear image quality, better color gamut, less power consumption when compared to LCD technology.

What you need to choose is AMOLED for your TV and mobile phones instead of PMOLED. If you have budget leftover, you can also add touch screen functionality as most of the touch nowadays uses PCAP (Projective Capacitive) touch panel.

This kind of touch technology was first introduced by Steve Jobs in the first-generation iPhone. Of course, a TFT LCD display can always meet the basic needs at the most efficient price. An IPS display can make your monitor standing out.

Thin-Film Transistor Liquid Crystal Displays use thin-film transistors to control the voltage applied to the liquid crystal layer at a sub-pixel level. The structure of TFT LCDs consists of a TFT “sandwich” and a BLU (Backlight Unit). A typical configuration is shown in the schematic diagram below.

Firstly, between the back and front polarizers, TFT LCD cells are made with two glass substrates – one for color filters, the other for a TFT array – and a liquid crystal layer sandwiched in between.

Secondly, BLU (Backlight Unit) usually consists of three components: BEF (Brightness Enhancement Film), DBEF (Dual Brightness Enhancement Film), and LGP (Light Guide Plate).

For normally black TFT LCDs, if we follow along a piece of light setting off from its backlight source, it will bea)guided uniformly by LGP;b)reflected and enhanced by BEF and DBEF;c)polarized by the back polarizer;d)polarization changed by twisted LC under the voltage applied by TFT arrays;e)“tinted” red/green/blue by corresponding color filter of the subpixel;f)let through the front polarizer by matched polarization; andg)finally, it will reach the surface and appears in viewer’s eyes.

For normally white panels, processd)will be the opposite – known as the polarization rotation effect, light is twisted in a voltage-off stage and can pass through the front polarizer by default, thus displaying white normally. However, when the voltage applied increases, this polarization rotation effect would be gradually diminished. And the light would not be able to pass through the front polarizer anymore without changing its polarization. In this way, certain pixels will appear in different colors.

Normally black LCDs have higher contrast and wider viewing angles without grayscale inversion phenomenon compared to their normally white relatives. And whether TFT LCDs are normally black or white depends on their LC switching mode:

2Chen, HW., Lee, JH., Lin, BY.et al.Liquid crystal display and organic light-emitting diode display: present status and future perspectives.Light Sci Appl7,17168 (2018).https://doi.org/10.1038/lsa.2017.168

Schematic diagram of the (a) TN mode, (b) VA mode, (c) FFS mode, and (d) IPS mode. *LC orientations shown are under applied voltages. C/F stands for the color filter.

As previously mentioned, TN mode functions with the polarization rotation effect. Under traditional TN/VA display mode, the liquid crystal molecules are vertically arranged, with a relatively narrow visual angle. When an external force is exerted on the screen, the liquid crystal molecular structure will sink in a herringbone pattern to slowly recover – a pattern called vertical alignment. Therefore, an evident “water ripple” usually appears when the display surface is touched and impacts the user experience. In comparison, the VA mode provides higher contrast. And MVA (multi-domain vertical alignment) is an upgraded version of VA with improved viewing angles.

Under IPS mode, the LC directors are horizontally (homogeneously) aligned, which makes them free from ripple effects when made into touch panels. The drawback is lower transmittance, especially for LCs in a “dead zone”close to electrodes.

In an FFS cell, LC molecules rotate in both vertical and horizontal dimensions, enabling excellent viewing angles, high transmittance, low driving voltage/power consumptions, and high contrast ratio.

3 Yang DK, Wu ST.Fundamentals of Liquid Crystal Devices. 2nd edition. New York, USA: John Wiley & Sons. 2014.4 BOE ADSDS Ultra Hard screen Technology, Restoring Real and Beautiful Life. 2020 BOE Technology Group Co., Ltd.  Retrieved December 01, 2020, fromhttps://www.boe.com/en/cxkj/boecx/boecxxqy/dynamic/pecbbd751.html