tft lcd layers factory

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.

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.

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.

Important technical improvements of LCD, such as LED backlighting and wide viewing Angle, are directly related to LCD. And account for an LCD display 80% of the cost of the LCD panel, enough to show that the LCD panel is the core part of the entire display, the quality of the LCD panel, can be said to directly determine the quality of an LCD display.

The production of civil LCD displays is just an assembly process. The LCD panel, the main control circuit, shell, and other parts of the main assembly, basically will not have too complex technical problems.

Does this mean that LCDS are low-tech products? In fact, it is not. The production and manufacturing process of the LCD panels is very complicated, requiring at least 300 process processes. The whole process needs to be carried out in a dust-free environment and with precise technology.

The general structure of the LCD panel is not very complex, now the structure of the LCD panel is divided into two parts: the LCD panel and the backlight system.

Due to the LCD does not shine, so you need to use another light source to illuminate, the function of the backlight system is to this, but currently used CCFL lamp or LED backlight, don’t have the characteristics of the surface light source, so you need to guide plate, spreadsheet components, such as linear or point sources of light evenly across the surface, in order to make the entire LCD panel on the differences of luminous intensity is the same, but it is very difficult, to achieve the ideal state can be to try to reduce brightness non-uniformity, the backlight system has a lot to the test of design and workmanship.

In addition, there is a driving IC and printed circuit board beside the LCD panel, which is mainly used to control the rotation of LCD molecules in the LCD panel and the transmission of display signals. The LCD plate is thin and translucent without electricity. It is roughly shaped like a sandwich, with an LCD sandwiched between a layer of TFT glass and a layer of colored filters.

LCD with light refraction properties of solid crystals, with fluid flow characteristics at the same time, under the drive of the electrode, can be arranged in a way that, in accordance with the master want to control the strength of the light through, and then on the color filter, through the red, green, blue three colors of each pixel toning, eventually get the full-screen image.

According to the functional division, the LCD panel can be divided into the LCD panel and the backlight system. However, to produce an LCD panel, it needs to go through three complicated processes, namely, the manufacturing process of the front segment Array,the manufacturing process of the middle segment Cell, and the assembly of the rear segment module. Today we will be here, for you in detail to introduce the production of the LCD panel manufacturing process.

The manufacturing process of the LCD panel Array is mainly composed of four parts: film, yellow light, etch and peel film. If we just look at it in this way, many netizens do not understand the specific meaning of these four steps and why they do so.

First of all, the motion and arrangement of LCD molecules need electrons to drive them. Therefore, on the TFT glass, the carrier of LCD, there must be conductive parts to control the motion of LCD. In this case, we use ITO (Indium Tin Oxide) to do this.ITO is transparent and also acts as a thin-film conductive crystal so that it doesn’t block the backlight.

The different arrangement of LCD molecules and the rapid motion change can ensure that each pixel displays the corresponding color accurately and the image changes accurately and quickly, which requires the precision of LCD molecule control.ITO film needs special treatment, just like printing the circuit on the PCB board, drawing the conductive circuit on the whole LCD board.

First, the ITO film layer needs to be deposited on the TFT glass, so that there is a smooth and uniform ITO film on the whole TFT glass. Then, using ionized water, the ITO glass is cleaned and ready for the next step.

This completes the previous Array process. It is not difficult to see from the whole process that ITO film is deposited, photoresist coated, exposed, developed, and etched on TFT glass, and finally, ITO electrode pattern designed in the early stage is formed on TFT glass to control the movement of LCD molecules on the glass. The general steps of the whole production process are not complicated, but the technical details and precautions are very complicated, so we will not introduce them here. Interested friends can consult relevant materials by themselves.

The glass that the LCD board uses makes a craft also very exquisite. (The manufacturing process flow of the LCD display screen)At present, the world’s largest LCD panel glass, mainly by the United States Corning, Japan Asahi glass manufacturers, located in the upstream of the production of LCD panel, these manufacturers have mastered the glass production technology patents. A few months ago, the earthquake caused a corning glass furnace shutdown incident, which has caused a certain impact on the LCD panel industry, you can see its position in the industry.

As mentioned earlier, the LCD panel is structured like a sandwich, with an LCD sandwiched between the lower TFT glass and the upper color filter. The terminal Cell process in LCD panel manufacturing involves the TFT glass being glued to the top and bottom of a colored filter, but this is not a simple bonding process that requires a lot of technical detail.

As you can see from the figure above, the glass is divided into 6 pieces of the same size. In other words, the LCD made from this glass is finally cut into 6 pieces, and the size of each piece is the final size. When the glass is cast, the specifications and sizes of each glass have been designed in advance.

Directional friction:Flannelette material is used to rub the surface of the layer in a specific direction so that the LCD molecules can be arranged along the friction direction of the aligned layer in the future to ensure the consistency of the arrangement of LCD molecules. After the alignment friction, there will be some contaminants such as flannelette thread, which need to be washed away through a special cleaning process.

After the TFT glass substrate is cleaned, a sealant coating is applied to allow the TFT glass substrate to be bonded to the color filter and to prevent LCD outflow.

Finally, the conductive adhesive is applied to the frame in the bonding direction of the glass of the color filter to ensure that external electrons can flow into the LCD layer. Then, according to the bonding mark on the TFT glass substrate and the color filter, two pieces of glass are bonded together, and the bonding material is solidified at high temperatures to make the upper and lower glasses fit statically.

Color filters are very important components of LCD panels. Manufacturers of color filters, like glass substrate manufacturers, are upstream of LCD panel manufacturers. Their oversupply or undersupply can directly affect the production schedule of LCD panels and indirectly affect the end market.

As can be seen from the above figure, each LCD panel is left with two edges after cutting. What is it used for? You can find the answer in the later module process

Finally, a polarizer is placed on both sides of each LCD substrate, with the horizontal polarizer facing outwards and the vertical polarizer facing inwards.

When making LCD panel, must up and down each use one, and presents the alternating direction, when has the electric field and does not have the electric field, causes the light to produce the phase difference and to present the light and dark state, uses in the display subtitle or the pattern.

The rear Module manufacturing process is mainly the integration of the drive IC pressing of the LCD substrate and the printed circuit board. This part can transmit the display signal received from the main control circuit to the drive IC to drive the LCD molecules to rotate and display the image. In addition, the backlight part will be integrated with the LCD substrate at this stage, and the complete LCD panel is completed.

Firstly, the heteroconductive adhesive is pressed on the two edges, which allows external electrons to enter the LCD substrate layer and acts as a bridge for electronic transmission

Next is the drive IC press. The main function of the drive IC is to output the required voltage to each pixel and control the degree of torsion of the LCD molecules. The drive IC is divided into two types. The source drive IC located in the X-axis is responsible for the input of data. It is characterized by high frequency and has an image function. The gate drive IC located in the Y-axis is responsible for the degree and speed of torsion of LCD molecules, which directly affects the response time of the LCD display. However, there are already many LCD panels that only have driving IC in the X-axis direction, perhaps because the Y-axis drive IC function has been integrated and simplified.

The press of the flexible circuit board can transmit data signals and act as the bridge between the external printed circuit and LCD. It can be bent and thus becomes a flexible or flexible circuit board

The manufacturing process of the LCD substrate still has a lot of details and matters needing attention, for example, rinse with clean, dry, dry, dry, ultrasonic cleaning, exposure, development and so on and so on, all have very strict technical details and requirements, so as to produce qualified eyes panel, interested friends can consult relevant technical information by a search engine.

LCD (LC) is a kind of LCD, which has the properties of light transmission and refraction of solid Crystal, as well as the flow property of Liquid. It is because of this property that it will be applied to the display field.

However, LCD does not emit light autonomously, so the display equipment using LCD as the display medium needs to be equipped with another backlight system.

First, a backplate is needed as the carrier of the light source. The common light source for LCD display equipment is CCFL cold cathode backlight, but it has started to switch to an LED backlight, but either one needs a backplate as the carrier.

CCFL backlight has been with LCD for a long time. Compared with LED backlight, CCFL backlight has many defects. However, it has gradually evolved to save 50% of the lamp and enhance the transmittance of the LCD panel, so as to achieve the purpose of energy-saving.

With the rapid development of LED in the field of lighting, the cost has been greatly reduced.LCD panels have also started to use LED as the backlight on a large scale. Currently, in order to control costs, an LED backlight is placed on the side rather than on the backplate, which can reduce the number of LED grains.

At the top of the diffusion plate, there will be 3~4 diffuser pieces, constantly uniform light to the whole surface, improve the uniformity of light, which is directly related to the LCD panel display effect. Professional LCD in order to better control the brightness uniformity of the screen, panel procurement, the later backlight control circuit, will make great efforts to ensure the quality of the panel.

Since the LCD substrate and the backlight system are not fixed by bonding, a metal or rubber frame is needed to be added to the outer layer to fix the LCD substrate and the backlight system.

After the period of the Module, the process is completed in LCM (LCDModule) factory, the core of this part of the basic does not involve the use of LCD manufacturing technology, mainly is some assembly work, so some machine panel factories such as chi mei, Korea department such as Samsung panel factory, all set with LCM factories in mainland China, Duan Mo group after the LCD panel assembly, so that we can convenient mainland area each big monitor procurement contract with LCD TV manufacturers, can reduce the human in the whole manufacturing and transportation costs.

However, neither Taiwan nor Korea has any intention to set up factories in mainland China for the LCD panel front and middle manufacturing process involving core technologies. Therefore, there is still a long way to go for China to have its own LCD panel industry.

When compared to the ordinary LCD, TFT LCD gives very sharp and crisp picture/text with shorter response time. TFT LCD displays are used in more and more applications, giving products better visual presentation.

TFT is an abbreviation for "Thin Film Transistor". The colorTFT LCD display has transistors made up of thin films of Amorphous silicon deposited on a glass. It serves as a control valve to provide an appropriate voltage onto liquid crystals for individual sub-pixels. That is why TFT LCD display is also called Active Matrix display.

A TFT LCD has a liquid crystal layer between a glass substrate formed with TFTs and transparent pixel electrodes and another glass substrate with a color filter (RGB) and transparent counter electrodes. Each pixel in an active matrix is paired with a transistor that includes capacitor which gives each sub-pixel the ability to retain its charge, instead of requiring an electrical charge sent each time it needed to be changed. This means that TFT LCD displays are more responsive.

To understand how TFT LCD works, we first need to grasp the concept of field-effect transistor (FET). FET is a type of transistor which uses electric field to control the flow of electrical current. It is a component with three terminals: source, gate, and drain. FETs control the flow of current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source.

Using FET, we can build a circuit as below. Data Bus sends signal to FET Source, when SEL SIGNAL applies voltage to the Gate, driving voltage is then created on TFT LCD panel. A sub-pixel will be lit up. A TFT LCD display contains thousand or million of such driving circuits.

Topway started TFT LCD manufacturing more than15 years ago. We produce color TFT LCD display from 1.8 to 15+ inches with different resolutions and interfaces. Here is some more readings about how to choose the right TFT LCD.

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.

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.

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.

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.

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.

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.

Generally, LCDs are filled with a liquid crystal layer with a thickness of about 3~4um between the upper and lower transparent electrodes, and the electric field of the liquid crystal interlayer is controlled by the method of filling the pixel electrode voltage, and then the intensity of the transmitted light is adjusted to produce a full brightness. Gray level between and full darkness. At present, LCD is mainly composed of three parts: color filter (CF), TFT array (TFT Array) substrate and backlight module (Backlight) as shown in Figure 1 (a). Each Pixel of TFT-LCD has a set of TFTs to control its voltage value, and to make the light generated by the backlight module and transmitted through the LC have different colors, red, blue, and green (R/B/G) are needed. Three colors of color resist are formed on the CF glass, and the gray scales are used to produce a full-color effect; after the TFT array and the CF substrate are respectively completed, then the CF upper plate and the TFT lower plate are filled with LC and bonded together. Finally, attach the polarizer. This process is called the "LCD process"; and the final "LCM process" is the connection between the driver IC and the control circuit board (PCBA) and the glass substrate (JI Process). Assemble with the backlight module (MA Process), and finally the lighting detection of the module... and so on as shown in Figure 1 (b).

AU Optronics (hereinafter referred to as AU Optronics) has developed a process above the 8.5 generation factory to produce large-size LCD TV panels (see Figure 2). In December 2008, AUO successfully lighted the first 46-inch LCD TV panel produced in the G8.5 plant in China. The process technology once again led the whole Taiwan, marking a new page in the milestone of the new generation of TFT-LCD plant. Also established a new model of TFT-LCD green plant. The size of the G8.5 glass substrate is equivalent to the size of a pool table, but the thickness of the glass is less than 1mm. Therefore, the new-generation plant requires higher process technology; as the technology of large-size panels gradually matures, AUO will still Continue to focus on the development of new-generation plants, and continue to advance with the goal of increasing production capacity, improving process quality, and targeting customer service.

The development direction of next-generation process technology is nothing more than simplifying the process and selecting optimized raw materials and components to increase process yield and productivity, and reduce production costs. The capital investment of the front-end TFT Array and CF process equipment accounts for more than 60% of the total TFT-LCD expenditure. Therefore, the front-end process research and development first focuses on simplifying the process and improving the utilization of raw materials: for example, the four-pass mask technology that simplifies the mask process ( See Figure 3 (a)) and the pattern forming method without exposure and etching. In addition, the use of thinned glass substrates not only reduces the consumption of glass raw materials, but also has the advantages of lighter weight and thinner products; at the same time, it can achieve the goals of energy saving and waste reduction such as reducing packaging materials and improving transportation efficiency. As for LCM, with the rapid development of gate drive circuit substrate technology (Gate on Array, GOA) and HSD (Half source driving) technology in Figure 3 (b), it has not only simplified the material dependence of traditional panels on a large number of driver ICs. , Also contributes to the increase of LCM production capacity. In terms of module backlights, replacing traditional cold cathode tubes with light-emitting diodes (Light Emitting Diode, LED) not only avoids the harm of mercury (Hg) vapor in the tubes to the environment; the better luminous efficiency of LEDs also makes the products more efficient Energy saving.

TFT (Thin-Film Transistor) Displays are active-matrix LCDs with full RGB color screens. These screens feature bright, vivid colors and have the ability to show fast animations, complex graphics and crisp custom fonts. TFTs are perfect displays for providing a rich user interface for all types of products. While typically used in consumer devices like personal DVD players and handheld devices, TFTs are also well suited for industrial application.

TFTs are Active-Matrix LCDs that have tiny switching transistors and capacitors. These tiny transistors control each pixel on the display and require very little energy to actively change the orientation of the liquid crystal in the display. This allows for faster control of each Red, Green and Blue sub-pixel cell thus producing clear fast-moving color graphics.

The transistors in the TFT are arranged in a matrix on the glass substrate. Each pixel on the display remains off until addressed by applying a charge to the transistor. Unlike conventional Passive-Matrix displays, in order to activate a specific pixel, the corresponding row is turned on and a charge is sent down the proper column. This is where only the capacitor at the designated pixel receives a charge and is held until the next refresh cycle. Essentially, each transistor acts as an active switch. By incorporating an active switch, this limits the number of scan lines and eliminates cross-talk issues.

MVA (Multi-domain Vertical Alignment) displays can offer wide viewing angles, good black depth, fast response times, and good color reproduction and depth. Each pixel within a MVA type TFT consists of three sub-pixels (Red, Green and Blue). Each of these sub-pixels is divided further into two or more sub-pixels, where the liquid crystals are randomly lined up due to the ridged polarized glass. When a charge is applied to the transistor, the crystals twist. With these crystals being randomly placed, it allows the backlight to shine through in all different directions keeping the intended color saturation retained while giving the display a 150deg. viewing angle.

In-Plane Switching (IPS) TFTs were developed to improve on the poor viewing angle and the poor color reproduction of TN TFT panels at that time. The crystal molecules move parallel to the panel plane instead of perpendicular to it. This change reduces the amount of light scattering in the matrix, which gives IPS its characteristic wide viewing angles and good color reproduction. 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.

IPS (In-Plane Switching) displays provide consistent, accurate color from all viewing angles without blur or grayscale inversion. IPS displays show clear images with fast response time, and no halo effect is produced when touched. Each pixel within an IPS type TFT consists of three sub-pixels (Red, Green and Blue). Each sub-pixel has a pair of electrodes to control the twisting of the Liquid Crystals. Unlike TN type TFTs where the electrodes are on opposing plates, the electrodes in an IPS TFT are on only one of the glass plates (i.e. in the same plane). When voltage is applied to the electrodes, all the Liquid Crystal molecules align in parallel with that plane and allow light to pass through to the polarizers and RGB color filters. In effect, TN displays force the Liquid Crystal molecules perpendicular to the glass which blocks some light from coming out at wide angles, while IPS displays keep the Liquid Crystal molecules in line to allow light through at all angles.

Low-temperature polycrystalline silicon (LTPS) is polycrystalline silicon that has been synthesized at relatively low temperatures (~650 °C and lower) compared to in traditional methods (above 900 °C). LTPS is important for display industries, since the use of large glass panels prohibits exposure to deformative high temperatures. More specifically, the use of polycrystalline silicon in thin-film transistors (LTPS-TFT) has high potential for large-scale production of electronic devices like flat panel LCD displays or image sensors.

Transflective LCDs combine elements of both transmissive and reflective characteristics. Ambient light passes through the LCD and hits the semi-reflective layer. Most of the light is then reflected back through the LCD. However some of the light will not be reflected and will be lost. Alternately a backlight can be used to provide the light needed to illuminate the LCD if ambient light is low. Light from the backlight passes through a semi-reflective layer and illuminates the LCD. However as with ambient lighting some of the light does not penetrate the semi-reflective layer and is lost.

Transflective LCDs are used in devices that will operate in a wide variety of lighting conditions (from complete darkness to full sunlight). Under dim lighting conditions transflective LCDs offer visual performance similar to transmissive LCDs, whilst under bright lighting conditions they offer visual performance similar to reflective LCDs. However this performance is a tradeoff because the transflective mode is less efficient due to some light loss.

Color TFT LCDs (Thin Film Transistor LCDs) give your product a beautiful appearance with high-resolution, full-color graphics. Our modern, automated LCD factories can create custom TFT displays for extreme temperature functionality, sunlight readability, shock and vibration durability, and more. Whether you need a stand-alone TFT LCD display or fully integrated assembly with touch and cover lens, custom FPC, or custom backlight, our experienced team can develop the right solution for your project.

A liquid crystal display (LCD) has liquid crystal material sandwiched between two sheets of glass. Without any voltage applied between transparent electrodes, liquid crystal molecules are aligned in parallel with the glass surface. When voltage is applied, they change their direction and they turn vertical to the glass surface. They vary in optical characteristics, depending on their orientation. Therefore, the quantity of light transmission can be controlled by combining the motion of liquid crystal molecules and the direction of polarization of two polarizing plates attached to the both outer sides of the glass sheets. LCDs utilize these characteristics to display images.

An LCD consists of many pixels. A pixel consists of three sub-pixels (Red/Green/Blue, RGB). In the case of Full-HD resolution, which is widely used for smartphones, there are more than six million (1,080 x 1,920 x 3 = 6,220,800) sub-pixels. To activate these millions of sub-pixels a TFT is required in each sub-pixel. TFT is an abbreviation for "Thin Film Transistor". A TFT is a kind of semiconductor device. It serves as a control valve to provide an appropriate voltage onto liquid crystals for individual sub-pixels. A TFT LCD has a liquid crystal layer between a glass substrate formed with TFTs and transparent pixel electrodes and another glass substrate with a color filter (RGB) and transparent counter electrodes. In addition, polarizers are placed on the outer side of each glass substrate and a backlight source on the back side. A change in voltage applied to liquid crystals changes the transmittance of the panel including the two polarizing plates, and thus changes the quantity of light that passes from the backlight to the front surface of the display. This principle allows the TFT LCD to produce full-color images.

The TFT-LCD panel generally speaking is a liquid crystal layer that is sandwiched between two glass substrates, the upper glass substrate is combined with a color filter, and the lower glass is embedded with transistors. The upper glass is bonded with the color filter so that each pixel (Pixel) contains three colors red, blue, and green, and these red, blue and green pixels constitute the image on the panel.

Please check the following picture which shows the whole process of making a TFT LCD. This picture will introduce the whole manufacturing process to you with simple text and a picture description.

6) To form a usable thin film transistor, it is necessary to repeat the processes of cleaning, coating, photoresist, exposure, development, etching, photoresist removal, etc. Generally speaking, to manufacture TFT-LCD, it is necessary to repeat 5 to 7 times.

1) After completing the thin film transistor glass substrate, we will combine the liquid crystal panel. The liquid crystal panel is composed of a transistor glass substrate and a color filter. First, we must wash the glass first, and then proceed to the next step. a step. The entire manufacturing process of TFT-LCD must be in a clean room, so that there will be no impurities inside the display.

5) After sealing the frame, put the LCD panel into the vacuum chamber, pump the air out of the LCD panel through the gap just reserved, and then pour the liquid crystal into the liquid crystal with the help of atmospheric pressure, and then close the gap. A compound substance between solid and liquid, with the characteristics of regular molecular arrangement.

1) After the polarizer is attached, we start to install DRIVE IC on both sides of the LCD panel. DRIVE IC is a very important driving part, which is used to control the color and brightness of the LCD.

3) The light of the LCD panel is emitted from the backlight. Before assembling the backlight, we will first check whether the assembled LCD panel is complete, and then assemble the backlight. The backlight is the light source behind the LCD panel.

We provide wholesale and customization of common 1.3″-24″ TFT LCD panels, if you have any projects that need these products, welcome to contact us, besides, we have different size of FLCOS and OLED mini micro-displays in stock, some mall ads bar type LCD display we also could provide, and welcome a bulk production wholesale inquiry.

From the MOSFET, the TFT was born. The TFT varies from standard MOSFETs, or bulk MOSFETs, because, as the name implies, it uses thin films. The TFT began a new era of electronics. In 1968, just six years after the first TFT development, Bernard J. Lechner of RCA shared his idea of the TFT Liquid Crystal Display (LCD), something that would boom in popularity in our modern times. The TFT LCD was then first created in 1973 at the Westinghouse Research Laboratories. These LCDs were composed of pixels controlled by transistors. In FETs, substrates were just the semiconductor material, but in manufacturing TFT LCDs, glass substrates were used so that the pixels could be displayed.

But that was not the end of TFT developments. Soon after, in 1974, T. Peter Brody, one of the developers of the TFT LCD, and Fang-Chen Luo created the first active-matrix LCD (AM LCD). An active matrix controls each pixel individually, meaning that each pixel’s respective TFT had its signal actively preserved. This opened doors to better performance and speed as displays became more complex.

Though TFTs can use a variety of materials for their semiconductor layers, silicon has become the most popular, creating the silicon-based TFT, abbreviated as Si TFT. As a semiconductor device, the TFT, as well as all FETs, use solid-state electronics, meaning that electricity flows through the structure of the semiconductor layer rather than vacuum tubes.

Due to the variety in silicon’s possible structures, the Si TFT’s characteristics can vary as well. The most common form is amorphous silicon (A-Si), which is deposited during the first step of the semiconductor fabrication process onto the substrate in low temperatures. It is most usable when hydrogenated into the form A-Si:H. This then significantly alters the properties of A-Si; without the hydrogen, the material struggles with doping (the introduction of impurities to increase mobility of charges); in the form A-Si:H, however, the semiconductor layer becomes much more photoconductive and dopable. The A-Si:H TFT was first developed in 1979 which is stable at room temperature and became the best option for AM LCDs which consequently began rising in popularity after this breakthrough.

The biggest difference between these forms, notably A-Si and poly-Si, is that charge carriers are much more mobile and the material is much more stable when it comes to using poly-Si over A-Si. When creating complicated and high-speed TFT-based displays, poly-Si’s characteristics allow for this. Yet, A-Si is still very important due to its low-leakage nature, meaning that leakage current is not lost as heavily when a dielectric insulator is not totally non-conductive.

As TFTs began to increase their presence in display technology, transparent semiconductors and electrodes became more appealing to the manufacturers. Indium tin oxide (ITO) is an example of a popular transparent oxide used for its appearance, good conductivity, and ease of deposition.

Research of the TFT with different materials has led to the application of threshold voltage, or how much voltage is needed to turn on the device. This value is greatly dependent on thickness and choice of the oxide. When it comes to the oxide, this relates back to the idea of leakage current. With thinner layers and certain types of oxide, the leakage current may be greater, but this in turn could lower threshold voltage, as leakage into the device will also increase. In order to tap into the TFT’s potential for low power consumption, the lower the threshold voltage, the better the device’s appeal.

Another branch of development that stemmed from the TFT is that of organic TFTs (OTFT). First created in 1986, OTFTs usually use solution-casting of polymers, or macromolecules. This device made people hesitant, as it tended to have a slow carrier mobility, meaning slow response times. However, researchers have carried out experimentation with the OTFT because it has potential to be applied to displays different from those that traditional TFTs are used for, such as flexible, plastic displays. This research still continues today. With its simpler processing than traditional silicon technology, the OTFT holds much potential for modern day and future technologies.

Since its initial communalization in the 1990s, active matrix thin-film-transistor (TFT) displays have become an essential and indispensable part of modern living. They are much more than just televisions and smartphones; they are the primary communication and information portals for our day-to- day life: watches (wearables), appliances, advertising, signage, automobiles and more.

There are many similarities in the display TFT manufacturing and semiconductor device manufacturing such as the process steps (deposition, etch, cleaning, and doping), the type of gases used in these steps, and the fact that both display and semiconductor manufacturing both heavily use gases.

In general, there are two types of displays in the market today: active matrix liquid crystal display (AMLCD) and AMOLED. In its simplicity, the fundamental components required to make up the display are the same for AMLCD and AMOLED. There are four layers of a display device (FIGURE 1): a light source, switches that are the thin-film-transistor and where the gases are mainly used, a shutter to control the color selection, and the RGB (red, green, blue) color filter.

Technology trends TFT-LCD (thin-film-transistor liquid-crystal display) is the baseline technology. MO / White OLED (organic light emitting diode) is used for larger screens. LTPS / AMOLED is used for small / medium screens. The challenges for OLED are the effect of < 1 micron particles on yield, much higher cost compared to a-Si due to increased mask steps, and moisture impact to yield for the OLED step.

Although AMLCD displays are still dominant in the market today, AMOLED displays are growing quickly. Currently about 25% of smartphones are made with AMOLED displays and this is expected to grow to ~40% by 2021. OLED televisions are also growing rapidly, enjoying double digit growth rate year over year. Based on IHS data, the revenue for display panels with AMOLED technol- ogies is expected to have a CAGR of 18.9% in the next five years while the AMLCD display revenue will have a -2.8% CAGR for the same period with the total display panel revenue CAGR of 2.5%. With the rapid growth of AMOLED display panels, the panel makers have accel- erated their investment in the equipment to produce AMOLED panels.

There are three types of thin-film-transistor devices for display: amorphous silicon (a-Si), low temperature polysilicon (LTPS), and metal oxide (MO), also known as transparent amorphous oxide semiconductor (TAOS). AMLCD panels typically use a-Si for lower-resolution displays and TVs while high-resolution displays use LTPS transistors, but this use is mainly limited to small and medium displays due to its higher costs and scalability limitations. AMOLED panels use LTPS and MO transistors where MO devices are typically used for TV and large displays (FIGURE 3).

This shift in technology also requires a change in the gases used in production of AMOLED panels as compared with the AMLCD panels. As shown in FIGURE 4, display manufacturing today uses a wide variety of gases.