are tft lcd screens the future factory

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.

There’re more than 300 procedures to produce TFT LCD. The most advanced LCD, in which the array and cell process are highly automatic. Technically, every step in the process can lead to defects, and most of the defects have been eliminated through the development of TFT LCD technology.

In the LC filling process, if the quantity of LC injected is not enough, the spare space will form bubbles. And loose LC containing sealant will result in LC leakage.

Point defect is a kind of defect that some point on your screen don’t display correctly. There are mainly three situations: the point keeps displaying black or whitewhen the screen is working or the point can only display a single color.

For the first two situations, that’s because the circuit on the TFT and CF controlling that defective pixel point is shorted or broken. While the third situation is caused by damaged color pixel.

The production of the circuit and color pixel is under micro scale, and the technology is similar to semiconductor technology. Hundreds of thousands micro materials will be printed during the production process, you can understand some of the materials not being printed correctly, which result in the point defect.

Unlike point defect, this larger scale defect is caused by the failure of external FPC or PCBA, or a bad connection between FPC and cell. Therefore, a bunch of pixels connected to these IC are out of control, and we see those defects.

Usually, assembly of cell and IC is under heat and should be positioned accurately. Problems with IC connection will be checked out very soon, followed by the adjustment on machine parameter.

In LCD, newton’s rings may occur on screen when two glass substrate haven’t been sealed well, so that one of the glass may form a convex lens and lead to light interference.

To avoid this problem, we have to pay attention to the gap distance parameter in sealing process. By the way, newton’s rings has became a method to exam the glass sealing process in reverse .

The black matrix on CF glass or a additional shield bar is used to avoid this problem. So if this problem occurs, we have to check the CF deposition process.

You may notice there are some screens have uneven display, which means some white area appears in dark picture or vice versa. We call this ‘mura’, a word originated from Japanese.

Mura is very common but it doesn’t affect the screen function severely, however it still bring bad look. Hence, many high end display manufacturers have their own standards of mura, and the displays without mura are of the best quality.

Among the causes listed, thickness of the whole cell is the most critical one, and there are many factors related to that. Researches provide a lot of advice to adjust the thickness of the whole cell:

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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.

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.

Richard Ahrons (2012). "Industrial Research in Microcircuitry at RCA: The Early Years, 1953–1963". 12 (1). IEEE Annals of the History of Computing: 60–73. Cite journal requires |journal= (help)

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.

According to a recently released report by SEMI, thin-film transitor-LCD manufacturing capacity in China is expected to show 35 percent growth in 2007 and 50 percent growth in 2008, as new fab capacity begins to come online.

The report also predicts that investment in display production facilities will cool for the rest of the world, but China may eventually account for 20 to 30 percent of the total world market.

At present, China has two fifth generation (G5) TFT-LCD fabs in production, one coming online, one existing G5 fab expansion, one G1 plant and three Chinese-owned G2-G3 lines in Korea.

Some new investments in planning stages include a Truly Semiconductor G2.5 project, a Shanghai Tianma G4.5 line, plus an additional 60,000 sheets of G5 capacity per month by IVO. A Shenzhen Jiulong G6 plant and a G6 Shainghai SVA-NEC plant are awaiting environmental approvals.

“To date, there has been very little production of TFT-LCD materials or components in China,” said Mark Ding, president of SEMI China. “However, the influx of both Chinese and foreign-owned companies that are beginning to establish these local facilities is helping to significantly grow this market, and will ultimately help establish China as a global panel making market center of TFT-LCD materials and components.”

OLED is increasingly used in smartphones and televisions, but supply is tightening due to size issues and high production costs, making TFT LCD module demand stronger for the next 3 to 5 years. An organic light-emitting diode (OLED) refers to organic LED materials which light up in the presence of electric currents. OLED uses passive-matrix (PMOLED) or active-matrix (AMOLED). Most manufacturers use AMOLED.

OLED creates the deepest black, generating higher color quality than LCD displays. However, organic elements have lower lifespans than LCDs and AMOLED is not suitable for brightly-lit environments. Apple’s high demand has an impact on AMOLED production, among other factors, which has a subsequent positive effect on TFT LCD module demand.

AMOLED demands gets stronger, due to the pursuit for the best color in smartphones and televisions, but its supply is limited because of production factors. Apple is projected to require 100 million AMOLED panels annually for the next three years. Apple’s requirement creates high AMOLED demand in the small and medium display market. Displays are 9-inch in size, which creates a dent on AMOLED supply.

OLED is particularly harder to make than LCD modules because of the complexity in involved in creating substrate materials. OLED manufacturing is costlier than LCD modules, which may also create long-term production issues.

As AMOLED supply remains uncertain, numerous consumer product manufacturers would rather rely on TFT LCD modules. Innovations in TFT LCD can make them more competitive, especially as they cost less than OLED. Stronger TFT LCD demand will come from high-resolution smartphones and consumer electronics with short life cycles.

Though some say that the demand for TFT LCD is likely to contract, they are not considering the increasing use of OLED which already puts greater pressure on its suppliers. Without reducing OLED production costs, they might experience bottleneck problems in the future. Uncertain of OLED supply, some manufacturers of automotive, smartphone, and medical monitors would still prefer TFT LCD over OLED.

While OLED promises deeper colors, TFT LCD module can offer a more reliable, cost-efficient supply. As a result, companies that do not emphasize the demand for high color saturation would opt for TFT LCD. For the next 3 to 5 years, unless OLED vastly improves manufacturing costs and speed, TFT LCD makers are poised for higher demand.

TFT LCD is a mature technology. OLED is a relatively new display technology, being used in more and more applications. As for Micro LED, it is a new generation technology with very promising future. Followings are the pros and cons of each display technology.

TFT Liquid Crystal Display is widely used these days. Since LCD itself doesn"t emit light. TFT LCD relies on white LED backlight to show content. This is an explanation of how TFT LCD works.

Relatively lower contrast：Light needs to pass through LCD glasses, liquid crystal layer, polarizers and color filters. Over 90% is lost. Also, LCD can not display pure black.

Organic Light-Emitting Diode is built from an electro-luminescent layer that contains organic compounds, which emit light in response to an electric current. There are two types of OLED, Passive Matrix OLED (PMOLED) and Active Matrix OLED (AMOLED). These driving methods are similar to LCD"s. PMOLED is controlled sequentially using a matrix addressing scheme, m + n control signals are required to address a m x n display. AMOLED uses a TFT backplane that can switch individual pixels on and off.

Stroboscopic effect: most OLED screen uses PWM dimming technology. Some people who are easy perceive stroboscopic frequency may have sore eyes and tears.

​Micro LED, sometimes called μLED is made up of tiny LED, measure less than 100μm. Another way of looking at this is that MicroLEDs are simply traditional LEDs shrunk down and placed into an array.

Replacing organic material with inorganic GaN material eliminates the need of polarizing and encapsulation layer, found in OLED. Micro LED is smaller and thinner, consumes less power.

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.

Next, a photoresist is applied to the glass on which ITO film is deposited, and a uniform photoresist layer is formed on the ITO glass. After baking for a period of time, the solvent of the photoresist was partially volatilized to increase the adhesion of the photoresist material to the ITO glass.

Ultraviolet light (UV) is used to illuminate the surface of the photoresist through a pre-made electrode pattern mask, which causes the photoresist layer to react. The photoresist is selectively exposed under ultraviolet light by covering the photoresist on the glass coated with the photoresist.

The exposed part of the photoresist is then washed away with the developer, leaving only the unexposed part, and the dissolved photoresist is then washed away with deionized water.

Then etch off the ITO film without photoresist covering with appropriate acid etching solution, and only retain the ITO film under the photoresist. ITO glass is conductive glass (In2O3 and SnO2). The ITO film not covered by photoresist is easy to react with acid, while the ITO film covered by photoresist can be retained to obtain the corresponding wire electrode.

Stripping: High concentration of alkali solution (NaOH solution) is used as a stripping solution to peel off the remaining photoresist on the glass so that ITO glass can form ITO graphics exactly consistent with the photolithography mask.

Rinse the basic label of glass with an organic solution and remove the photolithographic tape after reaction to keep the glass clean. This completes the first thin-film conductive crystal process, which generally requires at least five identical processes to form a complex and sophisticated pattern of electrodes on the glass.

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.

Then, the organic polymer directional material is coated on the surface of the glass, that is, a uniform directional layer is applied to the appropriate position of ITO glass by the method of selective coating. Meanwhile, the directional layer is cured.

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.

A polarizer is an optical plate that allows only light from a certain direction to pass through. It is an optical element that converts natural light into straight polarized light. The mechanism of action is to make the vertical direction light pass through the straight incident light after passing through the vertical polarizer, and the other horizontal direction light is absorbed, or use reflection and scattering and other effects to make its shade.

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.

However, no matter CCFL backlight or LED backlight is placed in various ways, the nature of the backlight source cannot be a surface light source, but a linear light source or point light source. Therefore, other components are needed to evenly distribute the light to the whole surface. This task is accomplished by the diffuser plate and diffuser plate.

On the transparent diffuser plate, point-like printing can block part of the light. The LED backlight on the side drives the light from the side of the diffuser plate, and the light reflects and refracts back and forth in the diffuser plate, distributing the light evenly to the whole surface. Point-like printing blocks part of the light, screening the light evenly like a sieve.

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.

The backlight system also includes a backlight module laminator, located behind the backplane. In the CCFL backlight era, you can often see the long strip laminator like the one above, with each coil responsible for a set of tubes.

However, it is much simpler to use a side white LED as a backlight. The small circuit board on the far left of the figure above is the backlight of the LED.

This is the general structure of the backlight system. Since I have never seen the backlight mode of R.G.B LED, I cannot tell you what the backlight mode is like. I will share it with you when I see it in the future.

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.

Passengers and consumers in general are much savvier when it comes to knowing what they want from their visual display experiences. Smartphones and modern high resolution consumer displays have raised the bar for what is expected from information displays. End users are now accustomed to high brightness, great contrast, and smooth video playback, which not only requires more from the displays and panels but also from the hardware that is driving them.

Increased environmental requirements are also driving change in our industry, which has raised the need and focus on lower energy consumption and longer lifetime for displays and related hardware. At Teleste, these factors are considered from the moment our in-house team gets the design plans from our customers, and our built-in diagnostics tools ensure that the requirements are met long after the products are delivered and installed.

Among the biggest display technology advancements in the industry is the transition from Monochrome LED technology to RGB LED. The latest RGB small pixel pitch HD LED displays provide significantly sharper detail, vivid color reproduction and excellent readability at all viewing angles. The new technology also makes it possible to bump up the peak brightness to 6000 candelas (cd/m2) making it possible for RGB LED displays to be viewed in direct sunlight without issues. In addition, Teleste’s RGB LED solutions offer automatic brightness control that adjusts the brightness according to ambient light conditions.

Lifetime requirements are one of the key drivers of the future and RGB LED technology is also excellent in this regard. It offers an excellent lifespan with up to 100,000 hours of use and it is able to retain high brightness levels throughout its lifespan. Teleste’s RGB LED solutions are driven by extremely durable industrial grade PCs, making sure that the hardware driving the screens is equally as durable as the screens themselves, and this goes for all our display solutions. RGB LED technology is designed specifically for outdoor display applications, including main, platform, concourse and timetable displays. It is also extremely durable, and it is able to perform at any climatic conditions. The IP65-certified housing ensures that dust, rain and snow are never a concern.

For displaying more complex visual content, including moving graphics and video, Teleste offers a wide array of TFT LCD display solutions for different environments. Our outdoor TFT LCD display solutions are also designed and certified for the most challenging conditions and they provide an outstanding visual experience for graphics and moving content. Among the most interesting developments in TFT technology is that panels are now available in different shapes and sizes from squares and super ultra-wides to circular screens, which makes it possible to rethink how and where displays can be utilized. They allow for more creative freedom when designing new rail car interiors, but also provide flexibility for when retrofitting ones.

Ultrawide displays are now being used to replace train & route map stickers on trains, trams, and metro cars, after which they can offer much more relevant real time information to passengers. Viewing angles in these use cases are of course especially important, as route maps need to be able to be viewed from often obscure angles. PLS and IPS panels offer vastly improved viewing angles compared to displays equipped with for example TN-based LCD-panels, so it is important to choose panel types based on specific viewing needs.

Increased environmental requirements are also driving change in our industry, which has raised the need and focus on lower energy consumption and longer lifetime for displays and related hardware.

TFT LCD technology is a tried and tested technology that is still a very viable option for many scenarios. No matter the shape or size requirements, our in-house design team can customize the screens and housing to all specifications and validation standards. Requirements, naturally, vary depending on location. Small indoor displays cannot be used outdoors or at stations. Each has their own validation standards and requirements based on different use-case scenarios. Brightness requirements for outdoor displays are immensely higher than for those of indoor displays and modern outdoor displays are also required to endure all environmental conditions, including blizzards that surprised much of southern Europe at the beginning of 2021. With the climate in flux, it is essential to prepare for the worst-case-scenarios. Safety and electromagnetic compatibility requirements are also particularly important in the transportation industry, and our displays are validated against all the required standards case by case as per our customer’s needs.

Our high-quality displays are designed for 24/7 use in outdoor, indoor, and on-board. However, maintaining a high level of performance throughout the display’s lifespan requires more than just display itself. One of our highlight technologies is our new display diagnostic card that can be installed in all our POP displays. The diagnostic card provides a new layer of intelligence to existing display technologies. It works as a self-diagnostic tool and safeguard that ensures the stability and long lifespan of the displays with features such as automatic brightness control and preventive maintenance prediction. As an example, the diagnostic card can sense if the display is running too hot in the sunlight, and it can dynamically lower the brightness and power usage of the display among taking other preventive measures. The diagnostic card is a tool that helps our customers maintain their displays and predict maintenance costs in the long term, ensuring a long lifespan.

We are constantly keeping tabs on emerging display technologies to be able to offer the best solutions to our customers. MiniLed and MicroLED technologies in particular are looking like promising candidates to replace traditional LCD technology in the future. MicroLED is a self-emissive display technology that offers super high brightness and contrast with unmatched modularity and lifespan. MicroLED is debuting on the consumer market this year, and mass scale production can be expected in a handful of years from now, after which the technology will eventually become available to the railway industry as well.

Teleste stays ahead of the curve with the continuous development of our product families as well as new product platforms. We are engaged with development projects to improve competitiveness, modularity, and increased requirements. Much of our recent development efforts have focused on wireless systems in the RSM business as well RGB LED outdoor display technology and we expect this trend to continue. We are also continuously investigating technologies and fast implementation to respond to market needs. This is made possible by high investments into our in-house engineering and our strategy for offering our customers flexibility in our modular designs. Display technology is constantly evolving, but our commitment to strive to succeed together with our customers remains constant.

All we do is usually affiliated with our tenet " Buyer to start with, Belief to start with, devoting about the food packaging and environmental defense for Difference Between Lcd And Tft Display, Wide Temperature Ips Lcd Module, Round Lcd Display, Lcd Display With Tn Panel,Industrial Tft Display. We are keeping durable business relationships with more than 200 wholesalers in the USA, the UK, Germany and Canada. If you are interested in any of our products, please feel free to contact us. The product will supply to all over the world, such as Europe, America, Australia,luzern, Morocco,Hungary, Mauritius.We offer OEM services and replacement parts to meet the varying needs of our customers. We offer competitive price for quality products and we will make certain your shipment is handled quickly by our logistics department. We sincerely hope to have the opportunity to meet with you and see how we can help you further your own business.

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Here at Phoenix Display, we talk about LCD displays every day. With LCDs being such a big part of our daily lives, we thought it would be useful to explore the history of this important technology and where we see it going in the future.

In 1973, Sharp Corporation made use of LCD displays in calculators. Shortly after, the company followed BBC’s lead and mass produced TN LCD displays for watches in 1975.

1980s. After wristwatches came televisions (TVs), with the first color LCD TVs being developed as handheld TVs in Japan. In 1982, Seiko Epson released the first LCD TV, the Epson TV Watch, a wristwatch equipped with a small active-matrix LCD TV.

1990s. The 90s gave way to technology acceleration in the LCD space. Through multiple breakthroughs, researchers and inventors were able to improve contrast and viewing angles, as well as bring costs down.

2000s. After 30+ years of competition, LCD technology surpassed longstanding CRTs. Namely, in 2007, LCD TVs could claim better image quality than CRT-based TVs. Subsequently, in the fourth quarter of 2007,

Next, let’s take a brief look at how the technology works. Essentially, the LCD glass is just a light valve whose sole purpose is to either block light or allow light to go through it. We go into greater details in our post,

It accomplishes this simple task through the liquid crystal fluid, which is a fluid that’s rotated in a steady natural state between two pieces of glass. This rotation, when combined with front and rear polarizers, allows the light to be either transmitted through the glass or blocked. This light blocking state is changed when a voltage is applied to LC fluid which stops the light’s rotation.

Finally, let’s look at the LCD display landscape in the near future. There’s three big areas that are being explored with LCD displays: Flexible displays, 3D displays, and reel-to-reel manufacturing.

Flexible Displays. Even now, you’re probably hearing buzz about flexible displays, which are bendable displays that are virtually shatterproof and unbreakable.

Development has been moving forward with these displays in both military and industry. Funding by the military makes sense given that flexible displays won’t break like traditional displays, providing for numerous field applications that require a more durable display.

In addition, there are plenty of industrial applications that would benefit from flexible displays, such as products that could use displays that wrap around objects.

3D Displays. With 3D being such a popular technology, it’s no surprise there’s activity in this space. These displays are capable of conveying depth perception to viewers, which provides for a more realistic user experience.

Specifically, 3D displays with passive glasses (or no glasses) remove the requirement for syncing up with more expensive, active, shutter-based glasses. Naturally, this will lead to cost savings.

In contrast, reel-to-reel manufacturing enables the continuous building of glass panels. This will represent a dramatic reduction in costs, which can be passed along to the customer and allow for more competitive pricing.

Liquid-crystal image generation was conceived and realized by RCA in the 1960s. Nearly a decade later, the development of liquid crystal display (LCD) technology led to the manufacture of such products as wrist watches and pocket calculators. In the 1980s, thanks to the commercialization of twisted-nematic (TN) and super twisted-nematic (STN) LCDs, the first notebook computers with LCD screens became widely available.

Since then, intense research, development, and production have led to the emergence of thin-film-transistor liquid crystal display (TFT-LCD) as one of the leading flat panel display technologies, competing with plasma display panels (PDP), organic light emitting diode (OLED) displays, and field emission displays (FED), to name a few. A wide range of applications of TFT-LCD has been developed and commercialized, including notebook and desktop PCs, video camcorders, cameras, televisions, and public displays, creating a multibillion-dollar industry (global panel production value1 of more than US $68 billion in 2007).

With the growth of the industry, vertical integration of local and global TFT-LCD supply chains (mainly located in the Pacific Rim) became more pronounced, starting in Japan, Korea, and now Taiwan. Consequently, the entry barriers for businesses steadily rose.

Despite the aggressive growth worldwide, the TFT-LCD industry is still at a moderate distance from saturation and maturity. As is described in a June 2007 Morgan Stanley Research report2 on global TFT-LCD, the TV display market, using the current leading application for LCD technology, is only half way through its potential penetration.

As in the manufacture of integrated circuits, photolithographic manufacture of displays has challenges to overcome to achieve large-scale production that drives down price. The TFT-LCD industry is wrestling with uniformity, thermal, and critical dimension issues as it attempts to fabricate even larger displays. And these are only a fraction of a long list of challenges and opportunities for the research, development, and commercial manufacturing of the exponentially growing TFT-LCD industry.

Scientists in this exciting field are addressing the challenges through the engineering of materials, electronics, chemistry, equipment, processing, and metrology. The examples presented below are a general and brief preview of Wen-yi Lin"s plenary session at SPIE Lithography Asia, to be held in Taipei, Taiwan, in November 2008.

Figure 1 illustrates the strong influence of TV applications on glass substrate size and the generation of fab facilities and technologies. But, what are the challenges encountered by process and equipment technologies to meet the increasingly rigorous requirements of thin-film-transistor array production on a state-of-the-art Generation 8.5 (Gen 8.5) mother glass (2.2 x 2.5 m) with microscopic precision, compared to the requirements in advanced semiconductor IC processing?

It is well known that TFT-LCD manufacturing utilizes clean-room processing similar to semiconductor production. However, unlike IC, whose critical dimension is being driven down to nanoscale (32 nm) to increase computing speed and reduce cost, TFT-LCD technology development focuses on materials, equipment, and processing engineering of critical-to-quality "uniformity" throughout the entire display, while maintaining a transistor channel length in the range of 2-4 microns.

Additionally, modern IC technology is being developed to confront 45-cm wafers, while a state-of-the-art Generation 10 TFT-LCD fab (substrate size: 285 x 305 cm) is being constructed to produce 65-inch flat panel display.

This comparison indicates that there is clearly a different set of technical challenges to the commercial advancement of the TFT-LCD industry, and this is an area that is attracting tremendous R&D and production interest.

As with size expansion, the advancement of today"s display picture quality and performance, coupled with high definition digital broadcasting and/or blue ray DVD signals, has brought crystal-clear, vivid picture quality that human eyes had never experienced in the past.

Figure 2 is an example of how technologies can help the naked eye see a colorful but dark night sky. This is made possible with the improved capability of LED-LCD TV with stringent specifications (Full HD at 1920 x 1080, contrast ratio of 8000 to 1, frame rate of 120-180 Hz, and color saturation at NTSC 92%, cold cathode fluorescence lamp-base, NTSC 120%, LED-base). To get this kind of clarity, it is imperative to have precise control of key photolithography parameters and other processing factors.

Just as semiconductor chips produced on a single wafer might perform differently (clock speed), TFT-LCD with "sufficiently" different electronic and chemical behaviors in local areas can exhibit mura, a Japanese term describing non-uniformity, on the final display. Many factors such as critical dimension, metal line conductivity, and parasitic capacitance-all of which are familiar to people in the IC fields-contribute to mura.

In comparison, TFT-LCD-exclusive concerns are, for example, differential overlay of critical functional structures and total pitch control (a measurement of both microscopic and macroscopic dimension match of color filter and TFT array glass substrates of a display panel). Though human eyes have a very limited spatial resolution, on the order of one tenth of a millimeter, they are extremely sensitive to minute, gradual change (particularly, in orderly fashion) of local non-uniformity, as shown in Figure 3.

In physics terms, the changes of differential overlay contribute to deviation of parasitic capacitance coupled between, say, data lines and their nearby pixels, interfering pixel voltage charging ratio. Consequently, this alters the liquid crystal orientation/alignment of the affected pixels, compared to those in the vicinity, resulting in display mura. Equipment, processing, design, and metrology are now being investigated to improve the monitoring and control over the process.

As glass substrates used for TFT-LCD applications are produced through rapid quenching from its molten state (greater than 1000°C) to room temperature in minutes (in the case of fusion flow production process), they are in a metastable state. This results in the tendency of the substrate to irreversibly shrink as a function of temperature and time during subsequent thermal exposure, necessary for TFT-LCD processing.

For example, the irreversible thermal shrinkage of a Gen 8.5 glass is on the order of several microns diagonally, after LCD processing. Beside the aforementioned phenomenon, reversible thermal expansion of nearly 1000 microns (in diagonal) of Gen 8.5 glass per 1°C change can be observed.

Because an LCD panel is a sandwich of TFT and color filter glass sheets, each with its own distinctive thermal treatment history after their production processing, it is critical to effectively control both the irreversible and reversible thermal expansion. Otherwise, poor total pitch control will frequently lead to TFT-color filter glass dimension disparity and we would see partial light leakage through supposedly "dark" matrix or lines. The slight perception of gray level change again results in mura. Work to address these thermal issues includes process and metrology control.

Another unique challenge for TFT-LCD production includes color filter resist materials and processing to achieve higher color contrast and color saturation. Our recent unpublished study3 showed that 2008 year-end color filter resist contrast (purely material effects) was expected to have a 4-fold increase from its 2004 counterparts. The improvement of color contrast and saturation has mainly been achieved through reducing pigment particle size and increasing its concentration, respectively.

However, as pigment size decreased, more dispersion agent was needed to maintain uniform pigment distribution in the resist. The combined effects, in turn, led to a lower ratio of other essential color resist constituents, namely photo initiators and resin (mainly polymer and monomer). A reduced quantity of resin would challenge the process window of photo exposure and development, potentially leading to, for example, undesired rugged pattern profile at pixel fringes or lower adhesion of resist to glass substrates.

During resist deposition, non-uniform thickness of resist coating has often been observed around the edge of the underlying structure. The uneven over-coating (tsuno) lessened optical contrast because it disturbed the alignment of liquid crystal under electric field operation, displaying incorrect gray level to the human eye.

Therefore, it is extremely important to reduce tsuno. This can be accomplished by applying another top coating to average out the non-uniformity or reducing the underlayer"s thickness. A combination of equipment, materials, and processing innovations are being engaged to deal with this issue.

Lin received his PhD from the School of Materials Science and Engineering at Georgia Institute of Technology (USA). He has 14 U.S. patents, numerous equivalent international patents, and 20 publications.

His L6A fab is the leader in the Lean Production and Assistant Engineers Systems in AUO. In addition, he chairs the Thin Film Technology across fab committee at AUO.

Asahi Glass, Co., Ltd. (Headquarters: Tokyo; President: Shinya Ishizu) decided to increase its manufacturing capacity of glass substrates used for TFT-LCD (Thin Film Transistor Liquid Crystal Display). With this increase the company will install new furnace of glass substrate at its Kansai factory and augment its glass panel polishing line in Taiwan. Engineering will commence from August of this year and is expected to be completed in October, 2003. Total funds to be injected into the project are estimated at 17 billion yen. The total production capacity as a result of this increase is estimated to be 10 million square meters annually, using four furnaces of glass substrates.

The demand for TFT-LCD displays is predicted to increase at a rate of 30% annually through the year 2005, since a steady increase is predicted not only for their use in notebook PCs, but even more so for their use in PC monitors. Their use in TVs is also expected to sky rocket. In addition, TFT-LCD substrate panel manufacturers announce they plan to use the large substrates to reduce their cost, and that in the future the "5th Generation Size" of glass substrates with a surface are exceeding one square meter, will be the industry mainstay.

Unlike many competitors, Asahi Glass incorporates floating method in manufacturing process of the glass substrates, which is suited to the mass production of large size. The company decided to increase the manufacturing capacity of its TFT-LCD glass substrates because it felt that the increasing demand for TFT-LCD displays and calls for larger glass substrates for TFT-LCD displays presented a great opportunity to further expand this business area and become the global leader in the impending. Details of the future capacity increase are as follows:

We will install the fourth furnace of TFT-LCD glass substrate at the Kansai Factory (Amagasaki City, Hyogo Prefecture). The new furnace will enable highly efficient multi-line production of ultra-large-sized substrates, primarily ultra-large glass substrates larger than one square meter, making possible the manufacture of glass substrates of approximately four meters in width. The manufacturing capacity of this furnace is four million square meters annually, nearly twice that of our existing furnaces, and requires a capital investment of roughly 12 billion yen.

We will augment the TFT-LCD glass panel polishing line, which is targeted for the fifth generation size glass substrate, at Asahi Glass Fine Techno Taiwan Co., Ltd. (a fully owned subsidiary of Asahi Glass, Co., Ltd., located in Douliu City, Taiwan), which has been operating a polishing line since 2001. Capital investment for the new line is roughly five billion yen. Although Asahi Glass Fine Techno in Japan (a fully owned subsidiary of Asahi Glass, Co., Ltd., located in Yonezawa City, Yamagata Prefecture) also conducts polishing of TFT-LCD glass substrates, the line addition will be made in Taiwan, since future production volumes of TFT-LCD substrates will greatly increase there and since it is expected that Taiwanese TFT-LCD panel manufacturers will employ the