construction of tft display brands

STONE Technologies is a proud manufacturer of superior quality TFT LCD modules and LCD screens. The company also provides intelligent HMI solutions that perfectly fit in with its excellent hardware offerings.

There is also a downloadable design software called STONE Designer. This is a completely free GUI design software you can use to create responsive digital module-ready user interfaces.

STONE TFT LCD modules come with a microcontroller unit that has a 1GHz Cortex-A8 CPU. Such a module can easily be transformed into an HMI screen. Simple hexadecimal instructions can be used to control the module through the UART port. Furthermore, you can seamlessly develop STONE TFT LCD color user interface modules and add touch control, features to them.

You can also use a peripheral MCU to serially connect STONE’s HMI display via TTL. This way, your HMI display can supply event notifications and the peripheral MCU can then execute them. Moreover, this TTL-connected HMI display can further be linked to microcontrollers such as:

Becoming a reputable TFT LCD manufacturer is no piece of cake. It requires a company to pay attention to detail, have excellent manufacturing processes, the right TFT display technology, and have a consumer mindset.

Now, we list down 10 of the best famous LCD manufacturers globally. We’ll also explore why they became among the top 10 LCD display Manufacturers in the world.

BOE Technology Group Co., Ltd., founded in April 1993, is an IoT company providing intelligent interface products and professional services for information interaction and human health. BOE’s three core businesses are Interface Devices, Smart IoT Systems, and Smart Medicine & Engineering Integration.

Interface Devises Business includes Display and Senor, Sensor, and Application Solutions. As a leading company in the global semiconductor display industry, BOE has made the Chinese display industry develop from scratch to maturity and prosperity. Now, more than one-quarter of the global display panels are made by BOE, with its UHD, flexible display, microdisplay, and other solutions broadly applied to well-known worldwide brands.

Smart IoT Systems Business includes Intelligent Manufacturing Services, IoT Solution, and Digital Art IoT Platform. BOE provides integrated IoT solutions in smart retail, smart finance, digital art, business office, smart home, smart transportation, smart education, smart energy, and other fields. In the field of digital art, BOE has launched its digital art IoT solution – BOE iGallery, realizing the perfect combination of technology and art. For smart retail, BOE provides IoT solutions in price management, shelf management, and customer behavior analysis to achieve seamless online and offline convergence.

In 2019, BOE’s yearly new-patent applications amounted to 9657, of which over 90% are invention patents, amounting to over 70,000 usable patents in total. Data from IFI Claims also shows that BOE has ranked 13th among the Top 50 USPTO (The United States Patent and Trademark Office), Patent Assignees, in 2019. According to the 2019 International PCT Applications of WIPO, BOE ranked No.6 with 1,864 applications.

LG Display is a leading manufacturer of thin-film transistor liquid crystal displays (TFT-LCD) panels, OLED, and flexible displays.LG Display began developing TFT-LCD in 1987 and currently offers Display panels in a variety of sizes and specifications using different cutting-edge technologies (IPS, OLED, and flexible technology).

LG Display now operates back-end assembly plants in South Korea, China, and Vietnam. In addition, LG Display operates a sales subsidiary with a global network to effectively serve overseas markets.

Samsung Electronics is South Korea’s largest electronics industry and the largest subsidiary of the Samsung Group. In the late 1990s, Samsung Electronics’ independent technology development and independent product innovation capabilities were further enhanced. Its product development strategy not only emphasizes “leading the technology but also using the most advanced technology to develop new products to meet the high-end market demand at the introduction stage”.In addition to the matching principle, it also emphasizes the principle of “leading technology, developing new products with the most advanced technology, creating new demand and new high-end market”.

With innovative and differentiated technologies, QINNOOptoelectronics provides advanced display integration solutions, including 4K2K ultra-high resolution, 3D naked eye, IGZO, LTPS, AMOLED, OLED, and touch solutions. Qinnooptoelectronics sets specifications and leads the market. A wide range of product line is across all kinds of TFT LCD panel modules, touch modules, for example, TV panel, desktop and laptop computer monitor with panels, small and medium scale “panels, medical, automotive, etc., the supply of cutting-edge information and consumer electronics customers around the world, for the world TFT – LCD (thin-film transistor liquid crystal display) leading manufacturers.

AU Optronics Co., LTD., formerly AU Optronics Corporation, was founded in August 1996. It changed its name to AU Optronics after its merger with UNIOPtronics in 2001. Through two mergers, AU has been able to have a full range of generations of production lines for panels of all sizes.Au Optronics is a TFT-LCD design, manufacturing, and r&d company. Since 2008, au Optronics has entered the green energy industry, providing customers with high-efficiency solar energy solutions.

Sharp has been called the “father of LCD panels”.Since its founding in 1912, Sharp developed the world’s first calculator and LIQUID crystal display, represented by the living pencil, which was invented as the company name. At the same time, Sharp is actively expanding into new areas to improve people’s living standards and social progress. Made a contribution.

Sharp is committed to creating a unique company, creating life in the 21st century through unparalleled “originality” and “sophistication”, and is a sales company, operating video, home appliances, mobile phones, and information products throughout the major cities of the country. Establish a business point, establish a perfect after-sale service network, satisfy consumer demand.

Toshiba is a famous multinational company with a history of 130 years. It covers a wide range of businesses, including social infrastructure construction, home appliances, digital products, and electronic components. It covers almost every aspect of production and life. Toshiba has the largest research and development institution in Japan. Through unremitting innovation and development, Toshiba has been at the forefront of science and technology in the world.

From the introduction of Japan’s original washing machines, refrigerators, and other household appliances, to the world’s first laptop, the first 16MB flash memory, the world’s smallest 0.85-inch HDDs; Create advanced HDDVD technology; Toshiba created many “world firsts” in the research and manufacture of new SED displays and contributed to changing people’s lives through constant technological innovation.

Kyocera was founded in 1959 as a manufacturer of technical ceramics. Industrial ceramics is a series of advanced materials with unique physical, chemical, and electronic properties. Today, most of Kyocera’s products are related to telecommunications, including semiconductor components, RF and microwave packaging, passive electronic components, wireless mobile phones and network equipment, crystal oscillators and connectors, and optoelectronic products for optoelectronic communication networks.

Tianma microelectronics co., LTD., founded in 1983, the company focus on smartphones, tablets, represented by high order laptop display market of consumer goods and automotive, medical, POS, HMI, etc., represented by professional display market, and actively layout smart home, intelligent wear, AR/VR, unmanned aerial vehicles (UAVs) and other emerging markets, to provide customers with the best product experience.IN terms of technology, the company has independently mastered leading technologies such as LTPS-TFT, AMOLED, flexible display, Oxide-TFT, 3D display, transparent display, and in-cell/on-cell integrated touch control. TFT-LCD key Materials and Technologies National Engineering Laboratory, national enterprise Technology Center, post-doctoral mobile workstation, and undertake national Development and Reform Commission, The Ministry of Science and Technology, the Ministry of Industry and Information Technology, and other major national thematic projects. The company’s long-term accumulation and continuous investment in advanced technology lay the foundation for innovation and development in the field of application.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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Flat-panel displays are thin panels of glass or plastic used for electronically displaying text, images, or video. Liquid crystal displays (LCD), OLED (organic light emitting diode) and microLED displays are not quite the same; since LCD uses a liquid crystal that reacts to an electric current blocking light or allowing it to pass through the panel, whereas OLED/microLED displays consist of electroluminescent organic/inorganic materials that generate light when a current is passed through the material. LCD, OLED and microLED displays are driven using LTPS, IGZO, LTPO, and A-Si TFT transistor technologies as their backplane using ITO to supply current to the transistors and in turn to the liquid crystal or electroluminescent material. Segment and passive OLED and LCD displays do not use a backplane but use indium tin oxide (ITO), a transparent conductive material, to pass current to the electroluminescent material or liquid crystal. In LCDs, there is an even layer of liquid crystal throughout the panel whereas an OLED display has the electroluminescent material only where it is meant to light up. OLEDs, LCDs and microLEDs can be made flexible and transparent, but LCDs require a backlight because they cannot emit light on their own like OLEDs and microLEDs.

Liquid-crystal display (or LCD) is a thin, flat panel used for electronically displaying information such as text, images, and moving pictures. They are usually made of glass but they can also be made out of plastic. Some manufacturers make transparent LCD panels and special sequential color segment LCDs that have higher than usual refresh rates and an RGB backlight. The backlight is synchronized with the display so that the colors will show up as needed. The list of LCD manufacturers:

Organic light emitting diode (or OLED displays) is a thin, flat panel made of glass or plastic used for electronically displaying information such as text, images, and moving pictures. OLED panels can also take the shape of a light panel, where red, green and blue light emitting materials are stacked to create a white light panel. OLED displays can also be made transparent and/or flexible and these transparent panels are available on the market and are widely used in smartphones with under-display optical fingerprint sensors. LCD and OLED displays are available in different shapes, the most prominent of which is a circular display, which is used in smartwatches. The list of OLED display manufacturers:

MicroLED displays is an emerging flat-panel display technology consisting of arrays of microscopic LEDs forming the individual pixel elements. Like OLED, microLED offers infinite contrast ratio, but unlike OLED, microLED is immune to screen burn-in, and consumes less power while having higher light output, as it uses LEDs instead of organic electroluminescent materials, The list of MicroLED display manufacturers:

Sony produces and sells commercial MicroLED displays called CLEDIS (Crystal-LED Integrated Displays, also called Canvas-LED) in small quantities.video walls.

LCDs are made in a glass substrate. For OLED, the substrate can also be plastic. The size of the substrates are specified in generations, with each generation using a larger substrate. For example, a 4th generation substrate is larger in size than a 3rd generation substrate. A larger substrate allows for more panels to be cut from a single substrate, or for larger panels to be made, akin to increasing wafer sizes in the semiconductor industry.

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Distributor of component LCDs for equipment which provide high-contrast ratio, color saturation, luminance and performance enhancements such as advanced wide viewing (AWV) for true color fidelity, super-high brightness (SHB) and wide temperature range. Focus on industrial, instrumentation, hand-helds, medical and other low-to-medium volume markets. High-bright LED backlights for outdoor use. LVDS interfaces decrease EMI. Factory installed touch screen solutions. 3.5" to 12.1" QVGA, HVGA, VGA, WVGA, SVGA, XGA, WXGA. Also distributes other related products including LED drivers, lamps, indicators, LED assemblies, segment displays, LED mounts, LEDs, and light pipes. Distributor of electronic components, hardware and fasteners and provides design/value engineering support, fulfillment strategies, procurement services and transactional models to meet specific needs and priorities.

In Taiwan.  It was formed in 2001 by the merger of Acer Display Technology Inc and Unipac Optoelectronics Corporation. It has G3.5 to G8.5 production lines.

In Taiwan. One of the daughter company of Foxconn/Hon Hai.  In 2010, it bought the then famous LCD manufacturer, ChiMei, then changed its name to Innolux. It has G7.5 production lines.

In Korea and China. It is used to be the 2nd biggest TFT LCD manufacturers. LG also planned to stop the production but delayed the plan after the price increased. LG has G7.5 and G8.5 (Guangzhou) production lines.

In China. Original Matix is the partner of CPT (Chunghwa Picture Tubes 中华映管). After CPT filed bankruptcy in 2019, Mantix took over CPT G6 production line.

In Korea. It used to be the biggest TFT LCD manufacturers before it was dethroned by BOE in 2019. Because of tough competition, Samsung planned to stop the production in 2021 but delayed because the price increase during the pandemic.  Samsung has G7 and G8.5 production lines.

In Japan and China. The pioneer and queen of LCD industry. Because of high cost and tough competitor, Sharp was acquired by Foxconn/Hon Hai in 2016. Sharp has G8, G8.5(Suzhou), G10, G10.5 (Guangzhou) production lines.

Focus Displays offers a wide range of standard full color TFT displays. 64 million unique colors, high brightness, sharp contrast, -30C operating temperature, and fast response time are all good descriptions of a TFT display. This is why TFT technology is one of the most popular choices for a new product.

Thin Film Transistor (TFT) display technology can be seen in products such as laptop computers, cell phones, tablets, digital cameras, and many other products that require color. TFT’s are active matrix displays which offers exceptional viewing experiences especially when compared to other passive matrix technologies. The clarity on TFT displays is outstanding; and they possess a longer half-life than some types of OLEDs and range in sizes from less than an inch to over 15 inches.

CCFL’s are still available, but are becoming a legacy (obsolete) component. TFT displays equipped with a CCFL require higher MOQs (Minimum Order Quantities) than displays with LED backlights.

RGB backlights require a controller to regulate the different intensities of each color. The controller’s function is to combine unique levels of Red, Green and Blue to produce any of 64M different colors.

Backlight brightness (Luminance) is measured in nits. A nit being the amount of light that one candle delivers in a 1 square meter box. The intensity of the LED backlight can be critical when operating in low light or in direct sun light and is usually controlled by adjusting the DC voltage. In many applications this is accomplished through pulse-width modulation (PWM)

The majority of TFT displays contain a touch panel, or touch screen. The touch panel is a touch-sensitive transparent overlay mounted on the front of the display glass. Allowing for interaction between the user and the LCD display.

Some touch panels require an independent driver IC; which can be included in the TFT display module or placed on the customer’s Printed Circuit Board (PCB). Touch screens make use of coordinate systems to locate where the user touched the screen.

Resistive touch panels are the lowest cost option and are standard equipment on many TFT modules. They are more common on smaller TFT displays, but can still be incorporated on larger modules.

Resistive touch panels are constructed using flexible materials with an air gap between and are coated with a resistive layer. When an object applies pressure to the top layer, it makes contact with microdots located on the bottom layer. This allows the touch screen to find the location of the touch using X and Y coordinates.

Resistive touch panels allow a single touch, although advances in new resistive technology will allow multi-touch operation in the near future. One main advantage of a resistive touch screen is the ability to be activated by the touch of any material. This includes a range of items from a bare finger, to a pencil, to even the edge of a credit card; regardless of its composition.

They also have the added advantage of operating in a wide temperature range and environments, including anything from the arctic cold of Alaska to the extreme heat of Death Valley.

Capacitive touch panels have become popular with such software as Windows 8®, Android® and Apple®. Additionally it is used in products such as cell phones and tablets, where multi-touch and zoom capabilities are important.

Contrast ratio, or static contrast ratio, is one way to measure the sharpness of the TFT LCD display. This ratio is the difference between the darkest black and the brightest white the display is able to produce. The higher the number on the left, the sharper the image. A typical contrast ratio for TFT may be 300:1. This number ratio means that the white is 300 times brighter than the black.

TFT LCD displays are measured in inches; this is the measurement of the diagonal distance across the glass. Common TFT sizes include: 1.77”, 2.4”, 2.8”, 3”, 4.3”, 5”, 5.7”, 5.8”, 7”, 10.2”, 12.1 and 15”.

As a general rule, the larger the size of the glass the higher the cost of the display, but there are exceptions to this rule. A larger display may be less expensive than a smaller display if the manufacture produces higher quantities of the larger displays. When selecting your color display, be sure to ask what the cost is for one size smaller and one size larger. It may be worth modifying your design requirements.

TFT resolution is the number of dots or pixels the display contains. It is measured by the number of dots along the horizontal (X axis) and the dots along the vertical (Y axis).

The higher the resolution, the more dots per square inch (DPI), the sharper the display will look. A higher resolution results in a higher cost. One reason for the increase in cost is that more driver chips are necessary to drive each segment.

Certain combinations of width and height are standardized and typically given a name and a letter representation that is descriptive of its dimensions. Popular names given to the TFT LCD displays resolution include:

Transmissive displays must have the backlight on at all times to read the display, but are not the best option in direct sunlight unless the backlight is 750 Nits or higher. A majority of TFT displays are Transmissive, but they will require more power to operate with a brighter backlight.

Transflective displays are readable with the backlight off provided there is enough ambient light. Transflective displays are more expensive than Transmissive also there may be a larger MOQ for Transflective. However, Transflective displays are the best option for direct sunlight.

Drivers update and refresh the pixels (Picture Elements) of a display. Each driver is assigned a set number of pixels. If there are more pixels than a single driver can handle, then an additional drivers are added.

A primary job of the driver is to refresh each pixel. In passive TFT displays, the pixel is refreshed and then allowed to slowly fade (aka decay) until refreshed again. The higher the refresh frequency, the sharper the displays contrast.

The controller does just what its name suggest. It controls the drivers. There is only one controller per display no matter how many drivers. A complex graphic display with several thousand pixels will contain one controller and several drivers.

The TFT display (minus touch screen/backlight) alone will contain one controller/driver combination. These are built into the display so the design engineer does not need to locate the correct hardware.

Response Time is the measurement of time it takes for a pixel/segment to change from black (OFF state) to white (ON state) and then back to black again. In other words, how fast the picture can be changed. A slow response time can result in the blurring of the picture in games, movies and even cad type programs.

If you do not see a Thin Film Transistor (TFT) Display module that meets your specifications, or you need a replacement TFT, we can build a custom TFT displays to meet your requirements. Custom TFTs require a one-time tooling fee and may require higher MOQs.

Ready to order samples for your TFT design? Contact one of our US-based technical support people today concerning your design requirements. Note: We can provide smaller quantities for samples and prototyping.

Let us start with the basics first; refresh the knowledge about TN and LCD displays in general, later we will talk about TFTs (Thin Film Transistors), how they differ from regular monochrome LCD displays. Then we will go on to the ghosting effect, so we will not only discuss the technology behind the construction of the TFT, but also some phenomena, like the ghosting effect, or grayscale inversion, that are important to understand when using an LCD TFT display.

Next, we will look at different technologies of the TFT LCD displays like TN, IPS, VA, and of course about transmissive and transflective LCD displays, because TFT displays also can be transmissive and transflective. In the last part we will talk about backlight.

Let us start with a short review of the most basic liquid crystal cell, which is the TN (twisted nematic) display. On the picture above, we can see that the light can be transmit through the cell or blocked by the liquid crystal cell using voltage. If you want to learn more about monochrome LCD displays and the basics of LCD displays, follow this link.

What is a TFT LCD display and how it is different from a monochrome LCD display? TFT is called an active display. Active, means we have one or more transistors in every cell, in every pixel and in every subpixel. TFT stands for Thin Film Transistor, transistors that are very small and very thin and are built into the pixel, so they are not somewhere outside in a controller, but they are in the pixel itself. For example, in a 55-inch TV set, the TFT display contains millions of transistors in the pixels. We do not see them, because they are very small and hidden, if we zoom in, however, we can see them in every corner of each pixel, like on the picture below.

On the picture above we can see subpixels, that are basic RGB (Red, Green, Blue) colors and a black part, with the transistors and electronic circuits. We just need to know that we have pixels, and subpixels, and each subpixel has transistors. This makes the display active, and thus is called  the TFT display. TFT displays are usually color displays, but there are also monochrome TFT displays, that are active, and have transistors, but have no colors. The colors in the TFT LCD display are typically added by color filters on each subpixel. Usually the filters are RGB, but we also have RGBW (Red, Green, Blue, White) LCD displays with added subpixels without the filter (White) to make the display brighter.

What is interesting, the white part of the RGB and RGBW screen will look exactly the same from a distance, because the lights are mixed and generate white light, but when we come closer to the screen, we will not see white light at all.

Going a little bit deeper, into the TFT cell, there is a part inside well known to us from the monochrome LCD display Riverdi University lecture. We have a cell, liquid crystal, polarizers, an ITO (Indium Tin Oxide) layer for the electrodes, and additionally an electronic circuit. Usually, the electronic circuit consists of one transistor and some capacitors to sustain the pixel state when we switch the pixel OFF and ON. In a TFT LCD display the pixels are much more complicated because apart from building the liquid crystal part, we also need to build an electronic part.

That is why TFT LCD display technologies are very expensive to manufacture. If you are familiar with electronics, you know that the transistor is a kind of switch, and it allows us to switch the pixel ON and OFF. Because it is built into the pixel itself, it can be done very quickly and be very well controlled. We can control the exact state of every pixel not only the ON and OFF states, but also all the states in between. We can switch the light of the cells ON and OFF in several steps. Usually for TFT LCD displays it will be 8-bit steps per color, so we have 256 steps of brightness for every color, and every subpixel. Because we have three subpixels, we have a 24-bit color range, that means over 16 million combinations, we can, at least theoretically, show on our TFT LCD display over 16 million distinct colors using RGB pixels.

Now that we know how the TFT LCD display works, we can now learn some practical things one of which is LCD TFT ghosting. We know how the image is created, but what happens when we have the image on the screen for a prolonged time, and how to prevent it. In LCD displays we have something called LCD ghosting. We do not see it very often, but in some displays this phenomenon still exists.

If some elements of the picture i.e., your company logo is in the same place of the screen for a long period of time, for couple of weeks, months or a year, the crystals will memorize the state and later, when we change the image, we may see some ghosting of those elements. It really depends on many conditions like temperature and even the screen image that we display on the screen for longer periods of time. When you build your application, you can use some techniques to avoid it, like very rapid contrast change and of course to avoid the positioning the same image in the same position for a longer time.

You may have seen this phenomenon already as it is common in every display technology, and even companies like Apple put information on their websites, that users may encounter this phenomenon and how to fix it. It is called image ghosting or image persistence, and even Retina displays are not free of it.

Another issue present in TFT displays, especially TN LCD displays, is grayscale inversion. This is a phenomenon that changes the colors of the screen according to the viewing angle, and it is only one-sided. When buying a TFT LCD display, first we need to check what kind of technology it is. If it is an IPS display, like the Riverdi IPS display line, then we do not need to worry about the grayscale inversion because all the viewing angles will be the same and all of them will be very high, like 80, 85, or 89 degrees. But if you buy a more common or older display technology type, like the TN (twisted nematic) display, you need to think where it will be used, because one viewing angle will be out. It may be sometimes confusing, and you need to be careful as most factories define viewing direction of the screen and mistake this with the greyscale inversion side.

On the picture above, you can see further explanation of the grayscale inversion from Wikipedia. It says that some early panels and also nowadays TN displays, have grayscale inversion not necessary up-down, but it can be any angle, you need to check in the datasheet. The reason technologies like IPS (In-Plane Switching), used in the latest Riverdi displays, or VA, were developed, was to avoid this phenomenon. Also, we do not want to brag, but the Wikipedia definition references our website.

We know already that TN (twisted nematic) displays, suffer from grayscale inversion, which means the display has one viewing side, where the image color suddenly changes. It is tricky, and you need to be careful. On the picture above there is a part of the LCD TFT specification of a TN (twisted nematic) display, that has grayscale inversion, and if we go to this table, we can see the viewing angles. They are defined at 70, 70, 60 and 70 degrees, that is the maximum viewing angle, at which the user can see the image. Normally we may think that 70 degrees is better, so we will choose left and right side to be 70 degrees, and then up and down, and if we do not know the grayscale inversion phenomena, we may put our user on the bottom side which is also 70 degrees. The viewing direction will be then like a 6 o’clock direction, so we call it a 6 o’clock display. But you need to be careful! Looking at the specification, we can see that this display was defined as a 12 o’clock display, so it is best for it to be seen from a 12 o’clock direction. But we can find that the 12 o’clock has a lower viewing angle – 60 degrees. What does it mean? It means that on this side there will be no grayscale inversion. If we go to 40, 50, 60 degrees and even a little bit more, probably we will still see the image properly. Maybe with lower contrast, but the colors will not change. If we go from the bottom, from a 6 o’clock direction where we have the grayscale inversion, after 70 degrees or lower we will see a sudden color change, and of course this is something we want to avoid.

To summarize, when you buy older technology like TN and displays, which are still very popular, and Riverdi is selling them as well, you need to be careful where you put your display. If it is a handheld device, you will see the display from the bottom, but if you put it on a wall, you will see the display from the top, so you need to define it during the design phase, because later it is usually impossible or expensive to change the direction.

We will talk now about the other TFT technologies, that allow us to have wider viewing angles and more vivid colors. The most basic technology for monochrome and TFT LCD displays is twisted nematic (TN). As we already know, this kind of displays have a problem with grayscale inversion. On one side we have a higher retardation and will not get a clear image. That is why we have other technologies like VA (Vertical Alignment), where the liquid crystal is differently organized, and another variation of the TFT technology – IPS which is In-Plane Switching. The VA and IPS LCD displays do not have a problem with the viewing angles, you can see a clear image from all sides.

Nowadays all TV sets, tablets and of course mobile phones are IPS or VA. You can turn them around and see the image clear from all sides. But, for monitor applications the TN technology is still widely used, because the monitor usually is in front of you and most of the time you look directly at it, from top, left or right side, but very rarely from the bottom, so the grayscale inversion viewing angle can be placed there. This technology still is very practical because it is affordable and has some advantages for gamers because it is very fast.

Apart from the different organization of the liquid crystals, we also organize subpixels a little bit differently in a VA and IPS LCD displays. When we look closer at the TN display, we will just see the subpixels with color filters. If we look at the VA or IPS display they will have subpixels of subpixels. The subpixels are divided into smaller parts. In this way we can achieve even wider viewing angles and better colors for the user, but of course, it is more complicated and more expensive to do.

The picture above presents the TN display and grayscale inversion. For IPS or VA technology there is no such effect. The picture will be the same from all the sides we look so these technologies are popular where we need wide viewing angles, and TN is popular where we don’t need that, like in monitors. Other advantages of IPS LCD displays are they give accurate colors, and wide viewing angles. What is also important in practice, in our projects, is that the IPS LCD displays are less susceptible to mechanical force. When we apply mechanical force to the screen, and have an optically bonded touch screen, we push the display as well as squeeze the cells. When we have a TN display, every push on the cell changes the image suddenly, with the IPS LCD displays with in-plane switching, different liquid crystals organization, this effect is lesser. It is not completely removed but it is much less distinct. That is another reason IPS displays are very popular for smartphones, tablets, when we have the touchscreens usually optically bonded.

If we wanted to talk about disadvantages, there is a question mark over it, as some of them may be true, some of them do not rely on real cases, what kind of display, what kind of technology is it. Sometimes the IPS displays can have higher power consumption than others, in many cases however, not. They can be more expensive, but not necessarily. The new IPS panels can cost like TN panels, but IPS panels definitely have a longer response time. Again, it is not a rule, you can make IPS panels that are very fast, faster than TN panels, but if you want the fastest possible display, probably the TN panel will be the fastest. That is why the TN technology is still popular on the gaming market. Of course, you can find a lot of discussions on the internet, which technology is better, but it really depends on what you want to achieve.

Now, let us look at the backlight types. As we see here, on the picture above, we have four distinct types of backlight possible. The most common, 95 or 99 per cent of the TFT LCD displays on the market are the transmissive LCD display type, where we need the backlight from the back. If you remember from our Monochrome LCD Displays lecture, for transmissive LCD displays you need the backlight to be always on. If you switch the backlight off, you will not see anything. The same as for monochrome LCD displays, but less popular for TFT displays, we have the transflective LCD display type. They are not popular because usually for transflective TFT displays, the colors lack in brightness, and the displays are not very practical to use. You can see the screen, but the application is limited. Some transflective LCD displays are used by military, in applications where power consumption is paramount; where you can switch the backlight off and you agree to have lower image quality but still see the image. Power consumption and saving energy is most important in some kind of applications and you can use transflective LCD displays there. The reflective type of LCD displays are almost never used in TFT. There is one technology called Low Power Reflective Displays (LPRD) that is used in TFT but it is not popular. Lastly, we have a variation of reflective displays with frontlight, where we add frontlight to the reflective display and have the image even without external light.

Just a few words about Low Power Reflective Displays (LPRD). This kind of display uses environmental light, ambient light to reflect, and produce some colors. The colors are not perfect, not perfectly clear, but this technology is becoming increasingly popular because it allows to have color displays in battery powered applications. For example, a smartwatch would be a case for that technology, or an electrical bike or scooter, where we can not only have a standard monochrome LCD display but also a TFT LCD color display without the backlight; we can see the image even in

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strong sunlight and not need backlight at all. So, this kind of TFL LCD display technology is getting more and more popular when we have outdoor LCD displays and need a low power consumption.

On the picture above, we have some examples of how transmissive and reflective LCD displays work in the sunlight. If we have a simple image, like a black and white pattern, then on a transmissive LCD display, even with 1000 candela brightness, the image probably will be lower quality than for a reflective LCD display; if we have sunlight, we have very strong light reflections on the surface of the screen. We have talked about contrast in more detail in the lecture Sunlight Readable Displays. So, reflective LCD displays are a better solution for outdoor applications than transmissive LCD displays, where you need a really strong backlight, 1000 candela or more, to be really seen outdoors.

To show you how the backlight of LCD displays is built, we took the picture above. You can see the edge backlight there, where we have LEDs here on the small PCB on the edge, and we have a diffuser that distributes the light to the whole surface of LCD screen.

In addition to the backlight, we have something that is called a frontlight. It is similar to backlight, it also uses the LEDs to put the light into it, but the frontlight needs to be transparent as we have the display behind. On the example on the picture above we can see an e-paper display. The e-paper display is also a TFT display variation, but it is not LCD (liquid crystal), it is a different technology, but the back of the display is the same and it is reflective. The example you see is the Kindle 4 eBook reader. It uses an e-paper display and a frontlight as well, so you can read eBooks even during the night.

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Get rich colors, detailed images, and bright graphics from an LCD with a TFT screen. Our standard Displaytech TFT screens start at 1” through 7” in diagonal size and have a variety of display resolutions to select from. Displaytech TFT displays meet the needs for products within industrial, medical, and consumer applications.

TFT displays are LCD modules with thin-film transistor technology. The TFT display technology offers full color RGB showcasing a range of colors and hues. These liquid crystal display panels are available with touchscreen capabilities, wide viewing angles, and bright luminance for high contrast.

Our TFT displays have LVDS, RGB, SPI, and MCU interfaces. All Displaytech TFT LCD modules include an LED backlight, FPC, driver ICs, and the LCD panel.

We offer resistive and capacitive touch screens for our 2.8” and larger TFT modules. Our TFT panels have a wide operating temperature range to suit a variety of environments. All Displaytech LCDs are RoHS compliant.

We also offer semi-customization to our standard TFT screens. This is a cost-optimized solution to make a standard product better suit your application’s needs compared to selecting a fully custom TFT LCD. Customizations can focus on cover glass, mounting / enclosures, and more - contact us to discuss your semi-custom TFT solution.

LCD is the abbreviation for liquid crystal display. An LCD basically consists of two glass plates with a special liquid between them. The special attribute of this liquid is that it rotates or “twists” the plane of polarized light. This effect is influenced by the creation of an electrical field. The glass plates are thus each coated with a very thin metallic film. To obtain polarized light, you apply a polarization foil, the polarizer, to the bottom glass plate. Another foil must be applied to the bottom glass plate, but this time with a plane of polarization twisted by 90°. This is referred to as the analyzer.

In the idle state, the liquid twists the plane of polarization of the incoming light by 90° so that it can pass the analyzer unhindered. The LCD is thus transparent. If a specific voltage is applied to the metallic film coating, the crystals rotate in the liquid. This twists the plane of polarization of the light by another 90°, for example: The analyzer prevents the light getting through, and the LCD thus becomes opaque.TN, STN, FSTN, blue mode, yellow-green mode

Liquids that twist the plane of polarized light by 90° are referred to as TN (Twisted Nematic). STN (Super Twisted Nematic) liquids twist the plane of polarized light by at least 180°. This gives the display improved contrast. However, this technology does color the display to a certain extent. The most common colors are referred to as yellow-green and blue mode. There is also a gray mode, which in practice is more blue than gray, however.

In order to counteract the undesired color effect, the FSTN technology uses an additional foil on the outer side, but this causes a loss of light and means that this technology is only effective with lit displays.

However, the different colors occur only in displays that are either not lit or that are lit with white light. If there is any color in the lighting (e.g. yellow-green LED lighting), it overrides the color of the display. A blue-mode LCD with yellow-green LED lighting will always appear yellow-green.Static or multiplex driving method

Small displays with a small viewing area are generally statically driven. Static displays have the best contrast and the largest possible angle of view. The TN technology fulfills its purpose to the full here (black and white display, reasonably priced). The bigger displays get, however, the more lines become necessary in static operation (e.g. graphics 128x64=8192 segments =8192 lines). Since there is not enough space on either the display or a driver IC for so many lines, multiplexing is used. The display is thus divided up into rows and columns, and there is a segment at each intersection (128+64=192 lines). Scanning takes place row by row (64x, in other words a multiplex rate of 1:64). Because only 1 row is ever active at any one time, however, the contrast and the angle of view suffer the higher the multiplex rate becomes. This makes it essential to use STN.Angle of view 6°°/12°°

Every LCD has a preferred angle of view at which the contrast of the display is at its optimum. Most displays are produced for the 6°° angle of view, which is also known as the bottom view (BV). This angle corresponds to that of a pocket calculator that is lying flat on a desktop.

12°° displays (top view, TV) are best built into a table-top unit. All displays can be read vertically from the front.Reflective, transflective, transmissive

LCDs without lighting are hard to imagine these days. However, since there are basically four different types of lighting, the type selected depends very much on the application. Here is a brief overview to clarify the situation:LED

However, the lighting also determines the optical impression made by the display, and the display mode; blue or yellow-green – does not always have an influence. Below you can see the EAP162-3N display with different types of lighting by way of example:Lighting

Standard LCDs have a temperature range of 0 to +50°C. High-temperature displays are designed for operation in the range from -20 to +70°C. In this case, however, additional supply voltage is generally required. Since the contrast of any LCD is dependent on the temperature, a special temperature-compensation circuit is needed in order to use the entire temperature range, and this is particularly true for high-temperature displays (-20 to +70°C). Manual adjustment is possible but rather impractical for the user.

However, the storage temperature of a display should never be exceeded under any circumstances. An excessively high temperature can destroy the display very quickly. Direct exposure to the sun, for example, can destroy an LCD: This is because an LCD becomes darker (in positive mode) as it gets hotter. As it gets darker, it absorbs more light and converts it to heat. As a result, the display becomes even hotter and darker... In this way, temperatures of over 100°C can quickly be reached.Dot-matrix, graphics and 7-segment displays

The first LCDs were 7-segment displays, and they are still found today in simple pocket calculators and digital watches. 7 segments allow all of the digits from 0 to 9 to be displayed.

Text displays require what is known as a dot matrix, an area consisting of 5x7=35 dots, in order to display all of the letters in the alphabet as well as various special characters. Graphics displays have a similar structure to text displays. In this case, however, there are no spaces between the lines and characters.Display drivers and controllers

The semiconductor industry now offers a very large range of LCD drivers. We generally distinguish between pure display drivers without intelligence of their own, controllers with a display memory and possibly a character set, and micro-controllers with integrated LC drivers.

Pure display drivers work in a similar way to a shift register. They generally have a serial input. They require an external pulse, and in multiplex operation with high frequency they require new display data continuously in order to achieve a refresh frequency that is as high as possible (MSM5219, UPD7225, HD44100, LC7942, etc.). An example of a genuine controller is theHD44780 for dot-matrix displays: Once it has received the ASCII code, the controller manages its character set, memory and multiplexing entirely on its own. The following controllers are widely used for graphics displays: HD61202/3, HD61830, SED1520, SED1330, T6963.

Many ask themselves, "What is the difference between an LCD display and a TFT-display?" or "What is the difference between a TFT and an OLED display?". Here are these 3 sometimes extremely different display technologies briefly explained. LCD vs. TFT vs. OLED (comparison).

- The LCD (Liquid Crystal Display) is a passive display technology. The operation and the structure are described above. Passive means that an LCD can only darken or let out light. So it always depends on ambient light or a backlight. This can be an advantage because the power consumption of a LCD display is very, very low. Sometimes even less than the accumulated power consumption of an E-paper display, which in static operation requires absolutely no energy to maintain the content. To change the contents, however, a relatively large amount of power is required for an E-paper display.

LCDs can also be reflective, so they reflect incident light and are therefore legible even at maximum brightness (sunlight, surgical lighting). Compared to TFT and also OLED, they have an unbeatable advantage in terms of readability and power consumption :; the "formula" is: Sunlight = LCD.

- A TFT-display (of Thin-Film Transistor) is usually a color display (RGB). From the construction and the technology it corresponds to the LCD. It is also passive, so it needs a backlight. This is in any case necessary except for a few, very expensive constructions. However, a TFT needs much more light than the monochrome relatives, because the additional structures on the glass as well as the additional color filters "swallow" light. So TFTs are not particularly energy-efficient, but can display in color and at the same time the resolution is much higher.

- OLED displays (by Organic-Light-Emitting-Diode) are as the name implies active displays - every pixel or sign generates light. This achieves an extremely wide viewing angle and high contrast values. The power consum