tft display theory price

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.

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.

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

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.

Logic Technologies began it"s life as a custom display design and manufacturing company back in 2008. Over the past 8 years we have developed hundreds of custom display solutions from 1.1" TFT displays for gaming button consoles, small true transflective TFTs, ruggedised 7" TFT and Touch Panel modules all the way to full-customised 15" computers, complete with IP67-rated stainless steel housing for ruggedized environments.

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.

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

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 consumption is dependent on the display content. Here OLEDs to TFTs and LCDs differ significantly, which have a nearly constant power consumption even with different display contents. Unfortunately, the efficiency of converting the electric current into light energy is still very poor. This means that the power consumption of OLEDs with normal content is sometimes higher than that of a TFT with the same size. Colored OLEDs are increasingly used in consumer devices, but for the industry, due to their availability and lifetime, currently only monochrome displays are suitable (usually in yellow color).

In the reaction time, the OLEDs beat each TFT and LCD by worlds. Trise and Tfall are about 10μs, which would correspond to a theoretical refresh rate of 50,000 Hz. Possibly an advantage in very special applications.

Finally the question "What is better, LCD, OLED or TFT?" Due to the physical differences you can not answer that blanket. Depending on the application, there are pros and cons to each individual technology. In addition to the above differences, there are many more details in the design and construction that need to be individually illuminated for each device. Write us an e-mail or call us: we have specialists with some 20- and 30-year experience. We are happy to compare different displays together with you.AACS and IPS technology

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.

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.

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

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

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

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

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

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

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

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

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Reports suggest that Apple is getting closer to implementing MicroLED in its future product releases, including the Apple Watch, with the display technology potentially offering a number of benefits compared to other methods. AppleInsider explains how the current TFT and OLED display technologies work, and how MicroLED differs.

MicroLED shows promise as a display technology, potentially offering power savings and a reduced screen thickness when put beside current-generation display panels. Apple has recognized the potential, and has invested heavily into developing the technology over the last few years, with a view to using it in the company"s future products.

To understand fully how MicroLED can benefit Apple, it is worth understanding how the commonly-used display technologies work in the first place, before examining how different MicroLED really is in a comparison.

The most common display technology used by consumer products today, and the oldest of the technologies examined in this article, TFT"s full name of TFT LCD stands for Thin-film-transistor liquid-crystal display. This technology is extensively used by Apple in its products, found in iPads, iPhones, MacBooks, and iMac lines.

The LCD part relates to the concept of defining small translucent or transparent areas in a thin and flexible liquid crystal-filled panel, like the displays used in calculators. Passing current through the segment changes the molecular properties of the defined segment area, allowing it to switch between being see-through or opaque.

TFT takes this a stage further, by effectively covering an entire panel with a grid of isolated liquid crystal segments, which again can vary between opaque and transparent based on the level of electrical current. In this case, there are far more segments needed to make up the display than with a normal calculator.

Polarizing filters on either side of the TFT display sandwich are used to prevent light from passing through directly, with the liquid crystal reaction of each segment affecting polarized light passing through the first filter to go through the second.

Sometimes these types of display are known as "LED," but this somewhat of a misnomer, as this actually refers to the use of Light Emitting Diodes as a light source. The LED backlight shines light through the various layers making up the TFT LCD.

Displays that use collections of LEDs as individual pixels do exist, but it isn"t usually found in consumer products. LED screens are commonly used for billboards, in attractions, and as a large-scale display for events.

TFT LCD screens continue to be widely used in production for a number of reasons. Manufacturers have spent a long time perfecting the production of the display panels to make it as cheap as possible, while its high usage allows it to benefit from economies of scale.

Used in consumer devices in a similar way to TFT LCD, OLED (Organic Light-Emitting Diode) is a display technology that is similar in the basic concept, but differs considerably in its execution. Again, the idea is for a thin panel to be divided up into segments, with charge applied to each section to alter its molecular properties, but that"s where the techniques diverge.

These self-emitting pixels gives OLED a considerable advantage over LCD-based systems in a number of areas. Most obviously, by not needing a backlight, OLED panels can be made far thinner than an equivalent LCD-based display, allowing for the production of thinner devices or more internal area for other components, like a larger battery.

The power efficiency of OLED panels can be far greater, as while a TFT screen requires an always-on backlight, the brightness of OLED pixels themselves determine power usage, with a black pixel consuming no power at all. OLED screens are also faster to respond than LCD displays, making them more useful for VR displays, where response time needs to be as rapid as possible.

This also allows OLED to provide superior contrast ratios compared to TFT, as the lack of backlight bleed-through that occurs in TFT simply doesn"t happen in OLED.

OLED also can be produced on plastic substrates instead of glass, allowing it to be used to create flexible displays. While this is currently embodied in curved and other non-flat screens in some devices, it has the potential to be employed in foldable smartphones or rolled up for storage, an area Apple is also allegedly examining.

Despite the advantages, OLED is still lagging behind TFT in terms of adoption. The cost of production is far higher, in part due to the need for extremely clean environments, as a single speck of dust can potentially ruining a display during fabrication.

OLED panels are also affected by the presence of water, both in production and in use. Small amounts of water contacting the organic substrate can cause immediate damage to the display, rendering parts of the screen useless.

Thought to be the next big thing in display technology, MicroLED basically takes the idea of using LEDs for pixels in a large stadium-style screen and miniaturizes it all.

Using extremely small LEDs, three MicroLEDs are put together to create each pixel, with each subpixel emitting a different color from the usual red, blue, and green selection. As each LED emits light, there is no need for a backlight as used in TFT screens.

MicroLED doesn"t use an organic compound to produce light, making it less susceptible to failure compared to OLED. Just like OLED, it can be applied onto a flexible material, allowing it to be used for curved displays or non-stationary components, like a watch strap, and can result in an extremely thin display panel.

MicroLED offers the same lower power consumption and high contrast ratio benefits as OLED when compared to TFT. However, MicroLED is also capable of producing a far brighter image than OLED, up to 30 times brighter, and is in theory more efficient in converting electricity into light.

As a relatively new and in-development technology, the cost of MicroLED production is extremely high in comparison to the more established OLED and TFT mass production lines, in part due to lower than required yields. Manufacturing equipment vendors have produced hardware for MicroLED production that cuts defects in half and reduces deposition deviance from 3 nanometers down to 1 nanometer, but it is unclear if this is enough to help mass production move forward.

While MicroLED is an attractive proposition for Apple, it is not the only technology under development by the company"s engineers. Apple has previously filed patent applications for a technology described as "Quantum Dot LED and OLED Integration for High Efficiency Displays."

Quantum Dots are photoluminescent particles included in an LED-backed TFT display that can produce brighter and more vibrant colors, with the colors produced depending on their size. While available in current QLED televisions, the technology is only really being used to enhance the backlight, rather than being used to illuminate individual pixels.

Image: Lee, Changhee & BAE, Wanki & KWAK, Jeonghun. (2014). "Quantum Dot LED (QLED) Emerging as a Next-generation Display Technology" in Physics and High Technology

The technology in theory can create an even thinner display than OLED, along with a more streamlined manufacturing process. True QD displays are also capable of high pixel densities of up to 1,000ppi, multiple times the density required to be called a Retina-quality display, and based on Apple"s hybrid invention, will also boast the response times of OLED technology.

The QD patent application certainly shows Apple is thinking about display technology in multiple ways, and how it can be applied to future devices, but short of getting firm supply chain information or an official announcement from Apple directly, it is difficult to confirm which direction it will be heading.

Apple has been interested in using the technology for some time now, with the first notable sign being its acquisition of LuxVue in May 2014, alongside assorted related patents. A MicroLED specialist, LuxVue was rumored to have been the display producer for the ill-fated Google Glass headset, but was also the holder of assorted patents in the LED display field, including MicroLED.

At the time, the acquisition was thought to be an attempt by Apple to bring part of its display technology development in-house, with suggestions the MicroLED technology would be used in another rumored-at-the-time device, the Apple Watch. A more recent report suggests Apple is working with TSMC to make small panels for a future premium Apple Watch, potentially starting mass production by the end of the year.

The facility is also claimed to be sufficient in size to perform small scale manufacturing of display panels, allowing the company to keep development and testing in-house without involving third-parties. Considering Apple"s previous history in developing technologies before issuing information to manufacturing partners, it is possible that Apple is trying to work out the kinks in production before suppliers even attempt to make MicroLED panels.

The rumored small screen production may be for the Apple Watch now, but it may also benefit another often-rumored device, namely the VR or AR headset. This type of hardware relies on light components to keep the weight off the user"s head and neck, as well as displays with a high refresh rate and as close to perfect color reproduction as possible.

Apple is also apparently planning to use the technology in larger displays, said to be bigger in size than those in the MacBook Pro lines. This could be an iMac or iMac Pro, or even an external display, but ultimately there"s no real indication of Apple"s plans at this point, regardless of the scale of the screen.

Reports from last year also suggest Apple"s investment in MicroLED was a cause for concern for Samsung, LG, and other South Korean suppliers who provide display panels for the company"s products. Owning the process for MicroLED manufacturing could allow Apple to migrate away from its existing display suppliers in the coming years, reducing revenues and profits.

Aside from Apple"s development, there has been little in the way of announcements from other firms for products using the technology that could be bought by consumers in the coming months. The exception is Samsung, Apple"s main rival in the mobile marketplace and a major supplier of display panels, but its usage of MicroLED is not aimed at producing smaller screens.

The impending use of the technology in a high-priced consumer product could be considered proof that MicroLED display technology is maturing enough for use in devices. If the reports claiming Apple is getting close to mass producing panels is true, the inclusion of MicroLED in the Apple Watch could end up being the first mainstream usage of the technology.

Our eternal pursuits are the attitude of "regard the market, regard the custom, regard the science" plus the theory of "quality the basic, have faith in the main and management the advanced" for Tft Display, Portable Touch Screen, Lcd Front Panel, Tft Device,Tft Panel. Our customers mainly distributed in the North America, Africa and Eastern Europe. we will source top quality goods using the really aggressive selling price. The product will supply to all over the world, such as Europe, America, Australia,Orlando, Morocco,California, The Swiss.Since our establishment, we keep on improving our products and customer service. We are able to provide you with a wide range of high quality hair products at competitive prices. Also we can produce different hair products according to your samples. We insist on high quality and reasonable price. Except this, we provide best OEM service. We warmly welcome OEM orders and customers all over the world to cooperate with us for mutual development in the future.

The traditional mechanical instrument lacks the ability to satisfy the market with characters of favorable compatibility, easy upgrading, and fashion. Thus the design of a TFT-LCD (thin film transistor-liquid crystal display) based automobile instrument is carried out. With a 7-inch TFT-LCD and the 32-bit microcontroller MB91F599, the instrument could process various information generated by other electronic control units (ECUs) of a vehicle and display valuable driving parameters on the 7-inch TFT-LCD. The function of aided parking is also provided by the instrument. Basic principles to be obeyed in circuits designing under on-board environment are first pointed out. Then the paper analyzes the signals processed in the automobile

instrument and gives an introduction to the sampling circuits and interfaces related to these signals. Following this is the functional categorizing of the circuit modules, such as video buffer circuit, CAN bus interface circuit, and TFT-LCD drive circuit. Additionally, the external EEPROM stores information of the vehicle for history data query, and the external FLASH enables the display of high quality figures. On the whole, the accomplished automobile instrument meets the requirements of automobile instrument markets with its characters of low cost, favorable compatibility, friendly interfaces, and easy upgrading.

As an essential human-machine interface, the automobile instrument provides the drivers with important information of the vehicle. It is supposed to process various information generated by other ECUs and display important driving parameters in time, only in which way can driving safety be secured. However, the traditional mechanical automobile instrument is incompetent to provide all important information of the vehicle. Besides, the traditional instrument meets great challenge with the development of microelectronic technology, advanced materials, and the transformation of drivers’ aesthetics [1, 2]. Moreover, the parking of the vehicle is also a problem puzzling many new drivers. Given this, traditional instruments should be upgraded in terms of driving safety, cost, and fashion.

The digital instrument has functions of vehicle information displaying, chord alarming, rear video aided parking, LED indicating, step-motor based pointing, and data storage. The instrument adopts dedicated microcontroller MB91F599, a 7-inch LCD, and two step-motors to substitute for the traditional instrument. All the information generated by other ECUs can be acquired via not only the sample circuits but also the CAN bus.

The CAN bus interface and the 7-inch TFT-LCD make it more convenient to upgrade the instrument without changing the hardware. If the software needs to be upgraded, we need not bother to take the instrument down and program the MCU. Instead, we can upgrade the instrument via the vehicle’s CAN network without taking the instrument down, which makes the upgrading more convenient. Most of the information from other ECUs can be transmitted via the CAN bus; so, we do not have to change the hardware circuits if some of the ECUs’ signals are changed in different applications. Besides, since most of the driving parameters are displayed on the TFT-LCD, and the graphical user interface can be designed with great flexibility by programming, only the software needs to be revised to meet different requirements of what kind of driving parameters to display and so forth. These characters, together with the reserved interfaces, enhance the instrument’s compatibility in different applications.

On the one hand, there are some automobile instruments which adopt 8-bit MCUs or 16-bit MCUs which have limited peripherals, so it is difficult for them to meet some requirements such as rearview video and high real-time data processing performance. And many extra components are needed if the designer wants to accomplish some functions such as video input. On the other hand, there are some advanced automobile instruments which adopt high performance MCUs (such as i.MX 53, MPC5121e, and MPC5123) and run Linux on them. They even use larger TFT-LCDs (such as the 12.3-inch TFT-LCD with a resolution of 1280 × 480 pixels) to display driving parameters. These automobile instruments show higher performances than the instrument in this paper. However, they are more expensive than this automobile. This instrument is able to provide almost all the functions of the advanced automobile instrument with a lower cost.

Respecting the above mentioned factors, we finally chose the MB91F599 produced by Fujitsu as the microcontroller. The MB91F599 is particularly well-suited for use in automotive instrument clusters using color displays to generate flexible driver interfaces. It integrates a high performance FR81S CPU core which offers the highest CPU performance level in the industry. Besides, it has a graphics display controller with strong sprite functionality, rendering engine, and external video capture capabilities. These greatly reduce the need for extra components and enhance the stability of the system. The rendering engine can operate in combination with the video capture to enable image manipulation. Overlaid graphics such as needles or parking guidelines can be rendered in conjunction with captured video, which helps to accomplish the aided parking. What is more, multiple built-in regulators and a flexible standby mode enable the MB91F599 to operate with low power consumption.

Here, the sync signal is not present, so the clamp level is controlled by the clamp level output pin of the microcontroller, which is called “keyed clamp” [5]. The graphics display controller of the microcontroller let the clamp level output occur in coincidence with the sync pulse; that is, the clamp level output occurs during the sync tip in Figure 6, thus we get the “sync tip clamp” [5].

Since the FLASH size of the microcontroller is only 1 MB which is limited for the storage of pictures displayed on the LCD, external FLASH is needed to store different kinds of meaningful pictures such as the background of the dial. Two S29GL256N chips with a memory capacity of 256 Mb are chosen for picture data storage for their high performance and low power consumption. The application circuits of the chips are provided in their datasheets, so it is unnecessary to go into the details of them here.

The 7-inch TFT-LCD has a resolution of pixels and supports the 24-bit for three RGB colors. The interface of the 60-pin TFT-LCD can be categorized into data interface, control interface, bias voltage interface, and gamma correction interface.

The data interface supports the parallel data transmitting of 18-bit (6 bits per channel) for three RGB colors. Thus, a range of colors can be generated. The control interface consists of a “horizontal synchronization” which indicates the start of every scan line, a “vertical synchronization” which indicates the start of a new field, and a “pixel clock.” This part is controlled by the graphics display controller which is integrated in the MB91F599. We just need to connect the pins of the LCD to those of the microcontroller correspondingly.

Bias voltages are used to drive the liquid crystal molecules in an alternating form. The compact LCD bias IC TPS65150 provides all bias voltages required by the 7-inch TFT-LCD. The detailed circuit is also provided in the datasheet of TPS65150.

The greatest effect of gamma on the representations of colors is a change in overall brightness. Almost every LCD monitor has an intensity to voltage response curve which is not a linear function. So if the LCD receives a message that a certain pixel should have certain intensity, it will actually display a pixel which has intensity not equal to the certain one. Then the brightness of the picture will be affected. Therefore, gamma correction is needed. Several approaches to gamma correction are discussed in [20–22]. For this specific 7-inch LCD, only the producer knows the relationship between the voltage sent to the LCD and the intensity it produces. The signal can be corrected according to the datasheet of the LCD before it gets to the monitor. According to the datasheet, ten gamma correction voltages are needed. These voltages can be got from a resistive subdivision circuit.

The main task for the program is to calculate the driving parameters of the vehicle and display them on the TFT-LCD. The calculation is triggered by the input signals via the sampling circuits or the CAN bus. The main program flow chart of the system is shown in Figure 10.

The design scheme of a TFT-LCD based automobile instrument is carried out form aspects of both the hardware and the main program flow chart. The MB91F599 simplifies the peripheral circuits with its rich on-chip resources and shows high performance in real-time data processing. The automobile instrument is capable of displaying the velocity of the vehicle, the engine speed, the cooling water temperature, the oil pressure, the fuel volume, the air pressure, and other information on the TFT-LCD, which contributes a lot to driving safety and satisfies drivers’ aesthetics. Besides, the rearview video makes the parking and backing easier and safer for the driver. Moreover, the CAN bus interface and TFT-LCD make it easier for the upgrading of the instrument without changing the hardware, thus saving the cost.

※Price Increase NotificationThe TFT glass cell makers such as Tianma,Hanstar,BOE,Innolux has reduced or stopped the production of small and medium-sized tft glass cell from August-2020 due to the low profit and focus on the size of LCD TV,Tablet PC and Smart Phone .It results the glass cell price in the market is extremely high,and the same situation happens in IC industry.We deeply regret that rapidly rising costs for glass cell and controller IC necessitate our raising the price of tft display.We have made every attempt to avoid the increase, we could accept no profit from the beginning,but the price is going up frequently ,we"re now losing a lot of money. We have no choice if we want to survive. There is no certain answer for when the price would go back to the normal.We guess it will take at least 6 months until these glass cell and semiconductor manufacturing companies recover the production schedule. (Mar-03-2021)

ER-TFTV043A3-3 is 480x272 pixel 4.3 inch color tft lcd display for the Raspberry Pi with optional USB port resistive or capacitive touch panel screen,optional USB cable and HDMI cable. Of course ,it is not limited to the Raspberry Pi ,it can be used for all the universal HDMI port hardwares such as mini PCs, Raspberry Pi, BB Black, Banana Pi, as well as general desktop computers.

Costco may present evidence of its “umbrella theory” of damages at trial, pursuant to a Sept. 23 order from the U.S. District Court for the Western District of Washington, which denied TFT-LCD makers’ motion in limine to exclude evidence of this aspect of Costco’s damage theory in its price fixing case (Costco Wholesale Corp. v. AU Optronics Corp., 2014 BL 263376, W.D. Wash., 2:13-cv-01207-RAJ, 9/23/14).

While buying a mobile phone we might have heard these words – IPS LCD display, TFT LCD display, OLED display, Super AMOLED display, etc. We often get confused as to which is the best. So, let us explain each of the displays.

LCD means Liquid crystal display. In the LCD display, there is a light in the background of pixels which is called a backlight that provides light to the pixels for projecting the content. If there is no light in the background we could not able to see the content which is displaying on the screen. There are a few types of LCD panels. In the LCD panel, we have CCFL backlighting which means Cold Cathode Fluorescent Lamp. These are explained as following below.Twisted Nematic (TN) –

Twisted Nematic displays are widely used in computer monitors in some industries. These displays are commonly used by gamers for a better experience. Because they are inexpensive and faster response.

The vertical alignment panel falls under the middle of the TN panel and IPS panel. This display has better viewing angles and better color reproduction as compared to the TN display.

This type of display used for commercial purposes in cockpits. AFFS display is extremely quality of LCD display as of now because they have good color reproduction, best viewing angles than the IPS panel and TN panel. It also minimizes color distortion.

Thin Film Transistor display is the cheapest display in LCD. In this display, every pixel is attached to a capacitor and transistor. The main advantage of this display is the high contrast ratio and very cheap to build by the way we see this type of displays in budget mobiles below 10K price.

In-Plane Switching is the most popular display between the 10k to 20k price range in mobiles. By the way, this is the best display on LCD. They are very much the best than the TFT display. This display can produce better viewing angles, best color reproduction, and direct sunlight visibility.

Super LCD is the marketing term of HTC. Generally, it is also a type of IPS LCD but there is a slight change. In the IPS LCD display, there is some gap between the outer glass and the touch sensor. In the SLCD display, there is no gap between the outer glass and touch sensor.

There are so many types of LED displays. Generally, we may see these two displays in the flagship category mobiles. they are, OLED and AMOLED displays. Technology is almost the same, but OLED is developed by a company named LG, and AMOLED is developed by a company called Samsung.AMOLED (Active-Matrix Organic Light Emitting Diode) –

This technology completely belongs to Samsung. They took patients also. The main function of the AMOLED display is the individual pixel act as an LED bulb. Which means they do not require backlighting. This technology helps in power saving and projecting true black colors. The pixels stop projecting light when the video has black color.

This technology belongs to LG. LG took patents on the OLED panel. It is like the LGs trademark. This display is also like an AMOLED display. OLED has a series of organic thin-film between two conductors. When the current is applied, light is emitted. These are more efficient than LCD displays.

Retina display is the trademark of the company named APPLE. Actually, the retina display is an IPS LCD display only. APPLE modified the IPS LCD display and renamed it. In retina display, we can more PPI (Pixel per inch) than IPS LCD displays. It is not a separate technology. It is a modification of the IPS LCD display. We can see retina displays in apple mobiles.