how tft display works quotation

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.

Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.

Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.

K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. AIP. 37 (1): 1079–82. doi:10.1889/1.2433159. S2CID 129569963.

Kim, Sae-Bom; Kim, Woong-Ki; Chounlamany, Vanseng; Seo, Jaehwan; Yoo, Jisu; Jo, Hun-Je; Jung, Jinho (15 August 2012). "Identification of multi-level toxicity of liquid crystal display wastewater toward Daphnia magna and Moina macrocopa". Journal of Hazardous Materials. Seoul, Korea; Laos, Lao. 227–228: 327–333. doi:10.1016/j.jhazmat.2012.05.059. PMID 22677053.

TFT Liquid crystal display products are diversified, convenient and versatile, simple to keep up, upgrade, update, long service life, and have many alternative characteristics.

The display range covers the appliance range of all displays from one to forty inches and, therefore, the giant projection plane could be a large display terminal.

Display quality from the most straightforward monochrome character graphics to high resolution, high colour fidelity, high brightness, high contrast, the high response speed of various specifications of the video display models.

In particular, the emergence of TFT LCD electronic books and periodicals will bring humans into the era of paperless offices and paperless printing, triggering a revolution in the civilized way of human learning, dissemination, and recording.

It can be generally used in the temperature range from -20℃ to +50℃, and the temperature-hardened TFT LCD can operate at low temperatures up to -80 ℃. It can be used as a mobile terminal display or desktop terminal display and can be used as a large screen projection TV, which is a full-size video display terminal with excellent performance.

The manufacturing technology has a high degree of automation and sound characteristics of large-scale industrial production. TFT LCD industry technology is mature, with a more than 90% mass production rate.

From the beginning of flat glass plates, its display effect is flat right angles, letting a person have a refreshing feeling. LCDs are simple to achieve high resolution on small screens.

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

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

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

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

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

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

Compared with ordinary LCDs, TFT LCDs provide very clear images/text with shorter response times. TFT LCDs are increasingly being used to bring better visual effects to products.

TFT stands for “thin film transistor”. The transistor of a color TFT LCD is composed of a thin film of amorphous silicon deposited on glass. It acts as a control valve to provide the appropriate voltage to the liquid crystal for each sub-pixel. This is why TFT LCDs are also known as active matrix displays.

TFT LCDs have a liquid crystal layer between a glass substrate formed by the TFT and transparent pixel electrodes and another glass substrate with a color filter (RGB) and a transparent counter electrode. Each pixel in the active matrix is paired with a transistor that includes a capacitor, which gives each sub-pixel the ability to retain its charge without sending a charge every time it needs to be replaced. This means that TFT LCDs are more responsive.

To understand how a TFT LCD works, we must first grasp the concept of a field effect transistor (FET), which is a transistor that uses an electric field to control the flow of current. It is a component with three terminals: source, gate and drain. fet controls the flow of current by applying a voltage to the gate, thereby changing the conductivity between the drain and source.

Using the FET, we can build a circuit as follows. The data bus sends a signal to the source of the FET, and when SEL SIGNAL applies a voltage to the gate, a drive voltage is generated on the TFT LCD panel. A sub-pixel is lit. A TFT LCD display contains thousands or millions of such driver circuits.

Color TFT LCD from 1.8 inch ~ 15 inch, there are different resolutions and interfaces. How to choose the right TFT LCD, you can refer to the previous article “LCD | How to choose a liquid crystal display module

TFT displays have become increasingly common in our daily lives. They are used in cars, laptops, tablets, and smartphones, as well as in industrial applications and many more. But what are TFT displays and why are they so important?

A TFT (Thin Film Transistor) display is a type of display technology that uses a thin layer of transparent material to produce an image on the screen. The display is made up of thin layers of organic material called organic transistors, which are stacked together on a glass substrate and covered with a thin layer of plastic or metal oxide.

TFT displays are also used in many other industrial applications, such as industrial control systems, medical devices, automotive infotainment systems, and more.

The basic concept behind a TFT display is simple: it uses light to create an image on a screen. Light passes through the glass substrate and the organic transistors until it reaches the top layer of the display.

The number of pixels that can be displayed depends on how many organic transistors are used in each pixel or subpixel (a single-pixel is made up of multiple subpixels). For example, a 4-inch (10 cm) display has a pixel pitch of 0.0625 inches (1.57 mm).

The basic design of a TFT display has remained unchanged for more than 20 years. In this design, the sub-pixels are arranged in a grid pattern, with each subpixel connected to its neighbor by wires that form rows and columns.

The first large format TFT display was introduced in 1987 by NEC Corporation, which used a 1024×768 pixel screen for its PC monitor line, called CRT Professional Display System or “Videotronic” system. The technology was licensed to NEC’s competitors such as Hitachi and Toshiba for use in their own monitors and televisions. The system was marketed as “Super Video” and replaced the aging “Videotron” CRT monitors that were still being used at the time. The first LCD TV was also produced in 1987 by Sony.

In 1989, Sharp’s first TFT-LCD TV set was introduced with a resolution of 576×320 pixels, while the world’s first large format high definition screen with a resolution of 1024×768 pixels was introduced by NEC in 1994.

Over the years, TFT display technology has developed by leaps and bounds. It has been used in tablets, smartphones, notebooks, game consoles, and computer monitors. The technology is also used in digital cameras, camcorders, MP3 players, and GPS devices.

What does the TFT display technology comprise? From far, you can easily assume TFT to be a single unit. But in reality, it comprises different components that work together.

The backlight of the TFT display is a very important component. It provides the light for the pixels and is also responsible for illuminating the display. The light emitted by a backlight can be controlled by varying the amount of current running through it.

When it comes to LCD displays, there are two types of backlights; Active matrix and Passive matrix. Active matrix backlight has several layers of electrodes, which are used to control the amount of current flowing through them.

The pixel is the smallest unit in a TFT display. It is the basic unit of information that is displayed on the screen. The pixel consists of three sub-elements, namely; Red, Green, and Blue (RGB).

The number of sub-pixels that are used in each pixel varies with different display technologies. In full-color LCDs, there are three types of sub-pixel: red, green, and blue (RGB). Full color TFT displays use a combination of Red, Green, and Blue (RGB) sub-pixels to represent full color.

The light that is transmitted through each TFT is controlled by applying voltages of different values to each pixel in turn. To do this, a control circuit called a driver circuit is required. The driver circuit controls the voltage applied to each pixel with reference to a set of parameters known as “pixel information”.

This information includes color, brightness, and other characteristics that define how an individual pixel should be operated for display purposes. The parameters also include how many red, green and blue sub-pixels are used to produce each pixel.

The control system can be further divided into 3 sub-systems: the interface, the timing, and the data transfer system (DTS). These systems work together to provide all of the necessary functions for controlling TFT displays from external sources such as computers, printers, or TVs.

This is another component of a TFT display system. It consists of a liquid crystal material sandwiched between two glass plates. This material is responsible for controlling the light by changing its refractive index.

-Wide viewing angle: The viewing angle of the TFT display is larger than that of the CRT set. It is generally considered to be the best choice for applications requiring an extended viewing angle.

-Transparency: TFT display has better transparency than CRT set, which makes it more suitable for applications requiring high transparency such as window displays and computer monitors.

-High resolution: TFT display can produce higher resolution than CRT display. For example, the pixel density of TFT is about 3 million pixels per square inch (PPI), which is about three times that of conventional liquid crystal displays (LCDs) whose pixel density is about 100 ppi.

-Reliability: Since it uses no moving parts, the TFT screen does not need any maintenance or repair, and therefore the reliability is higher than that of LCDs and plasma displays.

-Power saving: TFT display consumes much less power than CRT. The power consumption of a mainstream TFT display is about 1/10 that of a typical LCD. In some applications, the power consumption can be reduced to 1/100 or less of that of a CRT.

-High brightness: The picture displayed on the screen can be bright enough to be seen in bright sunlight without any need for glare reduction filters.

-Compatibility: Since it uses no moving parts, the TFT screen does not have any mechanical problems such as screen flicker and image sticking problems found in plasma displays and LCDs.

-High resolution: Although the pixel density of TFT is about 3 million pixels per square inch (ppi), the resolution is more than 100 ppi which makes it more suitable for many applications where high resolution is needed.

-Consistency: Since it uses no moving parts, the image displayed on the TFT display is not affected by temperature and humidity, which makes it more consistent than LCDs and plasma displays.

-Cost: The cost of a TFT display is lower than that of LCDs and plasma displays. For example, in some applications where image quality is not critical, the cost of a TFT display may be only a few tens to a few hundreds of dollars while the cost of LCDs or plasma displays may be several thousand to several tens of thousands.

-Excellent color display: We can’t deny the fact that TFTs have a superior color display. This simply means that the color of pixels can be accurately reproduced.

-Very thin: When compared with LCDs and plasma displays, which are very thick, TFTs are very thin and lightweight. In addition, the cost of mounting a large size TFT screen to a wall panel is relatively low.

-No ghosting: ‘Ghosting’ refers to the fact that the display shows a bright spot on the screen when the screen is turned off. TFT screens do not show ghosting. TFTs produce a sharp image even when they are turned off.

-No geometric distortion: Geometric distortion refers to the shape of the display on a flat surface. TFTs produce a sharp image even when they are turned off.

-No radiation: TFTs do not emit any harmful radiation, and there is no need for shielding or shielding materials to protect people from harmful radiation.

Considering that TFTs use less power, it is possible to reduce energy consumption by up to 50% compared with LCDs. In addition, if you use LED backlights in TFT displays, you can reduce power consumption by up to 75% compared with conventional backlights.

If a product uses a backlight, there is a high possibility that the color of the screen will be affected after some time due to dust or dirt that comes into contact with it. But it is possible to prevent this problem by using TFTs with LED backlights, which have no problems such as those caused by dust and dirt.

Workability refers to the ease with which you can operate a product. When working with a screen that has TFTs, it is possible to increase the amount of information that can be displayed at one time. It is also possible to reduce the number of times you must change settings on a product by increasing its usability.

Design refers to what you can create with the use of a product. Using TFTs, it is possible to create products that have a thin profile and are lightweight, which makes them more convenient for transportation and storage.

Human interface refers to what you touch when using a product or what you see on the screen when using a product (e.g., buttons and other controls). By integrating the TFTs into the display part of a product, it is possible to make the human interface easier.

Amoled refers to a technology that replaces the traditional liquid crystal display (LCD) with an organic light-emitting diode (OLED). Modern TFTs are similar to Amoled in terms of their structure, but they differ from Amoled in terms of their performance.

The TFTs of the present invention have superior characteristics compared to Amoled, such as high contrast ratio and response speed. The TFTs also have superior characteristics compared to conventional display devices such as CRT and plasma display panels, which cannot be achieved by these conventional display devices.

IPS refers to a technology that replaces the traditional liquid crystal display (LCD) with in-plane switching technology. The IPS display has superior features to TFT due to its high contrast ratio, wide viewing angle, and high response speed.

There are certain limitations to TFTs. For example, there is a limit to the size of the display and the resolution of the image that can be displayed on a display. Also, because TFTs are considered to be a kind of organic semiconductor displays, they have a short life span and therefore need frequent replacement.

Because of their high resolution, TFT displays are used in display monitors. The type of TFT used in display monitors can be categorized as either active matrix or passive matrix. Active matrix TFTs use a thin film transistor (TFT) as its active component, whereas passive matrix uses a liquid crystal display (LCD).

TFTs are also being used in portable electronic devices such as mobile phones, personal digital assistants (PDAs), and cameras. These devices require high-resolution screens because the user must be able to view accurate images and text on the screen. TFTs are also being used in laptops, which have a much larger screen size than many other portable electronic devices.

Because of their size and high resolution, laptop computers use passive matrix TFT displays instead of LCDs for larger displays than those found on smaller-sized portable electronics devices that use LCDs for their displays (e.g., mobile phones and PDAs).

TFT displays are used in front-projection TVs. The type of TFT used in front-projection TVs can be categorized as either active matrix or passive matrix. Active matrix TFTs use a thin film transistor (TFT) as its active component, whereas passive matrix uses a liquid crystal display (LCD).

Head-mounted displays (HMDs) use liquid crystal on silicon technology to create small, inexpensive, low-power VR headsets that can be worn on the head. Some HMDs use active matrix TFT technology while others use passive matrix TFT technology. Active matrix HMDs use shorting bars or glass electrodes to control each pixel; passive matrix HMDs use a liquid crystal material that allows for the creation of an image by controlling the voltage applied to each pixel.

TFTs are used in projectors to create the on-screen image from the input signal. TFTs are used in both active matrix and passive matrix projectors. Active matrix projectors use shorting bars or glass electrodes to control each pixel, while passive matrix projectors use a liquid crystal material that allows for the creation of an image by controlling the voltage applied to each pixel.

CCDs are used in digital cameras and DV camcorders to capture still images and video, respectively. CCDs use a single array of photosites that each receives an electrical charge during exposure to light, resulting in an electrical signal that is output as an image. TFTs are used in CCDs as display circuits for previewing pictures.

TFTs are used in the display of gaming systems such as consoles, personal computers, and hand-held devices. TFTs are also used in the display of mobile telephones and in digital signs.

There are many factors to consider when buying a TFT display. The most important factors are the size of the display, the resolution of the display, and whether or not it is touch-sensitive.

It is also vital to consider where you are buying your TFT display system. A good place to buy a TFT display is from an authorized dealer or an online store. You should also consider whether or not the TFT display system you are looking for has a warranty.

At ICRFQ, we can connect you to the best TFT display suppliers and manufacturers in China. Just contact us and we will do what a reliable sourcing agent should do!

and added a reference:B.J.Lechner, "History Crystallized_A First-Person Account of the Development of Matrix-Addressed LCDs for television at RCA in the 1960s",Information Display 1/08 p26-27

I tried to pay due respect to RCA LCD group I admire the most: their LCD research work on TV finished in 1969, according to Lechner"s account, when I was still in the university, and I joined SHARP CRL in 1971 and started research on LCD for mini-calculator; on TFT-LCD for TV in 1984.

Display size, contrast, color, brightness, resolution, and power are key factors in choosing the right display technology for your application. However, making the right choice in how you feed the information to the display is just as vital, and there are many interface options available.

All displays work in a similar manner. In a very basic explanation, they all have many rows and columns of pixels driven by a controller that communicates with each pixel to emit the brightness and color needed to make up the transmitted image. In some devices, the pixels are diodes that light up when current flows (PMOLEDs and AMOLEDs), and in other electronics, the pixel acts as a shutter to let some of the light from a backlight visible. In all cases, a memory array stores the image information that travels to the display through an interface.

According to Wikipedia, "an interface is a shared boundary across which two separate components of a computer system exchange information. The exchange can be between software, computer hardware, peripheral devices, humans, and combinations of these. Some computer hardware devices such as a touchscreen can both send and receive data through the interface, while others such as a mouse or microphone may only provide an interface to send data to a given system.” In other words, an interface is something that facilitates communication between two objects. Although display interfaces serve a similar purpose, how that communication occurs varies widely.

Serial Peripheral Interface (SPI) is a synchronous serial communication interface best-suited for short distances. It was developed by Motorola for components to share data such as flash memory, sensors, Real-Time Clocks, analog-to-digital converters, and more. Because there is no protocol overhead, the transmission runs at relatively high speeds. SPI runs on one master (the side that generates the clock) with one or more slaves, usually the devices outside the central processor. One drawback of SPI is the number of pins required between devices. Each slave added to the master/slave system needs an additional chip select I/O pin on the master. SPI is a great option for small, low-resolution displays including PMOLEDs and smaller LCDs.

Philips Semiconductors invented I2C (Inter-integrated Circuit) or I-squared-C in 1982. It utilizes a multi-master, multi-slave, single-ended, serial computer bus system. Engineers developed I2C for simple peripherals on PCs, like keyboards and mice to then later apply it to displays. Like SPI, it only works for short distances within a device and uses an asynchronous serial port. What sets I2C apart from SPI is that it can support up to 1008 slaves and only requires two wires, serial clock (SCL), and serial data (SDA). Like SPI, I2C also works well with PMOLEDs and smaller LCDs. Many display systems transfer the touch sensor data through I2C.

RGB is used to interface with large color displays. It sends 8 bits of data for each of the three colors, Red Green, and Blue every clock cycle. Since there are 24 bits of data transmitted every clock cycle, at clock rates up to 50 MHz, this interface can drive much larger displays at video frame rates of 60Hz and up.

Low-Voltage Differential Signaling (LVDS) was developed in 1994 and is a popular choice for large LCDs and peripherals in need of high bandwidth, like high-definition graphics and fast frame rates. It is a great solution because of its high speed of data transmission while using low voltage. Two wires carry the signal,  with one wire carrying the exact inverse of its companion. The electric field generated by one wire is neatly concealed by the other, creating much less interference to nearby wireless systems. At the receiver end, a circuit reads the difference (hence the "differential" in the name) in voltage between the wires. As a result, this scheme doesn’t generate noise or gets its signals scrambled by external noise. The interface consists of four, six, or eight pairs of wires, plus a pair carrying the clock and some ground wires. 24-bit color information at the transmitter end is converted to serial information, transmitted quickly over these pairs of cables, then converted back to 24-bit parallel in the receiver, resulting in an interface that is very fast to handle large displays and is very immune to interference.

Mobile Industry Processor Interface (MIPI) is a newer technology that is managed by the MIPI Alliance and has become a popular choice among wearable and mobile developers. MIPI uses similar differential signaling to LVDS by using a clock pair and one to eight pairs of data called lanes. MIPI supports a complex protocol that allows high speed and low power modes, as well as the ability to read data back from the display at lower rates. There are several versions of MIPI for different applications, MIPI DSI being the one for displays.

Display components stretch the limitations of bandwidth. For perspective, the most common internet bandwidth in a residential home runs on average at around 20 megabits per second or 20 billion 1s and 0s per second. Even small displays can require 4MB per second, which is a lot of data in what is often a tightly constrained physical space.

Take the same PMOLED display with the 128 x 128 resolution and 16,384 separate diodes; it requires information as to when and how brightly to illuminate each pixel. For a display with only 16 shades, it takes 4 bits of data. 128 x 128 x 4 = 65,536 bits for one frame. Now multiply it by the 60Hz, and you get a bandwidth of 4 megabits/second for a small monochrome display.

A TFT LCD,  or a thin film transistor liquid crystal display, is one of the fastest growing forms of display technology today. The thin film transistor (TFT) is a type of semiconductor device used in display technology to enhance efficiency, compactness, and cost of the product. In conjunction with its semiconductor properties, the TFT LCD is an active matrix display, controlling pixels individually and actively rather than passively, furthering the benefits of this semiconductor device.

The TFT LCD is built with three key layers. Two sandwiching layers consist of glass substrates, though one includes TFTs while the other has an RGB, or red green blue, color filter. The layer between the glass layers is a liquid crystal layer.

The Architecture of a TFT Pixelbelow) from the other substrate layer of the device and control the amount of voltage applied to their respective sub-pixels. This layer also has pixel electrodes between the substrate and the liquid crystal layer. Electrodes are conductors that channel electricity into or out of something, in this case, pixels.

Between the two substrate layers lie liquid crystals. Together, the liquid crystal molecules may behave as a liquid in terms of movement, but it holds its structure as a crystal. There are a variety of chemical formulas available for use in this layer. Typically, liquid crystals are aligned to position the molecules in a certain way to induce specific behaviors of passing light through the polarization of the light waves. To do this, either a magnetic or electric field must be used; however, with displays, for a magnetic field to be usable, it will be too strong for the display itself, and thus electric fields, using very low power and requiring no current, are used.

Before applying an electric field to the crystals between the electrodes, the alignment of the crystals is in a 90 degree twisted pattern, allowing a properly crystal-polarized light to pass through the surface polarizer in a display’s “normal white” mode. This state is caused by electrodes that are purposely coated in a material that orients the structure with this specific twist.

However, when the electric field is applied, the twist is broken as the crystals straighten out, otherwise known as re-aligning. The passing light can still pass through the back polarizer, but because the crystal layer does not polarize the lights to pass through the surface polarizer, light is not transmitted to the surface, thus an opaque display. If the voltage is lessened, only some crystals re-align, allowing for a partial amount of light to pass and creating different shades of grey (levels of light). This effect is called the twisted nematic effect.

Fig. 3:The top row characterizes the nature of alignment in using IPS as well as the quality of viewing angles. The bottom row displays how the twisted nematic is used to align the crystals and how viewing angles are affected by it.

The light that passes through the device is sourced from the backlight which can shine light from the back or the side of the display. Because the LCD does not produce its own light, it needs to use the backlight in the OLED) have come into use as well. Typically white, this light, if polarized correctly, will pass through the RGB color filter of the surface substrate layer, displaying the color signaled for by the TFT device.

In this Arduino touch screen tutorial we will learn how to use TFT LCD Touch Screen with Arduino. You can watch the following video or read the written tutorial below.

As an example I am using a 3.2” TFT Touch Screen in a combination with a TFT LCD Arduino Mega Shield. We need a shield because the TFT Touch screen works at 3.3V and the Arduino Mega outputs are 5 V. For the first example I have the HC-SR04 ultrasonic sensor, then for the second example an RGB LED with three resistors and a push button for the game example. Also I had to make a custom made pin header like this, by soldering pin headers and bend on of them so I could insert them in between the Arduino Board and the TFT Shield.

Here’s the circuit schematic. We will use the GND pin, the digital pins from 8 to 13, as well as the pin number 14. As the 5V pins are already used by the TFT Screen I will use the pin number 13 as VCC, by setting it right away high in the setup section of code.

I will use the UTFT and URTouch libraries made by Henning Karlsen. Here I would like to say thanks to him for the incredible work he has done. The libraries enable really easy use of the TFT Screens, and they work with many different TFT screens sizes, shields and controllers. You can download these libraries from his website, RinkyDinkElectronics.com and also find a lot of demo examples and detailed documentation of how to use them.

After we include the libraries we need to create UTFT and URTouch objects. The parameters of these objects depends on the model of the TFT Screen and Shield and these details can be also found in the documentation of the libraries.

So now I will explain how we can make the home screen of the program. With the setBackColor() function we need to set the background color of the text, black one in our case. Then we need to set the color to white, set the big font and using the print() function, we will print the string “Arduino TFT Tutorial” at the center of the screen and 10 pixels  down the Y – Axis of the screen. Next we will set the color to red and draw the red line below the text. After that we need to set the color back to white, and print the two other strings, “by HowToMechatronics.com” using the small font and “Select Example” using the big font.

So the drawDistanceSensor() custom function needs to be called only once when the button is pressed in order to draw all the graphics of this example in similar way as we described for the home screen. However, the getDistance() custom function needs to be called repeatedly in order to print the latest results of the distance measured by the sensor.

Here’s that function which uses the ultrasonic sensor to calculate the distance and print the values with SevenSegNum font in green color, either in centimeters or inches. If you need more details how the ultrasonic sensor works you can check my particular tutorialfor that. Back in the loop section we can see what happens when we press the select unit buttons as well as the back button.

Ok next is the RGB LED Control example. If we press the second button, the drawLedControl() custom function will be called only once for drawing the graphic of that example and the setLedColor() custom function will be repeatedly called. In this function we use the touch screen to set the values of the 3 sliders from 0 to 255. With the if statements we confine the area of each slider and get the X value of the slider. So the values of the X coordinate of each slider are from 38 to 310 pixels and we need to map these values into values from 0 to 255 which will be used as a PWM signal for lighting up the LED. If you need more details how the RGB LED works you can check my particular tutorialfor that. The rest of the code in this custom function is for drawing the sliders. Back in the loop section we only have the back button which also turns off the LED when pressed.

In order the code to work and compile you will have to include an addition “.c” file in the same directory with the Arduino sketch. This file is for the third game example and it’s a bitmap of the bird. For more details how this part of the code work  you can check my particular tutorial. Here you can download that file:

IPS (In-Plane Switching) lcd is still a type of TFT LCD, IPS TFT is also called SFT LCD (supper fine tft ),different to regular tft in TN (Twisted Nematic) mode, theIPS LCD liquid crystal elements inside the tft lcd cell, they are arrayed in plane inside the lcd cell when power off, so the light can not transmit it via theIPS lcdwhen power off, When power on, the liquid crystal elements inside the IPS tft would switch in a small angle, then the light would go through the IPS lcd display, then the display on since light go through the IPS display, the switching angle is related to the input power, the switch angle is related to the input power value of IPS LCD, the more switch angle, the more light would transmit the IPS LCD, we call it negative display mode.

The regular tft lcd, it is a-si TN (Twisted Nematic) tft lcd, its liquid crystal elements are arrayed in vertical type, the light could transmit the regularTFT LCDwhen power off. When power on, the liquid crystal twist in some angle, then it block the light transmit the tft lcd, then make the display elements display on by this way, the liquid crystal twist angle is also related to the input power, the more twist angle, the more light would be blocked by the tft lcd, it is tft lcd working mode.

A TFT lcd display is vivid and colorful than a common monochrome lcd display. TFT refreshes more quickly response than a monochrome LCD display and shows motion more smoothly. TFT displays use more electricity in driving than monochrome LCD screens, so they not only cost more in the first place, but they are also more expensive to drive tft lcd screen.The two most common types of TFT LCDs are IPS and TN displays.

The electrode is hooked up to a power source like a battery. When there is no current, light entering through the front of the LCD will simply hit the mirror and bounce right back out. But when the battery supplies current to the electrodes, the liquid crystals between the common-plane electrode and the electrode shaped like a rectangle untwist and block the light in that region from passing through. That makes the LCD show the rectangle as a black area.

The provided display driver example code is designed to work with Microchip, however it is generic enough to work with other micro-controllers. The code includes display reset sequence, initialization and example PutPixel() function. Keep the default values for all registers in the ILI9341, unless changed by the example code provided.

Note that the WR pin becomes the D/CX signal in serial mode. CS is used to initiate a data transfer by pulling it low. At the end of the data transfer, pull the CS pin high to complete the transaction. The timing diagram indicates that you can pull the CS pin high in between the command byte and data bytes within a transfer, but it is unlikely needed if the display is the only device on the SPI bus. To keep things simple, we suggest to leave it low during the entire transaction.

This IPS TFT display has a high resolution 1024x600 screen. The IPS technology delivers exceptional image quality with superior color reproduction and contrast ratio at any angle. This 24-bit true color Liquid Crystal Display includes better FPC design with EMI shielding on the cable, is RoHS compliant, and does not include a touchscreen.

Choose from a wide selection of interface options or talk to our experts to select the best one for your project. We can incorporate HDMI, USB, SPI, VGA and more into your display to achieve your design goals.

Equip your display with a custom cut cover glass to improve durability. Choose from a variety of cover glass thicknesses and get optical bonding to protect against moisture and debris.