tft display driver circuit made in china

Our new line of 10.1” TFT displays with IPS technology are now available! These 10.1” IPS displays offer three interface options to choose from including RGB, LVDS, and HDMI interface, each with two touchscreen options as capacitive or without a touchscreen.

The new line of 3.5” TFT displays with IPS technology is now available! Three touchscreen options are available: capacitive, resistive, or without a touchscreen.

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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.

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.

In ruling NY N320557 (August 4, 2021), Customs and Border Protection (CBP) discussed the country of origin of five Thin Film Transistor – Liquid Crystal Display (TFT-LCD) modules. All five modules are virtually identical in composition, as they are all composed of a TFT-LCD cell, polarizers, a backlight, a driver and control printed circuit board (PCB), and a flexible PCB for connection. TFT display technology allows for the construction of high-resolution LCD displays, and the modules – once completed – can be incorporated into a variety of consumers display applications.

The manufacturing process for the five modules is also identical. The process begins in Japan where the TFT-LCD cell is manufactured. The TFT is created by depositing transistors onto a substrate through chemical vapor deposition, while the color filter is manufactured by building a color matrix on a glass substrate. The creation process of the cells is then completed when a layer of liquid crystal is deposited between the color filter and TFT as the two part are bonded together, creating a sheet of TFT-LCD cells. As next steps, the sheet of cells is delivered to China to be cut into individual cells. The cut-up cells are then bonded to the printed circuit board assembly (PCBA) – which contains the driver and control circuity – before the polarizers, backlight, and flexible connection PCBA are attached.

CBP also established that “substantial transformation” takes place when a particular product “emerges from a process with a new name, character or use different from that possessed by the article prior to processing.” The agency explained that the completed TFT-LCD cell is what imparts the essential function of the module and that the manufacturing process in Japan is what renders the end-use of the product. Despite the assembly that took place in China, the process did not substantially transform the cell into a new and different article. As such, CBP determined that the country of origin of the five modules is Japan.

Display technology has moved forward at light speed. For years, even sophisticated equipment made do with numeric and alphanumeric display technology, buttons, and LEDs.

With mass production, manufacturing refinements, and competition, thin film transistor (TFT) displays have drastically dropped in price while dramatically improving in performance. They are the de facto standard to the point where it is not only expected, it is demanded that any modern user interface be full color, brightly backlit, touch sensitive, and have high video speeds and a good viewing angle.

While simple low-cost 8-bit microcontrollers could easily handle the multiplexed 7- and 14-segment LED and alphanumeric LCD displays, the memory, processor speeds, and peripheral resources needed to drive a TFT are more than most modest microcontrollers can handle. As a result, dedicated controller chips, embedded modules, or faster, denser, and more streamlined processor architectures are needed.

This article looks at the factors that make a good MCU-to-TFT interface. This includes memory depths and architectures, paging, data transfer, signaling levels, interfaces, and on-chip peripherals to look for when selecting a microcontroller for a TFT application. It examines the TFT technology and present day product offerings, which your designs will need to drive. It also looks at some microcontrollers that provide native support for color TFT displays, looking at their techniques, features, trade-offs, and limitations. All displays, microcontrollers, drivers, inverters, and development tools mentioned in this article are available from Digi-Key Corporation.

TFT displays are a type of liquid crystal display in which the transistor controlling the pixel’s crystal is etched into a layer of amorphous silicon deposited on the glass (see Figure 1). As in an IC process, very small transistors are geometrically formed. The small size of the transistor means it will not significantly attenuate the light passing through.

The advantage of TFTs is that they are fast enough for video, provide a large and smooth color palette, and are pixel addressable through an electronic two-dimensional control matrix (see Figure 2). Most low-cost displays use an amorphous silicon crystal layer deposited onto the glass through a plasma-enhanced chemical vapor deposition.

Figure 2: Electronically, a stable VCOM reference is used throughout the display, and the gamma corrected drive voltage passes through each transistor.

Many versions of TFT technologies have led us to the modern displays. Early complaints like poor viewing angles, poor contrast, and poor backlighting have been addressed. Better light sources, diffusers, and polarizers make many displays very vivid, some even claiming to be daylight readable. Modern day techniques like in-plane switching improve viewing angles by making the crystals move in a parallel direction to the display plane instead of vertically. Better speeds and contrasts of modern display make them high performance for a fairly low cost.

Since TFTs are not emissive devices, they require backlighting. The most commonly deployed backlight technology is cold cathode florescent lighting (CCFL). These devices were designed, chosen, and used because they are very efficient and have very long lives. Typically, a CCFL bulb is rated as having in the ball park of a 50,000 hour ‘half-life. ’ This means that after 50,000 hours, it still works, but with half the intensity when it was new.

Modern displays, especially the smaller ones, have transitioned to white LED-based backlights. These are easier to manufacture, do not require the high voltage inverter which CCFL bulbs need, and are approaching a lower cost point compared to CCFL technology. Both CCFL and LED technologies will use diffuser layers inside the stackup to evenly distribute light. LED-based backlights may actually be side lights and use a lightpipe structure to distribute the light.

Transflective technology is steadily improving and is available in some TFT displays. This is where both a backlight and ambient external light are used to make the display visible. Sunlight may make it viewable, but generally speaking the transflective displays are less transmissive. This means that the backlight will have to be brighter (and require more power) to be on par with a purely transmissive display that requires a backlight all the time.

With TFT and most color display technologies, an individual pixel contains a red, a green, and a blue picture element (pel). The relative intensity of each color will determine the resulting blended color.

Some displays will use dithering and alternating pixel colors to achieve a better blend of intermediate colors. Higher frame rates are also used since the persistence effect of phosphor-based displays does not carry over to LCDs. Determine the quality and smoothness of the display you will use. Not every frame rate control technique yields flicker- and jitter-free performance, especially at some resolutions. If you notice it, so will your customers and end users of your design.

The memory required to map the display image is key. While some micros will contain enough memory to hold a single page of display data (and not much else), you can see that a lot of memory is required for even a modest ¼ VGA display. This is more than what a typical microcontroller can house (see Table 1). As a result, an external bus interface to external RAM (SRAM, DRAM, or SDRAM) will be needed, especially if paging will be used.

Table 1: The memory required to map to a display is proportional to three times the square of the resolution because of the three color elements of each pixel.

Paging will allow better display quality since one page can be displayed while the next is being built in the background, then made live. This eliminates ghosting and image flicker when graphics are changing rapidly in effects like scrolling, moving sprites (graphical objects), color shade blending (for overlapping graphics as they move), etc.

A key feature when selecting a microcontroller for TFT interfacing is the DMA support. Multi-channel, flexible DMA will make a world of difference, especially when it comes to moving data between pages, character generator and rendering tables, animations and video. Along these lines, a preprogrammed and autonomous DMA functionality will allow you to refresh a display while the core microcontroller goes to sleep. This is a key power-reducing feature that can make a world of difference when operating from batteries.

Very high volume applications may justify using an OEM only for the glass and implementing your own control electronics from the glass up. This is especially true when designing a very small form factor device where the added flexibility of using your own PCB layout is critical to success. For those designing from the glass up, the primary interface will be drivers for the thin film transistors. The stable common voltage reference to which all pixels are referenced is key. This is called VCOM and several discrete and integrated solutions for generating a VCOM signal are available.

One effective solution is to use the National Semiconductor LMH6640MF/NOPB which is a rail-to-rail (up to 16 volts), voltage feedback, high output (up to 100 ma) amplifier optimized for TFT transistor driving. The fast 170 V/µS slew rate yields a 28 MHz full power bandwidth (at five volts) and its small SOT-23 package can be fit into tight spaces (see Figure 3).

The larger the panel, the more current will be required to operate the transistors. For larger panels, another contender is the Maxim MAX9550EZK+T which can drive up to 800 ma peaks up to 20 volts. It settles to within 0.1 percent in less than 2 µSec and features a soft start circuit to limit inrush current during startup. Note, the VCOM level is usually set between the upper voltage level and ground instead of being set to ground. This allows full scale alternating polarity to be driven to the pixels without the need for a negative power supply.

Also , the VCOM function and all its subtleties are often times integrated into more encompassing TFT driver chips like Texas Instruments’ LM8207MT/NOPB which combines an 18 channel gamma corrected driver with VCOM referencing buffer (see Figure 4). Note that the built-in VCOM buffer will allow a buffer tree to be created from a single reference for larger displays.

One approach to driving a TFT display without the need for a higher end processor is to use a discrete TFT controller chip that can be interfaced to a processor of lesser horsepower. An example is the Intersil TW8811-LD2-GR TFT controller chip (see Figure 5).

Aimed at a specific market segment, in this case automotive applications, the TW8811 combines control and even video standard (analog, RGB, S-Video, NTSC, PAL, and Secam) integration into a single chip controller. It supports and ties together different video sources to allow the same display to be used for navigation systems, engine displays, environmental control, in-car entertainment systems, backup cameras, etc.

The on-chip SDRAM interface provides the depth and cost-effective performance needed for displays up to WXGA resolutions, and the –40 to +85 degree temperature range makes this usable for a variety of harsh environment applications.

If a single microcontroller can control the task at hand as well as the embedded display, this is usually the most cost-effective solution. Most people will use a TFT module which already houses the VCOM, gamma correction, and TFT transistor drivers. As a result, the interface to the module is TTL, CMOS, or Low Voltage Differential Signaling (LVDS).

Thankfully, to help make TFT design tasks doable in a reasonable amount of time, the chip makers provide solutions targeted at display designs. Typically, these are higher-end, 32-bit, RISC-type processor architectures with streamlined peripherals and resources that handle both display-oriented and non-display-oriented functions such as communications, sensor interfacing, etc.

Devices like this need development environments and evaluation units and NXP is right there. The DK-57VTS-LPC2478 is a programmer’s development system that includes a 5.7 inch TFT with touch interface as well (see Figure 6). Note the 2M x 32 SDRAM for page buffering and graphic manipulations. NXP also offers the DK-57TS-LPC2478 which aims at sensor-based applications.

NXP Semiconductors is not alone by any means. Renesas Electronics America also provides processors with built-in support for TFTs. Take for example the DF2378RVFQ34V, an H8-based processor with advanced block transfer functionality built into the DMA. Like the NXP parts, it incorporates a slew of peripherals, Flash, memory interfaces, and I/O.

Not every processor needs to have a dedicated TFT interface to make it a viable candidate. For example, the TI TMS470R1B1MPGEA is a RISC-based 60 MHz ARM7 processor that can easily interface to a slew of TFT modules that are driven via a digital interface. While some modules need constant refreshing, others can be loaded with display data and generate all the timing and display data movement internally unburdening the host CPU. The CPU must be fast enough to keep up with any animations or video if this is the case.

Many displays are readily available as test vehicles. Many of these can be directly driven with the processors mentioned here. Many other processors can also be used, like offerings from Atmel (AT91SAM9261B-CU) and STMicroelectronics (STM32F107VBT6).

No matter how many data sheets you read, what it boils down to is this: a display is a visual device. What will ultimately make the decision is how it looks when you display your screens on it.

TFT LCD modules are thin film field effect transistors. The so-called thin film transistor means that each liquid crystal pixel on the liquid crystal display is driven by a thin film transistor integrated behind it so that it can display screen information with high speed, high brightness, and high contrast. The composition of the liquid crystal display is not complicated. The liquid crystal panel plus the corresponding driving board (also called the main board, whose compositional structure is not intended to be the row and column driving circuit in the liquid crystal panel), power supply board, high voltage board, button control board, etc., constitute a complete liquid crystal display.

Power supply part: The power supply circuit of the liquid crystal display is divided into two parts: switching power supply and DC/DC converter. Among them, the switching power supply is an AC/DC converter, its function is to convert the AC 220V or 110V (European standard) into a 12V DC power supply (some models are 14V, 18V, 24V, or 28V), supply DC/DC Converter and high-voltage board circuit; DC/DC DC converter is used to convert the DC voltage (such as 12V) generated by the switching power supply into 5V, 3.3V, 2.5V and other voltages, which are supplied to the driver board and the liquid crystal panel.

The driver board of the TFT LCD screen is also called the main board, which is the core circuit of the liquid crystal display. It is mainly composed of the following parts: input interface circuit, A/D conversion circuit, clock generator, Sealer circuit, microcontroller circuit, and output interface circuit.

Key board part: The key circuit is installed on the key control board, and the indicator lights are generally also installed on the key control board. The function of the key circuit is to make the circuit on and off. When the switch is pressed, the key electronic switch is turned on, and when the hand is released, the key electronic switch is turned off. The switch signal output by the key switch is sent to the MCU on the driver board. After being recognized by the MCU, the control signal is output to control the relevant circuit to complete the corresponding operation and action.

High-voltage board part: The high-voltage board is commonly known as a high-voltage strip (because the circuit board is generally long and in the form of a strip), and is sometimes called an inverter circuit or an inverter. Its function is to convert the low-voltage DC voltage output by the power supply into a liquid crystal panel ( The high-frequency high-voltage AC above 600V required by the Panel) that lights the backlight on the LCD panel. The high-voltage board of the TFT LCD screen mainly has two installation forms: 1. A dedicated circuit board; 2. It is installed together with the switching power supply circuit (the switching power supply adopts the internal type).

LCD panel part: The LCD panel is the core component of LCD, mainly including the LCD screen, LVDS receiver (optional, LVDS LCD screen has this circuit), driver IC circuit (including source driver IC and gate driver IC), timing sequence Control IC (TC0N) and backlight.

Nevertheless, I soldered on the connector and lit it up. Once it was lit up, it was obvious that not all the column drivers were lighting the pixels evenly. When I ran full screen color test, it became really obvious under pure white that the LCD itself had been damaged during production or mis-adhered with whatever tape or glue they were using. It looked like someone clamped it too hard because there was a distinct distortion that was to one side the display. It looked like either a clamp had been secured to tightly during the production process or the adhesive the bonded the display to the board was warping the LCD itself. Either way, these were an unacceptable pair of defects and made the display look awful.

DDIC for the large-sized screenisthe breaking point due to the lowthreshold in technology and large capacity. With the trend of display industry transfer and increasing investment, DDIC supply chain in mainland China is entering into thefast developing stage.

Driver IC industry chain is generally composed of IC design -wafer foundry – packaging and testing – panel factories. The current bottleneck of supply mainly lies in the capacity of the wafer foundry.

The DDIC industry chain is relatively simple. As an important part of the display imaging system, the cost of DDIC in electronic products is about 10-15%. However, due to a large number of chips embedded, it’s a low gross profit product in the chip design industry.

In the stage of tight production capacity, display chips are often squeezed by wafer foundries due to low profit and other characteristics. Because of the diversity of display products, the process range of DDICs are also relatively wide, and the main products cover the process of 28nm-150nm.

Other driver chips with lower specifications, such as wearables, white electric appliances, and small household appliances which apply with lower resolution will not be discussed in this chapter.

In 2020, the DDICs of LCD and AMOLED panels accounted for 20% of the total demand. However, because the driver chips of smartphones often integrate the functions of touch and T-CON, the area of a single grain is about triplethat of TV driver chips, resulting in the consumption of wafers close to half of the downstream main current display.

Samsung LSI occupied more than half of the market share of AMOLED display drivers in 2020. As exclusive suppliers of Samsung SDC, LSI and Magnachip (formerly SK Hynix Semiconductor) have not yet cooperated with panel makers in mainland China.

In 2020, Novatek and Radium are the main AMOLED driver chip suppliers for panel factories in mainland China, with a market share of 7% and 6% respectively.

In the second half of 2021, the trial production of the OLED driver chip developed by Huawei Hisilicon has been completed, and planned to officially complete mass production and delivery to suppliers in 2022. In the second half of 2021, the chip sample has been sent to BOE, Huawei, Honor and other manufacturers for testing.

The DDIC controls the on-off state display of millions of pixels through the source line of the voltage-driven panel. In regular IC design, the factor that has the greatest impact on the amount of driver IC is resolution.

A single driver IC of a TV panel generally has 960-1366 channels. The regular design of an OC with HD resolution requires 3 driver ICs, generally 6 for FHD, and 12 for UHD.

In addition to conventional designs, panel manufacturers are also developing dual gate (one driver channel drives two columns) or triple gate designs (one driver channel drives three columns). The entry-level 32-inch HD has one or two driver IC designs. However, at present, UHD accounts for more than 50% of the overall TV. This kind of solution is difficult to achieve when the resolution is getting higher and higher.

According to DISCEIN, the number of driver ICs required for TV panels corresponds to 270 million annual shipments, with a volume of about 2.5 billion, which is the display category with the largest consumption.

(3) After several industrial transfers of display panels, China took the lead in realizing the mainland’s dominant industrial pattern in the field of large-size LCD TVs. The top three competition patterns have been formed. Together with other panel manufacturers such as CHOT, the demand for TV driver ICs is dominated by mainland manufacturers.

At present, TV is also the most competitive field, and the overall share is relatively close. Among them, mainland China manufacturers Chipone and EAWIN also occupy a certain share. According to CINNO Research, among local driver chip manufacturers, the sum of both for more than 90% of the market share in medium and large-sized applications such as TVs, MINs, and NBs in the first half of 2022.

Combined with the overall size of MNT and the tendency to use more channels of driver ICs, the number of driver ICs required for MNT panels corresponds to 160 million annual shipments, with a volume of about 900 million, which is only larger than TPC in several major applications.

Among them, the BOE ranks first in the world in terms of shipments. Other top-ranked manufacturers mainly include South Korean LG Display, Taiwan AUO and Innolux. At present, mainland manufacturers are increasing MNT investment to continue to catch up.

It seems that the MNT driver IC product is not much different from the TV specification, but it is not the first choice for new manufacturers to enter the market due to overall scale, product diversity, customization and other reasons. The current high concentration is mainly dominated by Taiwan manufacturers.

Because NB pays special attention to power consumption, image quality and COG design, which has raised the technical threshold of driver IC, its supply is completely dominated by Taiwan manufacturers. The first Novatek and the second Raydium account for more than 60% of the shares, and the participation of mainland manufacturers is lower compared to TV and MNT.

In 2021, due to the high oligopoly of the suppliers, the driver IC became a constraint on the supply of NB panels, especially because of the technical threshold, it is difficult for mainland manufacturers to quickly supplement.

In addition to the technical threshold, due to the number of channels, COG design and power consumption of NB driver ICs, a 12-inch wafer can produce about 5K TV ICs or more than 7K MNT ICs, but only 2-3K NB ICs. It is expected that the supply and demand of NB driver ICs will improve later than MNT and TV in 2022 with the core shortage disturbance.

According to TrendForce, the market penetration rate of AMOLED panels for smartphones have been 42% in 2021. Despite the continuous shortage of AMOLED display panel ICs, the trend of smartphones, and OEM manufacturers to expand the use of AMOLED panels in their new models, which will drive the growth of AMOLED market penetration, and is expected to increase to 46% in 2022.

The process range of AMOLED driver chips is 28-55nm, which is the most tight production in mature processes. In this range, there are more competitive products with more profitable advantages, such as automotive MCU, high-end CIS, consumer electronics SoC, etc., which makes AMOLED production capacity crowded out, and its demand priority is low and difficult to meet.

Similar to the structure of AMOLED panel manufacturers, the top three driver ICs of AMOLED are all Korean, including Samsung LSI and LG Silicon Works. The share of the top three has exceeded 80%, and the second is mainly Taiwan manufacturers such as Novatek and Raydium.

The Korean wafer foundries are deeply bound with the OLED driver chip design manufacturers, forming a vertical integration model and is in a leading position in the world.

Taiwan wafer foundries also have in-depth cooperation with local OLED driver chip design manufacturers, giving priority to OEM for local manufacturers.

Mainland China wafer foundries mainly OEM LCD driver chips, while OLED driver chip OEMs have less experience, so most mainland manufacturers have to hand over orders to Taiwan.