tft display simulator factory

TFT displays bring life to the project. Why shy with the LCD character display? OLED displays look good and stand out too but small size and limited colors limit the application to basic graphics but are still colorless. No color? No life!

Having the option of TFT display in your next Arduino project can add so many vibrant menu options, can display images, and hence can be a very rich user experience thing.

This is a very basic example of displaying a few texts on the display. We will use the library from Adafruit for the same. The best thing about the Wokwi Embedded systems simulator is that you can run the code straight from the browser. It means, you can easily share the project (as a link) and your friend can run it and lay with the project.

In this article, you will get a working Arduino project which has a simulated TFT display. The display will exactly work in the same way how it would work in the real world and with the real hardware. You can try any TFT project you have!

Let us get started. You will complete the code, connection diagram as well as live working Arduino simulation link so that you can start playing with the code instantly! For more information on the Simulated TFT display,click here.

TFT-LCD technology is based on semiconductor IC manufacturing processes, and is unique in that it uses glass substrates rather than traditional silicon wafers. For the TFT manufacturing process, thin film formation, such as CVD and PVD processes, is a very important part. The ODF process has been developed for the assembly of color filters and TFT substrates, and is used in large size LCDs.

First of all, the movement and arrangement of liquid crystal molecules need electrons to drive, so in the carrier of liquid crystal – TFT glass, there must be able to conduct the part to control the movement of liquid crystal, here will use ITO (Indium TIn Oxide, transparent conductive metal) to do this thing. ITO is transparent, also known as thin film conductive crystal so that it will not block the backlight.

The different arrangement of liquid crystal molecules and the rapid movement changes to ensure that each pixel accurately display the corresponding color, and the image changes precisely and quickly, which requires precision control of the liquid crystal molecules. ITO film requires special processing, as if printed circuitry on a PCB board, drawing conductive lines throughout the LCD board.

For array panels with back-channel etched TFT structure.The main process can be divided into 5 steps (5 lightings) according to the sequence of the layers to be made and the interrelationship between the layers.

The process includes: PECVD triple layer continuous film formation, island lithography, island dry lithography and other processes. After these processes, the final amorphous silicon island for TFT is formed on the glass substrate. The graphics obtained after the process is completed are shown in the following figure.

Specific processes include: S/D metal layer sputtering into a film, S/D lithography, S/D wet lithography, channel dry lithography and other processes. After these processes, the source, drain, channel and data lines of the TFT are finally formed on the glass substrate. At this point, the TFT has been produced. The graphics obtained after the process is completed are shown in the following figure.

The process includes PECVD, photolithography, and dry lithography of vias. After these processes, the final TFT channel protective insulation layer and guide through the hole are formed on the glass substrate. The graphics obtained after the process is completed are shown in the following figure.

Pre-Tilt Angle (Pre-TIlt Angle or TBA: Tilt Bias Angle) characteristic refers to the arrangement of liquid crystal molecules on the mating film is not parallel to the film surface, but one end of the molecule in the friction direction relative to the film surface has a certain warp, the stilt angle is called pre-tilt angle. If there is no pre-tilt angle, under the external electric field, the liquid crystal molecules can stand up randomly from two directions, which will cause poor display.

Assembly is the combination of backlight, screen, control circuit board, and touch screen and other components together to form a complete display module. Assembly is generally done by hand, and skilled workers are very important here.

The WA-HT HMI standard series is a complete application-ready-package which includes  a Thin Client Terminal with panel sizes from 6.5"~21.5" TFT LCD, 32GB CFast card, Microsoft Windows Embedded 7 Pro and WebAccess/HMI Runtime. This allows users to easily achieve efficient, integrated HMI solutions for flexible system integration in automation industries. The Thin Client Terminal with Intel ®  Atom™ or relevant processor providing computing performance in a compact fanless system for any field side operation.

While the MASM Conference is mostly focused on the current semiconductor industry state-of-the-art, neither presenters nor attendees need to be in the IC industry to participate. We are interested in methodologies, research and/or applications from other related industries such as TFT-LCD, flexible displays, bio-chip, solid state lighting (LED), and photovoltaic (PV) that might also share or want to share common and new practices. Interested individuals within academia, government agencies, equipment suppliers, manufacturers, students, contractors, and other interested parties are encouraged to participate.

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.

Luminance is an important quality characteristic of a TFT-LCD display. Consumers prefer to have a TFT-LCD display with enough luminance. Several control factors in manufacturing a TFT-LCD display may affect the luminance of a TFT-LCD display. Tuning the control factors using a trial and error method incurs significant overhead in time and resources such as the material and the workforce. Therefore, a more efficient method is required for tuning the control factors in manufacturing TFT-LCD displays. To fine-tune the control factors, we need to perform experiments to find the luminance of TFT-LCD displays for different settings of the control factors. An experiment to find the luminance for a specific parameter setting of the control factors requires about 1.5 months for the case company. To reduce the time in fine-tuning the control factors, we should not perform too many experiments in a new method. In this paper, we first used the traditional Taguchi method to find a control factors’ setting to enhance the luminance of TFT-LCD displays. However, because the Taguchi method allows only a few fixed levels for each control factor, it usually cannot find the global optimal setting for the control factors. Therefore, this paper proposes to improve the Taguchi method by incorporating the Taguchi method with the neural network and the genetic algorithm. In the proposed method, we used the data collected from the Taguchi method to train a neural network to predict the luminance of a TFT-LCD display for a given control factors’ setting. Then, we used a genetic algorithm to search for the global optimal control factors’ setting using the predicted luminance of a control factors’ setting as the fitness value of the setting.

The case company is a TFT-LCD display manufacturer in Taiwan. In performing the optical film lamination step in the liquid crystal module assembly process (LCM), the case company observed color streaks, as shown in Figure 1, on some of their TFT-LCD displays. The color streaks reduced the luminance of the TFT-LCD displays. Therefore, to enhance the luminance of TFT-LCD displays, the optical film lamination step needs to be optimized. The optical film lamination step consists of five stages: the raw material inspection, the soft-to-hard lamination, the circuit test, the protection film lamination, and the clean process, as shown in Figure 2. According to a failure analysis performed by the case company, the color streaks on a TFT-LCD display were mainly due to improper setting of control factors in the soft-to-hard lamination stage. Therefore, this paper focuses on optimizing the soft-to-hard lamination stage to improve the luminance of TFT-LCD displays.

For the quality improvement purpose, engineers of the case company selected five positions, as shown in Figure 3, on a TFT-LCD substrate to measure their corresponding values of luminance. The luminance of a TFT-LCD display is the average of the five values of luminance of the selected positions. The case company manufactured about 5000 TFT-LCD displays per day. Therefore, the TFT-LCD displays’ average luminance at a specific date was calculated by averaging the luminance of all the TFT-LCD displays made at that particular date. Figure 4 shows the trend chart for the TFT-LCD displays’ average luminance. The average of the average luminance at all dates in a selected time interval is defined as the baseline, the red line shown in Figure 4. Before fine-tuning the control factors in the sot-to-hard lamination stage, the baseline was 17.03, which was less than the required minimum luminance of 25. Thus, to enhance the TFT-LCD display’s luminance, one needs to find a setting of the control factors such that the baseline is larger than the required minimum luminance of 25. Therefore, we propose in this paper a new method that combines the Taguchi method, a neural network, and a genetic algorithm to fine-tune the setting of control factors in the soft-to-hard lamination stage to enhance the TFT-LCD displays’ luminance.