tft lcd display working quotation

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.

1. We’re interesting in Embedded Display: ENHANCEMENT OF NEW TFT LCDS EQUIPPED WITH EMBEDDED DISPLAY PORT INTERFACE 11.6” – 15.6” – 18.5” – 30”. We would like to order 1 unit for testing and checking if it’s suitable for our needs. Please submit your best price & delivery time. Appreciate to have your soonest reply.

2. Hello, Hope this message finds you well. We are looking for a display that meets the following requirements: Diagonal Size 10.1” (256.5mm), Resolution – Higher than 1280x800, Max thickness 8mm. Annual quantity needed is 10,000/year, Ideal voltage is 24V, Production parts guaranteed to be available for 10 years, Connector interface: eDP. Would you recoment this display? -- TFT Color Display 10.1inch 1920X1200 resolution in Medical system. What is the pricing / lead time for an order of Quantity 100 & 10,000? Thank you for your help

4. Dear Sir/madam, We are interested in two displays that you have listed on your website. Could we please arrange to order one of each for our engineering team to test with them. Regards

5. Hello, My coworker had worked in past with you with regards to the 3.46" 800*340 resolution display. We really liked the samples and I am looking to know more about that display. I also wanted to know if you have a 3.46" 400*170 resolution display as the 800*340 is a bit of overkill for our application. Thank you

11. Hi, I am interested in the above product, but need transflective display. It must be able to be read in sunlight with the backlight off. We are seeking quantity about 5,000 per year. Can you provide this? Thank you

The liquid crystal cannot emit light by itself, and the backlight should be added behind the LCD panel. A few years ago, CCFL cold cathode backlighting was the dominant market application, but with the development of technology, the LED backlight has gradually replaced the traditional CCFL backlight.

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

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

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

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

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

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

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

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

In 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.

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

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.

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

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

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

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

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

While in theory an Arduino can run any LCD, we believe that some LCDs are particularly suited to being an Arduino LCD display. We"ve currated this list of LCD displays that will make any Arduino-based project shine.

First is the interface. All of these displays support SPI. Builders often ask themselves (or us) "which interface uses the fewest GPIO pins? AND is that interface fast enough to update the screen at an acceptable rate for my application?" When using the relatively small procesor of the Arduino, SPI is usually the best interface because it takes few wires (either 3 or 4) however it does limit the overall size (number of pixels) that can be quickly controlled. I2C is another choice of interface to leave GPIOs open. We tend to recommend SPI over I2C for Arduino displays because SPI is quicker and better at handling more complex data transfer, like pulling image data from an SD card.

Which brings us to the second factor in choosing an Arduino display: the number of pixels. We typically recommend a display with a resolution of 320x240 or less for use with Arduino. Take for example a 320x240 24-bit display. Such a display takes 230,400 bytes *(8 + 2) = 2,304,000 bits for a single frame. Divide that by 8,000,000 (Arduino SPI speed of 8MHZ) = 0.288 seconds per frame or 3.5 frames per second. 3.5 fps is fast enough for many applications, but is not particularly quick. Using fewer bits-per-pixel or a display with fewer pixels will result in higher frame rates. Use the calculator below to calculate the frame rate for a display using SPI with an Arduino.

Third, we want to recommend displays that are easy to connect to an Arduino. Each of these displays has a ZIF tail or easily solderable throughholes, so no fine pitch soldering is needed. These displays can either be brought up on the CFA10102 generic breakout board, or with a custom CFA breakout board.

Most character displays can be run via Parallel connection to an Arduino. You"ll want to make sure you can supply enough current to operate the backlight.

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-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.

PVD (Physical Vapor DeposiTIon), i.e. physical vapor deposition, is an advanced surface treatment technology widely used in the international arena. Its working principle is to use gas discharge to partially dissociate the gas or evaporated material under vacuum conditions, and to deposit the evaporated material or its reactants on the substrate while the gas ions or the evaporated material ions bombard the action. At present, the most used PVD technology on the market is mainly divided into three categories: magnetron sputtering plating, multi-arc ion plating and evaporation plating.

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.

Color filters can be produced by various methods; photolithography is a typical method. In photolithography, color filters are produced by exposing a glass substrate coated with a photographic color resist through a photomask. The resist is hardened to form the RGB pattern of the LCD.

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.

When making LCD panels it is impossible to produce them one by one, which is too inefficient, so multiple pieces are processed at once and separated by cutting.

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 liquid crystal display (LCD) technology has been used in several electronic products over the years. There are more reasons for LCDs to be more endearing than CRTs.

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.

Liquid Crystal Display (LCD) screens are a staple in the digital display marketplace and are used in display applications across every industry. With every display application presenting a unique set of requirements, the selection of specialized LCDs has grown to meet these demands.

LCD screens can be grouped into three categories: TN (twisted nematic), IPS (in-plane switching), and VA (Vertical Alignment). Each of these screen types has its own unique qualities, almost all of them having to do with how images appear across the various screen types.

This technology consists of nematic liquid crystal sandwiched between two plates of glass. When power is applied to the electrodes, the liquid crystals twist 90°. TN (Twisted Nematic) LCDs are the most common LCD screen type. They offer full-color images, and moderate viewing angles.

TN LCDs maintain a dedicated user base despite other screen types growing in popularity due to some unique key features that TN display offer. For one,

TN TFTs remain very popular among competitive PC gaming communities, where accuracy and response rates can make the difference between winning and losing.

VA, also known as Multi-Domain Vertical Alignment (MVA) dislays offer features found in both TN and IPS screens. The Pixels in VA displays align vertically to the glass substrate when voltage is applied, allowing light to pass through.

Displays with VA screens deliver wide viewing angles, high contrast, and good color reproduction. They maintain high response rates similar to TN TFTs but may not reach the same sunlight readable brightness levels as comparable TN or IPS LCDs. VA displays are generally best for applications that need to be viewed from multiple angles, like digital signage in a commercial setting.

IPS (In-Plane Switching) technology improves image quality by acting on the liquid crystal inside the display screen. When voltage is applied, the crystals rotate parallel (or “in-plane”) rather than upright to allow light to pass through. This behavior results in several significant improvements to the image quality of these screens.

IPS is superior in contrast, brightness, viewing angles, and color representation compared to TN screens. Images on screen retain their quality without becoming washed out or distorted, no matter what angle they’re viewed from. Because of this, viewers have the flexibility to view content on the screen from almost anywhere rather than having to look at the display from a front-center position.

IPS displays offer a slightly lower refresh rate than TN displays. Remember that the time for pixels to go from inactive to active is measured in milliseconds. So for most users, the difference in refresh rates will go unnoticed.

Based on current trends, IPS and TN screen types will be expected to remain the dominant formats for some time. As human interface display technology advances and new product designs are developed, customers will likely choose IPS LCDs to replace the similarly priced TN LCDs for their new projects.

TFT LCD, acronym for Thin Film Transistor Liquid Crystal Display, is a technology developed for improve image quality and has countless consumer and industrial uses.

Specifically, within TFT monitors, liquid crystals allow faster and smoother state transitions while saving power, resulting in high image quality on the display, which appears without flickering or bright irregularities (unlike simpler LCD screens).

TFT screens can be of different sizes, ranging from small 3.5" screens to large displays, and can also be identified by their area of use or by certain special features and applications, such as multitouch.

TFT displays are always clearly visible in sunlight, making them particularly suitable for outdoor use. This type of display is also particularly light, thin and energy-efficient, as well as being relatively inexpensive in relation to the technical features offered.

Digimax has an extensive catalogue ofTFT screens from 7" to 23", LCD displays and professional monitors capable of handling a high number of pixels to enable high image quality, high resolution and a screen without glare or flicker.

TFT technology is now a consolidated reality for the choice of monitors, screens and industrial displays: following this market evolution, Digimax offers the latest generation of TFT touch screen solutions, multi touch monitors and transparent displays able to offer the right option for every need.

We offer both standard and customised TFT LCDs through strategic partnerships with leading international suppliers and brands: Ampire displays, Raystar monitors and DLC screens, as well as RockTech, RockTouch and AUO touch screens.

Together with Digimax consultancy, a specific service is also available to configure TFT kits consisting of a TFT LCD monitor and matching PC board: it is possible to customise CPU and coverlens, touch technology used and connection wiring between motherboard and display.

TFT-LCD (thin film transistor liquid crystal display) industries have been grown-up in Taiwan. Many workers are at light-on test workstations in TFT-LCD factories. At the light-on test station, the operator has been exposed to the lower ambient illumination (105.10 lx) for a long time (12hour/1day). There are few researches discussed about health effect of workers of TFT-LCD workers. The aim of this research is to measure the illumination of the light-on test station and to collect the work environmental data for exposure assessment. The work environment information of test workstations has been measured such as ambient illumination and illumination of the five types of test color of LCD (red, green, blue, white, gray), visual angle, and visual distance between worker and LCD test board. The results shows that: 1) the light-on test was a long-term operation of lower ambient illumination (4.00 lx to 105.1 lx) and shorter visual distance (28.04 cm to 34.43cm); 2) the means of illumination of LCD board of different test color are 10.90 lx in red, 41.20 lx in green, 18.00 lx in blue, 67.30lx in white, and 13.80 in gray. Light-on test is a task of low ambient illumination, short visual distance and long-term job in TFT-LCD factories. Some workers complained about visual fatigues. Under this working environment, the more working duration workers have the more visual discomfort they complain. Some administration controls have been suggested such as more time of rest, lubrication of eyes by appropriate solution and job rotation.