tft lcd application note manufacturer

Hantronix TFT LCDs will deliver a vibrant, high contrast user interface to any application. Our TFT displays are available in a wide range of sizes, and are easy to incorporate into any design. We offer the most popular and cost-effective Amorphous Silicon Thin Film Transistor or a-SiTFT panels. This application note discusses how to drive a TFT LCD using widely available microprocessors.

Note that some small, lower end panels may not have all of the electronics included with them because of size or cost restraints. Some panels have a simple row and column interface. Some may need an external timing controller. Some have a processor bus type Interface.

Many LCD controllers, including those integrated into microcontrollers, will directly drive the signals shown in Figure 1. This means that the biggest obstacle to quickly getting an image on the screen is generating the appropriate signal timing. The LCD controller is responsible for generating the timing; however software must be written to correctly program the controller for the specific LCD model.

An LCD panel comprises a matrix of pixels (picture elements), divided into red, green, and blue "sub-pix-els". Each sub-pixel is driven by a small transistor. Typically, LCD panels have internal row and column drivers, much like DRAM. A row is selected by the row driver, then the column driver sequences through each of the columns. After each of the columns has been written, the row driver selects the next row and the process repeats. The VSYNC signal resets both row and column drivers to the upper left pixel. The HSYNC causes the row driver to step to the new row. The clock sequences the column driver through each of the pixels, with each clock edge latching data values for the red, green, and blue sub-pixels. These values drive a form of D/A converter to store an electrical charge in a capacitor in each sub-pixel which controls the drive of the transistor; this in turn controls the brightness of the sub-pixel. A red-green-blue color mask is used to filter the light from each sub-pixel to form its corresponding color.

Like a DRAM, an LCD panel must be constantly refreshed or the image will fade. Most TFT LCD panels work when refreshed around 60 Hz. The imagedata is usually held in a section of main memory called a frame Buffer.

Each location in the frame buffer corresponds to a pixel on the LCD. The value in the location determines the color displayed for that pixel. See Figure 2. The size of the frame buffer depends on two things: the number of locations needed, and the size of each location.

TFT panels typically have an input of at least 6 bits of red data, 6 bits of green data, and 6 bits of blue data. A panel with 6 red, 6 green, and 6 blue data lines is termed a 6-bit panel. If the processor or LCD controller doesn"t drive as many data lines as the panel requires, use the data line configuration shown in Figure 3 or Figure 5.

Displaying Characters on an LCD Character Module describes the initialization, displaying of text and creating, down loading and displaying custom characters on our character modules. The code sample is in 8051 assembly language and a program flow chart is also provided. (79k)

Driving a character display from a PC printer port describes a simple method of controlling an LCD character module directly from the parallel printer port of a PC. There is little, if any extra hardware required and the module may even be powered from the PC. (40k)

Interfacing to a Graphics Module with a T6963C Controller describes the software and hardware to display an image on any Hantronix graphics module with a built-in T6963C controller. This note includes schematic, flow chart and sample software. The code is in 8051 assembly language. (53k)

Interfacing a 128 x 64 Graphic Module with an 8 bit Micro-controller describes the software and hardware to display an image on a Hantronix HDM64GS12. This note includes schematic, flow chart and sample software in 8051 assembly language. (76k)

Interfacing a 128 x 64 Chip-on-Glass Graphics module describes the set-up, initialization and interfacing of an HDG12864-1 LCD module. It describes the use of the built-in power supply and electronic contrast control. (61k)

An explanation of LCD Viewing Angle. This is a technical explanation of how viewing angle is specified and how it influences the selection of the right LCD for your application. (46k)

Temperature Compensation for LCD Displays. This paper discusses the issues involved in temperature compensation of the LCD operating voltage. A sample circuit to provide this compensation is also discussed. (23k)

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.

Established in 2007, Raystar has built its reputation by offering advanced products in PMOLED display and modules as well as in FSTN / STN LCD Display Module, COG LCD, TFT LCD Display.

With the continual development of LCD technologies, TFTs have become widely available at a lower price point. The manufacturing process of TFTs has been standardized which has changed the industry for display applications, making TFTs a feasible replacement option for graphic LCDs. This application note will discuss the options for replacing a graphic LCD with a TFT LCD. Considerations of price, size, features and functions will be analyzed to evaluate the options for TFT displays in place of a graphic LCD.

The two displays that will be reviewed in this application are described in the table below. These displays are similar in size and cost but vary in features and technical specifications.

Graphic LCDs are common for industrial applications where the features of TFTs are not justified by price. In recent years, TFT manufacturing has broadened its standard manufacturing process, making TFTs a competitor in typical graphic LCD applications.

TFTs offer additional features that graphic LCDs cannot provide. Such features consist of high color and resolution. TFTs also have the benefit of integrating capacitive and resistive touch functions to the display. If you are considering replacing a current graphic LCD, it may be time to switch to a TFT.

Graphic LCDs are a common display for industrial applications where vivid and high-resolution graphics are not essential to the application. Graphic displays typically have an 8-bit parallel interface which does not require a high frequency clock to communicate with the display. The graphic display in this example has 128 x 64 dots of resolution. This means the memory requirement of the frame buffer for this display is small and is provided by the IC on the display. Graphic LCDs do not offer RGB pixel color and display pixels as either on or off.

Significant limiting factors for graphic LCDs include the resolution and color depth of the display. The options for what can be displayed is restricted to a small area, in this example 128x64 pixels. This means that the image must be very low resolution and text must be very small. Typical graphic LCD applications display text or small user interface option.

The dimensions of G12864B-BW-LW63 are reviewed below. This graphic LCD is close in size to E30RA-FW400-N, the main differences being the mounting of the backlight and the depth of the displays. This graphic LCD is transmissive, STN blue, with a white LED backlight. The demo images will be displayed with white pixels and a blue background.

An example application for this graphic LCD will be reviewed in comparison with the TFT. The graphic LCD is interfaced over an 8-bit parallel connection. The display controller IC, ST7565, provides 8 pages of display RAM, an internal oscillator, and power regulation functions. This makes it easy to control a graphic LCD with a simple 8-bit controller because the main functions are provided internally.

The graphic LCD will display a menu followed by a temperature measurement screen. This is to provide an example of a typical graphic LCD application. Below is an example of the menu and the temperature measurement screen before they are uploaded onto the display.

Pixel size is limited for graphic LCDs. The full page consists of 128x64 pixels so the images must be low resolution and small. The amount of RAM provided by the embedded IC of the display will support 8 full pages of display data. The images must be black and white but will appear as white and blue once uploaded to the display. Below are the images of the display with these example applications uploaded.

The individual pixels can be seen on the graphic LCD and can be altered to project a monochrome image. STN blue graphic LCDs will display white pixels over a blue background. The amount that can be displayed in one page is restricted to 128x64 pixels. Simple icons and characters are common options for graphic display applications.

The design for graphic displays must be simplified to low resolution texts and icons. When you get down to a low resolution, such as 128x64 pixels, every pixel counts in creating a coherent image. This is why there is a standard set of icons used, and you will see them across graphic display applications. These icons are reminiscent of an early Windows computer era, 1980’s/1990’s. Most of these applications have already transferred to higher resolution and colored TFTs.

TFTs have begun to replace graphic LCDs in many applications. This is largely due to the price decrease of the displays and the electronics required to support them. The price of microprocessors and memory chips has substantially decreased, making TFTs a competitive alternative to graphic LCDs. TFT displays have the benefit of higher graphics quality, color, and speed for no extra cost.

The TFT used in this application is close in size to the graphic display. The display can be used both vertically and horizontally by changing the scan direction register. This can also be done by changing the page and column addresses before writing to RAM. The dimensions of the TFT are reviewed below from a vertical reference.

TFT displays offer a higher resolution and color depth. The TFT in this application has a resolution of 480x854 and can display up to 16.7 million colors. The combinations of color and the number of available pixels drastically increases the options for what can be displayed.

The TFT’s size is similar to the graphic LCD, but the resolution area is over six times larger. This makes a significant difference in image quality and available area. Below are the two graphic LCD demos displayed on the TFT.

Both graphic LCD demos can fit in the TFT display resolution and only take up a fraction of the total area available. The resolution of the TFT is highlighted by the amount of data that can be stored in one frame of the display area. Each pixel makes up only a small part of the image which means high resolution images can be portrayed. The same image is uploaded on both the graphic LCD and the TFT below.

TFTs also differ from graphic LCDs because they can display colors. This display supports 24-bits of color data for each pixel. This mean there are 16.7 million colors to select from. The graphic LCD writes to each pixel as on or off. The TFT assigns each pixel 24-bits of color data which means there are 16.7M unique colors that can be displayed.

TFTs have become increasingly standard for most display applications. Even if the application does not require high definition for its intended function, the comparable price for each display type makes the graphics quality an added bonus.

E30RA-FW400-N uses a 24-bit parallel interface and renders 24-bpp of color data for each pixel. This interface is fast enough to support this resolution and color depth to maintain a frame rate of 60 Hz. The only draw-back to this interface is the number of data pins that must be connected to a controller. TFTs come with many different interfaces depending on the resolution.

The graphic LCD demo can be recreated for the TFT to display more complex elements and colors. The addition of color and an increased pixel area gives the display more flexibility on what can be displayed and the quality of the image. TFT displays also have the benefit of touch interface options which can incorporate the user interface on the screen. Below is the example displayed on the TFT.

Some considerations should be made when switching from a graphic LCD to a TFT. A higher resolution means more pixels per frame. An increase in color depth means there is more data assigned to each of the pixels. The memory cost for one page of data can add up quickly depending on size and color depth chosen. The TFT in this example needs a minimum of 1.23MB if using the 24-bpp color depth. A lower color depth can be chosen through commands if you want to reduce memory costs.

Buyers and others who are developing systems that incorporate FocusLCDs products (collectively, “Designers”) understand and agree that Designers remain responsible for using their independent analysis, evaluation and judgment in designing their applications and that Designers have full and exclusive responsibility to assure the safety of Designers" applications and compliance of their applications (and of all FocusLCDs products used in or for Designers’ applications) with all applicable regulations, laws and other applicable requirements.

Designer agrees that prior to using or distributing any applications that include FocusLCDs products, Designer will thoroughly test such applications and the functionality of such FocusLCDs products as used in such applications.

LCD History | LCD Introduction | Twisted Nematic LCD | Supertwisted Nematic LCD | Positive & Negative Mode | Temperature Range | LCD Pixel Terms & Resolution Guide | LCD & TP Glossary

LCD Diagonal Dimension Calculator | How to Improve LCD Viewing Angle | How to Increase LCD Contrast | How to Improve LCD Response Time | Temperature Compensation for LCD Contrast & Voltage | V10 V90, Von Voff, Vth Vsat, Vsel Vnsel |  Vertical alignment display (VTN)  |  Bistable LCD | Character LCD | Embedded LCD | Demo Board

TFT LCD Basic Knowledge | TFT Wide Viewing Angle Technologies | Sunlight Readable TFT LCD | TFT vs. IPS Display | LCD Controller Datasheet | TFT Controller Sample Codes | Electro-Optical Characteristics

With how fast technology changes, constantly learning and staying open-minded helps us stay on top of our game especially when we’re striving to be the best in our field. Brush up on your LCD knowledge with us!

Established in 1998, Winstar Display Co., Ltd. is a reliable LCD Display Module Manufacturer and LCD Panel Supplier. Winstar has development of high-quality display module products. We operate worldwide, configure, service products, and also provide logistics support to deliver products and services competitively. We provide LCM Modules including monochrome TN/STN/FSTN LCM, COG LCD, TFT LCM / TFT panels, FSC-LCD, graphic LCM, character LCD displays, OLED display modules (PMOLED), custom LCD displays, OLED and LCD panel.

Low-temperature polysilicon (LTPS) technology has drawn the attention of many display manufacturers because it has several potential advantages over amorphous thin-film-transistor liquid crystal display TFT LCD). The mapping operation matches one TFT and one color-filter (CF) glass plate together to form one LCD plate. Each plate contains a certain number of cells that are independent devices. The matched LCD cell is good only when the TFT and CF cell match is good. When only a TFT or CF cell is good, there is a yield loss. The sorter is a robot used in LCD manufacturing systems to achieve higher yield in matching TFT and CF plates. This sorter contains several ports that can transfer CF glasses from CF cassettes to match TFT glasses. This is an important determinant for post-mapping yield. This study first proposes a linear programming formulation to optimize the plates-matching problem for the various ports. Next, we propose an algorithm to reduce the number of ways for choosing different matched objects when the number of matched cassettes is large. This algorithm avoids computer overload and provides an excellent solution. The empirical results illustrate the efficiency and effectiveness of the proposed approaches. Note to Practitioners - Yield is an important competitiveness determinant for thin-film-transistor liquid crystal display (TFT LCD) factories. TFT-LCD contains three major manufacturing sectors: the array, cell and module assembly processes. The yield loss from the cell process is one of the most critical steps. This study first formulates a linear programming for the TFT color-filter plates-matching problem in the cell process and a reduction algorithm then is developed to reduce the computational efforts. Our proposed approach is workable and it does not require a significant investment to produce yield improvement by applying the proposed matching algorithm.