FAQ

A SAW touch screen uses a solid glass display as the touch sensor. Across the surface of the glass, two surface acoustic sound waves are transmitted – one for vertical detection and the other for horizontal detection. Each sound wave spreads across the screen by bouncing off reflector arrays along the edges of the display, […]

An infrared touch screen surrounds the face of the display with a bezel of light-emitting diodes (LEDs) and diametrically opposing phototransistor detectors. A sequence of pulses is directed to each of these LEDs by the controller circuitry directs, which scan the screen with invisible infrared light beams just in front of the surface. The controller […]

A capacitive touch screen is constructed out of glass with a coating of capacitive material electrodeposited over its surface. Oscillator circuits at the corners of the capacitive glass measure the capacitance of a person touching the glass surface. Each oscillator will vary in frequency according to where a person touches the surface. The touch screen […]

A resistive touch panel typically uses a conductive glass backplane with a plastic conductive- coated inner surface. These conductive inner layers are separated by spacer dots evenly distributed across the active area. Finger or stylus pressure causes internal electrical contact at the point of touch, which supplies the touch screen controller with a vertical and […]

The four most common touch screen technologies are: resistive, infrared, capacitive, and SAW (surface acoustic wave). Resistive and capacitive touch screen technologies are the most popular for industrial and small format applications. If the application requires that operators wear gloves when using the touch screen, then resistive is preferred over capacitive. Generally, capacitive technology offers […]

Chip-On-Flex is where the LCD driver is mounted directly to a flexible circuited board. These IC-Flex combinations would come from the driver manufacturer on a reel form referred to as TAB, or tape automated bonding. In the past, this was a very useful configuration of LCD driver ICs, as they take up much less space […]

Chip-On-Glass is the mounting of the LCD IC directly onto the ledge of the LCD glass itself. The IC is bonded with an anisotropic conductive film (ACF), which facilitates the mechanical adhesion, as well as the conduction from the IC to the glass. What is Chip-On-Glass (COG)? was last modified: May 18th, 2012 by kkyang

Chip-On-Board is the construction method with the LCD driver wafer mounted on the PCB with contacts facing up. The contacts are then wire bonded to the PCB pads, followed by a complete epoxy encapsulation for a hermetic seal. What is Chip-On-Board (COB)? was last modified: May 18th, 2012 by kkyang

common drivers and segment drivers are the two unique types of driver ICs. common drivers produce signals to create rows or numbers of lines. Segment drivers produce signals to create the characters or columns. The controller IC receives data written in ASCII or JIS code from the MPU. This data in stored in RAM and […]

Most LCD controllers can be interfaced by an 8-bit, 4-bit, or 2-bit I2C, or 1-bit interface. What types of interfaces are available LCD Controller? was last modified: May 18th, 2012 by kkyang

The bias ratio of an LCD, or the voltage margin, is defined as the ratio of V on (voltage on pixels that are currently addressed to the ON-state) divided by V off (voltage on pixels that are not currently addressed). What is the definition of bias ratio? was last modified: May 18th, 2012 by kkyang

A duty rate, also known as the multiplex rate, is the fraction of the total frame time that each row of the LCD is addressed. What is the definition of a duty rate? was last modified: May 18th, 2012 by kkyang

Passive-matrix LCD is an LCD technology that uses a grid of vertical and horizontal conductors comprised of Indium Tin Oxide (ITO) to create an image. Each pixel is controlled by an intersection of two conductors. By creating a potential voltage difference at an intersection, the LC fluid is able to respond by creating an “on” […]

An LCD is nothing more than a light value that either allows light to go through the display or blocks the light from passing. To create a full-color display, each pixel is actually divided into three rectangular sub-pixels. When combined, these three sub-pixels are dimensionally similar to a typical square pixel. These sub-pixels are then […]

This is the angle representing the preferred viewing direction where the LCD display exhibits the highest contrast. Viewing angles are usually defined in the horizontal and vertical directions, and measured in degrees perpendicular to the LCD surface. As the user physically moves to either side of the LCD screen, the images displayed will degrade. The […]

The contrast ratio is the ratio of the luminance between a pixel in the “light” state compared to the same pixel in the “dark” sate. Typical contrast ratios for the different technologies are: • TN 9:1 • STN 10:1 • FSTN 15:1 • CSTN 25:1 • TFT 300:1 and up What is the contrast ratio? […]

Glare and reflection are terms that are often confused. Both anti-glare and anti-reflective enhancements attempt to improve or optimize readability while using different techniques to address the causes of reduced readability due to external ambient light sources. Anti-glare deals with external sources of reflection off a surface – like bright sunlight or high ambient lighting […]

Born of a need for outdoor applications and a lack of available transflective panels, Sunlight Readable Displays combine the right type of anti-reflective front polarizer and high-efficiency rear polarizer, allowing the cell to reuse some of the sunlight’s energy. Used in concert with a higher-brightness backlight, the overall image quality in an indoor, high ambient […]

Each color display application will vary depending on the intended use of the LCD, the contrast, and the ambient light environment that the display is in. A typical standard notebook or desktop LCD display in office lighting conditions are in the 200-250 NIT range. In an LCD display intended for mixed use of both indoors […]

A NIT is a measurement of light in candelas per meter square (Cd/m2). The unit is based on the candela, the SI unit of luminous intensity, and represents a measure of light emitted per unit area. This is a common metric used in characterizing the brightness of a display device. This can apply to either […]