This is a glossary of terms for electronic digital displays and signs. Please remember that the definitions shown here apply to the electronic display industry and may have different connotations in other fields. Nor is this a complete list. Further, since new technologies frequently birth new terminology, we ask that you see this as a working -- and often upgraded -- list. If you’d like to add or tweak these definitions, please e-mail me at darek.johnson@stmediagroup.com.
Advanced Television (ATV) A phrase associated with High Definition Television systems.
Analog Analog technology is based upon continually varying values or voltages, as opposed to a signal created from digital codes (ones and zeros). An analog system records and replays data in the form of analog waves.
Aspect ratio The relationship of width to height in a television set screen.
Binary file Computer-readable data for program instructions.
Bit The basic unit of information in a binary numbering system; a bit map is a video image stored in a computer as a set of bits.
Candela The base unit of luminous intensity as defined by the International System of Units.
Cathode ray tube (CRT) A vacuum tube that utilizes a cathode-based electron gun which emits an electronic signal that energizes phosphors on the inside of a television display screen. This is standard television screen technology.
Chip A complete integrated circuit (mass produced) on small pieces of silicon wafers.
Color calibration The necessary color adjustment that causes the colors on the monitor to match the ones produced by a printer or other display devices.
Color depth Color depth is determined by the number of bits that produce color in each pixel on a monitor display. The more bits used, the greater the number of colors that can be displayed.
Digital In digital-based electronics, digital is two electronic states, ones and zeros, which form the basis of all digital data. Data is coded into strings of numbers and doesn’t degrade in the same manner as analog (magnetic-based) data.
Diode A two-electrode (anode and cathode) device that passes current in only one direction. It may be designed as an electron tube, rectifier or a semiconductor device.
Discrete circuitry An individual circuit component, complete in itself, such as a resistor, diode, capacitor or transistor. It’s used as an individual and separable circuit element.
Doping Adding a controlled amount of impurities to a material to modify some intrinsic characteristic, such as resistance, conductance, melting point, hue or color.
Dot-matrix display A display format comprising small, arrayed, light-emitting elements, which are selectively energized (lighted) to depict an image or graphic shape.
Dot pitch The distance between the same color (red to red, for example) pixels on a monitor. Depending on the manufacturer, dot-pitch distance is measured diagonally, horizontally or both. The smaller the dot pitch, the sharper the image.
Dynamic signage Flat-panel display technology as defined by various users and distributors. (See EDS and Narrowcasting)
E-ink Electronic ink display technology in which tiny, arrayed globes are magnetically reversed to display either a white or black side. A few manufacturers offer similar, full-color systems.
Electroluminescence (EL) Thin-film, flat-panel lamp comprising a phosphor dielectric layer between a cathode and anode. Applied voltage charges the phosphors, causing them to light.
Electronic Digital Display (EDD) Electronic-based and digitally controlled displays of any size or technology -- automotive applications, cell-phone panels, flat-panel displays or stadium scoreboards.
Electronic digital signage (EDS) Electronic-based and digitally controlled graphical or information-based signs and displays.
ElectronicDisplayCentral.com (EDC) ST Media Group Intl.’s Website that addresses all areas of the electronic display industry.
Film enhancement A brightness, contrast and anti-reflective coating that improves a flat-panel display’s visual quality.
Flat panel display (FPD) Thin-screen technologies (usually LCD-, plasma- or EL-based) that, generally, use active-matrix or TFT display screens, such as those found in laptop computers.
Format A flat-panel display format that defines the pixel matrix on a display screen by vertical and horizontal pixel count.
Frame The entire set of image data (for animation or video images) in a packet, or frame. Frame rate is the rate in which a frame of data (in frames/sec.) is transmitted and displayed. Frame-rate conversion is a technique to change the number of frames/sec transmitted and displayed. A frame buffer is a hardware device that stores a frame.
Gamma The luminance response (the degree of contrast) of a particular display technology. Most broadcast video images have been compensated for CRT gamma, which results in incorrect luminance for non-CRT displays; gamma correction (“look up”) tables correct the broadcast video images for non-CRT display devices.
Ghosting Visible streaking or shadowing across a passive LCD, usually caused by a visual abnormality that occurs when voltage from an energized element leaks to an adjacent, “off” element.
High-definition television (HDTV) A digital standard that enables television stations to broadcast high-resolution video and sound.
Hue The perceptual term for that aspect of color described by such words as red, yellow or blue; HSL is hue angle, saturation and lightness; HSV is hue saturation and value.
Indium gallium nitride (InGaN) Semiconductor material used in LED modules.
Integrated Services Digital Network (ISDN) A transmission-system architecture that permits higher quality digital audio and video images to be transmitted via telephone lines for video conferencing.
Inverter Hardware that converts low-voltage DC power to high-voltage AC. Inverters are commonly used in the backlighting systems for flat-panel displays.
Institute of Electrical and Electronics Engineers (IEEE) A United States-based professional organization comprising electrical and electronics engineers, computer scientists and educators. IEEE establishes standards for emerging electronic-based technologies.
Joint Pictures Expert Group (JPEG) A committee of computer experts sponsored by the International Standards Organization (ISO). The acronym also applies to compression standards for static, computer-based images.
Latency The time delay that occurs when a computer is converting a signal into a form it can read (for example, from analog to digital).
LED lighting system Includes a power source, an electronic power regulator (driver) and an LED. The LED driver functions as a current regulator that controls the brightness, color and intensity of the LED bulb.
Liquid crystal display (LCD) A flat-panel display formed by a layer of liquid-crystal material sandwiched between two sheets of glass. The glass is coated with a transparent, conductive material that’s etched to form character segments. Applied voltage darkens the molecules in the appropriate segments as they change their arrangement. An active matrix LCD is one that has an active driving element for each sub pixel; a passive matrix LCD has one active driving element per row and per column, rather than at each sub pixel. The passive system is less expensive, with lower contrast and longer response time.
Light emitting diode (LED) A small, electronic lighting device comprising semiconductor materials. LEDs emit light radiation when current is biased in the forward direction. LEDs have a long life and are highly resistant to mechanical shock.
Lumen A unit of measurement that indicates the total amount of light energy in any particular situation. In displays, luminance is the brightness of a picture. Luminous efficiency is the ratio of light output to power input, and luminous intensity is the measure of the visibility of a lightsource expressed in candelas.
Motion Pictures Expert Group (MPEG) A compression standard for moving image sequences. MPEG-1 was the first MPEG standard providing VCR image quality. MPEG-2 is the architecture for Digital Video Disc, DSS and HDTV compression.
Narrowcasting Digital delivery of visual content through a network of displays. Generally, the system is centrally managed and controlled. The term also applies to discriminating-broadcast television and radio systems, such as those found on college campuses.
Native resolution LCD displays are manufactured to display a single resolution, known as the native resolution. Other methods of setting the resolution will result in an unsatisfactory image.
Near-field imaging (NFI) Used in touch-screen technology, in which the screen itself is the sensor. NFI allows user interaction, via a fingertip or stylus.
North American Television Standards Committee (NTSC) The committee that governs the development and maintenance of standards for the current North America broadcast system.
Organic light emitting diode (OLED) A light-emitting device built with organic semiconductors (compared to LEDs built with inorganic semiconductors).
Phosphor A chemical substance that exhibits fluorescence when excited by ultraviolet radiation, x-rays or an electron beam. The amount of visible light is proportional to the amount of energy applied. The term phosphorescent applies if the fluorescence decays slowly (see delay time) after the exciting source is removed.
Pitch The distance between the centers of one pixel and an adjacent one. Pitch is determined by adding the width and/or height of a pixel, plus the gap between pixels.
Pixel Pixels (a contraction of the words “picture element”) are comprised of three red, green and blue (RGB) sub-pixels. Together, three (or sometimes four) pixels create a single image. In a display device, convergence describes the clarity and sharpness of a pixel. Scan rate is the frequency at which one complete horizontal line of pixels is displayed.
Plasma Ionized gases that have been highly energized, for example, by a radio frequency or energy field. This technology excites inert gases to directly generate light or to illuminate phosphors. A plasma display is a FPD using plasma technology.
Resolution The number of pixels displayed on a monitor. Resolution is defined by listing the number of pixels in each horizontal row by the number of pixels in each vertical column (640 x 480, for example). More pixels equal higher resolution.
Router An intelligent switching device used in a local area network (LAN) that examines coded data and decides where to send it.
Saturation Color amplitude or intensity; a given color’s absoluteness.
Semiconductor A material whose electrical conductivity is intermediate between conductors and non-conductors that, by the application of impurities (dopants), can be modified physically or chemically to increase or decrease its conductivity.
Thin film transistor (TFT) An LCD flat-panel display screen in which each pixel or sub-pixel comprises controlled transistors. TFT technology is applied to flat-panel technologies. TFT LCD screens are also called active matrix LCD's.
Viewable area The viewable area of a display. A CRTs viewable area is the diagonal measure of the glass in the display, which may not be the actual picture size. A flat-panel display’s image size is usually identical to what is advertised.
Video wall
Matrixed and arrayed CRT or flat-panel displays linked with a videowall processor.
