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Active Area Area (L x H) of the LCD that has active segments.
Active Plate Another term for the glass substrate that contains the array or thin film transistors (TFTs) in an active matrix liquid crystal display (LCD). This is also known as an array or backplane.
AMLCD (See also LCD) Active matrix liquid crystal display (LCD). A Liquid crystal based display technology that uses a switch at each pixel to create high resolution and fast response times. One type of LCD is known as thin film transistor (TFT)-LCD, in which the switch used is a thin film transistor. Displays based on this technology range from as small as 1" diagonal up to 40" diagonal.
Amorphous silicon (a-Si) A semiconductor film used as the active layer in most active matrix liquid crystal displays (LCDs). It is based upon the electronic properties of a glass alloy of silicon and hydrogen.
Analog to Digital Controller (AD Controller) A controller which converts an analog signal to a digital signal thus providing the input to the display in a digital format.
Analog Resistive Touch Panel This touch panel is comprised of two transparent resistive layers, separated by small spacers. Touching the screen causes the two layers to come in contact and form a switch closure. By measuring the voltage gradient in the horizontal and vertical axis, position can be determined.
Analog RGB Separate Red, green, and blue video signals used in conjunction with composite sync or separate horizontal and vertical sync.
Analog Signal A signal that travels continuously. An analog signal may be either direct or alternating current.
Annunciator A word or special symbol which is driven as a single segment
Array Rows and columns of thin-film-transistors (TFTs) made on a glass substrate to form the pixel-addressing component of an active matrix liquid crystal display (LCD). The TFTs are made by depositing a series of films via chemical vapor deposition and patterning these films by photolithography. This process is very similar to the manufacturing process for silicon-based microelectronics. This is also known as a backplane.
Array Process Method of manufacturing whereby displays are arranged in rows and columns on a large laminate, and separated after they are filled with LCD fluid.
Backlight The light source for an active matrix liquid crystal display (LCD), located behind the panel. It is usually made up of several fluorescent lamps, a light guide, reflectors, and brightness enhancing films.
Backplane The common electrode connection. There can be multiple backplanes in a multiplexed display.
Black Matrix A light-shielding film that separates the pixels of the color filter.
Bezel A frame of plastic or metal, fitting over the LCD glass, to protect the edges of the glass and act as a pressure device, compressing the elastomer connector between the PCB and LCD glass.
Blue Negative Display configuration of a backlit negative image STN display
Borosilicate A family of glass compositions in which boron trioxide and silicon dioxide are major components.
Brightness This is the measure of the luminosity in a display.
Burn-in A tendency for an image that is shown on a display over a long period of time to become permanently fixed on the display. This is most often seen in emissive displays such as CRT (cathode ray tube) and plasma, because chemical changes can occur in the phosphors when exposed repeatedly to the same electrical signals. This is most noticeable in electronic signage such as in airport information displays, or displays that are used with video games, and is less noticeable in consumer televisions.
Capacitive Touch Screen A capacitive touch screen includes an overlay made of glass with a coating of capacitive (charge storing) material deposited electrically over its surface. Oscillator circuits located at corners of the glass overlay will each measure the capacitance of a person touching the overlay. Each oscillator will vary in frequency according to where a person touches the overlay. A touch screen controller measures the frequency changes to determine the X and Y coordinates of the touch. Because the capacitive coating is even harder than the glass it is applied to, it is very resistant to scratches from (SIC) sharp objects. It can even resist damage from sparks. A capacitive touch screen cannot be activated while wearing most types of gloves (non-conductive).
CCFL Cold Cathode Florescent Lamp
CCFT Cold Cathode Fluorescent Tube. Same as CCFL.
CELL GAP The space containing liquid crystal fluid between the two pieces of glass.
CHIP-ON-BOARD The LCD driver wafer is mounted on the PCB with gold wires used to connect it to other circuits. It is covered with epoxy.
CHIP-ON-GLASS A new technology that mounts the LCD driver to the contact edge of the LCD glass.
CHIP-ON-FLEX The contact edge of the LCD glass is mounted to a flex connector that incorporates an LCD driver.
COB Chip on Board. The LCD driver is formatted into an area of the PCB.
COG Chip on Glass construction process
COLD CATHODE BACKLIGHT (CCFT) In medium to large LCD graphic modules, a type of fluorescent backlighting or edge lighting.
- 3-Bit = 512 colors
- 4-Bit = 4096 colors
- 6-Bit = 262K colors
- 8-Bit = 16M colors
Color Filter A component of the active matrix liquid crystal display (LCD) panel. The color filter contains primary colors - red, green and blue - that enable the LCD to produce more than 16 million colors.
COF Chip on Flex. The LCD driver is incorporated into a flex connector, which is attached to the contact edge of the LCD glass.
COT Chip on Tab construction process
Common Plane See Backplane
Component video improves the picture quality even more than S-Video. Component refers to video transmitted as three separate signals (subsignals if you prefer) to represent all colors. The first component video was RGB since the three signals represented pure red, pure green, and pure blue content respectively. Today, most video experts use the term "component video" as short for "analog component video" consisting of the three signals Y (luminance), Pr or R-Y, and Pb or B-Y. For NTSC or PAL (interlaced video formats) the Y signal is the same as that used to construct composite video or that found in S-Video.
Composite video also referred to as baseband or RCA video, is the most common of all video signals. A composite video signal consists of an analog waveform that conveys the image data in a conventional National Television Standards Committee (NTSC) television signal. Composite video contains chrominance (hue and saturation) and luminance (brightness) information, along with synchronization
and blanking pulses, all together in a single signal.
Composite video is the standard that connects almost all consumer video equipment through a phono-jack, also known as an RCA connector. In composite video, interference between the chrominance and luminance information is inevitable resulting in poor quality video when signals are weak. The cable has 3 jacks: yellow, white, and red. One jack sends the audio (left), the second the stereo (right), and the third the video, respectively.
The picture quality is decent but pales in comparison to S-Video
Contact Edge The area of the LCD with conductive leads/traces where electrical connection is made by use of a connector.
Contact Ledge The area along the edge of the parts where electrical connections are made.
Contrast Ratio The ratio of the luminance between the dark and light areas of the display.
CROSS-TALK CURSOR Dots used to indicate the location of the next character or symbol to be entered.
CRT Cathode ray tube (CRT), a technology used in many traditional television sets and desktop computers. A CRT uses a vacuum tube that produces images when an electron beam strikes a phosphorescent surface. CRT devices are bulkier and require more space than active matrix liquid crystal display (LCD) devices.
CSTN (Color STN) Color STN Technology. Each pixel of a CSTN display is actually 3 separate colored pixels of Red / Green / Blue. Each of those colors are controlled individually by the graphic controller chip. So in actually; a 320 by 240 pixel CSTN display actually contains 960 by 240 individually colored pixels
CTE Coefficient of thermal expansion (CTE). The slope of the expansion versus temperature curve. For glasses, it is typically expressed as a value multiplied by 10-7/oC.
Dual in Line Pins (DIL) Two rows of pins attached along parallel sides of a display.
DLP™ Digital Light Processor (DLP™), a proprietary technology developed by Texas Instruments as a microdisplay projection element. DLP uses an array of tiny mirrors on a silicon chip to reflect light from a projection lamp to form an image. Requires a lamp, color wheel, and optics to make front-projection and rear-projection displays.
Diffuser Translucent material used for light diffusion placed between backlight lighting sources and the back side of an LCD. This material will create a more uniform backlight for an LCD from several unique sources of light.
Direct Drive A method of driving a display whereby individual segments are driven from separate edge connections.
Direct view A term used to refer to active matrix liquid crystal displays (LCDs), cathode ray tubes (CRTs), plasma displays, and other displays that create the exact image that the user views. In contrast, projection displays need magnification optics to create the final image that is viewed.
DMD Digital Micro-mirror Device (DMD), a generic term for Texas Instrument's DLP™ chip.
DOT/PixelAn active element that forms a character or symbol when combined in a matrix.
DOT Matrix A group of dots/pixels forming a character or symbol, usually five dots across and seven dots down.
DIL (Dual-In-Line) Two parallel rows of connection holes on a PCB. Also, the type of connector used with this array.
Driver IC Microprocessors (“chips”) that send data to (address) the rows and columns of pixels in an active matrix liquid crystal display (LCD) to create the image. This functionality can be integrated into the panel if a low temperature poly-crystalline silicon LTPS backplane is used, otherwise the driver integrated circuits (ICs) are attached to the display via a tape-automated bonding method (TAB) or are attached to the edges of the display (Chip-on-Glass or COG).
DSTN Double Supertwist Nematic Display. A technology that uses a second LCD layer to correct the color shift in STN display and so produces a black and white image.
Dual Scan A technique used in passive color and monochrome displays, which effectively divides the screen in half, which doubles the duty cycle in order to increase performance.
Duty Ratio1/N when N is equal to the number of segments selected by one complete cycle.
DVI Digital Visual Interface
Edge Lighting A backlight in which the tube(s) are located at the side of the display and uses a scattering sheet to get even lighting across the display, which allows for thinner displays.
Effective Area Same as Active Area. In the viewing area of the LCD glass, the dimensions of the perimeter of the conductive area.
Elastomeric Connectors A thin conductive material used to make connections between an LCD and a PC board.
Electrophoresis A dead short is created when excess DC voltage is applied to an LCD. Conductive particles from one piece of glass are transferred through the liquid crystal fluid and deposited on the conductive surface of the opposite piece of glass.
Electrochromic Display This is a reflective display that uses electrochromic materials to switch pixels on and off. Electrochromic materials change color when the oxidation state of the material is changed by an applied voltage. NTERA is working on a display based on this technology. Electrically switchable automobile rear-view mirrors are an example of this technology.
Electrophoretic Display This is a reflective display that uses electrophoresis to switch pixels on and off. Electrophoresis is the motion of charged particles suspended in a liquid in response to an electric field. Positively charged particles move toward the cathode, and negatively charged particles move toward the anode. If these particles are colored, the display shows different colors to the user as the particles move. E Ink and Gyricon are examples of this type of display.
EL Electroluminescent (EL). This is a display technology based on the light-emitting ability of certain phosphors (typically ZnS) in an electric field. EL displays can be further subdivided into thick film, thin film, alternating current, and direct current type displays.
Emissive A direct-view display, such as cathode ray tube (CRT), field emission display (FED), plasma, electroluminescent (EL), and organic light emitting diode (OLED), where the light generation, switching, and coloring are all done at once by the display. These displays do not need a separate backlight to provide light for the image. See also Transmissive, Reflective, and Projection.
ELED Edge Lit LED backlight configuration
ELP Electroluminescence Panel
FED A Field Emission Display (FED) is an emissive flat panel display that uses many small electron emitters to excite a phosphor screen and emit light. Also known as Thin CRT or carbon nanotube FED. This technology is still in the development phase and is not currently available commercially.
Fill Hole The space left between the epoxy seals on one end of the LCD glass after assembly. This space, used to fill the glass with the liquid crystal fluid, is noted by a mound of epoxy.
First Minimum An LCD construction technique where the cell geometry is optimized for maximum contrast and viewing angle. The geometry is different for each LCD fluid.
Font The style of a letter or digit.
FPD Flat panel display (FPD). FPD can be used to refer to any of a number of "flat" display technologies including LCD, plasma, FED, or others.
FRM Frame rate modulation.
FSTN (Film compensated STN) STN Technology with the addition of a retardation film to the display that compensates for the color added by the birefringence effect. This allows a black and white display to be produced and provides for a higher contrast and wider viewing angle.
Ghosting A condition where segments which are in the "off" condition become slightly visible.
Grey Scale Heat Seal A flexible adhesive connector bonded by heat to the contact edge of the glass.
HDTV High Definition Television (HDTV), a term that can refer to certain TV sets or programming that conforms to a set of standards that define next-generation television resolution, sound, and format. The most common HDTV formats in the U.S. are 480p, 720p, and 1080i, which correspond to lines of resolution and progressive or interlaced scanning. Each country or region has different HDTV definitions and standards.
Heat Seal A flat, flexible, adhesive connector which is bonded to the contact edge of the glass by heat.
Heat Seal Cable A thin flexible cable used to connect the LCD to the PC board which is bonded by heat cured adhesive at each end..
Image Area The total area bounded by the display characters
Infrared Touch Screen An infrared touch screen surrounds the face of the display with a bezel of light emitting-diodes (LEDs) and diametrically opposing phototransistor detectors. The controller circuitry directs a sequence of pulses to the LED's, scanning the screen with an invisible lattice of infrared light beams just in front of the surface. The controller circuitry then detects input at the location where the light beams become obstructed by any solid object. The infrared frame housing the transmitters can impose design constraints on operator interface products.
Ink Overlay The process of applying opaque, colored inks to the display to provide colors, or highlight certain areas of annunciators.
Interconnect DOT Consisting of silver impregnated epoxy, it connects the pattern piece of glass to each backplane.
Inverter, DC to AC Converts DC to AC at a high frequency, and powers electroluminescent lamps.
IP Ratings (Ingress Protection) - The IP rating system provides a means of classifying the degrees of protection from solid objects and liquids afforded by electrical equipment and enclosures. The system is recognized in most European countries and is set out in a number of British and European standards. These include: Classification of Degrees of Protection Provided by Enclosures, BS (British Standards) 5490:1977; IEC (International Electrotechnical Commission) 529:1976.
Specifications for Degrees of Protection of Enclosures of Switchgear and Control Gear for voltages up to and including 1000 VAC and 1200 VDC, BS 5420:1977; and IEC 144:1963.
First number Protection against access to hazardous parts
||Protected against access with back of hand (50 mm)
||Protected against access with jointed finger (12 mm x 80 mm)
||Protected against access with a tool (2.5 mm)
|4, 5, 6
||Protected against access with a wire (1.0 mm)
First number Protection against Ingress of solid objects
||Objects equal or greater than 50mm
||Objects equal or greater than 12.5mm
||Objects equal or greater than 2.5mm
||Objects equal or greater than 1mm
Second number Protection against liquids
||Water dripping vertically
||Water dripping, enclosure tilted up to 15°
||Spraying water, up to 60° angle from vertical
||Splashing water, any direction
||Jetting water, any direction
||Powerful jetting water, any direction
||Temporary immersion in water
||Continuous immersion in water
IP-43 Rating - The first digit designation "4" means protection against "solid objects equal or greater than 1mm (0.04") in diameter". The second digit "3" means protection against "sprayed water" ; "Spray water falling perpendicularly at an angle of up to 60-deg may not have any damaging effects".
IP-54 Rating - The "5" means "Dust Protected. Ingress of dust is not totally prevented, but dust does not enter in sufficient quantity to interfere with satisfactory operation of the equipment. The "4" means "Protected against splashing water. Water splashed against the enclosure from any direction shall have no harmful effect."
IP-66 Rating - A strong water jet directed at the scale from any direction must not have any harmful effects. A jet nozzle with an inside diameter of 0.49 inches splashes a volume flow of approximately 26.4 gallons per minute, from a distance of approximately 8.2 - 9.8 Feet from all sides onto the scale. The test time is 3 minutes.
IP-67 Rating - Temporary Submersion. The device is placed in water at a depth of 3.28 feet for 30 minutes
IP-68 Rating - Long Term Submersion
IP-69K Rating - A strong water jet directed at the sensor from 4 directions must not have any harmful effects. A jet nozzle at 0°, 30°, 60° and 90° to the scale on a rotating table at 176° + 8°F, 4-6 inches away at 1250-1500psi. The test time is 2 minutes.
IR Touch Panel Infrared light emitting diodes and detectors are positioned along the screen edges to create a grid of light. A finger or stylus interrupts the light beams and position is determined on the grid.
Isotropic Stage The point where the fluid heats or cools to where it is no longer in the twisted nematic state. Since the molecules can no longer twist light, all incoming light is absorbed.
LCD Liquid Crystal Display
LCD Module An LCD which includes a PCB, driver electronics, bezel, and possibly a backlight.
LCD Panel A thin film transistor-passive or active matrix liquid crystal display (TFT-LCD) that includes the array, color filter, and liquid crystal. May also include a backlight and driver integrated circuits (ICs), but sometimes is used to refer to just the glass-liquid crystal composite. Often used interchangeably with LCD module.
LCD Projection A projection technology that uses small thin film transistor-active matrix liquid crystal displays (TFT-LCDs), of 2” diagonal or less, as picture elements. The light from the projection lamp is switched and given color by one of three TFT-LCDs, and then is combined into a picture by optics, and finally projected onto a screen. These can be used to make a rear-projection TV or a front-projection data projector.
LCoS Liquid Crystal on Silicon (LCoS), a type of reflective micro-display that can be used to make front-projection, rear-projection, or near-eye displays. A thin film transistor (TFT) array is made on a silicon chip and becomes a display by adding a liquid crystal layer to control the reflection of light off the chip. A color wheel or color scroll, a light source, and a lens array are other system components needed for LCoS projection.
LEADS The conductive traces on the contact edge of the glass.
LED Light Emitting Diode.
Lifetime A measure of the durability of a display, expressed in how many hours of operation it takes for a display to show half the brightness as compared to the brightness it showed when it was new. For example, if a display is rated for 50,000 hours lifetime, it should take 50,000 of cumulative operation before it is half as bright as compared to when it was new. Most displays degrade slowly over time so the effect is not noticeable unless compared directly with a new display.
Liquid Crystal Fluid An organic material which has both liquid and crystalline properties.
Luminance is the scientific term for "Photopic Brightness" which specifies the visual brightness of an object. In layman's terms, it is commonly referred to as "brightness". Luminance is specified in candelas per square meter (Cd/m2) or nits. In the US, the British unit Foot-lamberts (fL) is also frequently used. To convert from fL to nits, multiply the number in fL by 3.426 (i.e. 1 fL = 3.426 nits).
Luminance is an influential factor of perceived picture quality in an LCD. The importance of luminance is enhanced by the fact that humans will react more positively to a brightly illuminated screen. In indoor environments, a standard active-matrix LCD with a screen luminance of around 250 nits will look good. In the same scenario an LCD with a luminance of 1,000 nits or more will look utterly captivating.
LVDS Low Voltage Differential Signal.
Module An LCD glass connected to a PCB with drivers on board. It may also have controllers, temperature compensation circuits, or other features.
Multiplex (Mux) A method of driving a display whereby multiple segments are driven from the same edge connection.
Native Resolution This is the optimum resolution of an LCD monitor.
Negative Image A display which has a dark background and lighter active segments, i.e. clear characters on a black background
NEMA 1 Type 1 enclosures are intended for indoor use primarily to provide a degree of protection against contact with the enclosed equipment or locations where unusual service conditions do not exist.
NEMA 2 Type 2 enclosures are intended for indoor use primarily to provide a degree of protection against limited amounts of falling water and dirt.
NEMA 3 Type 3 enclosures are intended for outdoor use primarily to provide a degree of protection against windblown dust, rain, and sleet; and to be undamaged by the formation of ice on the enclosure.
NEMA 4 Type 4 enclosures are intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose directed water; and to be undamaged by the formation of ice on the enclosure.
NEMA 4X Type 4X enclosures are intended for indoor or outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, and hose directed water; and to be undamaged by the formation of ice on the enclosure.
NEMA 7 Type 7 enclosures are intended for indoor in locations classified as Class , Groups A, B, C, or D as defined in the National Electrical Code. Type 7 enclosures shall be capable of withstanding the pressures resulting from an internal explosion of specified gases, and contain such an explosion sufficiently that an explosive gas-air mixture existing in the atmosphere surrounding the enclosure will not be ignited. Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting explosive gas-air mixtures in the surrounding atmosphere. Enclosures shall meet explosion, hydrostatic, and temperature design tests.
NEMA 9 Type 9 enclosures are intended for indoor in locations classified as Class , Groups E, F, or G as defined in the National Electrical Code. Type 9 enclosures shall be capable of preventing the entrance of dust. Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting or discoloring dust on the enclosure or igniting dust-air mixtures in the surrounding atmosphere. Enclosures shall meet dust penetration and temperature design tests, and aging of gaskets if necessary.
NEMA 10 Type 10 Enclosures Constructed to meet the applicable requirements of the Mine Safety and Health Administration.
NEMA 12 Type 12 enclosures are intended for indoor use primarily to provide a degree of protection against dust, falling dirt, and dripping of non-corrosive liquids.
NEMA 13 Type 13 enclosures are intended for indoor use primarily to provide a degree of protection against dust, spraying of water, oil, and non-corrosive coolant.
NIT (cd/m2) is a measurement of light in candelas per meter square (Cd/m2)
For an LCD monitor it is brightness out of the front panel of the display. A NIT is a good basic reference when comparing brightness from monitor to monitor. Most desktop LCD's or Notebook LCD's have a brightness of 200 to 250 Nits. These standard LCD's are not readable in direct or even indirect sunlight as they become washed out.
NTSC National Television Standard Committee. International television standard which uses 525 lines per frame at 60Hz field rate.
OLED Organic light emitting diode (OLED), an emissive flat panel display that uses organic compounds to emit light. OLEDs can be passive or active matrix. Passive matrix devices are easier to make, but not capable of full color or high resolution. Currently, active matrix devices use a poly-crystalline silicon thin film transistor (TFT) array, similar to low temperature poly-crystalline silicon (LTPS) active matrix liquid crystal displays (LCDs). There has been limited production to date because of short product lifetimes and differential aging rates of the OLED materials. This is also known as Organic EL.
Organic EL Organic electroluminescent (EL). This is an organic analog to the EL type display in which the active material is organic. This is another name for organic light emitting diode (OLED) technology.
OSD On Screen Display
Pacific Display Devices The logical place to purchase all of your LCD products
PAL Phase Alternation Line. International television standard which uses 625 lines per frame at 50Hz field rate
Photolithography The patterning step of the process by which transistors are made for displays or microprocessors. Thin films of silicon or other materials are deposited on a substrate then covered with another material (photoresist) that reacts to light. This material is exposed to light through a mask that is patterned for one layer of the transistor. Then the exposed area is etched away, taking the underlying thin film with it. Then the photoresist is cleaned off, leaving the patterned thin film. This is repeated several times with different thin films to create the transistor array.
Plug and Play A monitor with plug and play support can be plugged in and ready to go with few installation steps. This means that the monitor can notify the operating system of it's capabilities and the operating system will automatically configure the video card to work at the best setting for the top performance.
Pitch The center dimension of adjacent conductive traces, dots, or connector holes.
Pixel An individual active segment
Plasma Emissive flat panel display technology that uses a gas plasma to excite phosphors and make them glow. Used for large-size displays (typically 32" diagonal and up), but has a limited market because of the high cost of production. Also called plasma display panel (PDP).
Polarizer A stretched polymer which transmits light in only one axis. A typical display has polarizers on the front and back.
Positive Image A display which has a light background and darker active segments, i.e. black characters on a silver background.
Poly-crystalline silicon TFT-LCD Type of thin film transistor- active matrix liquid crystal display (TFT-LCD) that uses transistors made from poly-crystalline silicon rather than amorphous silicon.
Projection A display that uses from one to three small emissive, reflective, or transmissive displays to create a picture that is enlarged by a set of optics to the final viewable size. The light is provided by a projection lamp, the switching is done by the small displays, and the color can be provided by the small displays or separate color elements. See also Emissive, Transmissive, and Reflective.
QSXGA Resolution 2560x2048 pixel count.
QXGA Resolution 2048x1536 pixel count.
RCF Film Reflective A smooth silver piece of aluminum foil, bonded to the rear polarizer, that reflects incoming ambient light. Backlighting cannot be used with a reflective LCD.
Reflective A viewing mode which uses ambient or other front lighting to provide the illumination for the display.
Refresh Rate The time interval required for the electronics to fully address a display. This rate determines the capability of the display to show video images.
Resistive Touch Screen A resistive touch screen typically uses a display overlay consisting of layers, each with a conductive coating on the inner surface. The conductive inner layers are separated by special separator dots, evenly distributed across the active area. Finger pressure causes internal electrical contact at the point of touch, supplying the electronic interface (touch screen controller) with vertical and horizontal analog voltages for digitization. For CRT applications, resistive touch screens are generally spherical (curved) to match the CRT and minimize parallax. The nature of the material used for curved (spherical) applications limits light throughput such that two options are offered: Polished (clear) or antiglare. The polished choice offers clarity but includes some glare. The antiglare choice will minimize glare, but will also slightly diffuse the light throughput (image). Either choice will demonstrate either more glare (polished) or more light diffusion (antiglare) than associated with typical non-touch screen displays. Despite the tradeoffs, the resistive touch screen technology remains a popular choice, often because it can be operated while wearing gloves (unlike capacitive technology). Note that resistive touch screen materials used for flat panel touch screens are different and demonstrate much better optical clarity (even with antiglare). The resistive technology is far more common for flat panel applications.
Resolution The number of pixels available for information display. More pixels (higher resolution) enables finer details to be displayed and generally results in a better image quality.
Response time Total delay time (Td off) and rise time (Tr).
RGB Analog Red, Green, Blue analog interface.
S-Video (Super-Video, Super-VHS) and sometimes referred to as Y/C Video was introduced in the 1980s and solved some of the problems that were inherent with composite video. S-Video provides better color separation and a much cleaner signal by keeping the transmitted luminance and chrominance video signals separated.
Today, S-Video signals are generally connected using 4-pin mini-DIN connectors using a 75 ohm termination impedance. S-Video provides for a high quality method of delivering a clean crisp video signal.
Saturation Voltage RMS voltage required to turn fluid to 90% on.
Segment An active area within the display which can be turned on and off. This can be a single segment of a 7-segment character, an annunciator, or a pixel in a dot matrix array.
SAW (Surface Acoustic Wave) Touch Screen A SAW touch screen uses a solid glass display overlay for the touch sensor. Two surface acoustic (sound) waves, inaudible to the human ear, are transmitted across the surface of the glass sensor, one for vertical detection and one for horizontal detection. Each wave is spread across the screen by bouncing off reflector arrays along the edges of the overlay. Two receivers detect the waves, one for each axis. Since the velocity of the acoustic wave through glass is known and the size of the overlay is fixed, the arrival time of the waves at the respective receivers is known. When the user touches the glass surface, the water content of the user's finger absorbs some of the energy of the acoustic wave, weakening it. The controller circuitry measures the time at which the received amplitude dips to determine the X and Y coordinates of the touch location. In addition to the X and Y coordinates, SAW technology can also provide Z axis (depth) information. The harder the user presses against the screen, the more energy the finger will absorb, and the greater will be the dip in signal strength. The signal strength is then measured by the controller to provide the Z axis information. Today, few software applications are designed to make use of this feature.
SHA Super High Aperture.
Static Drive See Direct Drive
SIL (Single-In-Line) An LCD module that has a single row of connection holes, and an LCD glass with a signle contact edge.
STN (Super Twisted Nematic) A type of display which uses fluids which "twist" greater than 90o. An STN display has improved viewing angles and contrast at high multiplex rates
Sub-Pixel A sub portion of a pixel showing only one of the primary colors - green, red or blue. Three or more sub-pixels make up a single pixel.
Sunlight Readable LCD Display First, the display screen on a sunlight readable/outdoor readable LCD should be bright enough so that the display is visible in direct or strong sunlight. Second, the display contrast ratio must be maintained at 5 to 1 or higher.
Although a display with less than 500 nits screen brightness and a mere 2 to 1 contrast ratio can be read in outdoor environments, the quality of the display will be dreadfully poor and not get the desired information across effectivley. A true sunlight readable display is normally considered to be an LCD with at least 1000 nits of screen brightness and a contrast ratio greater than 5 to 1. In outdoor environments under the shade, such a display can provide an excellent image quality.
SVGA Resolution 800x600 pixel count.
SXGA Resolution 1280x1024 pixel count.
TFT Thin-film transistor (TFT). Electronic technology upon which active matrix liquid crystal displays (LCDs) are based. The foundation of the TFT is a semiconductor layer (typically based on silicon) which can switch current flow on or off by the application of an electric field.
TFT Array A component of the LCD display. The glass substrate containing the thin film transistors used to switch the sub-pixels on or off.
Threshold Voltage RMS voltage required to turn fluid to 10% on.
Touch Screen Controllers Most manufacturers offer two controller configurations--ISA Bus and Serial-RS232. ISA bus controllers are contained on a standard printed circuit plug-in board and can only be used on ISA or EISA PCs. Depending on the manufacturer they may be interrupt driven, polled or be configured as another serial port. Serial controllers are contained on a small printed circuit board and are usually mounted in the video monitor cabinet. They are then cabled to a standard RS232 serial port on the host computer.
Touchscreen A transparent glass or hard plastic sheet that mounts over the display viewing area and allows users to make a choice and input via touching the screen.
Transflective A viewing mode which can use ambient light or backlighting to provide the illumination for the display.
Transflective LCD An active matrix liquid crystal display (LCD) that combines reflective and transmissive qualities. In dark ambient light environments, the backlight can be used to provide light for the display, in bright ambient light environments, the backlight can be switched off and the display used in reflective mode to save battery life. Most often used in PDAs and mobile phones.
Transmissive A viewing mode which cannot use any type of front lighting to provide the illumination for the display, it therefore must use a backlight
TN (Twisted Nematic) Twisted Nematic A type of display where the liquid crystal fluid rotates the plane of polarization 90o.
TSTN Triple Super Twist Nematic. Sharp name for film compensated super twist display which uses a retardation film to correct the color shift in STN displays, and so produces a black and white image.
User (OSM, OSD) Controls These are on-screen user controls, usually from the front of the monitor a menu can be accessed to adjust language, brightness, color and so on.
UXGA Resolution 1600x1200 pixel count.
VESA Hole Configuration Usually in mm, such as 75mm or commonly 100mm, this relates the type of brackets the monitor needs to be wall or arm mounted.
VGA Resolution: 640x480 pixel count.
VFD Vacuum Fluorescent Display.
Video Electronics Standards Association (VESA) "A non-profit member organization dedicated to facilitating and promoting personal computer graphics through improved graphics standards for the benefit of the end user."
Viewing Area The area of a display which is visible through a bezel or cut-out in an instrument. This area is made up of the "Active Area" and the boarder around the active area.
Viewing Angle The angle at which the viewer must be in comparison to the screen, in order to see the image on a display. For example, a 0° horizontal viewing angle is directly in front of the display and a 90° horizontal viewing angle is directly to the side. Emissive displays show the same brightness and color regardless of viewing angle, however, rear projection displays and transmissive displays can show some differences in color, brightness, and gray scale, with the most difference being noticed at the steepest viewing angles.
Wall Mount Optional The monitors in this review have either a VESA 75mm or 100mm wall mount connections so an arm or wall mount bracket can be added safely.
XGA Resolution 1024x768 pixel count.
Zebra(r) Connector a trademark of Fujipoly America Corp.