Resources

Glossary

Absolute White
In theory, a material that perfectly reflects all light energy at every visible wavelength. In practice, a solid white (with known spectral data) that is used as the “reference white” for all measurements of absolute reflectance.

Achromatic
A neutral color (white, gray, or black) that has no hue. See Hue.

Acousto-optics
A method where the direction of light passing through a crystal is changed using a high frequency sound wave.

Active Area / Effective Area
The dimensions of the perimeter of the conductive area in the viewing area of the LCD glass. The actual area of the touch panel or display that is useful for touch input or display.

Active Matrix
A liquid crystal display structure in which switching transistors or diodes are attached to each pixel to control the on/off voltage. It produces a brighter and sharper display with a broader viewing angle than a passive matrix display. Also known as AMLCD (active matrix liquid crystal display). See TFT (thin film transistor).

ADC (Apple Display Connector)
Proprietary connector used to carry digital video signal and USB data to the CPU. Also used to power the display.

Additive Primaries
In color reproduction, red, green, and blue. When lights in these colors are combined in equal amounts, they produce the visual sensation of white light. When these are combined at varying intensities, a range of different colors is produced. Combining two primaries at 100% produces a subtractive primary, either cyan, magenta, or yellow. See subtractive primaries.

Advanced TFT
Advanced TFT is a display technology that combines the advantages of a reflective display with a conventional transmissive display. The Advanced TFT has an internal reflective structure plus a small aperture in each subpixel to allow backlighting. Unlike transflective technology, it maintains color gamut independent of the ambient. It is more efficient and more effective than transflective displays.

Alignment Layer
A thin film layer that is applied by spin coating. This thin film is then treated to impart a desired direction at which the liquid crystal molecules will attach and align. See Buffing.

AMLCD
See Active Matrix.

Amorphous Silicon (a-Si)
A semiconductor material that is used to make the thin film transistors (TFTs) layer of an active matrix LCD.

Analog
A signal (such as that used to record video and audio images to standard tape-based systems) that can be continuously varied, as opposed to a digital signal, which is broken into numbers (either 0 or 1 in binary systems used in computers, CD-ROMs and other forms of digital recording).

Analog Resistive Touch Panel
Two transparent resistive layers that are 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.

Annunciator
An active element; a word, phrase, or symbol.

ANSI Lumen
American National Standard Institute standard for measuring brightness and resolution of a display device. ANSI lumens cannot be converted into other measurements of light as the measurement is an average of 9 points of light.

AOD (Acousto-Optic Deflector)
An AOD (Acousto-Optic Deflector) is used to create a sweep of the exposure laser beams in the laser pattern generators.

AOM (Acousto-Optic Modulator)
An AOM (Acousto-Optic Modulator) is used to control the intensity of the exposure laser in the generators.

Aperture Ratio
The ratio between the transmissive portion of the pixel and its surrounding electronics, also known as fill factor. Generally, this is a limiting factor for luminance. The higher the aperture ratio, the brighter the luminance. The light-transmitting area of a subpixel divided by its screen area (SubpixelPitch x RowPitch).

Aspect Ratio
The width-to-height ratio of the active area of a display. Standard U.S. video has an aspect ratio of 4:3.

Backlight
The light source for a transmissive LCD. Basically, two techniques are used in transmissive LCD designs, direct lighting and side lighting. Direct-lit backlights use CCFTs (cold cathode fluorescent tubes) and a diffuser panel directly in back of the LC (liquid crystal) layer. Side-lit backlights use CCFTs and a light pipe on one or more of the edges of the display.

Bezel
A protective frame fitted over an LCD to protect the glass edges and act as a pressure device by compressing and securing the elastomer connector between the PCB and LCD glass.

Bit Depth
See Color Depth.
Black
Ideally, the complete absorption of incident light; the absence of any reflection. In the practical sense, any color which is close to this ideal in a relative viewing situation, i.e., a color of very low saturation and of low luminance.

Brightness
The dimension of color that is referred to an achromatic scale, ranging from black to white, also called lightness or luminous reflectance. Normally indicated in ANSI lumens (American National Standards Institute measurement of “candle” power).

Buffing
A technique where the alignment layer on the LCD substrate is rubbed in one or more directions. This process aligns the liquid crystal molecules parallel to the buffing direction. See Alignment Layer.

Cable Assembly
A complete connectorized cable that connects the display to the controller (Interface Cable) and the backlight to the inverter (Backlight Cable). These can be customized for any applications.

CAD
CAD (Computer Aided Design) data that describes the patterns written on pattern generators. The data is created using software for the design of electronic circuits. Common data formats created with the CAD software are DXF, Gerber, GDS II.

Candelas (cd/m2)
An international unit of luminous intensity per projected area normal to the line of observation. Luminance may be described in units of candelas per square meter, or nits.

Capacitive Touch Panel
Voltage is applied to four corners of the screen, and a uniform electric field is created. A finger or conductive stylus touching the screen creates a capacitive ground path in the circuit. This creates a voltage drop, which can be measured to determine position.

Captive Mask Shop
A mask shop that produces photomasks for internal use.

Cathode Ray Tube (CRT)
The traditional picture tube for TVs and computer monitors.

CCFT (Cold Cathode Fluorescent Tubes) /
CCFL (Cold Cathode Fluorescent Light)
Cold Cathode Fluorescent Tube. A type of backlight using a fluorescent tube.

CDC
Critical Dimension Correction. A set of functions that helps compensate for effects that cause the dimensions in the exposed pattern to differ from the dimension in the pattern input data. There are several sources for such aberrations including stray light, etch undercut, chemical loading in dry etch, proximity to other pattern structures and writing structures that are small compared with the exposure laser wavelength.

cd/m2
Candelas per square meter, the unit measure of luminance; also called a nit.

Cell Gap
The space containing liquid crystal fluid between the two pieces of glass.

Character Display
Also called alpha numeric. A display used to display letters, numbers and symbols only.

Chip-On-Board
Mounting of the LCD driver wafer on the PCB with gold wires used to connect it to other circuits. It is covered with epoxy.

Chip-On-Glass
Technology that mounts the LCD driver to the contact edge of the LCD glass.

Chromatic
That part of color specification which does not involve illuminance. Chromaticity is two-dimensional and specified by pairs of numbers such as dominant wavelength and purity.

Chromaticity
That part of color specification which does not involve illuminance. Chromaticity is two-dimensional and specified by pairs of numbers such as dominant wavelength and purity.

Cholesteric
Describes a liquid crystal material whose elongated molecules are in layers, where they are parallel to each other and parallel to the layer.

Cold Cathode Backlight (see CCFT)
In medium to large LCD graphic modules, a type of fluorescent backlighting or edge lighting.

Color Calibration
The necessary adjustment of colors that causes the colors on the monitor to match the ones produced by the printer. Without adequate calibration, the printed page may not accurately reproduce what is displayed on the computer screen.

Color Depth
Color depth is determined by the number of bits used to produce color in each pixel on a monitor display. The more bits used, the greater the number of colors that can be displayed, provided that a graphics card and monitor have the capability to display them. Common bit ranges are 8-bit color (256 colors), 16-bit color (thousands of colors), and 24-bit color (millions of colors). Most monitors in use today can display at least 16-bit color, and new monitors can usually handle 24-bit color.

Color Filter
A pixel in a Liquid Crystal Display (LCD) can only change between light and dark. In a color display, each pixel consists of 3 subpixels. Over each subpixel there is an area of red, green or blue. The substrate with the colored areas covering the display is called a color filter. To create a color filter 4-5 photomasks are required.

Column Driver
Small electronic circuits that provide voltages to the individual subpixel through the source lines. These are generally 8-bit driver circuits that provide 256 unique values per subpixel.

Common/Backplane
The superimposition of the conductive pattern from one piece of glass to the second piece. The duty ratio is determined by the number of backplanes.

Contact Edge
The area of the LCD with conductive leads where electrical connection is made by use of a connector.

Contrast
The level of variation between light and dark values areas in an image, or the ratio between their maximum and minimum values.

Contrast Ratio
The ratio of intensity between the brightest white and the darkest black of a particular device or a particular environment, or the difference in luminance between the unselected area and the selected area.

Controller
IC usually mounted in the graphics board, that receives the microprocessor output and tells the display which pixels to light up to produce the required image.

Convergence
Alignment of the vertical and horizontal lines in an image.

Cross-Talk Cursor
Dots used to indicate the location of the next character or symbol to be entered.

CRT (Cathode Ray Tube)
Display technology whereby a rapidly moving electron gun inside the set passes across the screen, casting a beam that lights selected phosphor dots as it moves. The dots are arranged in groups of three, forming “pixels” which can be lighted as red, blue, or green. By moving across rows of these pixels rapidly from top to bottom, the electron beam creates a continuously changing, lighted screen that the eye resolves into an image.

CSTN (Color STN)
CSTN stands for Color Super Twisted Nematic LCD. CSTN is a version of LCD technology that overcomes the inherent problems that occur when trying to highly multiplex “Twisted Nematic” LCDs. Using a highly twisted LC configuration, the display functions by using a switchable phase retardation which in combination with linear polarizers acts as a light valve.

Degauss
To remove an unwanted magnetic field from an electronic device, e.g. television tube or CRT monitor. Magnetic interference caused by a change in the position of a monitor in relation to the earth’s magnetic field or the presence of an artificial magnetic field can cause discoloration. To correct this, all color CRT monitors automatically degauss at power-on and some also have a manual degaussing button. This allows the monitor to compensate for the change in the magnetic field by realigning the electron guns. In some low cost monitors without degauss buttons it is necessary to leave the power turned off for at least 20 minutes in order to get maximum degaussing. LCD displays do not need to be degaussed.

DICOM
(Digital Imaging and Communications in Medicine). The DICOM standard contains a display function standard.

Diffuser
Flat sheet of white plastic which emits even light over the surface when lighted by a CFL tube on one or two edges.

Digital
Recording and playing back of data as strings of zeroes and ones (binary data). Because this data is coded into strings of numbers, it is not susceptible to signal degradation in the same manner as analog data.

Digital Driving Level (DDL)
A digital value which, given as input to a display system, produces a luminance. The set of DDLs of a display system is all the possible discrete values that can produce luminance values on the display system. The mapping of DDLs to luminance values for a display system produces the characteristic curve of that display system. The actual output for a given DDL is specific to the display system and is not corrected for the grayscale standard display function.

DIL (Dual-In-Line)
Two parallel rows of connection holes on a PCB. Also, the type of connector used with this array.

DIL PINS
Metal pins bonded with epoxy to each conductive lead on the contact edge.

Direct/Static Drive
Method in which each conductive lead on the contact edge connects to one segment or annunciator.

Dithering
Method of simulating or implying color by placing pixels of approximate or similar colors close together in order to save space or reasonably achieve colors that are otherwise not available.

DMTN
Double Metal or Diode Matrix LCD. This is an active matrix technology that has lower production costs since the diode structure is less complicated than the transistor structure of TFTs. Though they are as fast as a transistor, DMTNs lack the ability for grayscale and are generally offered only on monochrome displays. They do offer better contrast, response time and lower power than STN LCDs.

Dot Matrix
A group of dots/pixels forming a character or symbol; usually five dots across and seven dots down.

Dot Pitch
In monitors, the dot pitch is the distance (measured in millimeters) between the holes in the shadow mask; the smaller the number, the sharper the image. If you have the option, a .28mm dot pitch is preferable, although .31mm is acceptable to many people. A dot pitch larger than this will probably lead to fuzzy text. The size of each pixel that illuminates on a display.

Dot/Pixel
An active element that forms a character or symbol when combined in a matrix.

Doubledomain
A technique used to improve the viewing angle where multiple alignment directions are produced on the same subpixel.

Drain
This is the output terminal of a thin film transistor (TFT).

Driver
Voltage IC mounted on the display which provides the voltage to each row and column by switching them on or off. (Do not confuse with the controller IC.)

DSTN
Dual-scan STN, an enhanced STN passive matrix LCD display. The screen is divided into halves, and each half is scanned simultaneously, thereby doubling the number of lines refreshed per second and providing a sharper appearance.

Duty Ratio
1/N when N is equal to the number of segments selected by one complete cycle.

DUV
DUV (Deep Ultra Violet) Light with very short wavelength used in semiconductor microlithography. The most common wavelengths are 248 nm and 193 nm due to good availability of lasers. A shorter wavelength gives better resolution.

DVI (Digital Video Interface)
An emerging standard for digital display connections to personal computers.

Edge Lighting
A backlight in which the tube is at one or both sides of the display and uses a scattering sheet to get even lighting across the display; allows for thinner displays.

Effective Area
Same as "active area"

EL Backlight
A type of backlight using electroluminescent material. The thinnest available backlight. (Also can be a type of display: see EL display).

EL Display
A type of display using electroluminescent material. Produces an orange glowing image.

Elastomer Connector
A silicone rubber strip made up of sequentially spaced conductive and non-conductive material. The most common method of connection for LCD modules.

Electronic Packaging
The manufacturing step that packages a semiconductor chip so it is protected and can be connected to other electronic components in electronic equipment.

Electrophoresis
A phenomenon which occurs when excess DC voltage is applied to an LCD. Conductive particles from one piece of glass are transferred through the LC fluid and deposited on the conductive surface of the opposite piece of glass. A conductive spike is created, thus causing a dead short.

Enclosure
A metal or molded plastic case that protects the display for standalone operation.

Encoders
Linear or circular scales that are used to determine position or rotation.

Fill Hole
Space left between epoxy seals on one end of LCD glass after assembly; used to fill the glass with the liquid crystal fluid.

Flat Panel Display
A Flat Panel Display is any type of display that is comprised of two sheets of glass in close proximity to one another, where addressing is by rows and columns. Also referred to as a Flat Panel Monitor.

Flat Panel Monitor
A Flat Panel Monitor is any type of display that is comprised of two sheets of glass in close proximity to one another, where addressing is by rows and columns. Also referred to as a Flat Panel Display.

Flicker Fusion Rate
This is the rate above which the human eye can no longer recognize discontinuous changes in brightness as a flicker. Provided the frame frequency is above this rate, the eye integrates the signal into a consistent image. The flicker fusion rate is 31.25 Hz. The appearance of flicker can occur if the frame frequency is close to the frequency of fluorescent lights. That value can vary slightly between different individuals.

Fluorescent Lamp
A glass tube filled with mercury gas and coated on its inner surface with phosphors. When the gas is charged with an electrical current, radiation is produced which in turn energizes the phosphors, causing the phosphors to glow.

Font
Active pattern containing information to be displayed in the LCD glass.

Foot Lamberts (fL)
A unit of luminance in the U.S. One foot Lambert is equal to 3.4262591 candelas per square meter.

Format
Format is the term defining the pixel matrix on a display; i.e. 640 x 480, 1024 x 768, etc. Though the term “resolution” is often confused with “format”, resolution involves a more complex measurement dealing with format, as well as pixels per inch.

Form Factor
The ratio of viewable display area divided by overall module area.

FRM (Frame Rate Modulation)
Method a controller can use to achieve a gray scale by rapidly switching subpixels on and off.

FSTN Ghosting
Phenomenon occurring when voltage from an energized element leaks to an adjacent OFF element and turns the adjacent element partially ON.

Fully Integrated (All-in-One) Display
Most liquid crystal displays require a variety of support chips (e.g. timing chips, grayscale chips, etc.) to operate. Fully integrated “all-in-one” LCDs are complete monitor systems that accept standard video signals (like VGA, NTSC, DVI-D, etc.) without the need for additional electronics. These panels also include the backlight inverter, so the only power input required is the supply voltage (ex. +12V DC).

Gamma
Screen luminance as a function of video voltage approximately follows a mathematical power function of the input video signal, the exponent of which is called gamma.

Gate
This is the control terminal of a TFT.

Gate Electrode
The "row" electrode in an active matrix LCD that controls whether a voltage is applied to a subpixel.

Ghosting
Regarding passive LCD displays, this is a visual anomaly that causes streaking or shadowing across the display. This phenomenon occurs when voltage from an energized element leaks to an adjacent OFF element and turns the adjacent element partially ON.

Graphic Display
A display made up of an array of pixel elements. Can be used to display graphics and pictures, as well as text.

Graphics Controller
A generic term used to describe the video hardware in a computer. Although graphics hardware was traditionally integrated into the motherboard hardware, today this hardware is most frequently available as a separate PCI or AGP card. The graphics controller is responsible for generating the video signal that is sent to the monitor. Graphics controllers today are often built with their own processors and RAM on the card.

Grayscale
An achromatic scale ranging from black through a series of successively lighter grays to white.

Heat Seal
A flexible adhesive connector bonded by heat to the contact edge of the glass.

Hue
The main attribute of a color that distinguishes it from other colors. For example, a color may have a green, yellow or purple hue. Colors defined as having hue are known as chromatic colors. White, black, and grays possess no hue.

IC
Integrated Circuit (IC) is a term referring to all electronic components containing more than one circuit element on the same electronic chip, e.g. memories, processors and amplifiers.

Integration
The process of mounting a display in an enclosure along with any controllers or inverters that are necessary. The result is a complete standalone unit.

Interconnect Dot
Consisting of silver impregnated epoxy, it connects the pattern piece of glass to each backplane.

Interferometer
An interferometer uses the wavelength in laser light as an extremely high precision ruler.

Inverter
The hardware device that converts a low voltage DC input to a high voltage AC output to power an EL or fluorescent backlight.

Inverter DC To AC
Used to power EL and CCFL backlights by converting DC to AC voltage at a high frequency of 300 Hz to 1 KHz.

IPS (In Plane Switching)
A technique of improving the viewing angle of an LCD where the liquid crystal molecules are switched in the plane of the LCD layer rather than vertical to it.

IR Touch Panel
Infrared light emitting diodes and detectors are positioned along the screen edge to create a grid of light. A finger or stylus interrupts the light beams, and position is determined on the grid.

Isotropic Stage
Point where 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.

JND (Just Noticeable Difference)
The luminance difference of a given target under given viewing conditions that the average human observer can just perceive.

Landscape
A page or screen orientation that is wider than it is tall.

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). A long latency period can result in such behavior as pausing or hanging video.

LCD (Liquid Crystal Display)
LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so light cannot pass through them. Each crystal is like a shutter, either allowing light to pass through or blocking the light, resulting in the display image. Typically, a light is passed through the LCD to illuminate the pixels.

LCD Module
Terminology typically used to describe an assembly of LCD glass, PCB, drivers, bezel , backlight, etc.

LCD Monitor
A lightweight, portable and compact alternative to the CRT monitor. Available with touch screen option.

LCD Screen
LCD Screen is another name for an LCD display.

LCD TV
An LCD TV is an LCD monitor designed to display TV images. LCD TVs are configured to accept input from a tuner or alternative video sources, such as a DVD player or VCR.

LCD Video Monitor
An LCD Video Monitor is an LCD monitor designed to display TV images.

Leads
Conductive traces on the contact edge of the glass.

LED (Light Emitting Diode)
Traditionally LEDs are created from two semiconductors. By running current in one direction across the semiconductor, the LED emits light of a particular frequency (hence a particular color) depending on the physical characteristics of the semiconductor used. The semiconductor is covered with a piece of plastic that focuses the light and increases the brightness. These semiconductors are very durable, there is no filament, they don’t require much power, they’re brighter and they last a long time. By densely packing red, blue and green LEDs next to each other on a substrate, one can create a display. A semiconductor diode that emits monochromatic (single color) light when forward biased. The emitted light can be red, yellow, orange, green, blue or non-visible infrared.

LED Backlight
A backlight option for small to medium size LCDs that uses an LED light source. The light from the LED is either diffused from direct illumination or directed through a light pipe from side illumination.

LED Frontlight
Allows a reflective display to be used at night by lighting the edges of a front-mounted, transparent diffuser.

Liquid Crystal Fluid
Having properties of both a solid and a liquid, liquid crystal consists of rod-shaped bipolar molecules which are capable of twisting polarized light when in the “off” state. It reacts predictably when electrically stimulated, making it the ideal compound to turn LCD pixels “on” or “off”.

Lumen
Measurement of how bright a light source is. The higher the number, the brighter the source, e.g., a wax candle generates 13 lumens, a 100-watt bulb generates 1,200.

Luminance
A measure of the brightness or luminous intensity of light, usually expressed in units of candelas per square meter (cd/m2) or foot Lamberts. 1 fL = 3.426 cd/m2.

Lux
A measurement of light. 1 lux equals the illumination produced by 1 lumen falling on a surface measuring 1 square meter.

LVDS (Low-Voltage Differential Signaling)
A de facto standard for digital interfacing of a Flat Panel Display that permits the panel to be positioned up to 25 feet from the host system.

Merchant Mask Shop
A mask shop that sells the photomasks to external customers.

Metal Halide
Superior lamp technology offering high brightness and longevity at extra cost. See also Quartz Halogen.

Module
LCD glass connected to a PCB with drivers on board. It may also have controllers, temperature compensation circuits, or other features.

Multiplex
Using multiple backplanes in order to reduce the number of connections between the LCD and the drivers.

Mura
A key quality requirement for display photomasks is the absence of mura. Mura is caused by systematic deviations in the photomask and can be visible as stripes. Mura compromises the image quality of the finished display. Usually the deviations causing the mura are very small, below a few hundred nanometers. Deviations of that size spread over a large area can be difficult to detect by measuring. Still the human eye can see them due to its high sensitivity to systematic changes in grayscale.

Native Resolution
Unlike traditional CRTs that can display multiple resolutions, LCD displays are manufactured to best display a single resolution, known as the native resolution. While it may be possible to change the resolution of an LCD (depending on the video card and software used with the LCD), setting the resolution to something other than the native resolution will result in a stretched image, a blurry image, or no image on the screen at all.

Nematic
Describes a liquid crystal material whose elongated molecules rest parallel to each other but are not in layers.

NIT
Measure of brightness properly called candela per meter square (cd/m2); equal to 1 cd/m2 or 0.292 ftL.

Normally Black
A twisted nematic LCD design where the backlight is blocked when pixels are in the unselected state. Therefore, when no voltage is applied, the screen is black.

Normally White
A twisted nematic LCD design where light is transmitted when pixels are in the unselected state. Therefore, when no voltage is applied, the screen is white.

NTSC
The 525-line American color TV format as specified by the National Television Systems Committee.

PAL
The Phase Alternate by Line color TV format used in the UK and in most of Europe, where each frame has 625 lines comprised of two interlaced fields.

Passive
A technique by which each row and column of the display are multiplexed or addressed in turn (also called duty type).

Passive Matrix
LCD design which does not have a transistor in each subpixel. Subpixels are switched entirely by row and column driver ICs.

Persistence
The time it takes for the visible glow of a CRTs phosphor to darken after the scanning electron beam is removed. A long persistence means less flicker, but may create smearing when images are in motion.

Phosphor
The coating on the inside of CRTs. Phosphor glows when struck with electrons. Images appear on a CRT by controlled scanning of an electron beam.

Photomask
Can be described as a photo negative. The image on the negative is written with a pattern generator. In the production of the end product, e.g. IC or FPD, the image on the photomask is transferred to the substrate via a photographic process. There are two types of microlithographic photomasks: standard photo emulsion on glass and chrome on glass. The photosensitive material on the chrome photomask is a layer of photoresist covering the chrome layer. Photoresist is a light-sensitive material with properties such that it can be washed away after exposure.

Pitch
Center dimension of adjacent conductive traces, dots or connector holes.

Pixel
Pixels are tiny picture elements comprised of three subpixels (one red, one green, and one blue.) Although a single pixel displays one color, collectively those pixels create a complete image recognizable by the human eye. A single LCD consists of thousands, even millions of pixels.

Pixel Anomaly
A pixel anomaly is a pixel that displays only one color (white, black, red, green, or blue.) These are commonly referred to as “stuck” or “void” pixels. If a pixel on an LCD appears to be stuck on one color, it will sometimes come back to life by gently massaging the pixel and the area surrounding it in a circular pattern. A small number of pixel anomalies are considered normal, or at least inevitable, on LCDs. The number of pixel anomalies it takes for a display to be considered defective varies by hardware manufacturer.

Plasma Display Panels (PDP)
PDPs use helium, neon and xenon gases, which are placed between two glass substrates. The gases are then activated with accelerated electrons, causing them to produce ultraviolet rays which simulate red, green and blue fluorescent materials at each pixel. PDP technology requires higher power and can be used in applications that do not have such stringent weight requirements while offering the obvious advantages of being thin and flat. Additionally, PDPs provide a better viewing angle.

PM-LCD
Passive Matrix Liquid Crystal Display. An LCD technology where the pixels have no internal drive transistors (see TFT-LCD). This is used for applications where the quality requirements are lower or the size is small. Typical applications include mobile phones and handheld electronic games. The photomasks required for PM-LCD have lower requirements than for TFT-LCD since there are no small transistors in the pattern.

Polarizer
A light filter which only allows light waves of a certain rotation through. Polarized material with perpendicular filtering is used in LCDs to enclose the liquid crystal. The liquid crystal is then used as the medium which twists the light waves 90° in order to allow the light to pass through or not.

Polysilicon
Newer LCD panel material that offers better performance and color contrast than TFT. Usually requires three panels per projection device (red, green and blue) and consequently tends to be more expensive. See also Amorphous TFT.

Portrait
A page or screen orientation that is taller than it is wide.

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
LCD modules selectively reflect subpixels of ambient light through the liquid crystal cells, back to the viewer. They do not have backlights, which greatly reduces their power requirement. Good in bright lighting or outdoors.

Refresh Rate
Applicable to CRTs but not LCDs, refresh rate equals the number of times per second that the electron gun redraws the image on the screen. For example, if a CRT’s refresh rate is set to 60 Hz, the screen image will be redrawn 60 times a second. Low refresh rates will cause the image to flicker, resulting in eye strain or other problems. For this reason, refresh rates on CRTs should be set as high as possible.

Resolution
The number of pixels in a given active area arranged horizontally by vertically that make up an image. More pixels means higher and better image quality. LCD devices have a single fixed “true” resolution but may accommodate other resolutions using in-built compression or expansion technology.

Resist, Photoresist
The light-sensitive material used in the manufacture of photomasks. Resist is also used in the next step in the production where the pattern on the photomasks is projected on a substrate. So called i-line resist is a common type used for 365 nm exposure wavelength.

Retardation Film
The retardation film compensates the birefringence effect on the display. “Normal” STN appears yellow/green and blue. When compensated with a retardation film, the display is compensated to appear black and white.

RFC/Reflective Color LCD Module
Reflective Color LCD module.

RGB
Abbreviation for Red, Green, Blue, which are the component colors of white light.

Saturation
Saturation is the degree to which the hue of the color is undiluted by its complimentary color to form white.

Saturation Voltage
RMS voltage required to turn fluid to 90% on.

SAW (Surface Acoustic Wave)
A touch screen that functions using sound waves giving you X Y and Z axes.

SECAM
A French and international broadcast standard for video and broadcasting, it’s higher resolution than NTSC.

Segment
An active element of a digit, usually 7 segments for numeric and 14 segments for alpha/numeric digits.

Shadow Mask
Central component in all color television screens and computer monitors. The shadow mask is a thin metal plate covered with very small holes that define the pixels in a Cathode Ray Tube (CRT). It is mounted inside the screen close to the front glass. Without the shadow mask, it is not possible to project a color image on the screen.

SIL (Single-In-Line)
An LCD module that has a single row of connection holes, and an LCD glass with a single contact edge.

SLM
The SLM (Spatial Light Modulator) technology uses an array of individually controlled micro mirrors on a silicon chip. A small part of the pattern to be exposed is programmed into the chip and transferred to the photomask with a flash from a laser. The technology is reflective and can be used with short wavelengths that are absorbed by transmissive optics. Another advantage is that the SLM exposes a large part of the pattern in one flash, a million pixels, which increases the throughput.

Smectic
Describes a liquid crystal material whose elongated molecules in layers are oriented perpendicular to the layer.

Solar Technologies
Your LCD Partner that assists your company with panel requirements and excess inventory.

Static Drive
Same as Direct Drive.

STN
Abbreviation for passive matrix. It is derived from Super Twisted Nematic which describes the liquid crystal molecular arrangement.

Strike Voltage
Another name for Starting Discharge Voltage, the voltage necessary to initially light a CFL.

Stuck Pixel
See Pixel Anomaly.

Subpixel
The individually controlled element of an LCD display. Each pixel is made up of three independently controlled subpixels. In a color display, these subpixels have red, green or blue color filters. Or in the case of a grayscale display, each subpixel will have a clear transparent filter, allowing the full grayscale range to be displayed. Each subpixel is capable of generating different intensities, creating a range of colors or grayscale values, which is perceived as a mixture of each subpixel value.

Substrate
The material on which the image from the photomask is projected in the lithographic process. The material can be glass, metal or silicon; a light sensitive layer of photoresist or photo emulsion is deposited onto the surface, which enables exposure.

SVGA Resolution
800 x 600 pixel count (800 pixels across by 600 rows high). Derived from Super VGA.

Tape Automated Bonding (TAB)
A bond is made between a flexible PWB and the ITO conductive lines on the glass at the edge of the display with a multitude of conductive paths enabled by compressing conductively coated plastic microspheres in an epoxy matix.

TFT
Abbreviation of Thin Film Transistor. Usually refers to an active matrix display in which each pixel is driven by a thin film transistor deposited on the glass. Provides the best in terms of contrast and speed.

TFT Monitor
A TFT Monitor is a monitor that is fabricated from an active matrix LCD. TFT refers to a Thin Film Transistor array that allows a high level of data to be multiplexed for driving the LCD material.

Threshold Voltage
Electric field required to reorient the liquid crystal molecules to the point where the optical transmissivity of the transfer curve is 10% of the fully on state.

TMC
Transmissive Color LCD module. See Transmissive.

TN
Twisted Nematic. A type of LCD material. The original LCD technology. No longer used except in low-priced character modules.

Touch Drivers/Touch Panel Controller
The hardware element that translates the information between the touch panel and the host.

Touch Screen Overlay
A transparent glass or hard plastic sheet that mounts over the display and allows the user to make choices and input information by touching the screen.

Transflective
A type of backing, bonded to the rear polarizer, which enables light to pass through the back as well as reflecting light from the front. Combines the features of Transmissive and Reflective; each subpixel is both reflective and transmissive. They are readable in any ambient light.

Transmissive
An LCD which does not have a reflector or transflector laminated to the rear polarizer. A backlight must be used with this type of LCD configuration.

Transparent
Adjective to describe a material that transmits light without diffusion or scattering.

TSTN
Triple Supertwist. 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.

Twisted Nemetic (TN)
A type of liquid crystal where the alignment surface and therefore the liquid crystal molecules are oriented 90 degrees from each surface of glass.

Uniformity
Uniformity or the lack thereof is the gradual change of luminance and/or chrominance (color) across the display.

User Controls/OSD
The on-screen display of menu options available to the user of an LCD monitor for adjustments.

UXGA Resolution
1600 x 1200 pixel count.

VGA Resolution
640 x 480 pixel count (640 pixels across by 480 rows high). It originally meant a Video Graphics Adapter board found on early personal computers, whose output was an analog RGB signal on a 15-pin connector, to drive a computer’s monitor in a 640 x 480 format.

Video Monitor
Video Monitors are any of a variety of display monitors principally configured to display video data.

Viewing Angle
A cone perpendicular to the LCD in which minimum contrast can be seen. The angle over which a display can be seen.

Viewable Area
The dimensions measured from the inside perimeter of the LCD bezel or LCD glass epoxy seal; the part of the LCD display that is seen inside the bezel.

Void Pixel
See Pixel Anomaly.

XGA Resolution
Short for Extended Graphics Array, a high-resolution graphics standard introduced by IBM in 1990. XGA was designed to replace the older 8514/A video standard. It provides the same resolutions (640 x 480 or 1024 x 768 pixels), but supports more simultaneous colors (65,000 compared to 8514/A’s 256 colors). In addition, XGA allows monitors to be non-interlaced.