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Glossary of displays, power supplies, BI-UPS and touch screen monitors and associated terms and definitions

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

Active Matrix TFT
A common type of LCD used in laptops, cameras, and LCD projection panels that were produced in the late 1980s to early 1990s. A typical active matrix TFT display is a single panel of LCD glass that controls all three primary colors. TFT displays are noted for their quick response time and their ability to display full motion video and animations without image ghosting.

Anamorphic Widescreen
Refers to the stretching or squeezing of an image so that it utilizes the entire area of a film frame with a different aspect ratio. The most common usage has a 1.85 to 1 or greater wide screen movie "squished" on film with 43 aspect ratio frames. A special lens is used on the projector to exactly reverse this distortion and produce the correctly proportioned picture on the screen. "Anamorphic" in video is a misnomer. Video has no aspect ratio until it is displayed on the screen. The TV set or monitor determines the aspect ratio using settings specified by the viewer or sometimes automatically by taking some format data (not the picture data) from the video signal. So far the label "anamorphic" is used only for the DVD 169 enhanced wide screen programs or 169 high-resolution programs.

ANSI Contrast
Contrast is the ratio between white and black. The larger the contrast ratio the greater the ability of a projector to show subtle color details and tolerate extraneous room light. There are two methods used by the projection industry 1) Full On/Off contrast measures the ratio of the light output of an all white image (full on) and the light output of an all black (full off) image. 2) ANSI contrast is measured with a pattern of 16 alternating black and white rectangles. The average light output from the white rectangles is divided by the average light output of the black rectangles to determine the ANSI contrast ratio. When comparing the contrast ratio of projectors make sure you are comparing the same type of contrast. Full On/Off contrast will always be a larger number than ANSI contrast for the same projector.

ANSI Lumens
A standard for measuring light output, used for comparing projectors. Unfortunately, there are enough variables, that the eye will often disagree radically with the ANSI rating. At best, ANSI lumens do fairly well comparing "apples" to "apples". If however one projector uses Halogen lamps and another metal-halide, the halogen projector will seem noticeably dimmer even if the two units rate the same. Other variables, including type of LCD technology (active matrix TFT, Poly-Si, passive), type of overall technology (LCD vs.DLP vs. CRT), contrast ratios, etc. all effect the end result.

Aperture
In television optics, it is the effective diameter of the lens that controls the amount of light reaching the photoconductive or photo emitting image pickup sensor.

Aperture Correction
Compensation for the loss in sharpness of detail because of the finite dimensions of the image elements or the dot-pitch of the monitor.

Apparent Power
The product of RMS voltage and RMS current.

Aspect Ratio
The most popular aspect ratio is 43 (4 by 3). Early television and computer video formats are in a 43 aspect ratio, which means that the width of the image is 4/3 times the height. Examples A 15 inch monitor is 12 inches wide by 9 inches high (9 x 4/3 = 12). A resolution of 640x480 is a 43 format (480 x 4/3 = 640). Other formats are 54 used by the 1280x1024 SXGA resolution, 169 is used by HDTV, and 32 for 35mm slides.

ATA Rated Case
A case rated strong enough to be shipped by common carrier; freight lines, UPS, FedEx, etc. Most cases of this type are easily recognized by their metal reinforced corners and handles. These cases are often referred to as "Anvil cases" bearing the name of one of the manufacturers.

Auto Balance
A system for detecting errors in color balance in white and black areas of the picture and automatically adjusting the white and black levels of both the red and blue signals as needed for correction.

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B

BNC
A bayonet type connector commonly used on video equipment.

Brightness
The attribute of visual perception in accordance with which an area appears to emit more of less light (Luminance is the recommended name for the photo-electric quantity which has also been called brightness).

Brownout
A drop or sag of the input voltage below a converter's rated input range.

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C

Candela
The measurement used referring to brightness.

Chromatic Aberration
An optical defect of a lens which causes different colors or wave lengths of light to be focused at different distances from the lens. It is seen as color fringes or halos along edges and around every point in the image.

Chromaticity
The color quality of light that is defined by the wavelength (hue) and saturation. Chromaticity defines all the qualities of color except its brightness.

Chrominance
A color term defining the hue and saturation of a color. Does not refer to brightness.

Coated Optics
A variety of materials are put on to high quality lenses for several reasons. One of the key reasons is to minimize the amount of light reflected back to the lamp, and the amount of ambient light that mingles with the focused light leaving t he lens. Generally good coatings can add 15% or more to the lenses brightness. Other coatings are used for filtering colors.

Color Dynamics
"The whitest whites, reddest reds, etc." High color dynamics are a result of dynamic range/contrast ratio's. When we describe a unit as having excellent color dynamics, the practical description might be "rich colors, excellent definition, high contrast".

Color Temperature
A method of measuring the "whiteness" of a light source. Metal halide lamps have very high temperatures compared to halogen or incandescent lights.

Colour
Displayable colours ie 16.77 million.

Component Video
Component Video is a method of delivering quality video (RGB) in a format that contains all the components of the original image. These components are referred to as luma and chroma and are defined as Y'Pb'Pr' for analog component and Y'Cb'Cr' for digital component. Component video is available on some DVD players and projectors.

Composite Video
Refers to a video signal where both the luminance component and the colour component(s) are transmitted on a single wire or broadcast in a limited bandwidth. Each of the major systems NTSC, PAL, and SECAM has its own definition of how the luminance and colour are combined. The luminance and colour information must be separated before the picture can be displayed. It is well worth investing in a better connection such as RGB SCART or S-Video.

Composite Video Signal
The combined picture signal, including vertical and horizontal blanking and synchronizing signals.

Compressed Resolution
Most projectors automatically accept images that are of greater resolution than the native (true) resolution of the projector. The resulting image is scaled to fit the native resolution of the projector using a variety of scaling algorithms. Not all projectors use the same compression algorithms; therefore, the quality of compression can vary. The nature of compression in a digital device means that some image content is lost.

Compressed SVGA
Unlike CRT based monitors, LCD and DLP projectors only have one "true" resolution. Most projectors out there are VGA (640x480) resolution. To project an 800x600 image to a VGA projector, the original 800x600 signal must be compressed down to VGA. This is done by interpolating the data, and trying to best display all the information with only two thirds of the pixels (307,000 vs 480,000). The resulting image gives you the SVGA page size, but some sacrifice of image quality. For the vast majority of people with SVGA laptops or desktops, they will have more satisfying results, outputting VGA to a VGA projector.

Compressed XGA
Found on SVGA projectors, compressed XGA handling allows these projectors to handle 1024x768 XGA resolution. How good the compressed XGA is on a given model is a key factor in the decision process for most people choosing an SVGA projector. This is true as the market shifts from SVGA laptops to those with XGA screens.

Contrast Ratio
The ratio between white and black. The larger the contrast ratio the greater the ability of a projector to show subtle color details and tolerate extraneous room light. There are two methods used by the projection industry 1) Full On/Off contrast measures the ratio of the light output of an all white image (full on) and the light output of an all black (full off) image. 2) ANSI contrast is measured with a pattern of 16 alternating black and white rectangles. The average light output from the white rectangles is divided by the average light output of the black rectangles to determine the ANSI contrast ratio. When comparing the contrast ratio of projectors make sure you are comparing the same type of contrast. Full On/Off contrast will always be a larger number than ANSI contrast for the same projector.

Controller
A communications device that provides communication (RS 232 or USB) between the touchscreen and computer.

CRT (Cathode Ray Tube)
Electronic vacuum tube in which a thin beam of electrons is shot through the space inside and against the far wall (faceplate; screen) or a plate inside. This includes all picture tubes used in TV sets or computer monitors.

CRT Projector
Generally much more expensive than the LCD projector, the Cathode Ray Tube projector has linear doublers that double the scanning rate of TV pictures, in turn enhancing the picture quality. A CRT projector produces a higher quality picture than an LCD one, but is trickier to install and set up.

Current Limit
The point where the operation of a converter changes from constant voltage mode to constant current mode.

Current Sharing
Equal division of the total load current between two or more modules.

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D

De-Interlacer
Device or circuit to convert interlaced video to progressive scan video with the same number of scan lines per full video frame. Loosely referred to as a line doubler. Although "outputting each scan line twice" will produce reasonable progressive scan video, "de-interlacer" should refer to devices with more sophistication to interpolate intervening scan lines or fetch scan lines from the previous and/or next field for a better quality picture.

Dichroic
A mirror or lens that reflects or refracts selective wavelengths of light. Typically used in projector light engines to separate the lamps "white" light into red, green, and blue light.

Digital Light Processing (DLP)
The commercial name for this technology from Texas Instruments (TI) The technology inside is often referred to as either "micro-mirrors", or DMD It works this way build a few hundred thousand tiny mirrors, and line them up in 800 rows of 600 mirrors each. Now attach a hinge to each of those 480,000 mirrors. Attach each of those 480,000 hinges to its own very tiny motor! Power each motor with electrostatic energy! The motors tilt their mirrors up to 20 degrees at incredible speeds. This allows the mirrors to modulate light from a lamp, and send the "modulated signal" out through a lens, on to a screen. The most amazing part of DLP micro mirrors, is the scale of size. The 480,000 mirrors (actually 580,000 are used), hinges and motors are packed onto a "wafer" a bit larger than your thumbnail.

Digital TV
A digitised TV signal is one that's compressed in size by reducing repeated information in order that several TV channels can occupy the space of one analogue channel. Traditional analogue television's days are numbered as the Government has announced it will be switched off as early as 2008. Current estimates suggest that this isn't realistic as the take up of digital TV hasn't been as fast as expected.

Direct View
This is the standard type of TV we have been used to, where the CRT projects the image directly on to the glass. For people on a modest budget this is a good option, but always go for the flattest screen possible.

Dispersive Signal Technology
Latest technology from 3M which offers a fundamentally different approach to touch. Unlike other solutions that recognize touch by the interruption of electrical fields, acoustic waves, or infrared light, Dispersive Signal Technology recognizes touch through vibrations made to the substrate.  By measuring specific vibrational energy, it eliminates issues with screen contaminants and surface scratches, while offering enhanced palm rejection – allowing accurate touch recognition while an object rests on the screen.  The Microtouch™ DST substrate can be glass, tempered glass, glass integrated with 3M’s Vikuiti™ films, or even acrylic – all of which offer excellent optical qualities.

Distribution Amplifier
An amplifier used to maintain a clean noise free signal to the projector over significant distances. Even with good heavily shielded cables, range of video and computer signals is limited to a few dozen feet before noticeable degradation. In ceiling mount situations, where the wiring may pass along side or across electrical conduits, etc. a distribution amp may be needed with shorter distances. Many distribution amps can also split the signal into 2 or more amplified signals for driving multiple projectors, projectors and monitors.

DLP
Stands for Digital Light Processing. Is Texas Instruments' answer to the LCD, as used in many high-end video/data projectors. The DLP imaging device compromises thousands of microscopic 'mirrors', each representing a single pixel, which are angled towards (or away from) the light source to make the projected image darker or lighter. Three of these 'digital micromirror devices' (DMDs) are used for colour. They are more efficient at transmitting light than LCD's, meaning they are brighter.

DLP (Digital Light Processing)
The commercial name for this technology from Texas Instruments (TI) The technology inside is often referred to as either "micro-mirrors", or DMD It works this way build a few hundred thousand tiny mirrors, and line them up in 800 rows of 600 mirrors each. Now attach a hinge to each of those 480,000 mirrors. Attach each of those 480,000 hinges to its own very tiny motor. Power each motor with electrostatic energy. The motors tilt their mirrors up to 20 degrees at incredible speeds. This allows the mirrors to modulate light from a lamp, and send the "modulated signal" out through a lens, on to a screen. The most amazing part of DLP micro mirrors, is the scale of size. The 480,000 mirrors (actually 580,000 are used), hinges and motors are packed onto a "wafer" a bit larger than your thumbnail.

Dual Scan Passive Matrix
Newer version of the original passive matrix technology, where the screen is controlled by two processing systems. A bit faster than "single scan," response is still horrendously slow, they cannot do multimedia or video either. Contrast remains terrible. Dual scan is used in the least expensive LCD panels.

DV
Stands for Digital Video. Is a popular video format in worldwide use. It employs a compression similar to MPEG in basic principle. There are two tape sizes, the full sized 3 hour one, which is fairly rare, and the 'mini' 1 hour version used in camcorders.

DVI
DVI means Digital Visual Interface. DVI is a standard that defines the digital interface between digital devices such as projectors and personal computers. For devices that support DVI, a digital to digital connection can be made that eliminates the conversion to analog and thereby delivers an unblemished image. Specifications on DVI are available at www.ddwg.org.

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E
Efficiency
The ratio of output power divided by input power, expressed as a percentage.

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F
Fault Tolerance
The capability of a power supply system to sustain one or more faults without degrading the power to the load.

Field
One of the two equal but vertically separated parts into which a television frame is divided in an interlaced system of scanning. A period of 1/60 second separates each field start time.

Flatscreen TV
We always recommend a flatscreen TV. They may cost a bit more but reflections on the screen are cut down and your picture is displayed, as it would be on a cinema screen rather than being wrapped round a curved monitor.

Flex Tail
Flexible ribbon connecting cable that provides connectivity between the glass touchscreen and the controller.

Full On/Off Contrast
Contrast is the ratio between white and black. The larger the contrast ratio the greater the ability of a projector to show subtle color details and tolerate extraneous room light. There are two methods used by the projection industry 1) Full On/Off contrast measures the ratio of the light output of an all white image (full on) and the light output of an all black (full off) image. 2) ANSI contrast is measured with a pattern of 16 alternating black and white rectangles. The average light output from the white rectangles is divided by the average light output of the black rectangles to determine the ANSI contrast ratio. When comparing the contrast ratio of projectors make sure you are comparing the same type of contrast. Full On/Off contrast will always be a larger number than ANSI contrast for the same projector.

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H

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I
Input Overvoltage
An increase or surge of the input voltage above a converterÕs rated input range.

Input Reflected Ripple
The AC component of the input current of a converter resulting from the converterÕs operation (high frequency switching), expressed as a percentage of the DC component.

Input Ripple Rejection
The attenuation of AC ripple a converter provides from its input to its output, expressed in dB.

Inrush Charge
The amount of charge, in Coulombs, that will flow into a converter upon application of nominal input voltage.

Interlace
The drawing of all of the odd lines, then all of the even lines, to display each video frame. Every once in a while a TV set has the defect (line pairing) of having the even lines not land exactly between the odd lines, which results in loss of vertical resolution.

International Power Supply
A unit that can operate under an international selection of power requirements. The specs of units vary widely, but the minimum is 105-230 volts, and 50-60 cycles AC (alternating current). If you see a specification like 110v, 220v instead of a range, those ratings are usually +/- a given percent such as 10%. Some units are "self-switching" they will automatically switch to whatever power source you plug it into. Others will have to be switched (internally or externally to accommodate a difference volt age or cycle range.

IR Communication
Standard Many new laptops have an Infra-Red transceiver that follow a recent standard for wireless communicating with peripherals (new laser printers complying with the standard) and networks or desktop systems. If you have a laptop like this, you know the pleasure of walking into a room with a configured laser printer, and printing out documents without having to "plug-in." Only a couple of projectors are now shipping that follow this standard. This allows their remote controls to talk directly to your laptop for remote mousing. A tremendous new capability, as you are normally much closer to your computer than the projector in medium or large rooms.

Isolation Voltage
The voltage that can be applied between related circuits of a device without voltage break down occurring in the insulation between them.

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K

Keystone Correction
Using optics design or other methods to apply a "negative" keystone to the image, which will partially cancel the effects of keystoning. If you aim a projector with keystone correction at a screen with the lens level with the middle of the screen, you will not that the image at the bottom is wider than at the top. When the projector is in normal position, pointing upward 10-25 degrees, the resulting image is fairly rectangular.

Keystoning
Keystoning is caused when the projected image is not perpendicular to the screen, making the top and bottom of the image different lengths.

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L

LCOS
Stands for Liquid Crystal on Silicon. LCOS is an advanced form of LCD using a combination of liquid crystal and silicon processors. Manufacturers with LCOS products include Philips, Thomson, JVC and Hitachi.

Line Doublers
A set of circuits whose purpose is to paint each scan line on the picture tube twice (three times, four times) and thus fill in the gaps between scan lines. A device (with circuits inside) which converts interlaced video to progressive scan video is also referred to as a line doubler. It too delivers output that has twice as many scan lines per second as its input and it may also use the technique equivalent to painting each scan line twice. This is one of the main reasons as to why a lot of people swear by the CRT projector for home cinema use.

Line Regulation
The change in a converter’s output voltage resulting from a predefined change in the input voltage, expressed as a percentage of the output voltage.

Lux
A standard for measuring light, numbers provided by manufacturers usually do not provide necessary additional information to compare one product to another.

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M

MPEG (Moving Pictures Experts Group)
An organization, or more correctly a large enough collection of groups that could be called an institution, which among other things developed various data encoding and compressing schemes so an full length movie could be recorded on a five inch disk (a DVD).

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N

NICAM
Stands for Near Instantaneous Companding Audio Multiplex. Is the digital stereo audio system used for terrestrial analogue broadcasting in the UK (but not satellite).

Novram
Non volatile random access memory.

NTSC
The United States broadcast standard for video and broadcasting. An older standard and lower resolution than systems used in most of the world.

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P
PAL
A European and international broadcast standard for video and broadcasting. Higher resolution than NTSC.

Pan and Scan, or P&S
Term used to describe a wide screen movie committed to video with a lesser aspect ratio. The picture is zoomed in on so that more or all of the TV screen is filled (to satisfy popular demand and improve vertical resolution), but both sides of the original picture obviously don't fit. A video technician "pans" the conversion machine (e.g. telecine) back and forth to capture what he considers or what he was told is the most important part of each scene while cropping the sides. Even film to film copies, notably 16mm and 8mm prints, have been made using the pan and scan technique.

Panel
Also known as a projection panel, LCD projection panel, or plate. The panel is the predecessor of today's projectors. It is slightly larger and heavier than a notebook computer and the LCD it uses to produce an image is very similar to that of the notebook computer. Because panels lack their own light source, they are designed to sit on top of a transmissive overhead projector (OHP). (See the definition of Overhead Projector for lumen performance.) Because of its small size, low cost, and versatility, panels have been a popular solution for education applications where an OHP is frequently available in the classroom for other instructional purposes. A few products have been built that integrated the panel and the OHP. These were some of the earliest projectors.

Passive Matrix LCD
The original LCDs, these are controlled by a single processing system, for the whole screen, unlike active and poly-si, which have descrete circuits for each "pixel." This results in a panel with terrible color dynamics and contrast (typically 151). They are also incredibly slow On passive laptop computers, the cursor (or anything else) moving on the screen, goes invisible until you stop moving it (submarining) Only one or two projectors use any type of passive matrix display.

PIP
Picture In Picture

Pixel, or Pel
Picture element; the smallest spot on the screen that can be resolved as having a different brightness or colour from what is next to it. The "number of pixels vertically" is equal to the number of scan lines; for example if you block off all but a narrow vertical stripe on the screen, you will see a series of dots, one per scan line. For a computer screen or digital video, the screen is divided into several hundred "grid positions" horizontally as well; a pixel must be exactly one of the grid positions, not half of one and half of the next. For analog TV pictures, we can say that the number of pixels horizontally is equal to the maximum number of alternating black and white dots that can be reproduced all the way across the screen, which equals the aspect ratio times the number of lines of resolution horizontally.

Plasma Screens
Plasma screens have two plates with about O.1 mm between them. Tiny cells are contained within this gap and these are coated with red, green or blue phosphors. Plasma is trapped between the plates and voltages are then passed over the different cells to trigger a colour reaction. Because of this, the ultra-thin screens can display an astonishing 16.8 million different colours. Expensive, but high quality.

Poly-Si (silicon)
LCD A popular LCD technology for the top of the line LCD projectors. Monochrome Poly-Si LCDs are typically placed in each of the three color light paths inside a projector, one each for Red, Green, and Blue. This results in increased color saturation, with contrast ratios above 2001. Poly-Si technology is also a bit faster than the Active Matrix TFT, for smooth video and multimedia.

Profile Sensor
A flat touchscreen with a matched controller.

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Q

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R

RGB
Red, Green, Blue; the normal type of monitor used with computers, examples of usage RGB input or output often referred to as Computer input or output.

RS-232
A connection used for signalling devices.

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S

SECAM
A French and international broadcast standard for video and broadcasting. Higher resolution than NTSC.

SVGA
SVGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. An SVGA display has 800 horizontal pixels and 600 vertical pixels giving a total display resolution of 480,000 individual pixels that are used to compose the image delivered by a projector.

S-Video
A video transmission standard that uses a 4 pin mini-DIN connector to send video information on two signal wires called luminance(brightness, Y) and chrominance(color, C). S-Video is also refered to as Y/C. A composite signal, typically found coming out of an RCA jack on the back of most VCRs has the Y and C information combined into one signal. The advantage of having luminance and chrominance separated is that a comb filter is not needed inside the video projector to separate the composite signal into the luminance and chrominance signals. A comb-filter can reduce the sharpness of your video image.

SXGA
SXGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. An SXGA display has 1280 horizontal pixels and 1024 vertical pixels giving a total display resolution of 1,310,720 individual pixels that are used to compose the image delivered by a projector.

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T
TFT
Thin Film Transistor.

Throw
The term used to describe the ratio between the distance of the projector lens to the screen and the size of the image. The size of the room dictates what sort of projector you buy, and if you have a small room you will need a projector that can produce large images over a short distance.

Touchscreen
Normally a glass panel with special coatings and properties that allow a user to touch and interface with a visual display.

Touchscreen Drivers
A program that is required to allow interface between a touchscreen, controller and a computer.

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U
USB
Stands for Universal Serial Bus. Is a fast, but not as quick IEEE1394 serial interface.

UXGA
UXGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. A UXGA display has 1600 horizontal pixels and 1200 vertical pixels giving a total display resolution of 1,920,000 individual pixels that are used to compose the image delivered by a projector.

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V

Vikuiti™ Image Directing Film
Image directional film that can be incorporated within a visual display to shift the visual output from a vertical to a 20 Degree angle.

Vikuiti™ Light Control Film (LCF)
Light control film using micro louvers to control the viewing from a visual display so that only those viewers directly in front of the visual display can see its contents.

Vikuiti™ Smart Mirror Film
A reflective polarizer film that when placed in front of a display allows for both transmissive and reflective images.

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W
Wide Screen
Refers to a video program whose picture has a wider aspect ratio than 43.

WSXGA
WSXGA defines a class of SXGA displays with a width resolution sufficient to create an aspect ratio of 169. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. A WSXGA display has 1920 to 1600 horizontal pixels and 1080 to 900 vertical pixels respectively that are used to compose the image delivered by the projector.

WXGA
WXGA defines a class of XGA displays with a width resolution sufficient to create an aspect ratio of 169. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. A WXGA display has 1366 to 1280 horizontal pixels and 768 to 720 vertical pixels respectively that are used to compose the image delivered by the projector.

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X

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