Glossary

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:

The most common type of LCD used in LCD projectors. Active Matrix TFT displays each pixel which are driven by a thin film transistor which allow a larger viewing angle.  These thin film transistors allow quicker response times and increased color saturation.

Ambient Light:

Ambient light can basically be considered the amount of light in the room not produced by the projector.

Anamorphic Lens:

An anamorphic lens allows the projector to project input signals at different aspect ratios. For example, a native 4:3 DVD image could be projected at a 16:9 aspect ratio without stretching or image degradation. With a 2:1 anamorphic lens for example, optical magnifications are automatically adjusted to essentially squeeze in 100% more into a frame than a normal lens.  The term comes from the Greek word anamorphosis which means to "reshape".

ANSI:

ANSI is the industry standard for measuring light output created by the American National Standards Institute (ANSI). The amount of ANSI lumens produced by a projector is the main determinant in projector image brightness. In addition, bulb type (Halogen or Metal Halide), Contrast Ratio, and Image Technology (LCD, DLP, LED, LCOS, CRT) play a part in final image brightness.

Aspect Ratio:

The aspect ratio of an image is its width divided by its height or simply the ratio of height to width of the projected image. Common aspect ratios include 4:3 (standard video), 16:9 (HD), 16:10, 1.85:1, and 2.39:1 (Both Movie Theater Films).  Projectors meant for home theaters will have a native resolution of 16:9 which is the aspect ratio meant for widescreen DVD and blu-ray films. Aspect ratios of 1.85:1 and 2.39:1 can be achieved with projectors equipped with anamorphic lenses.

Auto Balance:

A system that automatically corrects errors in color balance due to inappropriate levels of black or white areas and balances areas that need correction.

AV:

Audio/Video

 

B

Bandwidth:

The amount of data that can be passed along a communications channel in a given period of time.  For projectors the bandwidth is measured in MHz, the higher the resolution, contrast ratio, etc. the greater the bandwidth required.

BNC (Bayonet Nut Connector):

The BNC is a common type of RF connector used for terminating coaxial cable. With projectors, BNC cables are used to transmit analog and serial digital interface video signals. BNC inputs are common among commercial projection systems. BNCs differ from most connectors because of their snap-lock architecture which keeps the plug firmly in the socket. This snap-lock architecture makes BNC cables ideal for installations in which the projector is hard to access, thus insuring the cables will remain locked in place.

BrilliantColor Technology:

A technology developed for DLP projectors by Texas Instruments which increases the number of colors on the color wheel to 6 (red, green, blue, cyan, magenta, and yellow).  BrilliantColor technology boosts mid-tone colors to increase overall brightness to produce a more life-like picture.

 

C

Chrominance:

The color saturation and hue of an image.

Color Temperature:

Color temperature refers to the amount of "whiteness" in a light source. Metal halide lamps have much higher color temperatures than halogen lights and bulbs.

Color Wheel:

A color wheel is included in all DLP projectors.  Standard color wheels are made up of 3-6 different color segments. The more color segments in a given color wheel equates to boosted mid-tones and increased overall color brightness for more life-like pictures. Another factor in which to pay attention is the speed of the color wheel, a 1x color wheel cycles through all available colors within 1/60 of a second. Increased color wheel speeds are required for home theater projectors.  Common speeds for home theater projectors are 4x-6x.  The advantage of a color wheel is that it provides excellent color accuracy, low power consumption, high contrast, and no "screen door" effect which is common in LCD projectors.

Color Resolution:

The total number of colors available.

Component Video:

Component video delivers the best quality image possible with the exception of HDMI. Component cables divide video signals into two components, luma (colorless component), and chroma (color component).  The most common type of component video cable/input is YPbPr (green, blue, red cables) which splits the video signal into three components. YpbPr is a color space encoding scheme which was developed to save cable bandwidth requirements while separating the video signal to provide a quality image.  Component cables are prefered to S-Video and composite cables which mix all the signals together through multiplexing which degrades the image quality.

Composite Video:

Composite video is the standard RCA jack for video which includes a yellow and red video cable paired with a white audio cable. Composite video is still one of the most common A/V connections, however, certainly not the best. Composite video mix video signals together through a process called multiplexing which leads to degradation of the video signal. If the option is available, look to component, HDMI, or DVI cables for increased image quality.

Compression:

A method used by video processors within projectors to reduce the resolution of the displayed image.

Contrast Ratio:

The contrast ratio is a measure of a display system, defined as the ratio of the luminance of the brightest color (white) to that of the darkest color (black) that system is capable of producing. The larger the contrast ratio the greater the ability of a projector to show subtle color details and tolerate ambient room light. A high contrast ratio is desired for any display, but with no standard industry measurement remarkably different measured values can produce similar results.  The two most common standard of measurements are full on/off and ANSI contrast. When comparing two projectors contrast ratio make sure to know which method was used to measure the contrast ratio. Full on/off contrast ratio is always larger than ANSI contrast ratio.

 

D

Digital Keystone Correction:

An adjustment mechanism that re-scales the projector image when the projector is not set at a 90 degree angle to the projection surface.  Re-scaling an image using digital keystone correction allows the projected image to be undistorted.

DLP (Digital Light Processing):

DLP is an acronym for Digital Light Processing, a reflective projection technology developed by Texas Instruments which uses a microprocessor to display bright, colorful images. The actual DLP chip is roughly 1''-1.3'' and contains millions of microscopic mirrors (one for each pixel) which flip on an axis, reflecting light through the color wheel to create an image. Many feel that DLP technology creates the most accurate reproduction of color and images available today.

DMD (Digital Micro Mirror)

Digital Micro Mirror is the actual name of the imaging chip used within DLP projector systems which are developed by Texas Instruments.

DVI (Digital Visual Interface):

DVI is a video interface standard designed to provide very high visual quality on digital display devices such as flat panel LCDs and digital projectors. DVI cables carry uncompressed video data to a display.  Image quality is high with DVI due to the fact that a projector can send a digital-to-digital connection without converting the image to analog which degrades picture quality. Projectors with DVI-D inputs can handle full HDMI video signals through a simple DVI to HDMI adapter. Cable lengths should not exceed 3 meters or 15 feet to maintain full signal quality.

Dynamic Contrast Ratio:

A measure of contrast ratio in which there is a need to only display a dark image.  In this event, the projector decreases the aperture of the projectors lens using an iris but will proportionately amplify the transmission through the projectors panel. This gives the benefit of realizing the potential static contrast ratio of the projector in dark scenes when the image is watched in a dark room. However, if the scene contains a small area of super bright light, the image quality may be overexposed. Be careful when viewing contrast ratio specifications as some manufacturers are starting to list dynamic contrast (DC) ratios in place of the static contrast ratio. For example, a projector with a static contrast ratio of 5000:1 will show superior picture to a projector with 5000:1 dynamic contrast ratio and 1000:1 static contrast ratio.

 

E

Eco-Mode:

Eco-Mode is a now prevalent feature within projectors that reduces the brightness of the projector lamp thus decreasing heat which allows lamps to last longer. Typically, eco-mode will double the life of your projector lamp and provide quieter operation due to a decrease in fan speed due to cooler operation. This smart innovation saves money and eliminates the hassle of replacing lamps.

 

F

Focus:

The focus on a projector defines the minimum and maximum projection distances. Projectors equipped with either a manual or auto focus which all you adjust the focus at different distances from the projector screen.

FPS (Frames per Second):

The number of frames displayed per second.

 

G

Gain:

Gain is a measurement of reflectivity on a projection screen or surface. The gain represents the ratio of the light which is reflected from the screen compared with the ratio reflected from a standard white board. A screen with a gain of 1 will reflect the same amount of light as the standard white (magnesium oxide) board. Today's low gain screens are typically gray and carry as low as a .8 gain. Most white home theater screens typically carry a gain of 1.0 to 1.3.  High gain screens (> 1.3) are common place in conference rooms and classrooms where there is a need to boost image brightness. Screens with a gain greater than 1.3 are not recommended for home theater applications as they are subject to unequal color distribution, poor viewing angles, and hotspotting.

Gauge:

A measure of wire thickness. The lower the gauge, the larger the wire. Typically, the larger the wire the better the image quality. HDMI cables for example are capable of carrying much higher bandwidth through lower gauge wires.

 

H

HDMI (High Definition Multimedia Interface):

HDMI is an uncompressed, fully digital, audio/video interface that supports standard, high definition, and enhanced video as well as multi-channel audio and interactive controls through a single cable. The newest version of HDMI supports up to 8.2 digital audio.

HDTV (High Definition Television):

HDTV is a digital broadcasting system with higher resolution than traditional television systems.  HDTV is digitally broadcast and encompasses 480p, 720p, 1080i, and 1080p.

HDTV capable:

A television that supports any resolution higher than 720p and has a built in HDTV tuner for off-air reception of HDTV signals from a special antenna. A cable or satellite box is required to view HDTV programming.

HDTV ready:

HDTV ready is a television or other video product that supports resolutions higher than 720p but does not include a build in HDTV tuner. A cable or satellite box is required to view HDTV programming.

Hotspotting:

Hotspotting is an effect commonly known to plague high gain projection screens.  Hotspotting is when the center position of the screen is visibility brighter than the edges. This effect begins to be noticeable as screen gain raises past 1.3.

Horizontal Frequency:

The total number of horizontal lines scanned per second .

Horizontal Resolution:

The total number of vertical lines (or pixels) across the horizontal rows of a monitor. When viewing a resolution such as UXGA (1600x1200) the number of vertical lines is 1600.

Hue:

One of the main properties of a color, defined as the parameter of a color which allows us to distinguish it from another color.

Hz (Hertz):

The rate at which an image is refreshed.

 

I

Interlaced:

Interlace is a technique used to improve picture quality of a video signal without consuming extra bandwidth. Interlaced scan separates each line or row of pixels into two fields to create a single frame. Once field contains all the odd lines while the other the even lines. The two sets work together to create a full frame. This technique allows for twice the display refresh rate for a given line count which reduces flicker and improves the portrayal of motion.  Interlaced provides a higher refresh rate and spatial resolution when used with analog or uncompressed digital video signals. These improvements however are degraded with digital video compression such as current digital TV standards. Due to these inefficiencies progressive video is preferred.

Inter-pixel gap:

The inter-pixel gap encompasses the non-image area between individual pixels. Typically, LCD projectors have a larger inter-pixel gap than DLP projectors. In LCD projectors with a high inter-pixel gap the effect produced is commonly referred to as the screen door effect. The larger the projected image is the more prominent this adverse effect becomes.

Invert Image:

Inverted images are used when the projector is mounted  upside down from a ceiling mount to compensate for the projector being upside down. Projectors are mounted upside down due to the built in off-set which allows projectors to be mounted flush with the bottom or top of the screen and produce a non-distorted image without the use of keystone correction.

IRIS (R)   (Intelligent Room Illumination Sensor)

Most home theater projectors are now equipped with a  build in IRIS(R) which detects light volume and color density within a room and automatically adjusts the mid-range color tones required for optimum color reproduction under different lighting conditions.

 

K

Kensington Lock:

A lock which enables a projector or other compatible electronics to be secured by a key or combination lock to increase security.

Keystone Correction:

A special projector feature that creates a uniform image top to bottom by correcting an image if it is projected at an angle.  Keystone correction can be horizontal or vertical. Most new projectors on the market have vertical and horizontal correction but some only have one or the other.

 

L

Latency:

The amount of time that takes place between an action is requested and the action begins.  Latency is measured in milliseconds (ms), the shorter the better.

LCD (liquid Crystal Display):

LCD technology is prevalent in laptops, television sets, monitors, and projectors. LCD technology uses three glass panels within a projector which separate the projector spectrum in red, green, and blue. Light passes through these panels and creates the image on the screen.  LCD projectors are more efficient with regards to light efficiency which makes LCD projectors the dominant choice for conference rooms and school applications. LCD projectors also have greater color saturation DLP projectors, however, since LCD panels are only separated into three colors DLP projectors typically have higher contrast ratios.

LCoS (Liquid Crystal on Silicon):

LCoS is a type of LCD panel that reflects light instead of blocking it. LCoS projectors usually have extremely high fill rates and very small inter-pixel gaps which result in an unbelievably smooth image.  This technology, however, makes it difficult to deliver a projector with high contrast ratios. 

LED (Light Emitting Diode):

LEDs are a electronic light source which are now being incorporated into LCD televisions and monitors for backlight as well as a light source for DLP projectors. RGB LEDs can increase the color gamut by up to 45%. The main draw to LED projectors is the fact that the LED lamps last for an astounding 20,000+ hours compared to the typical projector lamp life of 2000-5000 hours. Currently only a small handful of LED projectors are on the market.

Lens Shift:

The main purpose of Lens shift is to eliminate the use of keystone correction. Lens shift allows the user to shift  the lens within the projector to allow greater flexibility in the placement of the projector or screen.

Long Throw Lens:

Long Throw lenses allow the projector to be placed much further from the screen while still maintaining the image size and brightness of projectors with a shorter throw.  Long Throw Lenses are ideal for installations in which the projector must be placed a long distance from the screen.

Lumen:

A measurement of light, the higher the lumen count the brighter the projected image.

Luminance:

Luminance is a measure of the color intensity of an image.

Lux:

A standard for measuring the intensity of light hitting a surface. Lux is derived based on lumen, the lux however takes into account the area in which the luminous lux is spread.

 

M

Multimedia:

A computer technology that allows the simultaneous presentation of information through graphics, sound, animation, and text.

Multiplexing:

The condensing of many signals into a few or one signal which still represents all signals that were inputted.

MSRP (Manufacturer's Suggested Retail Price):

Authorized dealers are legally bound to advertise products purchased by a manufacturer at the MSRP.  Due to this obligation some prices on this website may say "click here for price" in which the price will change to our price. This is a necessary step to make sure that we are operating in accordance with manufacturer policies.

 

N

Network:

A system which allows two or more computers to interact quickly and easily.

NTSC:

NTSC is the broadcast signal used in the USA for video.

 

O

OEM (Original Equipment Manufacturer):

An original equipment manufacturer produced products or components which are purchased by a purchasing company and retailed under the purchasing companies brand name.  OEM refers to the company that originally manufactured the good.

Optional Lenses:

The majority of projectors come with a single standard build in lens that is designed for a specific application. A projector that supports optional lenses allows the projector to address a variety of installation needs. This flexibility, however, comes at an incremental cost as optional lens projection systems are typically more expensive.

 

P

Pal (Phase Alternative by Line):

The television standard used throughout Western Europe, South America, Asia, and Oceania. The United States uses NTSC standard. These formats are not interchangeable.

Pixel:

A single dot on a display. Total pixels are expressed in horizontal and vertical dimension. For example, a 1600x1200 resolution image has 1600 lines of 1200 pixels for a total pixel count of 1,920,000.

Power Zoom:

A zoom lens is controlled by a motor instead of manual adjustments. Adjustments are made from a remote control or control panel. Zoom lenses are perfect for applications in which the projector is located high on a ceiling and is hard to reach.

Picture-in-Picture (PIP):

Allows the user to show two or more images simultaneously.

Projection Distance:

The projection distance is the distance between the projector lens and the projection surface. When choosing a projector make sure the projectors projection distance and throw distance are compatible. A projector with a zoom lens will have a range of throw distances for to choose from.

Progressive Scan:

A display mode in which all horizontal lines of an image are displayed simultaneously. Unlike, interlaced scan in which horizontal lines are broken into two fields progressive scan only uses one field. Progressive scan requires a faster refresh rate than interlaced but provides a higher overall image quality when produced at a sufficient refresh rate.

 

Q

 

R

Rainbow Effect:

DLP projectors which utilize a color wheel are subject to the anomaly know as the "rainbow effect". The rainbow effect can be described as brief flashes of perceived red, blue, and green shadows observed most often when the projected content features high contrast areas of moving bright/white objects on a mostly dark/black background. This effect is caused by the way the eye follows a moving object. This problem is characteristic of projectors with slow color wheels and low refresh rates. The rainbow effect can only be seen by a small percentage of the population.

RCA:

A common connection for audio/video sources which is also called composite video.

Resolution:

The resolution is comprised of the total number of individual pixels which make up an image. The more pixels a unit is capable of displaying the better the image quality and the higher the resolution.   Essentially, resolution is the ability of a display to render detail.  The higher the resolution, the more detail displayed.

RGB (Red, Green, Blue):

RGB is a component signal typically used with analog computer displays. RGB represents each of the three colors separately, red, green, and blue.

 

S

S-Video:

S-Video transmits video signals through two wires called luminance and chrominance. Luminance carries the brightness signals while the chrominance wire carries the color signals. S-Video offers a higher quality video than composite or RCA cables due to this separation of luminance and chrominance.

Screendoor Effect:

An image distortion cause particularly by LCD projectors with large inter-pixel gaps. The gaps surrounding each pixel give the effect that you are viewing the image through a screen door. This is particularly a problem with low resolution LCD projectors.

Screen Trigger:

A 12V connection from a projector to an electronic screen which tells the screen to deploy when the projector is turned on and roll up when the projector is turned off.

Short Throw Lens:

A special lens which allows large images to be projector from short distances. Average short throw lenses can produce upwards of an 80-100'' image from a mere 3 feet.

Saturation:

A measure of color intensity, a highly saturated image has a vivid, intense color, while the absence of saturation is represented by the color gray.

 

T

Throw:

The distance between the projector lens and the projection surface.

Throw Distance:

The throw distance is the distance needed between the projector and screen needed to produce the desired image size.

Throw Ratio:

Throw ratio is the ratio of the projection distance to projection surface width.    Throw ratio can be calculated by dividing the projection distance by the projection surface width.  These ratios are usually helpful when determining the appropriate projection distance for fixed installations.

 

U

Uniformity:

A measurement of the evenness in which the brightness of the projector is distributed throughout the picture. An image with 100% would produce an image that is just as bright at the center of the image as it is on the very edge of the image. A measurement of above 90% means that the brightness of the image is 15% less at its dimmest point compared to its brightest.

 

V

Vertical Frequency:

The total number of vertical lines scanned per second .

Ventilation:

Airflow throughout a projector that allows the lamp and other hot components to remain cool. Poor ventilation will result in lamp or temperature failures. It is important to keep your projector dust free and allow room for ventilation.

VGA:

VGA is your standard 15 pin monitor cable. These cables are typically used for a computer to monitor connection and are also commonly found on projectors. There are relatively few home theater applications for VGA inputs however there are adapters and cables available which allow conversion to component video cables and signals.

 

W

Wi-Fi (Wireless Fidelity):

A common type of network that allows computers, projectors, phones, and other devices to connect to a network without wires.

Wide Screen:

Any aspect ratio that is wider than 4:3. Common widescreen formats are 1.66:1, 1.85:1, and 2.35:1.

 

X

 

Y

Y-cable:

A cable that splits video sources. A common example would be a computer splitting an image between a projector an LCD monitor. Splitting the image will allow the same image to appear on the LCD monitor and the projector.

 

Z

Zoom Ratio:

The ratio between the smallest and largest image a projector can produce from a fixed distance. For example, a 1.4:1 zoom ratio meant that a 10 ft. image without zoom would be a 14 ft. image without zoom.  A zoom lens is not as bright as a fixed lens, however, the benefits of zoom lens make them quite common throughout the industry. In addition, the higher the zoom ratio, the less light output will be produced.

Zoom Lens:

Zoom lenses have variable focal lengths which allow them to adjust image size on a screen.  This handy features allow you to make the image size bigger or smaller without moving the physical location of the projector.

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