Useful Definitions

Brightness (ANSI Lumens)

ANSI lumens is a measurement of the overall brightness of a projector. Because the centre of a projected image is brighter than the corners, ANSI lumens is a more accurate representation of the image brightness than lux (one point on the screen). ANSI lumens are normally measured by dividing a square meter image into 9 equal rectangles, and taking a lux (or brightness) reading at the centre of each rectangle. Taking the average of these nine points gives the ANSI lumens of the projector.

Contrast ratio

Contrast ratio is an average measurement of a totally white image vs. a totally black image at the 9 points described in lumens measurements. Because there is always a light source even a totally black image from a computer or video source will produce some white light. The higher the contrast ratio, the more vibrant the colours will be.

Component Video

A signal that's recorded or transmitted in its separate components. Typically refers to Y/Pb/Pr, which consists of three 75-ohm channels: one for luminance information, and two for colour. Compared with an S-video signal, a Y/Pb/Pr signal carries more colour detail. HDTV, DVD are examples of component video sources.

Composite Video

A standard video signal containing colour, brightness, and sync information. VCRs and DVD players almost always include a composite video output although sometimes it is only available through the SCART connector.

Display Resolution

The display resolution of a digital television or computer display typically refers to the number of distinct pixels in each dimension that can be displayed.
When applied to fixed-pixel-array displays such as plasmas, LCDs, DLP projectors etc it is simply the physical number of columns and rows of pixels creating the display (e.g., 800×600 or 1024×768).
A consequence of having a fixed grid display is that for multi-format video inputs all displays need a "scaling-engine" (a digital video processor that includes a memory array) to match the incoming picture format to the display.


Digital Light Processing (DLP™) is a revolutionary new way to project and display information based on the Digital Micromirror Device (DMD™) developed by Texas Instruments. DLP technology is provided as a subsystem or "engine" to market leaders in home, business, and large screen/entertainment segments of the projection display industry. In the same way the compact disc revolutionized the audio industry, DLP is revolutionizing video projection.

Digital Micromirror Device (DMD)

The DMD is based on a Complementary Metal Oxide Semiconductor (CMOS) Static Random Access Memory (SRAM) with a superstructure array of aluminium micro-mirrors functionally located over each memory cell. The DMD digital light switch moves between its two states ("on" and "off") to create and reflect digital gray scale images from its surface when light is applied. The digitally created images are transferred through the appropriate optics and filters to create compelling projected or, in the future, digitally printed images.
Each mirror is 16 microns square (about 16/100 the size of a human hair) with a one micron space between mirrors on all sides. The number of mirrors in use on a single chip can range from 307,200 to 1.3+ million (with 1 mirror per pixel).


High Definition – It is accepted by some that 720 lines and upward is HD but most would argue an image should be 1080 lines to be true HD. HDTV also has a picture aspect ratio of 16:9. While there are many picture formats proposed and several in use, there is increasing consensus that 1080x1920 is a practical standard for global exchange.

HD Ready

Refers to an item’s ability to accept a high definition source not necessarily to display it in its full resolution.

HD ready requirements
In order to be awarded the label "HD ready" a display device has to cover the following requirements:

• Display, display engine
The minimum native resolution of the display (e.g. LCD, PDP) or display engine (e.g. DLP) is 720 physical lines in wide aspect ratio.

• Video Interfaces
The display device accepts HD input via:
• Analogue Y/Pb/Pr. “HD ready” displays support analogue Y/Pb/Pr as a HD input format to allow compatibility with tHD video sources in the market. Support of the Y/Pb/Pr signal should be through common industry standard connectors directly on the HD ready display or through an adaptor easily accessible to the consumer;

HD capable inputs accept the following HD video formats:
• 1280x720 @ 50 and 60Hz progressive scan (“720p”), and
• 1920x1080 @ 50 and 60Hz interlaced (“1080i”)
• The DVI or HDMI input supports copy protection (HDCP)


Infra-Red - A type of wireless transmission using infrared light waves

Keystone Correction

A projector's ability to correct the effects of "pointing up" or "pointing down" at a screen, enabling the projector user's audience to view a rectangular image rather than one with a wider top or bottom.


Widely recognized physical interface and protocol for low-speed serial data communication between devices


RS-485 defines a system for interconnecting several data terminals to a common twisted pair balanced line. The interconnection is similar to RS-422, but all of the connected devices listen with their transmitters off. The host transmits a signal which addresses one of the devices.

Signal Path

The route a particular signal takes through a chain of equipment and/or electronic components on the way to its destination.

S-Video (SVHS)

Carries standard quality video signal.
An encoded signal that separates the luminance (brightness) and chrominance (colour) of a image and transmits them using separate cables to improve picture quality.
Usually terminated on 4 pin PS-2 connectors.
Connections found on DVD players, switchers & projectors