60 InFocus Corporation — Introduction Guide - DLP Multimedia Projector
Term Description
LED Light Emitting Diode. A light generating technology that uses a semiconductor diode that emits
monochromatic (single colour) light when charged. LEDs are used in remote controls that are used
to control electronic devices such as large displays. They are also used in pocket projectors as a light
source, large outdoor electonic displays, and as indicators on electoronic devices such as power
supplies and cameras.
LED Lamp A type of projector lamp that uses one or more LEDs as its light source. The benefit of LED lamps is
their long life.
Lens Memory The ability to define and recall specific zoom lens positions so the projector can automatically
configure subject matter of a given aspect ratio to a particular screen. This requires a projector with
a powered zoom lens. Lens memory is often used to automatically set a zoom lens to fill a 2.4:1 format
screen when displaying a 2.4 format film, then reset the lens to allow 16:9 aspect ratio material to fit
the vertical height of the screen. Lens memory is typically used as a substitute for an anamorphic
lens.
Lens Shift The purpose of "lens shift" is to eliminate keystone correction and provide greater flexibility in
the placement of the projector relative to the screen or the alignment of stacked projectors. This
is accomplished by allowing the optical lens to be physically shifted vertically and/or horizontally.
These adjustments may be manual or motorized depending on the projector. Seehorizontal lens
shiftandvertical lens shiftfor typical adjustment ranges.
Letterbox A method of preserving the originally aspect ratio of a production when presented on a projector
with a different aspect ratio. This is accomplished by showing the full image and black where no
image exists.
Linearity A display’s ability to show an image’s geometric characteristics accurately. Also called geometric
linearity.
Long Throw
Lens
A long throw lens allows greater distance between the projector and the screen while being able to
maintain the image size and brightness of a shorter throw lens for any given projector. Depending
on the room, a long throw lens may be required due to mounting constraints nearer the projected
image.
Lumen A measurement unit of total illumination. Typically a 100-watt light bulb outputs 1700 lumens over
a wide area. Projector light output is measured in ANSI lumens. A projector with a higher lumen
number will produce a brighter image for a given image size. See ANSI Lumens
Luminance The black and white part of a video signal. It is signified by the letter Y. Signals with a separated
luminance and colour signal avoid interference. This interference can result in dot crawl among other
image artifacts.
Lux A standard for measuring light equal to the amount of visible light per square meter incident on a
surface. 1 lux = 1 lumen/square meter or 0.093 foot-candles.
M1-DA A DVI connector that supports analog, digital video, a USB connection, and FireWire (IEEE1394).
Used primarily with InFocus projectors.
M1-DA (EVC or P&D) is 3 rows or 10 pins and looks a lot like the DVI-I except for 6 more pins. The
maximum video resolution supported is 1280x1024.
Maximum Distance
Sometimes used to refer to the distance from the screen that a projector can focus the image. Most
of the time, it is the manufacturer's opinion of how far from a screen the projector can be to cast an
image that is useable (bright enough) in a fully darkened room. Consult the Projection Calculator for
guidance on proper placement of a projector for a given screen and content.
Maximum
Image Size
The largest image a projector can reasonable throw in a darkened room. Consult the Projection
Calculator for guidance on proper placement of a projector for a given screen and content.
Glossary
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