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Display - Presentation glossary
Category: Technical and IT > Display technology
Date & country: 19/01/2008, UK
Words: 170


Additive colour mixture
An ordinary colour mixture process in tube monitors and data/video projectors. When mixing red, green and blue light components with the same saturation, white will appear. The signal transmission usually happens splitted into an RGB signal via shielded cable.

AFS (slide)
Selective Autofocus. Corrects blurring fast and automatically. (Disengageable in a number of devices).

AGP-Bus
Acronym for 'Accelerated Graphics Port'. Along with ISA, EISA, Microchannel, LocalBus and PCI another port/Bus in the PC area. It makes graphics faster and more realistic. The AGP-bus is only suitable for Graphic cards.

ALIS
Alternate Lighting of Surfaces. A technology for Plasma Displays to improve the image quality by doubling the lines

ANSI-Lumen
Unit of measurement for the brightness of LCD projectors based on ANSI (American National Standards Institute). An area of 1 sqm on a screen is divided into 9 equally sized rectangles. The mathematical average of the light intensity in the centre of each area equals the ANSI lumens value.

Anti Jam System
Prevents jamming or damaging of slides in the slide duct. To avoid any damage the slide transport is disengaged and the cooling fan contiunues to run.

Aperture(slide)
The aperture is a measurement for the size of the opening of the lens. This size is alterable in small steps. The higher the aperture value the less light gets into the camera.

Barrel distortion
Aberration with projectors where the margin lines of the image are convex. This is caused by aberrations of the lens. Opposite cushion distortion.

Blanking
Shading a chart during a projection

Bluetooth
New wireless data transmission technology. Different kind of components and of different manufacturers can be combined to wireless networks for the first time.

BNC
A popular connector with video professionals which features a high loading capacity. Workstations have BNC cables with 5 connectors: one each for the three basic colours red, green and blue and one each for horizontal and vertical synch.

Brightness level (slide)
The brightness of the halogen lamp can be adjusted.

Burn in
Burn in means an effect where an image is still latent visible even when the plasma display is switched off. This effect occurs due to an uneven fading of the plasma cells, i.e., caused by the insertion of TV station logos.

CCD
CCD is the abbreviation of Charge Coupled Device. CCD sensors consist of a one- or two-dimensional array of memory elements. They are mainly useful as image sensor in video cameras, scanners and digital cameras.

CE
All electrical and electronic devices which have been available for sale in the EU as of 01.01.96 have to bear this official seal. It provides information on the electromagnetic compatibility of the device.

Cinch
A connector primarily used for the transmittance of video - and audio signals.

Cinch connector and jack
(Also called RCA) are today mainly used in the consumer electronics. Usually audio adapters are marked red and white (for Audio right/left) and video adapters are marked yellow.

Colour temperature
A measure for the predominant colour portion of the light, measuring unit Kelvin. The higher the blue share in the light, the higher the colour temperature.

Compact flash card
Mobile memory medium for presentations without PC

Component signal
Also described as colour difference or YUV signal. The video signal is split into one brightness and two colour difference signals, which are transferred separately. The image quality of the component signal is better than S-Video and therefore is employed frequently e.g. for the connection to DVD-players.

Compression
Many projectors are able to display higher resolutions than they actually have by skipping lines and columns. As this affects the picture quality, several manufacturers have developed special compression methods, which actually compress with only the slightest loss of information.

Condenser lens
Additional light focusing for improved sharpness of projection image along the margins.

Continuous projection
Continuous slide shows either via built-in timer or via IR-remote control with the help of the autotimer function. Different slide change times are possible.

Contrast
Indicates the difference between the darkest black and the brightest white. The higher the contrast ratio, the darker the black value on the projection screen. There are two different measuring methods: Full on/off: In a dark room the brightness of the projection screen is measured at full white and full black. This process does not consider the re …

Convergence
The congruence of the three LCD panels (red,green,blue) in a projector. Convergence error: Chromatic aberration in data projectors with three modules. Lines and outlines have coloured margins. The reason: The three projected component images for red, green, blue do not exactly comply with each other. Convergence errors mainly appear in corners.

CRT projectors
Three-tube projector for ceiling mounting. Unlike digital projectors, CRT projectors are considerably heavier, more expensive and the adjustment requires a great effort.

Cushion distortion
Geometry error of lenses during projection which leads to a pin-cushion distorted image. Horizontal and vertical margin lines of the image are distorted up to the image centre. This is caused by reproduction errors of lenses. Opposite barrel distortion.

Daylight
Natural sun light or the emission of light with a colour temperature of 5.400 K up to 6.000 K.

Diagonal
For 4:3 formats (SXGA, XGA, SVGA) the image width is= diagonal : 1,25 see image size

Dichroic mirror
A selective mirror which only reflects a certain part of the light spectrum (a certain colour), however, which lets all other portions of light passing. Used for example in a colour divider system of a digital projector with 3 tubes.

Dichroic mirror technology (slide)
The light source has a reflector, so that the beam hitting the slide in a right angle first hits the mirror then reflects the slide. The mirror has the feature to absorb a part of the heat radiation so that the slide is not affected by too much heat.

Diffuse (projection Screen)
A reflection characteristic of projection screens. Diffuse reflective projection screens evenly scatter the incident light in all directions. The viewing angle is approx. 45 up to 60 degrees. The luminance factor is approx. 1.2.

Digital zoom
A frame can be digitally x-times magnified

Dissolve (slide)
Gradual change of an image into another with changing the brightness of two overlaying images.

Distortion
Optical aberration particularly emerging with zoom lenses. Hence cushion or barrel distortions occur at maximum setting of the zoom lens. Due to the often built-in upwards projection this error is particularly eye-catching at the top side of the image. The better the lens the less the error.

DMD (TM) - DLP
The DMD/DLP (Digital Light Processing) technology developed by Texas Instruments contains hundreds of thousands of microscopically thin mirrors (1/1.000 of a human hair) on a semiconductor chip that are controlled electronically. Due to a newly developed control electronics the reflective projection light for each pixel is focused either onto the o …

DRIT
Digital Realized Interpolation Technology. Digital compression - and expansion processing from SANYO for full format images.

DVD
Digital Versatile Disk, a new standard to save data on a CD ROM similar structure. Due to its high memory capacity the DVD is also able to digitally store movies. The quality is considerably better than S-VHS.

DVI
Digital Visual Interface is a new transmission standard that enables the digital transfer of PC data to a monitor, plasma display, projector, etc. As there is no conversion to an analogue signal the image quality improves significantly. There are three different interfaces: DVI-D: Transmission of true digital informations; DVI-A: Transmission of tr …

Eco mode = Whisper Mode
Reducing the light output when using a digital projector. It reduces the fan noise and increases the lamp life.

Extra bright lamp module (slide)
Enables a higher light-source efficiency due to the dichroic mirror technology. (Kodak)

Fade (slide)
(Fade in, fade out). The increasing and decreasing of the lamp's light intensity, to make an image brighter or darker or to dissolve images.

Fan speed controller
A sensor constantly controls the outside temperature. If the temperature is falling, the speed of the fan is reduced, thus the fan noise is reducing automatically.

FAQ
Frequently Asked Questions.

Firewire
The IEEE 1394 - technology, initially called Firewire, characterises a relatively new (from 1995) serial interface technology for PC - and video devices to transmit digital data of up to 400 Mbit/sec.

Fixfocus lens
A lens where the focal width cannot be changed. The image size can only be varied through the projection distance.

Focal length
Is the distance between the central point of a lens and the point where the beams are bundled (focal point). The bigger the focal length the closer targeted objects appear to be on the image

Freeze
Freezes the projection image to enable programme changes without viewers noticing. With the freeze function, a soft dissolve (respectively fade in/fade out in single projection) in your movement can be frozen at any point, any time.

Frequency Range
Indicates the frequency range (in Hz), which a signal needs for transmission

Front projection
Projection process where the image is projected onto a reflective wall. Contrast - rear projection

Gain (projection screen)
Illuminance factor according to American Standard

Gear rack rube (slide)
Current feature of Ektapro/Ektalite lenses. Gear rack lenses are pushed that way into the lens mount housing that the gear rack rests on the gear wheel.The sharpness is achieved by turning the sharpness button. Gear rack lenses are used in Ektalite as well as in Ektapro models. (Opposite: Spiral tube (only Ektapro).

Gender changer
Adapter to change i.e. a plug into a jack. Is often required if the existing connection cable is only available in the wrong version.

Glare-free fresnel lens
Avoids light scattering thus allowing fatigueless working for longer periods.

GyroPoint (TM)
Patented technology to convert movements into electronic signals. Is used in products such as GyroMouse, GyroRemote and Ultra Professional which do not require any pad to control the mouse pointer thanks to this technology.

HDMI
High Definition Multimedia Interface. New standard for the digital transmittance of high resolution Audio - and Video signals. The HDMI standard supports the coding of data to be transmitted whereby the unauthorized copying shall be prevented. If the projector or plasma display has no electronic to decode the data, the image either remains black or …

HDTV
Abbreviation for High Definition TV. This means the television transmittance with a significantly higher number of lines than present PAL- (625 lines, Interload) or NTSC-format (525 lines, Interload). There are modi with 750 and 1.125 lines which have a progressive format without interlace.

High-light switch (slide)
Increase of light output (therefore reduced lamp life ). (Kodak)

Horizontal frequency
Indicates how many lines can be addressed per second (in kHz).

IEEE 1394
See firewire.

Image format
Aspect ratio from image width to image height. All video formats have the conventional 4:3 format. Also for data formats VGA, SVGA and XGA this ratio is maintained. The calculation of the image diagonal is very easy: Width to height to diagonal is 4:3:5. SXGA has a 5:4 image size while HDTV has the 16:9 standard size.

Image size
With an aspect ratio of 4:3 (VGA-, SVGA-,SXGA resolution) the image size values of a digital projector are determined as follows: Image diagonal = image width x 1,25; Image width = image diagonal : 1,25; image height = image diagonal x 0,6 or image width x 0,75.

Inline magazine projector (slide)
Is equate by many with amateur projector as it is the most common projector type. The slide is tugged laterally by a slide feed in the optical path. Disadvantage for dissolve projections. Since the slide is pulled against a stop unit (for example a spring), a bounce effect will result. Hence, the collateral positioning varies even though it is only …

Interchangeable lenses
Thanks to interchangeable lenses with different focal width the projection image can easily be adjusted to the screen - or room size.

Interlaced
This is an image formation where initially a half image (every second image line) is produced and thereafter the second half image is placed in the gap. Due to the double image frequency the flickering is reduced. All normal video norms work according to this principle while HDTV is working without line skip. Interlace is no longer common with data …

Interpolation
Mathematical process to approximate out of known data the values of unknown data. The process plays a decisive roll in the magnified or decreased reproduction of images, particularly when adjusting the resolution to the module size of the data projectors. Magnified reproduction is called Resizing, decreased reproduction is called compression.

IR
Infrared, invisible light with large wave length, used for the transmission of remote control signals

IR mouse remote control
The PC mouse can be controlled via the remote control of the projector.

Jack
Connector primarily used for headphones and microphone connection, partly also as Audio - or Video connection.

Keystone correction horizontal
If a projector cannot be placed in the right angle to the screen but due to space-saving reasons at a side, the distortions in an image are adjusted with an image processor.

Keystone correction vertical
Many digital projectors project as a presetting in a certain angle upwards to minimize the keystone effect. Some devices have an additional keystone correction, that means an image processor calculates the distortion-free image of the front - or downwards projection. Only a few devices resolve this optically (Lens Shift function).

Keystone effect
Trapezoid image distortions with front or downwards projections. Can be corrected with tilted projection screen and/or with keystone correction.

Lamp economy switch (slide)
It reduces the light output of the lamp thus increasing the lamp life.

LCD
Liquid Crystal Display. A system made of thin glass panels filled inbetween with a layer of liquid crystal. Thanks to electric mains all points of this layer can be activated individually. The precision of the activation is decisive for the quality of the projected image.

LCoS
Liquid Crystal on Silicon. LCoS displays have the size of half of a thumb nail. Despite their small size LCoS displays have more than two million pixels and enable a resolution beyond UXGA (1600 x 1200 pixels). LCoS displays consist of three parts. A silicon film, on top comes a thin coating with liquid chrystals and an extremely thin glass panel. …

Lens shift
The lens can be moved mechanically from the principal axis of a projector. Due to the change of the projection angle the keystone effect is minimising. The greater the angle, the higher the loss of light and the greater the image errors (cushion - or barrel distortions).

Line doubler
Electronic device or circuit turning video signals (half images) coded by the interlaced scanning into full images. The Line Doubler removes the annoying line structure. The simpliest form doubles the provided lines. This results in homogeneous images.

Manual zoom
The diagonal size of the image is adjusted manually at the lens.

Microlens technology
In front of the LCD panels of the projectors are micro lenses which have the task to bundle the light and guide it through the transistors so that the loss of light is as low as possible. Based on this technology a much higher Ansi-Lumen value can be achieved with the same lamp.

Microportable projectors
Particularly light digital projectors with a weight of 3 kg. Mostly on DLP basis.

Microprocessor (slide)
A small chip based central unit; the heart of the micro computer and memory coders. A micro processor control offers more ease-of-use and safety.

Motorised zoom
The size of the image diagonal can be adjusted via infrared remote control independent of the location of the projection.

MPEG
Compression standard for the data reduction of moving images. Unlike JPEG only the differences between two successive images are saved.

Multinorm
Projection system with multinorm compatibility can project PAL, SECAM and NTSC video images.

Muting
Muting, some devices also provide muting and dimming.

Network projector
Digital projector with the possibility to connect directly to PC networks. The function provided by this network connection varies by vendor and reaches from a simple remote control up to transmitting complete presentations.

New progressive scan system
A SANYO technology to enhance the image quality. Similar to a Line Doubler a special chip controls the reduplication of lines of moving image details at the projection of DVDs or other video images. The projections gain in image sharpness and colour depth.

No slide - no light (slide)
A shutter prevents the light spill in case no slide is in the slide gate. This is kind to the eyes and avoids the glare of the screen.

NTSC
National Television System Committee. A television standard with 525 lines and 60 half images per seconds interlaced popular in the USA, Canada and Japan.

OEM
Original Equipment Manufacturer. Manufacturer of products being sold under a different company name.

Optical axis
Responsible for the sharpness of a projection image. Only if the projection head is positioned vertically above the lamp house and the concave mirror the user is able to get a sharp projection image. It is important that there is a stable connection between projection head and projection arm.

OSD
On Screen Display The menue is inserted into the projected image.

PAL
Phase Alternation Line. A colour television principle developed by W. Bruch which is used in most parts of Europe with the exception of Czech Republic, Slowakia and France. The resolution is 625 lines, the frame rate 50 half images per seconds, the aspect ratio is 4:3. The enhancement is PAL Plus.

PAL Plus
Enhancement of PAL with an aspect ratio of 16:9 and improved signal processing.

Parallel projection (slide)
Several projectors are operated in parallel (simultaneously).

PCI-Bus
Stands for' Peripheral Component Interconnect Bus'. Along with ISA, EISA, Microchannel, LocalBus and AGP another slot/BUS in the PC area. Unlike AGP-Bus the PCI-Bus also accepts other add-on cards than graphic cards.

PCMCIA
Personal Computer Memory Card International Association. International standard committee for credit card sized add-on cards for notebooks and digital cameras. Apart from memory cards there are also modem -, sound - and video cards in the PCMCIA format.

PDF
Abbreviation for 'Portable Document Format'. This format is platform independent.

PIP
Picture in Picture. Several sources can be projected at the same time, i.e. simultaneous projection of a data - and a video source.

Pixel
Picture Element. Smallest triggerable image part.