Technical Projector Terms

There are many words that are specific or necessary to understanding projectors. Some think "jargon" is just a way of making a specialist feel special. But generally, having a well-defined language with which to discuss a topic helps to make certain that everyone involved has a clear picture of what is being discussed. Here we lay out some terms that will help the average person understand projector manuals, sales pitches and consultants.

Ambience - The light that is "ambient" in the room. How it is lit including lights and the amount of daylight that streams in. The more ambient light that is in the room, the more likely it is that the projector will produce a washed-out image. The way to counter this is with more light from the projector, but increased light from the projector will only combat so much of the ambient light. Ideally, you will want to find an optimum amount of ambient light for the optimum viewing experience.

ANSI - The American National Standards Institute is an quasi-official organization formed to create standards. This makes certain that many of the parts of projectors and other electronic devices can work together even if they are made by different companies in different countries. The power of the illumination and the contrast ratio on a projector are nearly always preceded by the ANSI designation to show that the manufacturer followed the ANSI guidelines and that the measurement is clearly defined.

Compression - Some projectors will convert one form of pixelated input into another. For example a computer might put out XGA and the projector might convert it to SVGA. This makes the projector more versatile.

Contrast - The ratio between darkness and brightness, contrast determines the clarity of images, especially letters and other symbols on a page. Typical contrast runs from 400:1 to 800:1 and more.

Distribution Amplifier - This will amplify or increase a source signal and distribute it over significant distances, through multiple outputs. This can be important, as signals that are sent over cheap cables at ranges above just a few feet can be intermitent or even non-existent.

DLP (Digital Light Processing) - This display technology was developed by Texas Instruments. It uses tiny mirrors (480,000 to over a million mirrors in a single small space) to display an image on a screen. This allows for deeper and more varied colors to be used.

Focus - Light and images coming out of the lens are concentrated to make clear, discernable images on the screen. The lens can only focus within certain parameters or distances so this will limit how far a projector can be from a screen as well as the size of the projection.

Keystone - When the image is bigger at top than the bottom this is called a keystone. Most projectors come with an adjustment that will remove this image distortion caused by an angled screen or projector.

LCD (Liquid Crystal Display) - uses electric current to align crystals suspended in a liquid. Because the rod-shaped crystals are contained between two parallel transparent electrodes, when a current is applied, they can change their orientation, creating varying degrees of color. Three colors and their shades are necessary to produce any color in the spectrum.

Lumens - This is a measure of the amount of light streaming out of the projector. More lumens will be necessary to light spaces with more ambient light. At least 1500 lumens is considered necessary for projectors used in auditoriums and bright rooms.

Pixel A pixel is a small dot of light that forms a part of the display of an image. On a computer screen, clarity can be defined as the number of pixels per square inch (resolution). The more pixels, the higher the definition possible, but also the larger the files must be to contain the image.

Resolution - the number of dots a display uses to create an image. These dots are called pixels. The more pixels per screen area the sharper the display will be.

Throw Distance The distance from the center of a projector lens measured to the center of the screen onto which it is projecting.

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Interesting Fact:

Besides discovering gravity and co-inventing calculus, Sir Isaac Newton was an early pioneer in the study of optics.


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