The Projector Selector
A "decoder ring" for all that jargon seminary never taught you

By Lars Yoder

When shopping for a projector, most people start with ANSI LUMENS, or brightness. The more lumens a projector boasts, the brighter it is, which also typically means a larger picture, the ability to use the projector in a well-lit environment, or a combination of the two. A single projector can deliver about 1,000 lumens--good enough for the average size conference room--all the way to 17,500 lumens, which is bright enough to project clear, sharp images in very large auditoriums.

For many shoppers, the next consideration may well be NATIVE RESOLUTION. This figure typically defines the number of pixels (those tiny dots that, when seen together, create the picture). Generally, the higher the resolution, the better the image quality. Today, the most common resolutions are SVGA (800 x 600 pixels) and XGA (1,024 x 768 pixels), but most projectors can also scale images electronically. For example, many projectors with SVGA native resolution can electronically adjust themselves to project a picture that was originally at XGA resolution. In this case, the end image is not as quality, but SVGA resolution projectors cost less than XGA resolution projectors.

When researching CONTRAST RATIOS in projectors, many shoppers do not understand what they should be looking for. Basically, this ratio defines the range between a projector's blackest black and its whitest white. A large contrast ratio--say, 1,000:1 or better--means that the image will appear much sharper and more lifelike because of its sharp detail. If you plan to incorporate video into your applications, contrast ratio is one of the key components of realistic images.

Also look for other important contributors to perceived image quality, one of which is brightness uniformity. Measured as a percentage, the degree of brightness uniformity tells you whether the picture will be evenly illuminated or whether it will appear slightly darker in the corner. The higher this percentage, the better.

Never underestimate the importance of OPERATING NOISE either. The brighter a projector, the more cooling it requires; thus, louder fan noise. At the lower end of the brightness spectrum, however, look for a noise rating as close to 30dB (or less) as possible.

Shoppers also have a technology choice to make between the two major projection technologies fighting for your dollar: DLP^™ and LCD. Which one you choose is less important than getting a projector with adequate brightness, the right resolution and appropriate contrast ratio and image uniformity for your application.

Finally, make sure you investigate each supplier's after-sales service. For each projector you like, find out how long its warranty is, how long its lamp is expected to last (see LAMP LIFE in The Matrix), and how much it will cost to replace that lamp. Also determine how quickly the projector can be repaired or replaced as well as the cost of installation.

Remember to practice the two "golden rules" of projector selection: 1) Before you buy, ask the dealer to show you how the machine operates in your environment; and 2) Remember that, just like most things in life, you get what you pay for.

Lars Yoder is the manager of Business Products for the DLP™ Products Division of Texas Instruments.

The Matrix