What to Look for While Shopping

If you're in the market for an installation LCD projector, whatshould you be looking for in the way of operating features? To be sure;lots more than you would have found on installation projectors from tenand even five years ago.

The most obvious areas for improved performance are in brightnessand contrast. There are many who believe that LCD installationprojectors are probably as bright as they'll ever need to be! For smalldesktop/installation projectors, the current performance bar is between2500 to 3000 lumens, using micro lens array technology. For largermodels, 3000 to 5000 lumens is practical.

More importantly, that level of performance should be achieved withhigh uniformity--typically, 75% or better is the benchmark. Thatmeans no hot spots or color shifts across the image, which is importantwith Windows applications such as spreadsheets. Better uniformity alsohelps improve video image quality.

Contrast has steadily improved in LCD projectors. It wasn't thatlong ago that 150:1 ANSI (average) contrast was considered goodperformance. Now, the bar has been raised to over 200:1 ANSI, and over300:1 peak. While the black levels on LCD projectors still aren't aslow as those seen on CRTs, the contrast is far higher.Remember--contrast is key to image legibility, as is smooth grayscalereproduction.

Today's installation projectors must be able to handle any signalformat thrown their way. That means a high-quality autosynccircuit must be incorporated; one which can quickly detect thehorizontal and vertical sync rates, and correctly size/scale and centerthe incoming signal. Very few projectors of any kind can pull this offwithout further manual adjustment of the image.

Expanded signal source compatibility is another 'must-have'.Even though many progressive?scan standards (such as 640x480 VGA) arenot as popular as they used to be, the new DTV standards require theirown attention. Outboard video scaling products add even more confusionto the mix, presenting computer-resolution standards as YPbPr (sync ongreen) and video signals as RGB (separate sync). Any LCD installationprojector worth its salt should be able to recognize even these unusualsignal formats.

Installation projectors are often put into unusual locations. As aresult, full-featured models should have full optical lens shift anddigital keystone correction to compensate for keystone distortion,which results from off-axis projection throws. Smaller installationprojectors have size limitations that prohibit mechanical lens shift,but should incorporate digital keystone correction circuitry. Whiledigital correction is not the same as true lens shift, it does re-mapthe image pixels to attain a square, symmetrical image geometry.

Although slowly gaining acceptance, the digital videointerface (DVI) is intended to be the future standard for RGBcomputer displays. Right now, the trend is to provide a dualanalog/digital connection, with implementation of 100% digitalinterfaces to come. It's a smart move to purchase an installationprojector with a DVI input, particularly for rental/stagingapplications where the computer video sources can vary widely.

One of the advantages of switching to LCD technology is easiermaintenance. Look for a projector that uses an efficient projectionlamp, to ensure long life. Some models incorporate a power savingfeature to further extend lamp life. Larger installation LCD projectorsuse more than one lamp, which improves brightness uniformity andprovides a back-up lamp in case one fails.

Full remote control of your installation projector should beavailable through a standard RS-232C command interface, or (on newermodels) via IP-protocol network control. IP networking of projectors isthe next wave in remote control, and allows remote downloads of filesto the projector as well as remote diagnostics and setup. Thisinterface can be through a USB port or standard EtherNetinterfaces.