DLP projectors light up a room with color

| GCN STAFFPiercing the darkness with a crisp beam of colored light from a projector is a surefire way to make a powerful PowerPoint. But until recently, you needed either a large conference room with a projector topping 70 pounds or tightly controlled presentation conditions.The first generation of portable LCD projectors changed that picture, although weight was still high. Most LCD projectors the GCN Lab has evaluated have weighed between 8 and 10 pounds. That's portable but annoyingly heavy for travel. And the units are so delicate and costly that you would not dare check them as baggage.When Texas Instruments Inc. invented digital light processing, or DLP, the obvious advantage to the projector market was much better picture quality than LCD projectors offer.A second advantage is low weight. The tiny components of a DLP setup mean true portability.The lab tested five DLP projectors for this review. In their weight class, a 4-pound unit feels heavy and 5 pounds downright portly.An LCD projector works like an LCD monitor; a DLP projector is a different animal altogether.The DLP unit has a digital processor that works a lot like a computer's CPU. It converts input into a digital stream. The processor forwards that stream to a digital micromirror device, which creates an image inside the projector. Each mirror is perfectly square and equals one pixel of an image. Mirrors are spaced less than 1 micron apart. A typical digital micromirror device has 750,000 microscopic mirrors.Interestingly, the image at this point is grayscale. The projector adds color as a last step in one of two ways.A projector with a single digital micromirror device adds color by projecting the image through a color wheel. The color wheel spins in sequence with the image, so it adds reds when the red part of the image is passing through, green when the green part passes and blue when blue passes. This happens so quickly that the human eye cannot detect any color flickering.A more sophisticated DLP projector has three digital micromirror devices. A prism separates the light into red, green and blue colors. The projector sends each color of light to its own device and later recombines the colors on screen.Most DLP projectors are bright enough to cast a viewable image onto almost any surface, though they have yet to reach the raw incandescence of LCD projectors'a disappointment. Even high-end DLP projectors fail to touch the brightness of low-end LCD projectors. The image quality is amazingly better from a DLP, but you may have to dim the lights. Bright rooms, especially ones lit by direct sunlight, will wash out most DLP presentations.For the review, the lab measured the projectors' raw light power using an LX-101 light meter from Lutron Electronics Co. of Coopersburg, Pa. The lab staff took measurements twice, at 3 feet from the projector and again at 10 feet.To test quality, I used stock images with known color balances; I also used some moving images. Finally, I factored weight, price, control layout and overall design into the grade. The most important factors were weight, brightness and image quality.The from InFocus Corp. was the only projector to come close to the lab's expectations. It merited an A and the Reviewer's Choice designation.Although the X350 lacked brightness, we could realistically use it almost anywhere. Against a screen in a completely dark room, we measured 795 lumens at 10 feet from the lens'about the average presentation distance'and 2,700 lumens at 3 feet.At 10 feet, there was a barely perceptible 100-lumen drop in brightness from the center of the image to the corners. The X350 was the only projector in the review to have slightly darker corners noticeable without instruments, but nothing else came close to its power.Image quality was outstanding, and the projector accurately reproduced a color wheel without any blurring or color scorching.The 3.5-pound unit was one of the quietest projectors reviewed. When I first turned it on, the bulb warmed up very quietly. I started checking connections, wondering about setup errors, until the light brightened to a point that I knew it was correctly configured. That's a silent projector.The otherwise anemic 1-watt speaker didn't compete with fan noise.The X350's case was impressive. Although made of metal, it felt more like sandstone. Besides being lightweight it did an excellent job of venting heat. The X350 was the only review unit always cool to the touch, even after hours of use.The projector has only a digital input to save weight, but the included cables incorporate an analog-to-digital signal converter.The from NEC Technologies Inc., designed especially for professional presenters, earned our Bang for the Buck designation.The 3.3-pound unit is easy to carry and fits into a standard notebook computer case with the PC. One of the best features, however, is that you don't necessarily have to bring the notebook along. The LT85 has a slot for a PC Card for loading your presentation. You simply set up the projector in the conference room, pop in the PC Card and run your presentation with a remote control.The LT85 did lack raw candlepower. It could muster only 370 lumens of brightness at 10 feet. I tested a preproduction unit. An NEC representative said consumer models would be brighter.The brightness drop-off from the center to the edge of the screen was minimal, about 15 lumens on average. So, as with the X350, a viewer wouldn't notice a difference.I have one minor complaint about the overall design: The lens protector came completely free of the unit when removed. The other DLP projectors had the caps integrated. There's a good chance the LT85's cap will get left somewhere out on the road.The from Sharp Electronics Corp. led the pack of second-string projectors. Although a solid performer, the Notevision was far behind the X350.For example, at 10 feet from the lens, a typical-size screen had only 380 lumens of brightness. That's fine for a completely dark room, but you risk losing detail in a dimly lit room.Image quality, however, was top of the line. And the edges of the screen appeared to the naked eye just as bright as the middle. Subsequent testing recorded a 20-lumen drop-off'so small that it's nearly insignificant.The from CTX International Inc. was the only projector that broke the mold of the little rectangular box. The EzPro 710 sits upright.The advantage of upright design is less material around the bulb, so the unit can vent heat out both left and right sides. That means a cooler, longer-lasting bulb.The adjustable control for the lens sits above the vent, but CTX replaced the metal dial on LCD models with a plastic one on the EzPro. A metal dial would get too hot; the plastic one remained consistently cool.One disadvantage to the upright configuration is that a considerable amount of weight and bulk is added to the chassis. The projector weighs 5 pounds, which is light compared with LCD projectors but nearly 2 pounds heftier than the next heavier unit in the review.Image quality, as with any DLP, was outstanding. But the EzPro 710's brightness was unimpressive, measuring 367 lumens at 10 feet. There was no noticeable drop in brightness, and measurements showed only a 7-lumen difference from center to edge.The from Mitsubishi Digital Electronics America Inc. is a nice unit but outclassed by cheaper projectors with greater power. The 3.1-pound model sacrifices brightness for portability. It produced wonderful images, but only in dark rooms. The lab recorded the weakest overall brightness levels for this projector, which could rally only 350 lumens at 10 feet.The LVP-X30U was sturdy; the lab used it in a testing room for weeks with no problems. But the room had to be completely dark without ambient light. In even a marginally lit room, we couldn't see the projector's amazing DLP technology because the colors had washed out.The advent of DLP projectors has given the market a jump-start. Projectors weighing less than 5 pounds'some as light as 3 pounds'are a boon to traveling workers. And DLP projector images are beautiful to behold.The Achilles' heel at the moment is raw power. There's no easy way to pump up brightness without harming delicate image controls.But if you can control the light sources in the presentation environment, a DLP projector will shave a few pounds off your travel load. indicates a desirable attribute or best performance; indicates an undesirable attribute or worst performance.