Large Venue Projectors
Oct 12, 2009 12:00 PM, By Jay Ankeney
More options for high-brightness projectors.
The market for what once was called "large venue projectors" is rapidly changing as the technology evolves, prices come down, and large flatpanel displays are increasingly considered competitors. Even the definition of large venue projectors has evolved as their applications are being expanded.
Traditionally, the most liberal definition of a large venue projector has been the one InfoComm used for its Large Venue Display Gallery, or more specifically, a projector that can put out at least 5000 ANSI lumens onto a screen 100in. in diagonal size or greater. But today, many other features would be considered necessary for a projector that is too big for a boardroom, yet too small for an outdoor arena. So modern large venue projectors also need to be equipped with sophisticated networking capabilities, interchangeable lenses, redundant lamps and power supplies, flexible remote controls, and as many different inputs as possible.
A key factor in this classification is the ability to view the projector's output on a screen in a room filled with ambient light since few audiences outside of a digital cinema are comfortable sitting in near total darkness. In fact, in house of worship installations, contractors need to keep in mind that the whole interior may be bathed in various forms of light. Therefore, contrast ratio is very important in evaluating a choice of large venue projectors that are going to be used in rooms where some of the lights are still on, with many considering 100:1 contrast ratio to be the useable minimum.
Another new wrinkle in the large venue projectors game is the budding call for 3D capability. Not only does this imply a refresh rate of at least 120Hz, but it also requires various forms of decoding capabilities not all of which have been standardized yet. But with SMPTE looking to announce standards for 3D mastering by early next year, we can expect to see Z-space images popping out in large venues for both entertainment and scientific presentations.
Fortunately, the two major imaging sources for projectors of this size—LCD panels from 3LCD and DLP micromirror arrays from Texas Instruments—have been increasing their capabilities to make it possible to fulfill these increased output requirements.
Once limited to significantly lower light output, 3LCD projectors can now put out up to 15,000 lumens and can be stacked if even more light is needed in situations unshielded from ambient light. Since 3LCD projectors are 3-chip RGB designs, they claim more energy efficiency per-lumen output, and since the pixel area and aperture ratio within the chips have increased, former concerns over the "screen door" effect that affected some earlier LCD projectors have been overcome by a larger active area letting more light through. In addition, with the ability of manufacturers to scale the chips up to 1.8in., 3LCD projectors have gained significantly in their output capability.
DLP micromirror sets from Texas Instruments are also capable of handling higher light energy than before. DLP sets now come in sizes including .55in. for education and corporate implementations up to 5000 lumens, and a 0.7in. platform is being used for the majority of large venue projectors. As manufacturers add their own icing to the DLP cake, they are getting increasingly creative about how they direct the light reflecting off all those tiny micromirrors, so DLP large venue projectors are now sharing almost half the market.
One of the advantages DLP technology provides is that since the chip is completely sealed, it resists the speckling from unwanted dust that can plague other designs. DLP proponents also tout the technology's lack of color decay over time since the light is divided by a multi-segmented color wheel whose chrominance does not shift with use. The more expensive 3-chip DLP designs have traditionally ruled the high end, but with the advent of Texas Instruments' BrilliantColor technology, even single-chip DLP light engines can emulate the color gamut of their larger brothers (if you don't mind seeing the color wheel artifact). Of course, many projector manufacturers are adding their own secret sauce to allow single-chip DLP projectors to move into the large venue projector arena.
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