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Electronics

Bright Ideas

Electronics June 2001
By Tim Clark


Bright Ideas
In the world of sunlight-viewable LCDs, wits deliver the nits.
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• Part 1: Bright Ideas
• Part 2: Bright Ideas continued


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Ninety percent of the time the only advantage I get from my laptop computer's compact size is extra space on my desk for added clutter. But not long ago on a motoryacht off the Florida coast, the combination of fine weather and a looming deadline urged me to exploit its portability. Seated comfortably on the flying bridge under a cloudless sky, I flipped open the screen and waited as it chirped to life.

And I waited. And waited.

Minutes went by, and still it didn't boot up. Or so I thought. In fact, the unit was ready and willing as usual (it's actually a fine computer by a reputable company), but the sun was so bright that the screen looked utterly black. The only way I would have been able to get any work done up there was if I had cloaked my head, shoulders, and computer in a black velvet hood, like a 19th century photographer.

Defeated, I headed below with a new respect for the engineers in the marine electronics industry who are developing sunlight-viewable LCDs. These new screens are so bright that at recent boat shows I could tell them from non-sunlight-viewable displays even indoors. That they're hard to miss may also be due to the fact that a number of the new ultra-bright screens are large, conspicuous, nondedicated displays. Including OceanPC's Sunlite, Digital View's SeaView, and Laser Plot's BriteChart, among others, these series of monitors are designed to display PC-based and "black box" navigational systems such as radar, chartplotter, and depthfinder, plus in some cases, video images.

Their versatility alone bespeaks technological accomplishment. But I wanted to know about the challenges posed by sunshine. So I called Kerry Crozier, an applications engineer at Computer Dynamics, the Greenville, South Carolina, firm that developed the 15-inch BriteChart with Auburn, Massachusetts-based Laser Plot. I learned that much of Computer Dynamics' experience came through developing ultra-bright flat-panel displays for oil companies to use in the field. On those LCDs it managed to coax out 1,000 nits of light (an average laptop LCD puts out about 400 nits). In marine applications these wits are getting even more nits.

In describing the hurdles faced by those developing bright displays, Crozier kindly kept it in terms a regular nitwit like me could understand. Liquid crystals don't generate light, he says, they filter it. So you have to have a light source behind all the layers of polarizers, diffusers, guides, liquid crystals, transistors, films, and coatings that make up an LCD. What Laser Plot calls an "ultra-high-bright" display can use eight, 10, 12, or even 16 backlights, as opposed to the one or two lighting standard displays. The kind of lights used--Cold Cathode Fluorescent Tubes (CCFTs)--are direct descendants of the long white tubes that have illuminated most offices for decades, but they are unusually bright and small, and their chromaticity (i.e. color purity) is precisely defined in order to meet the specific color output of the screen.

Next page > Bright Ideas continued > Page 1, 2

This article originally appeared in the May 2003 issue of Power & Motoryacht magazine.

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