3D on the Desktop

Katherine Stevenson

In the world of desktop monitors, 3D displays are arguably the “next big thing.” It stands to reason, given the plummeting cost of LCDs and the subsequent glut of these panels on the market. The dropping costs help spur more-advanced LCD tech, and more-advanced LCD tech might be just what manufacturers need to stand out in a jam-packed market. Three-dimensional displays lure PC enthusiasts—particularly gamers—with the promise of a more immersive experience.

That is, until a gamer actually uses one. At least that’s been the case in our limited experience. The screens that require a user to wear special polarizing glasses aren’t even worth mentioning, but their successors—the LCDs that have a polarizing layer built into the display (to perform the same function as the glasses)—haven’t been much more practical. Take for example, Sharp’s 3D displays , which garnered a lot of attention when they were released in 2004. Like the screens that required glasses, and even the goggle-style wearable displays , a 3D image is created out of two near-identical images shown from slightly different viewpoints—to mimic the way your eyes work. In Sharp’s displays, a “parallax barrier” polarizes light so that each eye sees only the part of the stereoscopic image it’s meant to see. Your mind does the rest of the work, stitching together the two views into one three-dimensional rendering.

For this method to be effective, the viewer must be properly oriented in relation to the screen. Stray from that sweet spot and you lose the suspension of disbelief, and possibly your lunch—this image trickery is the reason 3D displays have a reputation for making users feel dizzy and even nauseous after just a short period of time. It’s also worth noting that when a screen must produce two distinct images, it lowers the overall resolution by half. Given these drawbacks, can we really expect 3D displays take off in large numbers?

Recently, I had an opportunity to check out an alternative 3D technology, developed by PureDepth , that seems like it might have legs. At least it’s not plagued by the issues mentioned above. PureDepth’s Multi-Layer Display (MLD) technology actually uses two distinct screens to simulate depth.

The two screens are encased in the same package—one atop the other, with a buffering layer in between. When an image is separated between the two screens, with foreground info on one and the background on the other, it appears to be 3D—from any angle, and without any loss to resolution.

The mechanics of Multi-Layer Display (MLD) technology .

Each screen connects to the PC via its own DVI connector, and Windows recognizes them as separate entities, as with any dual-monitor setup. A user can choose one of four modes to run the display: The screens can receive content from two separate sources, so, say, an image can have an informational overlay.

It can be used in single-screen mode, which would be preferable for standard desktop use. It can be used in 3D Auto mode, whereby an MLD driver would automatically separate content between the two screens, as with existing games. And 3D Compliant mode will display content that has been explicitly developed for use on the two screens—for optimum 3D simulation.

While this image can't adequately convey the first-hand experience of an MLD monitor, it helps you visualize how the two screens can be leveraged to simulate depth.

PureDepth is currently in negotiations to license its technology to major LCD manufacturers for use in gaming monitors, so we may see shipping product as soon as next year. In the meantime, I’m looking forward to getting a review prototype in our Lab for some hands-on testing.

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