Electronic Design

3D Projection Holograms: Reach Out And Try To Touch

While we were preparing this month's cover story on LCDs, I got an e-mail from a company working on the true bleeding edge of display technology--on "touchless holographic interfaces." Surely that's an intriguing technological innovation in and of itself. But the e-mail also got me wondering about the status of holograms as a display solution.

LCDs for flat screens are terrific technology, as are today's projection TVs, plasma screens, and our ever-growing array of high-resolution display options. Then again, isn't 3D, rather than "flat screen," the ultimate display goal? Futurists everywhere want to know: When are we going to have 3D video images projected with no screen--and no funny glasses--with images so real you think you can reach out and touch them? And while we're at it, when we reach out to touch the image, we should be able to "feel" and even interact with it, too.

Conventional holograms offer cool 3D, but they have essentially been limited to recording still images. And making a hologram has been a laborious one-off process, using laser beams that are split to "scan" the shape of an object and then recombined on film. While there are some new variations (like full-color, unlimited-size holograms from Zebra Imaging, found at www.zebraimaging.com), volumetric, moving holographic projections have remained in the realm of science fiction.

The concept is most notably portrayed in Star Trek's Holodeck aboard the Starship Enterprise. There, crew members not only view 3D projections, they also can touch and interact with the images. So how close to reality is this Trekkie vision? It's coming to fruition in pieces.

News of the touchless holographic interface comes from HoloTouch. In conjunction with Atlantex Corp., HoloTouch has produced the BeamOne, a device that allows operators to enter data by passing a finger through holographic images of "keys" projected into the air. The device also can project holographic keyboards and other "touchable" icons. For details, point your browser to www.holodemo.com.

The HoloTouch technology targets applications where mechanical switches aren't rugged enough, where sterilization or hygiene is an issue (such as medical or surgical applications), or where the user interface needs to be larger than the device itself. BeamOne combines a light box to project holograms with infrared sensors to detect and interpret finger movement. The device mimics a USB keyboard. Demonstration and configuration software is included, as well as a design guide for developing HoloTouch applications or integrating the technology into other design projects.

But what about projecting moving images in 3D? While prototypes of holographic movies were tried as early as the 1970s, leading university researchers are still working on creating projectable holograms.

This year, researchers at Japan's Chiba University announced that they've developed a hologram generator on a single circuit board that generates holograms on an LCD panel.

MIT's Spatial Imaging Group has been working for the last decade on creating moveable, interactive holograms in real time. The Holovideo project has prototype displays in operation. It's also working on a "haptic" holovideo project that enables viewers to "feel" and interactively modify simple holographic images using a force-feedback device.

The Light Biology Applications Laboratory at the University of Texas Southwestern recently used Texas Instruments' Digital Light Processing (DLP) digital micromirror devices to develop a real-time, digitally driven 3D holographic display. The lab has completed proof-of-concept demonstrations using computer-generated holograms.

While we're waiting for holographic projection to emerge from the lab ready for prime time, Laser Magic Productions has developed a family of 3D projection technologies that provide the illusion of screenless 3D projection. The TransScreen Transparent Video Projection Screen is built from a microscopic pattern of particles that makes the screen invisible to viewers. Check out www.laser-magic.com for the full story.

The screen can be combined with Laser Magic's LaserValve Video Projector (LVP), which projects video images using laser light instead of light from Xenon Arc lamps. The projector was developed jointly by Laser Magic and JVC. Laser Magic suggests the lightweight screens could be moved remotely around a performance area, as the use of laser technology in the LVP gives the projector nearly infinite depth of focus without adjustment.

Hey, that gives me some great ideas for Halloween!

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