Portland, Ore. -- If you've seen any of the new IMAX 3-D movies, you surely noticed the jump in quality over the 3-D experience of yesteryear. Now a 3-D display maker has tapped an encoding technology that reproduces that cinematic experience on a 19-inch LCD for scientific visualization and medical diagnostics.
"Our new display brings 3-D realism to professional users, but we think that eventually 3-D displays will start being used by high-end gamers and home viewers," said Boyd MacNaughton, founder of MacNaughton Inc.
MacNaughton's company is already known in 3-D for its NuVision LCD shutter glasses for PC use. Its new LCD display technology, code-named Gemini but ex- pected to debut as Renaissance when announced this fall, uses two LCDs instead of alternating images from a single projector, thereby enabling viewers to watch with passive polarized glasses. The first model will be a 19-inch LCD panel offering 1,280 x 1,024-pixel resolution; a 20-inch, 1,600 x 1,200 unit is due out next year.
The two LCDs are precision-aligned, then laminated on top of each other. The left and right images are separately displayed to the viewer's eyes, because the viewer wears passive glasses whose lenses are orthogonally polarized at 90° to each other.
Light from the back LCD must also pass through the front one. Thus the MacNaughton team couldn't just polarize the left image on the bottom and then use an orthogonal polarization for the right image on the top, since doing so would cause the top polarizer to cancel out the light from the bottom image.
Instead, MacNaughton licensed a mathematical recomposition technology that encodes the average intensity of both images on the bottom LCD and then uses the top LCD to rotate the polarization angle enough to reapportion the average intensity properly between the right and left eyes. A double layer atop the two LCDs--a quarter-wave retarder and a diffuser--enable angle-immune viewing with elliptically polarized glasses.
The display is illuminated with a high-intensity projection bulb instead of a traditional, fluorescent backlight. A 20-inch light path redirects a point source bulb into collimated light (in which all the photons travel in parallel) by bending it with mirrors and focusing it with a lens, all of which fit inside the 10-inch deep display. The light needs to be intense because it must pass through not only the LCDs but also through the polarizers, the quarter-wave retarder, the diffuser and a Fresnel lens that straightens collimated light.
"We worked very hard to fold up the light path small enough to keep our display's footprint about the same size as other LCDs . . . about 10 inches deep," said MacNaughton program manager Tom Woody.
A hardware accelerator inside the display translates a standard video stream (VGA or DVI) with alternating left and right images into the intensity and angle signals required to drive the two internal LCDs in a manner transparent to the user.
MacNaughton claims its display provides an image that is just as bright and high-contrast as in 3-D digital cinema, but with tenfold isolation between right and left images, and with a wide and undistorted viewing angle free from color shifts.
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