Microsoft SecondLight Makes 'Surface' Magic
Take Microsoft Surface, sprinkle it with fairy dust, and you might have something close to Microsoft's SecondLight, a new technology in the works from Microsoft Research. Did you think Surface was cool? This is Surface, squared.
The experimental SecondLight technology adds a second dimension to Surface, allowing users to slide "magic lenses" over the display to provide a second surface that can be linked to the first. In one example, Microsoft researchers projected a picture of a car on the Surface display. But add separate, portable pieces of glass that can be moved across the display, and presto! the glasses are transformed into "X-ray specs" allowing a wireframe model to be viewed.
It's all sleight of hand, of course. But if history is any guide, SecondLight will eventually be part of future Surface displays.
The research is being presented as part of the User Interface Software and Technology conference this week. In addition to SecondLight, Microsoft's was presented, as well as "tap" and "caress" movements for cell phones, plus a a new way to interact with images.
How does SecondLight work? As a trick of the light.
Surface projects images onto a display, and Microsoft hasn't abandoned that with SecondLight; the display still detects and interacts with objects or fingers that touch it.
The key technology, however, is a switchable diffuser, the same technology that is sometimes used in office buildings or in nightclubs as partitions. Specifically, SecondLight uses polymer stabilized cholesteric textured liquid crystal (PSCT-LC), tied to an optical switch.
When diffuse, the glass is frosted. But when a voltage is applied via the switch, the liquid crystal molecules align and allow light to pass through, becoming clear.
Normally, the Surface display itself serves as a projection screen. But SecondLight's optical switch rapidly flips the display between translucent and clear at 60 hertz (the same refresh rate as a PC's monitor), fooling the eye into creating both the traditional Surface display as well as secondary images projected onto the "magic lenses," which themselves serve as projection screens. Two off-the-shelf Hitachi CPX1 60-Hz projectors in combination with fast optical shutters create the two interleaved 60-Hz images, one on the Surface display, and one on the secondary display objects.
The cycle can also favor a display that's left diffuse for longer periods of time, to improve the brightness of the Surface display, while dimming the secondary "magic lenses".
To allow users to interact with virtual objects upon the screen, SecondLight includes an array of infrared LEDs, which provide the "illumination" necessary to light fingers and other objects with "invisible" IR light that can be detected by special cameras. The Surface/SecondLight technology then interprets those movements into gestures. An additional undersurface camera was also added, turned on during the intervals when the glass is clear to pick up finger gestures that interact with the top layer. Fortunately for the researchers, objects tend to blur when raised up away from the camera, helping the sensors determine when a user is actually "touching" the Surface or objects placed upon it.
Microsoft even demonstrated the capability to correct for distortion as the magic lenses were moved and tilted away from the display.
And using that additional camera to detect objects "above" the Surface has additional benefits, too, according to the Microsoft researchers. "Further, we have noticed occasions that the camera looking through the surface in clear states can image a user‟s face, as highlighted in Figure 13," the paper noted. "This data could be combined with face detection algorithms to determine the number of users around the display and potentially if they are looking at the surface."
The researchers went still farther, even demonstrating that blocks cut from translucent plastic could bend the light so that they themselves transmitted information.
"In the simplest scheme, a transparent object with a diffuse top surface allows a projected image to be displayed on top of the object," the paper's authors wrote. "In a more complex embodiment, shown in Figure 6, circular prisms built into the object allow the projected image to be totally internally reflected onto the sides of the object. In this example, we see a rolling tickertape that provides feedback to the user using the vertical sides of the object. Again this is only a proof-of-concept, but it demonstrates how a cheap (e.g. injection molded) tangible object can be illuminated and render graphics on its surfaces. Imagine game pieces, such as chess pieces, designed in this way allowing animated graphics to be rendered onto their faces and bodies."
Microsoft's researchers even noted that a future version of SecondLight could use visible light to actually capture a face or document, and image it like a scanner. Recognizing faces could also help determine which way to orient a display, how many users were seated around the display, and even to "shine black" or cut the light of the translucent display to avoid blinding users. Motorized focus systems or even laser projectors might improve the technology even more, they concluded.
The paper, "Going Beyond the Display: A Surface Technology with an Electronically Switchable Diffuser" is being presented by Shahram Izadi, Steve Hodges, Stuart Taylor, Dan Rosenfeld, Nicolas Villar, Alex Butler and Jonathan Westhues, all of Microsoft Research. The paper was supplied to reporters by Microsoft.