Steve Hodges from Microsoft Research shows Long Zheng a standard laptop that's been retrofitted with an imaging-based multi-touch sensor. The touch sensor is constructed out of a matrix of IR sensors and light sources that are placed directly behind the LCD display and project or sense through the display. The idea is that when your hand or a sufficiently IR reflective object is placed in front of the display it will reflect enough of the IR light back to the sensors which can then be used to visualize where the objects are.
The prototype sensor is shown being used on a standard laptop. What about Tablet PCs? Well, the catch here is that most Tablet PCs use active digitizers which often consist of an antenna layer also placed behind the display. This might not be a showstopper if the antenna layer can be made IR transmissive or the display/sensor technologies could be merged in some way. I seem to recall someone at Apple for instance talking about embedding the imaging sensors within the display itself. Eventually this is probably the direction these technologies will go. For now though, using layered techniques are probably more practical.
Why not swap out the active digitizer in exchange for the imaging-based multi-touch sensor? Precision. At least for now, an active digitizer is going to return more more precise pointing information that's going to still be invaluable for handwriting recognition and other precise user interactions. The multi-touch will be less precise and better suited for providing and tracking broad movements.
If Tablet PCs present some issues, what about UMPCs? Here there might be better news. Most UMPCs incorporate a resistive digitizer layer that's placed on top of the display. I'm guessing that this won't cause too much of a distortion to the reflected light. The catch is that most UMPCs are constructed so densely that there's not much room to place a sensor board like shown in the video behind the display. Then there's also the issue of battery life. I'm not sure what demands the extra sensing technology will place on the battery system. I'm also not sure if those annoying scratches and smudges that build up over time on the resistive layer would be something that couldn't be calibrated around. Anyway, of all the devices I'd really like to see a UMPC retrofitted with a multi-touch sensor. Whether this type of multi-touch sensor is the one that should be tried I don't know. There could be other, better choices.
Still, very cool to see Microsoft check out the multi-touch direction.


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