Video: Putting a handheld device鈥檚 touchscreen on the back 鈥� not the front 鈥� could make them much easier to use (Video: Mitsubishi Electric Research Laboratories)
A touch-sensitive gadget with the sensing panel on its back, instead of the screen, is being developed by US researchers. Using your fingers behind the device allows a firmer grip and more accurate performance without obscuring your view of the screen, they say.
Multi-touch interface technology hit the commercial market this year, with the US release of Apple鈥檚 iPhone in June. But the iPhone鈥檚 touchscreen is not perfect, says of Mitsubishi Electric Research Labs (MERL) and the University of Toronto, Canada.
鈥淎s soon as you put your hands on the display you [obstruct] the screen,鈥� he says, something he calls the 鈥渙cclusion problem鈥�. Users of iPhones have other problems too, he adds. 鈥淢ulti-touch devices detect the entirety of the touch area,鈥� Wigdor continues. 鈥淭hat鈥檚 what we call the 鈥榝at finger鈥� problem.鈥�
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The two problems combined make it difficult to select precise targets, such as the keys on a virtual keyboard.
Fat fingers
Wigdor at MERL, and at Microsoft Research and their co-authors have a novel solution to these problems. Their prototype, LucidTouch, is a device that can be held comfortably in two hands, similar to the PlayStation Portable (see video, right).
It has a large touch-sensitive LCD screen, similar to that used in the iPhone. But it can also be controlled using a touch-sensitive interface on its rear surface, a solution to the occlusion problem.
When using the rear touch interface, the user鈥檚 fingers appear as shadows on the screen, giving the illusion they are holding a transparent device. LucidTouch highlights the active point of each finger with a small green dot, removing the fat finger problem. 鈥淲e鈥檙e trying to address the problem of occlusion by giving the user an idea of their input, while still being able to see through the hands to the screen,鈥� Wigdor says.
鈥淚 like the idea,鈥濃�� says Alistair Edwards at the University of York. 鈥淚t clearly addresses the occlusion problem, and using dots 鈥榓ttached鈥� to the fingers also attempts to address the fat-finger problem.鈥�
Slimming problems
But Edwards would like to see the technology pushed further. 鈥淚f I had one of these, I would be wanting to try out all sorts of ideas. What about 鈥榯hrowing鈥� objects [from one hand to the other]?,鈥� he says. 鈥淎lso, why not build in some orientation detectors, so that you can also manipulate objects by tilting the device?鈥�
鈥淲e鈥檙e just researchers,鈥� says Wigdor, explaining that his team just explore new ideas that are taken on by more commercially minded groups if they are interested. 鈥淏ut from a research point of view, we are looking at improving the user interaction.鈥�
A more pressing concern is how to slim down the LucidTouch design. The rear touch interface is currently provided using an unwieldy 鈥渂oom camera鈥� strapped to the back of the device that records finger movements.
Using a souped up version of a touch panel like the iPhone鈥檚 screen is one option. But there are other alternatives. 鈥淲e could use LEDs to record the movement, because they are both emitters and sensors,鈥� says Wigdor.
鈥淵ou would have the back of the device covered with them, half turned on and half turned off. Then the light from the LEDs that are on would be reflected from the hands and back onto the LEDs that are off.鈥� That would generate a charge that could show where the hands are, Wigdor says.
