Unflattening Touch Screen Buttons

24 11 2009

Ever wish the flat touch screen buttons on your phone felt more like physical buttons?

Chris Harrison and Prof. Scott Hudson at Carnegie Mellon have developed a simple technology that turns touch screen buttons into physical buttons by using pneumatics.

The technology consists of a flexible surface area with a hard backing that acts as a mask for the button shapes.  An air chamber behind the backing can be pressurized or depressurized using pneumatic technology, in this case fan-based pumps.

When positive pressure is applied, the buttons pop out.  When the pressure is neutral, the screen is flat.  When negative pressure is applied, the buttons pop inwards.

Images are displayed on the surface using a projector behind the device, turning the surface into a display screen.  Button presses are detected using an infra-red camera pointed at the front of the screen that detects reflections of light from a fingernail.  When your fingernail gets close to the screen, a button press is recorded.  This technology cannot easily distinguish between a finger touching the screen and one merely close to the screen, so a press is not recorded until the finger presses down on the surface and causes a detectable change in pressure in the air chamber.

It is also possible to have the positive and negative forms take different shapes.  Additional parts are added to the mask, except these parts have no adhesive holding the latex down.  When positive pressure is applied, only the mask parts with adhesive are effective.  When negative pressure is applied, all the mask parts are effective.

See this excellent video demonstration.



Instead of pressing images that look like buttons on your phone, this technology could allow all the dynamically drawn button images on your phone to actually pop out like real buttons.  (One change that would be needed is making touch sensing based on capacitance technology, as current touch screens do, rather than a camera aimed at the screen.)

The pop-inwards feature is also pretty cool.  You could be playing a driving game on your cell phone and have the car’s dashboard pop inwards to appear like a real car’s.  Or, when you displayed the stopwatch on your phone, it could be displayed like a real concave stopwatch.



With a single air chamber, all the buttons must popped in or out at once.  However, it is straightforward to create separate air chambers, thereby allowing only certain elements of the UI to pop in or out.

An unavoidable limitation is that the mask itself is static, meaning that new shapes cannot be created dynamically.  The technology only allows controlling whether the shapes pop in, pop out, or remain flat.

Comment: When do you think pneumatic technology like this will turn the flat touch screen buttons on our phones into physical buttons?

  1. 2 years
  2. 5 years
  3. 10+ years
  4. Never

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17 responses

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26 11 2009

This is perfect for bank of america ATM’s, have you noticed its sometimes difficult to determine exactly which button you are selecting while pressing the touch screen? They need these buttons to pop out making it easier to make sure you are pressing the right button. Before BOA’s On Screen Display selection menu users at ATM’s would select the onscreen choices by pressing correspondingly aligned physical hard buttons on the sides of the screen display. And while I do not mind progress, I think there is something to be said about simplicity and about wanting certain appliances to behave in a standardized ubiquitous fashion versus having a different interface for the same function.

24 11 2009

The idea is good, but I also agree with most of the negative comments; especially the mechanical aspects (wear and tear) and the fact that you need to pre-define the buttons.

There may be a solution though, Electro-active polymers, a fine enough mesh of these could create bumps on the screen in any position, size and shape, I don’t know how advanced the research on them is but it would solve both of the above problems.

24 11 2009

Cool. I know that it’s a long shot, but this could also be used for helping seeing impaired people read braille on touch screen surfaces. Could be an interesting project.

24 11 2009

why not just use electricity? a small shock with the right tension/current would not hurt and could be interpreted as a different surface.

24 11 2009

This could be a good idea. Make the pop outs little dots. The software would use a set of dots for each button. That way, buttons could be anywhere on the screen.

This would allow smart phones to display in braille too, so that blind folks could use smart phones.

One problem I see that will probably be missed in the first few versions, the front membrane will be the weak point in the system. It would be best if it could be replaced. Flexible membranes wear out much too quickly.

Chip fabrication techniques could be used to allow for static control of each dot. There could even be a static pump (no moving parts) so no annoying fan.

24 11 2009
Bill Baxter

Honey, where’s the patch kit? I popped the screen again.

24 11 2009
Steve Schnepp

I think a piezoelectric-based surface with pixel-sized actuators will be much more convenient to implement than any air-based technology.

24 11 2009

It just won’t happen. I like the idea, but in a digital age where moving parts are being engineered out at every turn, this seems like a step backwards. I love the concept, it just doesn’t seem feasible. Part of what makes touchscreen so compelling is the ability to have dynamic buttons anywhere doing whatever you want, by limiting that to locations which can be raised (or effectively pumped up), then it is rather defeating the object. I like the guy Seans idea, trying to think laterally, but it still doesn’t address some of the major flaws with the idea.

It is clear something ought to be done to improve the physical experience associated with pressing a touchscreen button, but, frankly, this isn’t it. Don’t stop innovating till you get there guys!

24 11 2009

IMO, the lack of physical distinctions in the UI that we use is the step backwards. I find an actual physical keyboard, even if small, to be much easier to use than a completely smooth touchscreen keyboard. This stuff is a restorative step forwards to being able to use our fingertips sense of touch again.

24 11 2009

I think the reliance on touch is mostly a habit. At first typing on an iPhone was frustrating but now I don’t even think about it and can type nearly as fast as I can with a full size keyboard. The key is using it enough that you have muscle memory of where the buttons are so you can just type without looking.

Even when using a full size keyboard I don’t actually touch the keyboard except actually hitting the keys. I type oddly though – sort of a blind pecking with two fingers on each hand and my thumbs for the space bar – I still type as fast as most professional typists though.

I do think tactile feedback would be cool though.

24 11 2009

The obvious solution is to design a surface that is divided into what might be called ‘poxels’ (after ‘pixel’ and ‘voxel’) — a 2-D grid of addressible pop-out elements. The problem is that each poxel would be its own separate bump unless the surface were engineered so that two adjacent poxels, if elevated, would elevate the surface between them, which creates an issue with sealing the moving divider between the poxels. Making it reliable over long-term use will be the technical challenge in getting to an addressable pop-in/pop-out reconfigurable surface.

24 11 2009

sounds pretty good to me though 🙂

24 11 2009
Luigi Rosa

Never, at least in this form. Too fragile, since it depends on an air chamber and a pump.

Seems a little bit too steampunk to me.

24 11 2009

I think it’s a good basic idea, but if you have to define the possible buttons beforehand, it’s not very practical in the real world.
It would be great if there was a way to define the pop-out areas via software in order to change it according to the programs needs. Some kind of intelligent material 😉

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