An OLED screen has been developed on the surface of which raised buttons can appear and disappear

Researchers Craig Shultz and Chris Harrison of the Future Interfaces Group (FIG) at Carnegie Mellon University have developed a display that can create protrusions on its surface on command. This concept has existed before, but this version is thinner, lighter and more versatile.

Image source: Future Interfaces Group

A special layer of flat panel haptics can be placed under an OLED panel to create raised screens. Embedded Electroosmotic Pumps (EEOPs) are arrays of liquid pumps on a thin power layer embedded in a touchscreen device such as a smartphone or car display.

When an on-screen element requires a pop-up button, liquid fills part of the EEOP layer and the top OLED panel flexes to adopt that shape. The result is a “physical button” that protrudes from a flat surface up to 1.5mm, enough to make a difference. When the button is removed from the screen, the panel returns to the flat state. The research team says each area takes about a second to fill and they feel firm.

The technology is reminiscent of the Tactus’ flip-up touch keyboard, which came in the form of a chunky iPad mini case. The FIG prototype can take on more dynamic shapes and sizes, and the research team say the thickness of their solution sets it apart from others.

The researchers note that “The main advantage of this approach is that the entire mechanical system is in a compact and thin form factor. Our device stacks are less than 5mm thick but have a 5mm offset. In addition, they are autonomous, powered only by a pair of electrical cables and control electronics. They are also lightweight (less than 40 grams) and can withstand enough force to handle user interaction.“.

Floating buttons in their current form have a limited range of shapes and sizes, reducing their versatility. But if researchers can eventually apply the same principle to a layer with more/fewer popup buttons (higher pixel resolution), it could open up new possibilities for user interaction, including typing, games, auto controls, and even such special features as a braille screen.