The gist of it: the body of research into integrated haptics in displays is not necessarily broad, but it certainly holds interest for a couple of reasons: typing on a touch screen, like you do on a smartphone, is pretty annoying at times, and requires the thumb profile of a tween; enhancing the capabilities of touch screens and adding texture, if you will, is a selling point whether for smartphones, or as a palpable way of manipulating 3D images, and a host of other applications where people just want a button that feels like a button.
Flat Panel Haptics: Embedded Electroosmotic Pumps for Scalable Shape Displays
Researchers have developed a new type of miniaturizable shape-changing display using embedded electroosmotic pumps (EEOPs) to improve the haptic feedback of flat touch interfaces. The EEOPs are only 1.5mm in thickness, allowing for complete stackups under 5mm, and are controlled and powered directly by applied voltage. Despite their small size, the pumps are capable of moving their entire volume’s worth of fluid in 1 second, generating pressures of +/-50kPa, which is sufficient to create dynamic, millimeter-scale tactile features on a surface that can withstand typical interaction forces.
The researchers suggest that these technical capabilities could enable the creation of a pop-up keyboard on a flat smartphone, improving the user experience. The mechanical and psychophysical performance of the displays are experimentally quantified, and the researchers provide a set of example interfaces. Overall, this new type of shape-changing display using EEOPs has the potential to significantly enhance the haptic feedback of flat touch interfaces, making them more intuitive and user-friendly.
The traditional flat nature of smartphone displays makes typing slower and more prone to errors, compared to physical keyboards. To address this issue, the researchers built a prototype haptic display using a flexible AMOLED screen, which can be inflated and deflated from below the display to create tactile feedback.
The prototype includes pre-defined shapes for a variety of interface elements, such as application icons, a keyboard, snooze button, camera buttons, volume control, notification, and settings panel widgets. These shapes can be activated and co-located with visuals, as demonstrated in the video figure provided. The researchers measured the peak-to-peak deformations of these elements, with the app icon deforming by 0.46mm, a single keyboard letter key by 0.19mm, and the snooze button by 0.8mm. The display is capable of changing its state in a fraction of a second, and users can easily perceive and locate haptic feedback.
The researchers note that the increased compliance of the screen may cause slight deformation during the “OFF” state, which could be felt haptically by the user. This could be mitigated in future devices by removing the empty volume behind the button. Overall, the prototype demonstrates the potential of haptic displays to improve the user experience on smartphones, particularly in text entry.
Reference
Shultz, C., & Harrison, C. (2023). Flat panel haptics: Embedded electroosmotic pumps for scalable shape displays (p. 16). https://doi.org/10.1145/3544548.3581547
