How it works: 3D touchscreens
Heavily inspired by graffiti spray art, a team of researchers at the University of Bristol have developed a special spray coat that allows the creation of interactive displays on 3D objects. Eclipsing the appeal of traditional square and rectangular casings, the new technology, called ProtoSpray, makes it possible to ‘spray’ touch-sensitive screens onto objects as complex and irregular as a Möbius strip.
Introducing such flexibility would mean that virtually any surface – from inclined planes to the exterior of a dome – can be used to devise a user interface. The basis for this breakthrough comes from an interesting fusion of sprayable electronics and 3D printing.
“3D printers have enabled personal fabrication of objects, but our work takes this even further to where we print not only plastic but also other materials essential for creating displays,” recounts Ollie Hanton, PhD student and lead author of the research. “Our vision is to make screen/display a fundamental expressive medium in the same way people currently use ink, paint, or clay.”
A unique combination of art and science, the ProtoSpray tech also opens up new market opportunities for makers, hobbyists and researchers, all of whom appreciate creative freedom significantly. According to the researchers, the displays are easy to manufacture, and the process starts by assembling 3D-printing equipment and spraying materials.
There are two stages to crafting free-form displays using the ProtoSpray technique, which Hanton refers to as a “straight-forward fabrications process”. Firstly, an object is printed on a multi-material 3D printer to create the design of the interactive object. Secondly, users can spray on active materials to create a display element that lights up. This happens when an electrical charge is applied to the base electrode.
“Using 3D printing of plastics and spraying of materials that light up when electricity is applied, we can support makers to produce objects of all shapes that can display information and detect touch,” adds Hanton. “It is possible to spray all electroluminescent colours, which are roughly the same as the neon colours.”
The ProtoSpray technique is also an endeavour one can replicate at home, as no prior experience with conductive plastic or electroluminescent paint is required to achieve the results. Starting with handheld devices, wearables and signage, the potential applications of the process are many, and could one day lead to 3D interactive displays on smart watches or smartphones. In fact, the team have already created a series of objects using the ProtoSpray process to demonstrate its ability in producing irregularly shaped interactive displays. Among them are a traditional seven-segment display, which the team embedded into a 3D-printed block, and a dome, which both show their potential for wearables and displays that move.
“The display indeed has reduced visibility in bright lights, but the change of states (between on and off) can still be made out in most lighting conditions,” confirms Hanton.
Dr Ann Roudo, assistant professor at the University of Bristol, who vetted the research, says the next step would be to create an all-in-one machine that can print 3D shapes and automatically spray screens onto them.
