Tactile Cell Phone Interface Fluid

Problem

A high-profile start-up company in California contacted Phantom for help. They had developed a breakthrough tactile cell phone keyboard interface where keys jumped up out of the screen on demand, so that the user could have an interface providing tactile feedback. The patented technology worked by pumping fluid into pouches in an elastomeric (rubber-like) layer. However, it proved extremely challenging to identify a fluid that could meet the many requirements for viscosity, volatility, safety, cost and so on. Most crucially, the refractive index of the fluid had to be an exact match for the elastomer, so that the buttons remained invisible when the screen was in the flat state. They had a terrifically talented team but no chemist, so they called Phantom for help.

The image on the right shows a working example of the tactile cell phone keyboard. In the picture, the buttons are sticking up to provide a satisfying feedback when typing. However, when browsing, the buttons can be made to retract back into the screen where they remain invisible due to the optical properties of the fluid matching those of the screen material. The Wired video shows the screen in action.

Action

The customer provided a list of requirements and I used my knowledge of chemistry to determine the only class of liquids likely to meet the requirements. From there, the next step was to search huge chemical databases manually for an exact match. It was manual, painstaking work but the only way to home in on the best fluid.

Solution

Three candidate fluids were suggested and testing revealed them to perform superbly – well beyond anything the client had seen before. They were ecstatic and we went on to do more work together leading to new advances and patents such as WO 2015/031629. That tactile cell phone keyboard patent and other patents, can be found on the Publications & Presentations page.