Tanvas (Chicago, IL), a startup out of the Neuroscience and Robotics Laboratory at Northwestern’s McCormick School of Engineering (Evanston, IL), is developing a novel means to add haptic capability to touchscreen displays. The technology is called TanvasTouch.
Haptics is unique among the senses in that it is “two way.” The addition of TanvasTouch to a touchscreen display can add such two way haptic capability by providing tactile feedback to the existing touch input.
Tanvas technology is based on so-called ‘surface haptics’. As illustrated in the figure below, the configuration used to implement surface haptic capability consists of a SiO2 and an ITO transparent conducting layer on the top surface of a glass screen. The application of a voltage between the conductive surface and the skin of a user’s fingertip generates an electrostatic attraction between the two. This attraction increases the magnitude of the frictional force experienced by the finger as it slides across the surface of the glass screen.
The haptic effect produced by TanvasTouch was described in one on-line review as a “palpable, dynamic sense of touch.” The review goes on to state that, compared to TanvasTouch, “vibration-based feedback like Apple’s 3D Touch does not come close to replicating.”
Further description of the technology that underlies TanvasTouch can be found on the Northwestern web site. Included are descriptions of the several types of hardware used to produce vibrations and the means used to investigate the perception of these vibrations by a user.
Three types of hardware were used in the experiments.
A custom tribometrer was used to control the velocity and the normal force of a fingertip in contact with the test surface. In addition, elastographic techniques were used to measure the transmission and the propagation of acoustic energy into the tissue of the fingertip. Both surface wave and body wave measurements provided information on the nature of the tissue and its ability to capture the energy produced by the surface.
TanvasTouch technology is claimed to have an ultra-low sensing latency. As a consequence, the system is able to produce the haptic vibrational waveforms required to provide real-time control of the forces acting between the user’s fingertip and the touch surface.
Tanvas demonstrated a prototype at the recent Consumer Electronics Show in Las Vegas. The prototype consisted of a TanvasTouch device mounted on top of a Google Nexus 9 tablet. Regarding this last point, the company makes particular note of the fact that TanvasTouch can be adapted to the touchscreen of almost any smartphone or tablet.
Several different types of haptic capability were demonstrated by the prototype according to reports. One of these related to an automotive display. The idea behind this demonstration was to show the potential to mitigate the need for the driver to look at the display. This is accomplished by TanvasTouch providing the driver with tactile feedback, the sensation of a notched controller.
Demonstrations also included a draggable zipper. When the user moved the zipper up and down, their finger experienced a “tingling” sensation.
Another demonstration showed textures that were described as “grainy,” “choppy,” “fine,” and “wavy.” Finally, in yet another demonstration, a virtual guitar produced a tangible twang each time a finger strummed across the strings.
A video can be found at the end of this article that discusses and illustrates the performance of TanvasTouch.
Although showing great potential, the current generation of Tanvas technology certainly has room for improvement. One particular problem is that finger movement is required for TanvasTouch to provide tactile feedback. Put another way, TanvasTouch does not work for display elements that are stationary, such as buttons. Company researchers are currently investigating means to address this issue. On the business side, the Tanvas has yet to find a hardware partner willing to commercialize TanvasTouch equipped devices. -Arthur Berman
Tanvas, Traci Hailpern, 773-295-6220 x903, [email protected]
