Touch inputs to displays on electronic devices are now ubiquitous. Less available but well recognized as at least desirable, is tactile feedback. In recent weeks, two interesting tactile technologies were demonstrated to the public.

Art Berman
Insight Media Consultant

The first new device was developed by Sony Computer Science Laboratories, Inc. (Tokyo, Japan) or Sony CSL. The interesting aspect of the Sony technology is that it is capable of detecting contact pressure. As an example of a function that this technology could enable, imagine that, as the force of the touch increases, so does the rate at which an icon changes. The technology is based on the use of a piezoelectric Force-Sensing Resistor (FSR). Such a device changes resistance in response to applied pressure.

A few technical details were available. Apparently, a 16-layer piezoelectric device was used and this dropped the drive voltage down to ±9V. With this the case, a staffer was reported to have stated: "With step-up, we should be able to drive it off the rechargeable batteries in a mobile phone." The actuator board was just 30mm × 3mm × 0.8mm.

In fact, the prototype was based on a Sony Ericsson cell phone. Nikkei Electronics Asia reported that "the prototype has six FSRs and two piezoelectric actuators mounted under the display bezel. The FSRs are positioned at top, center and bottom, on both left and right sides. The two actuators are positioned at center left and center right."Sony CSL has yet to announce plans for commercializing the technology. Don’t be surprised if an early application of the technology is in a Sony Ericsson Mobile Communications cell phone.

The second new tactile technology was shown at the 13th Embedded Systems Expo & Conference. The prototype was developed by a joint venture between Senseg Oy (Helsinki, Finland) and Toshiba Information Systems Corp. (Kawasaki-city, Japan). The device imparts a variety of tactile sensations based on a technology that varies the intensity and frequency of weak electric fields. The device consists in part of a film mounted between the touch panel and the display cover. The electric field is controlled by a separate module.

The film is only a few microns thick and has a transparency of over 90%. Apparently there are no fundamental limits to the size of the film. The new technique is reported to be highly break-resistant and noiseless. In addition, the film can be applied in places where conventional technologies are difficult to implement. Examples of these might include the sides or the back of a device or on a curved surface. To demonstrate the range of possible sensations that can be produced by the system, the venture produced prototypes based on an iPod Touch and on a touchpad.

Users were invited to slid their fingertip across a button on the iPod touch. Doing so produced a slight "catch," as if the finger had traversed an actual button. The touchpad display had regions marked "brush," "rough," and "bumpy." Once again, by sliding a fingertip across these areas, users could experience each of the textures.

The company believes that the film can be produced very inexpensively, selling for a price on the order of ten to twenty yen apiece. The company hopes to see the technology implemented in notebooks, tablet and other devices with touch capability during the first half of 2011. Cell phones are anticipated by the second half of 2011.

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