A buttonless, bendable computer

gummi_ページ用01Gummi brings numerous trail-blazing ideas together

In 2001-03, Ivan Poupyrev, Carsten Schwesig and Eijiro Mori proposed Gummi as a concept for a new-age mobile computing device. Ultra-thin and about the size of a credit card, a Gummi computer is stripped bare of buttons and switches. The device can be held in both hands, and bent into various shapes. Users can slide their fingers over the back surface to bring the images and information they want to the screen on the front. By simply using the Gummi body itself, input and output computing operations can be performed at the same time.

Photo: Junko Kimiura

The development of Gummi

gummi_ページ用02Gummi resulted in large part from active use of the latest technologies at the time, supported by thorough examinations of users’ needs and preferences. Gummi development work accelerated as a raft of new technologies — printable batteries, roll-to-roll thin-film flexible transistors, full-color high-definition organic electroluminescent (EL) displays, etc. — progressed rapidly. The developers recognized that as new materials and their manufacturing technologies matured they would be likely to substantially change the nature of computing devices, and shape the interaction of man and machine. Against this backdrop, the trio hit on Gummi, as the realization of a compact, thin, cost-effective and bendable mobile computer.

The structure of Gummi


Gummi, while stripped of buttons and other mechanical moving parts, employs flexible electronic components arranged in layers. In between the organic display on the front and the position sensor on the back are processing and storage circuits, sensors and the power source, all flexible enough to allow for a bendable and expandable device. By installing a touch sensor on the back the design became button-less and the front screen could remain large relative to the size of the device.



Computing devices built on the Gummi concept faced many challenges, particularly in the area of human-machine interaction. Is it really user-friendly to bring contents to a front display by touching the back? Could it become possible to run the device by bending it to touch the back? Most importantly, can a button-less device execute a multitude of tasks? These questions nagged at the developing team. To solve these questions, the trio explored the possibility of a bendable device that could function as a switch and an analog joystick simultaneously. Gummi technology holds that bending the device, to some degree, is equivalent to "pushing," which makes it possible to control zoom-in (and zoom-out), speed, popup and image size. If bending exceeds a certain level, the device becomes “clicked,” a step that brings an image directly to the required position. To “choose” an object, it will be placed in the center of the screen by using the touch sensor on the rear. By following this sequence, you can execute a range of operations—among them, Web browsing, picture display, map navigation, 3D game playing and texting. To execute map navigation, for example, you


① touch the back and move the target, (for example, a railway station), to the center of the screen (shown in a red frame);
② bend the device to zoom in on the location. bend further and choose the street mode; then,
③ return the device to its natural flat condition to make the display easier to read (Note: By bending the device in the opposite direction, the operation will proceed in reverse. 

Evaluation of Gummi


An extensive performance test was conducted on an experimental model (a bendable but not fully flexible model) that met almost all the characteristics required for Gummi. This model was found to excel in user-machine interface – it was easy to use and maneuverable. Particularly highly rated as a technology was the approach of placing the operational controls on the back of the device, because this kept the display screen free from the intrusion of fingers.

Photo: An experimental model used to study Gummi's interface

gummi_ページ用07Gummi's concept received rave reviews internationally from scientists and groups working in the field of interface design and human-computer interaction. One study presented at the CHI 2004 Conference on Human Factors in Computing Systems indicated a direction in which bendable computer interfaces would develop in the future. Gummi dates back more than 10 years, when mobile phones were in their prime. Dominant then were models that had small screens and 12 keyboard entries. This still is at the forefront of mobile phone design and has lost none of its luster. Many years may still pass before computing approaches and devices based on Gummi technology hit the market. And yet Gummi triggered various research efforts in subsequent years due to, the concept of an interface based on touching the rear surface of the device. Some results of this research already have been translated into commercial models. The button-less device operation, for example, has now established itself as a standard interface for various types of mobile equipment. Given this, it is clear that Gummi was not just another idea for the future; it also was an approach to "inventing and creating" the future. This prescient concept was one of the few that saw the mobile revolution. coming.