PORTLAND, Ore. -- The EE who co-invented the electret microphone was recently recruited to help create the world's first graphical "haptic" display for the blind. James West, an electrical engineer, was awarded America's highest honor--the National Medal of Technology--for his work on the electret's charged polymer film that converts motion into an electrical signal.
For the National Science Foundation funded haptic-display project, West wants to turn this concept around, by sending signals to an electro-active polymer that responds with motion on its surface. The researchers hope their efforts will result in a display of graphical patterns for the blind to feel with their hands.
The project was dubbed, "A Dynamic Tactile Interface for Visually Impaired and Blind People," by team leader, Ilona Kretzschmar, an engineering professor at The City College of New York, who says she wants to "develop a viable dynamic tactile interface that allows graphic and pictorial information to be presented in real time in tactile rather than visual space."
Today, Braille displays are very expensive, even though they are confined to text and lack integral touch-screens. The haptic display device designed by Kretzschmar, West and their other collaborators, on the other hand, will include an integrated touch-screen so that users can push on areas of the screen to activate menus and other graphical icons that they feel there. With the ability to both display graphical images and activate them by touch, the wide world of graphical information displays available on computers today could finally be accessible by the blind.
"The amount of information available to visually impaired and blind individuals will increase dramatically," said Kretzschmar.
Charged polymer film
In 1962, West and Gerhard Sessler invented the electret microphone at Bell Labs. Their major invention was to add to a condenser microphone a permanently charged polymer film as the diaphragm, thereby eliminating the need for a power supply
to charge it. With a polymer film acting as the plate of a capacitor
that was permanently charged, sound could modulate the signal coming from the diaphragm by vibrating its membrane.
In the new haptic-display device, the mechanism will be reversed--with electrical signals causing the polymer membrane to move. The three-layer display will have the top layer made from a polymer film that works opposite to an electret microphone. Electrical signals are sent to the polymer film pixel-by-pixel, with the membrane responding by rising slightly. A middle layer of the film will have the embedded electrodes that enable individual pixels to be addressed in the top layer. The bottom layer of the display will hold a touch screen to enable users to push icons, buttons and other graphical screen elements with their fingers instead of a mouse. The software will also incorporate audible feedback to enable easy navigation of graphics and diagrams.
Kretzschmar, a materials-science expert, will contribute to the project by synthesizing Janus particles--nanoscale beads composed of two fused halves made from different materials (named for the Roman god Janus)--to coat the haptic display's surface. By using tiny Janus-particle dipoles to coat the electro-active polymer, the team hopes to accelerate its motion as it pushes up a tactile pixel, thereby enabling a person to feel an image more easily.
The research project, which is not expected to bear fruit for three years, will also include contributions from researchers Vivien Tartter, a fellow professor at City College of New York; Karen Gourgey, director of the Computer Center for Visually Impaired People, at Baruch College; EE professor Thrasos Pappas at Northwestern University; and professor Leigh Abts at the University of Maryland, College Park.