For most blind computer users, surfing the internet or catching up on e-mail means reading just one line at a time, because commercially available braille displays can't show full pages of text.
Researchers from North Carolina State University now say they have devised a display that would allow visually challenged users to read a full page at a time -- and at a much lower cost than existing displays.
"We have developed a low-cost, compact, full-page braille display that is fast and can be used in PDAs, cellphones and even GPS systems," says Dr. Peichun Yang, one of the researchers working on the project, who is himself blind.
A full-page display is better because it allows readers to skip paragraphs and read the parts they want, instead of forcing them to go over it line by line. Full-page display also presents more information in a shorter time.
Braille characters, developed by Louis Braille in 1821, are created by a pattern of raised dots. Alphabets, punctuation and numerals are represented in cells. Each cell is made of six dots arranged in a 2x3 dot matrix. A dot may be raised at any of the six positions to form the characters.
"Braille is very significant, and statistically about 90 percent of blind people who have a job can read braille," says Dr. Yang. "It's a very important part of their ability to read."
Braille displays on the market now use piezo-ceramics, in which a 2-inch-long lever forces up the dots, explains Dr Yang. "It's expensive and limiting," he says.
As a result, a typical braille display today has just one line of 80 cells, and can cost up to $8,000.
Instead, Dr Yang and his team developed a new way to create the raised dots. Each cell in their display uses what is called a “hydraulic and latching mechanism.”
"The mechanism can offer a large displacement and fast response time simultaneously, which is the key to a good commercial braille display," says Dr. Yang.
A four-line display developed using the new system could be around $1,000, and fullscreen displays could come later.
Here's how Dr. Yang's technology works. Picture each cell as a rectangular cavity that is filled with liquid. The top and bottom have a small opening that is sealed with a flexible diaphragm. There are four bendable actuators made of electroactive polymers -- which means they change shape when voltage is applied -- on each side.
By manipulating the voltage, two facing polymers can be made to displace the fluid housed within them. This pushes the fluid up towards the top, raising the dot. Once the dots are raised, a latching mechanism would support the weight being applied by a person’s fingers as the dots are read. A refreshable braille dot has a response time of around 30 milliseconds.
Dr. Yang and his team hope to create prototype displays within a year, and if successful they can be commercially produced.
See Also:
- Pulsing Touchscreen Tech Spells Out Braille
- Tattoos for the Blind
- All Eyes on Braille Software
- You Gotta Feel the Music
Photo: Braille sign at the Port Museum ( reinvented/Flickr)
