Braille books and computer screens use dots to represent data. Now researchers at Texas Instruments are hoping to create computer-actuated Braille pads for blind readers. Books for the blind and electromechanical Braille displays now present letters in a long line. This is fine for prose but causes problems when tables or columns of numbers are involved. With the rewritable 'tactile display' patented by Texas, blind readers could take in data and get to grips with spreadsheets and charts. The Dallas-based team of researchers proposes using a matrix of densely packed cylinders. The idea is for the cylinders to contain an organic polymer gel that expands in the presence of an electric field. A positive electrode sits at the base of each cylinder with a negative one on the side. Like the pixels on a computer screen, each cylinder has a unique address. When the electric field for that point is turned on, the gel expands and forms a tiny dot. A thin plastic sheet would be stretched over the screen protecting the gel. 'Just as a pixel on your PC screen lights up when addressed, ours creates a raised dot,' Texas software engineer Alan Gilkes said. Dots could even be made to pulse - like flashing text - to highlight words. The Texas team has only made one cylinder, but the researchers are confident they can create a whole pad of 80 by 25 Braille characters wide - the same number that appear on a small laptop screen. Presenting a screenful of information at a time had enormous advantages over existing methods, Mr Gilkes said. 'Braille books are expensive to print, cumbersome, and each time they are read, the dots wear down.' The Braille pad also would allow blind people to skim through documents to sections of interest. John Gill, chief scientist at the research unit of Britain's Royal National Institute for the Blind, said there would be real demand for such a pad. 'There is an unmet need for a Braille display that can represent the whole of a computer screen,' he said. He said it would have to be affordable and able to update itself quickly to become widely accepted. Mr Gilkes said Texas had no plans to make Braille displays. He said it was talking to other companies about licensing the technology.