Image Number 4 for United States Patent #5086287.
A display surface for presenting information in tactile form by means of a grid-shaped array of tactile elements. It can be selectively caused to project into the space above the display surface by using lifting elements. According to the invention, there are a number of line slides (8) corresponding to the number of lines of tactile dots, and a number of column slides (3) corresponding to the number of columns of tactile dots. On the line slides a part (9) is allocated to each lifting element (7) in such a way that the lifting element is fixed in the plane of the line, although it is movable in the plane of the column. Similarly on the column slides a part (4) is associated with each lifting element to shift the latter in the plane of the column. In a first step, the position of the tactile elements in each grid line is controlled by shifting the line slide carrying the lifting elements in a direction parallel to the grid line so that all the lifting elements in this line are positioned in such a way that they are engaged by the column slide, which is movably located in the interspaces between the grid columns, while this slide is in its middle position. In a second step, each lifting element is positioned in one of two possible positions (7a, 7b) on the line slide, by moving the associated column slide. Finally, in a third step, the line slide is moved. Depending on their position, the lifting elements are either moved into the space below the tactile elements, thereby raising them (7c), or they move into the spaces alongside the tactile elements without raising them (7b).