| 摘要 |
<p>Visual display apparatus comprises movable display elements E mounted in space between a transparent glass screen G and a magnetizable sheet M. The individually movable elements E are resiliently urged to advance positions in which they abut the screen G but can be held in withdrawn positions by magnetised spots printed on to the magnetizable sheet M, the elements being of a soft magnetic material. The elements are immersed in an opaque fluid by which they are masked from view when in their withdrawn positions. A pattern-writing carriage is arranged to traverse the sheet M, writing any required pattern of magnetized spots on to the sheet, in order to establish a corresponding arrangement of the elements E.</p> |
