| 摘要 |
A matrix display comprises an array of display elements arranged in vertical and horizontal rows. Each element comprises a vane pivotally mounted for movement between stable positions in one of which the vane covers a light-transmissive area contained in an opaque member arranged to be illuminated from behind by a first light source and displays a low-reflectance face to an observer. In a second stable position the vane exposes the illuminated area to the observer and also reflects light from a second source towards the observer, for which purpose the vane may be supported at an acute angle to the opaque member. Each vane is fastened to a permanent magnet arranged to cooperate with a reversibly polarizable electromagnet to be moved from one stable position to the other. In one embodiment an array of electromagnets, one for each horizontal or vertical row of shutters, is traversed across the array and the electromagnets are individually selectively energized to produce a required display. A small permanent magnet may be affixed to the reflective surface of each vane, or a diametrally polarized magnet may be attached to the pivot axis.
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