Matrix display device using movable vanes - has mirror on vanes reflecting light from lamp in front of display board and second lamp is situated behind board

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 polarisable electromagnet to be moved from one stable position to the other.