The liquid crystal material (40) is contained between two parallel substrates (30,50). Electrical signals are applied to switch between two textures. The structure includes a polariser (10) associated with the front surface of the device. A reflective specular or diffusing element (60) is placed on the rear surface, allowing light to pass through the device twice and return towards the observer. The bi-stable device comprises a liquid crystal material (40) contained between two parallel substrates (30,50), and an aligning system to provide two stable or meta-stable textures. The liquid crystal material may be a liquid crystal, or a mixture of liquid crystal in the nematic phase. Electrical signals are applied to switch between the two textures. The structure includes a polariser (10) associated with the front surface of the device. A reflective specular or diffusing element (60) is placed on the rear surface, allowing light to pass through the device twice and return towards the observer. A compensator (20) is placed between the liquid crystal material and the polariser, the compensator having an optical retardation (dc DELTA nc) which is close to lambda 0/4.
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