Abstract: Gravity-actuated display systems suitable for use as security markers, for example to incorporate into bank notes. The devices can be made very thin and flexible, yet are robust enough to endure the harsh conditions of paper currency in general circulation. Because the displays are gravity actuated, they do not require a power source or circuitry. The gravity-actuated displays can be fabricated using microembossing or photolithography and can be filled and sealed using roll-to-roll techniques. The microcells can also be patterned to provide custom designs, such as official seals.

Abstract: The present invention is directed to a sealing layer that comprises a combination of polyurethane and poly(vinyl alcohol), the poly(vinyl alcohol) containing an acetoacetate functional group in its molecular structure. The sealing layer is formed from an aqueous sealing composition and shows water resistance and good barrier properties to non-polar fluids. The sealing layer can be used to seal microcells of electro-optic displays.