Patent ID: 8755101

Claim:
A method of producing a two-sided microstructured product comprising the steps of: providing primary product features at a first surface of a substrate sheet; providing secondary product features at an opposed surface of the substrate sheet; providing primary registration features comprising a registration-array of focusing elements on the first surface of the substrate sheet; and providing secondary registration features comprising a registration-array of reference objects on the opposed surface of the substrate sheet, wherein the primary registration features are aligned with the primary product features at the first surface of the substrate sheet and the secondary registration features are aligned with the secondary product features at the opposed surface of the substrate sheet, and the registration-array of focusing elements and the registration-array of reference objects are arranged to provide a synthetic integral three dimensional image perceivable as a representation of the reference objects, wherein the registration-array of reference objects comprises one or more pairs of adjacent complementary sub arrays of reference objects that have different periods of repetition in at least one direction, so that the one or more pairs of complementary sub arrays gives rise to deviating synthetic integral three dimensional image representation effects in response to a misalignment; registering with a registration detection system the mutual alignment of the primary and secondary product features to estimate alignment parameters, involving identification of the relative positions of the primary and the secondary registration features of the registration structure, wherein the synthetic integral three dimensional image is used to improve the accuracy of the registration features; and aligning the provision of primary and secondary product features with an alignment control system by controlling at least one step of providing product features by feedback of alignment parameters.