Methods of manufacturing security documents and security devices

A method of making a security device, comprising:

• (a) forming an array of primary focusing elements on a first region of a focussing element support layer, by:
• (a)(i) applying at least one transparent curable material either to the focusing element support layer or to a casting tool carrying a surface relief over an area which includes at least the first region, the surface relief comprising portions corresponding to the primary focusing elements;
• (a)(ii) forming the transparent curable material(s) with the casting tool;
• (a)(iii) curing the transparent curable material(s) so as to retain the surface relief in the first region;
• and
• (b) providing an image array located in a plane spaced from the array of primary focussing elements by a distance substantially equal to the focal length of the primary focusing elements, wherein the primary focusing elements exhibit a substantially focused image of the image array,
• wherein the surface relief further includes a plurality of structures of greater depth than the height of the primary focusing elements such that the cured transparent material(s) include a plurality of features protruding above the height of the primary focussing elements between primary focusing elements of the array, wherein the surface relief is configured such that more than one of the primary focusing elements of the array space each of the plurality of features from the next, and
• wherein the features protruding above the height of the primary focusing elements are arranged with a spacing of at least one feature every 50 primary focusing elements.