| 摘要 |
A security substrate is disclosed, comprising: a polymer substrate having first and second surfaces; an array of focussing elements; an optical adjustment layer and at least one first masking layer. The array of focussing elements is in the form of a surface relief across a first region of the polymer substrate, the surface relief being definedin the surface of a transparent base layer, wherein the transparent base layer comprises either the polymer substrate or a layer disposed thereon. The optical adjustment layer is disposed on the transparent base layer across a second region of the polymersubstrate, which second region includes at least the first region. The optical adjustment layer has a first surface in contact with the surface relief of the transparent base layer and an opposing second surface having a profile which is not operative to focus visible light. The optical adjustment layer comprises a first transparent material extending across a first sub-region of the array of focussing elements, the first sub-region comprising all or only part of the first region, the first transparent material having a refractive index different from that of the transparent base layer, whereby the focussing element(s) in the first sub-region of the array are functional focussing element(s). The security substrate further comprises at least one first masking layer, comprising a reflective and/or non-transparent material, disposed over the optical adjustment layer across a third region of the polymer substrate, the third region defining at least one gap in the first masking layer(s) which gap includes at least part of the first sub-region, such that functional focusing elements of the array are revealed through the at least one gap. |
