Anti-counterfeiting medium
AssigneeToppan Printing Co., Ltd.
InventorsKozue Umeda, Mihoko Okawa
Life of this patent
Estimating the term…
Abstract
A anti-counterfeiting medium includes a support substrate, an OVD forming layer, and a latent image layer in this order. The latent image layer has plural regions with optical axes of a birefringent material aligned in directions different from each other. The OVD forming layer includes an uneven-structure-forming layer is made up of a first region and a second region, and a reflecting layer. The first region is a region made up of a flat part and plural convexities or concavities. The second region is configured by a flat part. Each of the plural convexities and concavities has a 0.3 to 5 μm long side dimension and short side dimension and height or depth of 0.1 to 0.5 μm or less.
Claims6
An anti-counterfeiting medium, comprising:
- a support substrate,
- an OVD forming layer, and
- a latent image layer, in this order;
- wherein the latent image layer includes a birefringent material;
- wherein the latent image layer has plural regions with optical axes of the birefringent material aligned in directions different from each other;
- wherein the OVD forming layer includes, in order from the support substrate side, an uneven-structure-forming layer and a reflecting layer;
- wherein the uneven-structure-forming layer consisting of one or more first regions and one or more second regions;
- wherein the reflecting layer is directly on the uneven-structure-forming layer, the reflecting layer consists of one or more first regions, which correspond to the one or more first regions of the uneven-structure-forming layer, and one or more second regions, which correspond to the one or more second regions of the uneven-structure-forming layer;
- wherein each of the one or more first regions of the uneven-structure-forming layer or the reflecting layer is selected from a group consisting of:
- (a) a region made up of a flat part substantially parallel to a surface of the support substrate, and plural convexities each having an upper surface substantially parallel to a surface of the support substrate;
- and (b) a region made up of a flat part substantially parallel to a surface of the support substrate, and plural concavities each having a bottom surface substantially parallel to a surface of the support substrate;
- wherein each of the second regions of the of the uneven-structure-forming layer or the reflecting layer is a flat part substantially parallel to a surface of the support substrate;
- wherein each of the plural convexities has a long side dimension of 0.3 μm or more and 10 μm or less, a short side dimension of 0.3 μm or more and 10 μm or less, and a depth of 0.1 μm or more and 0.5 μm or less;
- wherein each of the plural concavities has a long side dimension of 0.3 μm or more and 10 μm or less, a short side dimension of 0.3 μm or more and 10 μm or less, and a depth of 0.1 μm or more and 0.5 μm or less;
- and
- wherein in each of the one or more first regions:
- (1) the plural convexities or concavities occupy an area of 20% or more and 80% or less with respect to an area of the first region,
- (2) the plural convexities or the plural concavities are orderly arranged, and
- (3) the plural convexities have a substantially uniform height or the plural concavities have a substantially uniform depth.
Dependencies are inferred from the claim text.