High chroma optically variable color-shifting strand and woven products
View Patent ↗Opaque color shifting strands are disclosed that have an optically variable color with a change in angle of incident light. The strands have an organic substrate and an optical interference structure on one or both sides of the organic substrate. The optical interference design can be a Fabry-Perot structure or can be optically variable ink. Plural strands can be combined to form a textile for example such as a garment label.
1. An opaque color-shifting element comprising:
a color-shifting strand cut such that its width is substantially less than its length, the strand comprising an inorganic thin film optical interference structure providing a perceivable color-shift with a change in viewing angle or angle of incident light, in the visible spectrum, wherein said inorganic thin film interference structure of the color-shifting strand is supported by an organic support layer for providing rigidity and for preventing the strand from significantly curling, and wherein the inorganic thin film interference structure is permanently coated onto the organic support layer in the absence of a release layer, wherein the inorganic thin film interference structure is only on one side of the organic support layer.
2. Opaque color-shifting element as defined in claim 1 wherein the strand has a thickness of at least 6 microns and is suitable for forming a textile.
3. Opaque color-shifting element as defined in claim 1 , wherein the thin film interference structure is a Fabry-Perot interference structure and wherein the organic support layer is a light transmissive substrate which allows the Fabry-Perot interference color shifting effects to be seen from either side of the organic support layer, and wherein there is an absence of a Fabry-Perot structure on an opposite side from where the thin film interference structure resides.
4. Opaque color-shifting element as defined in claim 3 , wherein the thin film interference structure includes two Fabry-Perot interference structures coated on a same side of the organic support layer arranged such that color-shift effects can be seen from both sides of the organic support layer.
5. Opaque color-shifting element as defined in claim 4 , wherein the two Fabry-Perot structures share a common reflector layer.
6. Opaque color-shifting element as defined in claim 4 wherein the two Fabry-Perot structures are a five layer structure and are on a same side of the organic support layer.
7. Opaque color-shifting element as defined in claim 4 wherein the element forms a thread.
8. Opaque color-shifting element as defined in claim 4 , wherein the Fabry-Perot structures each have an absorber layer and wherein the thicknesses of the absorber layers are substantially different.
9. Opaque color-shifting element as defined in claim 4 , wherein the Fabry-Perot structures each have a dielectric layer and wherein the thicknesses of the dielectric layers are substantially different.
10. Opaque color-shifting element as defined in claim 1 wherein the inorganic thin film optical interference structure is a layer of optically variable ink.
11. An opaque color-shifting element as defined in claim 1 , further comprising additional color-shifting strands, which together with the strand of claim 1 form a textile.
12. An opaque color-shifting element as defined in claim 11 wherein the additional color-shifting strands are cut such that their width is less than 500 microns, said additional color-shifting strands each comprising an inorganic thin film optical interference structure providing a perceivable color-shift with a change in viewing angle or angle of incident light, in the visible spectrum, wherein said inorganic thin film interference structure of each strand is supported by an organic support layer for providing rigidity and for preventing the strand from significant curling.
13. An opaque color-shifting strand as defined in claim 1 wherein additional color-shifting strands and the strand of claim 1 form a weft sharing a common warp.
14. An opaque color-shifting element as defined in claim 1 , wherein the organic support layer has a diffraction grating or a holographic structure formed therein.
15. An opaque color-shifting element as defined in claim 14 , wherein the diffraction grating or the holographic structure is formed on a surface of the organic support layer and wherein the inorganic thin film optical interference structure supported by the organic support layer has the diffraction grating or the holographic structure formed in at least a layer thereof.
16. An opaque color-shifting element as defined in claim 15 , wherein the diffraction grating or the holographic structure is formed on a first face of the organic support layer and wherein the inorganic thin film optical interference structure is supported on an opposite face of the organic support layer.
17. An opaque color-shifting element as defined in claim 16 , wherein the organic support layer is light transmissive and wherein the inorganic support layer comprises a color-shifting Fabry-Perot structure that can be seen from both sides of a strand.