Matched interference pigments or foils having viewing angle dependent mismatch
A method of providing a configuration of a system of interference filters with a visible color shifting effect, includes: a hue matching step of identifying a configuration of a first interference filter including two first metal layers and a first spacer layer therebetween, and a configuration of a second interference filter including two second metal layers and a second spacer layer therebetween, wherein the first and second filters match in hue at the first viewing angle, and the mismatch in hue at the second angle; and a lightness adjustment step which may include modifying the layer material or the layer thickness of one of the metal layers; wherein a difference in lightness at the first viewing angle between the first and second modified filters is less that a difference in lightness at the first viewing angle between the first and second filters.
1. A system comprising:
a first interference filter comprising:
a reflector layer,
the reflector layer including one or more of aluminum, silver, copper, gold, platinum, tin, titanium, palladium, nickel, cobalt, rhodium, niobium, or chromium,
a first absorber layer,
a first dielectric portion,
a second absorber layer,
at least one of the first absorber layer or the second absorber layer including a metal layer,
a reflectivity of the first absorber layer and a reflectivity of the second absorber layer being less than a reflectivity of the reflector layer,
the reflectivity of the reflector layer being at least 40%,
the first absorber layer having a thickness in a range from 5 to 15 nm, and
the first dielectric portion being between the first absorber layer and the second absorber layer, and
a second dielectric portion,
the second absorber layer being between the first dielectric portion and the second dielectric portion, and
the second dielectric portion being between the second absorber layer and the reflector layer; and
a second interference filter,
the first interference filter and the second interference filter appearing to match at a first viewing angle, and
at least one of lightness, color, or hue of the first interference filter at a second viewing angle being different from at least one of lightness, color, or hue of the second interference filter at the second viewing angle.
2. The system of claim 1 , where the second interference filter comprises:
a third absorber layer, and
a different reflector layer.
3. The system of claim 2 , where the second interference filter further comprises a dielectric layer between the third absorber layer and the different reflector layer.
4. The system of claim 1 ,
where the first absorber layer has a first thickness, and
where the second interference filter comprises a third absorber layer having a second thickness.
5. The system of claim 1 , where the first interference filter and the second interference filter appear to match in hue, chroma, and lightness at the first viewing angle.
6. The system of claim 1 , where the first interference filter and the second interference filter have, at the second viewing angle, at least one of:
a difference in hue greater than 10 degrees, or
a difference in chroma greater than 30 units.
7. The system of claim 1 , where the system comprises a foil that includes the first interference filter.
8. The system of claim 1 , where the first absorber layer comprises a light-absorber material.
9. The system of claim 1 , where the metal layer comprises chromium.
10. A system comprising:
a first interference filter comprising:
a first absorber layer,
a dielectric portion,
a second absorber layer,
at least one of the first absorber layer or the second absorber layer including a metal layer, and
a reflector layer,
the reflector layer including one or more of aluminum, silver, copper, gold, platinum, tin, titanium, palladium, nickel, cobalt, rhodium, niobium, or chromium,
the dielectric portion being between the second absorber layer and the reflector layer,
a reflectivity of the first absorber layer and a reflectivity of the second absorber layer being less than a reflectivity of the reflector layer, and
the reflectivity of the reflector layer being at least 40%; and
a second interference filter,
the first interference filter and the second interference filter appearing to match at a first viewing angle,
at least one of lightness, color, or hue of the first interference filter at a second viewing angle being different from at least one of lightness, color, or hue of the second interference filter at the second viewing angle,
the second interference filter being different from the first interference filter, and
the second interference filter comprising a different reflector layer.
11. The system of claim 10 ,
where the first interference filter further comprises a different dielectric portion, and
where the second absorber layer is between the dielectric portion and the different dielectric portion.
12. The system of claim 10 ,
where the second viewing angle is different from the first viewing angle by more than 10 degrees.
13. The system of claim 10 , where the reflector layer is an opaque layer.
14. An interference filter comprising:
a first absorber layer;
a first dielectric portion;
a second absorber layer,
at least one of the first absorber layer or the second absorber layer including a metal layer, and
the first dielectric portion being between the first absorber layer and the second absorber layer;
a second dielectric portion,
the second absorber layer being between the first dielectric portion and the second dielectric portion; and
a reflector layer,
the second dielectric portion being between the second absorber layer and the reflector layer,
the reflector layer including one or more of aluminum, silver, copper, gold, platinum, tin, titanium, palladium, nickel, cobalt, rhodium, niobium, or chromium,
the interference filter and a different interference filter appearing to match at a first viewing angle, and
at least one of lightness, color, or hue of the interference filter at a second viewing angle being different from at least one of lightness, color, or hue of the different interference filter at the second viewing angle.
15. The interference filter of claim 14 , wherein the reflector layer is between 60 to 1000 nm thick.
16. The interference filter of claim 14 , wherein the reflectivity of the reflector layer is higher than 60%.
17. The interference filter of claim 14 , wherein the first absorber layer and the second absorber layer are metal layers with thicknesses in a range from 5 to 15 nm, and wherein the metal layers include the metal layer.
18. The interference filter of claim 14 , wherein the metal layer includes one or more of chromium, aluminum, nickel, silver, copper, palladium, platinum, titanium, vanadium, cobalt, iron, tin, tungsten, molybdenum, rhodium, or niobium.
19. The interference filter of claim 14 , further comprising a transparent protective layer that is incorporated within the reflector layer.
20. The interference filter of claim 14 , wherein a thickness of the first absorber layer is same as a thickness of the second absorber layer.