Thin film optical variable article having substantial color shift with angle and method
First Claim
1. In a thin film optically variable article having substantial color shift with varying angle of light incidence and viewing, an optically thick substantially transparent structural element carrying a colorant and having first and second surfaces and a multilayer interference coating carried on one of said first and second surfaces, said colorant being external of the multilayer interference coating, said colorant serving to modify in essentially a subtractive mode the color at normal incidence and the color shift with angle of the multilayer interference coating as seen by transmission of light through the article.
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Accused Products
Abstract
Thin film optically variable article having substantial color shift with varying angle of light incidence and viewing and including an optically thick, substantially transparent element carrying a colorant and having first and second surfaces. A multilayer interference coating is carried on one of said first and second surfaces. The colorant serves to modify in essentially a subtractive mode the color at normal incidence and the color shift with angle of the multilayer interference coating as seen by reflection or transmission.
265 Citations
28 Claims
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1. In a thin film optically variable article having substantial color shift with varying angle of light incidence and viewing, an optically thick substantially transparent structural element carrying a colorant and having first and second surfaces and a multilayer interference coating carried on one of said first and second surfaces, said colorant being external of the multilayer interference coating, said colorant serving to modify in essentially a subtractive mode the color at normal incidence and the color shift with angle of the multilayer interference coating as seen by transmission of light through the article.
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2. In a method for providing a color shift with angle in transmitted light by the use of a multilayer interference coating carried by a substantially transparent structural element, causing the light to pass through the structural element and the interference filter and selectively absorbing in essentially a subtractive mode unwanted colors in the light in a manner which is substantially independent of angle to provide an abrupt color shift from one color to another color at two different angles of incidence.
- 3. in a thin film optically variable article having substantial color shift with varying angle of light incidence and viewing, an optically thick structural element having first and second surfaces, a multilayer interference coating carried on one of said first and second surfaces and producing an inherent color shift with angle and subtractive colorant means external of the multilayer interference coating and on the side of the multilayer interference coating facing the incident light, said subtractive colorant means in combination with the multilayer interference coating serving to modify the inherent color shift induced by the multilayer interference coating to provide a discrete color shift from one distinct color to another distinct color at two different angles of incidence and substantially no color at another angle of incidence.
- 17. In a thim film optically variable article having substantial color shift with varying angle of light incidence and viewing, a multilayer interference coating producing an inherent color shift with angle, and subtractive colorant means external of the multilayer interference coating on the side of the multilayer interference coating facing the incident light, said subtractive colorant means in combination with the multilayer interference coating serving to modify the inherent color shift produced by the multilayer interference coating to provide a discrete color shift from one distinct color to another color at two different angles of incidence and substantially no color at another angle of incidence.
- 20. In a method for providing color shift with angle in reflected light by the use of a multilayer interference coating carried by a structural element and providing an inherent color shift with angle, causing light to impinge upon the multilayer coating, and selectively absorbing in essentially a subtractive mode unwanted colors to provide an abrupt color shift from one distinct color to another distinct color at two different angles of incidence.
- 23. In a method for providing a substantial color shift with varying angle of light incidence and viewing by the use of a multilayer interference coating and subtractive colorant means, the method comprising causing light to impinge upon the multilayer interference coating to provide an inherent color shift with angle and causing the same light to impinge upon the subtractive colorant means to selectively absorb in essentially a subtractive mode unwanted color from the inherent color shift provided by the multilayer interference coating to thereby modify the inherent color shift produced by the multilayer interference coating to provide a discrete color shift from one distinct color to another distinct color at two different angles of incidence.
Specification