Method of enhancing the visibility of diffraction pattern surface embossment
AssigneeAvery Dennison Corporation
InventorsRichard G. Miekka, Richard A. Fotland, Frederick N. Miekka, John J. Fitch, Karl Josephy
Life of this patent
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Abstract
Methods for enhancing the visibility of and imparting a metallic luster to holographic and diffraction pattern surface embossments on transparent media such as plastic films (12) are disclosed. Enhancement is achieved by (1), metallic effect dyes or (2), metal flake inks containing minimal quantities of resinous binders (3), inks containing crystalline pigments that have metallic visual effects, or (4), inks containing pigments formed of optical stacks. The solvent used during application of the dye or ink must not be a solvent for the embossed surface.
Claims33
A method of forming a security product, comprising the steps of:
- (a) forming a sheet of base material, said sheet having a first surface and a second surface, wherein the first surface is embossed with an optical diffraction grating pattern or a holographic image pattern, and wherein the sheet is light transmitting;
- (b) preparing a metallic effect ink adapted to bond to the first surface of the sheet and to form, with the first surface, an interface which approximates the light reflective properties of an interface formed by vacuum metallization, in which the metallic effect ink is selected from the group consisting of (1) a binder containing metallic flakes, (2) a dye selected from the group consisting of crystal violet, rhodamine B, fuchsine, methyl violet, safranine, fluorescein, rhodamine, and mauveine, (3) an ink containing graphite as its pigment, and (4) an ink containing a metallic sulfur compound as its pigment;
- (c) applying the metallic effect ink to the embossed first surface of the sheet by conventional printing equipment;
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- (d) bonding a backing sheet to the metallic effect ink-printed, embossed sheet, and further providing visual information between the backing sheet and the metallic effect ink-printed and embossed sheet, the visual information being obscured by or visible through the metallic effect ink when viewing the article through the embossed sheet.
A method for forming a decorative sheet, comprising the steps of:
- a) forming a sheet of base material, said sheet having a first surface and a second surface, in which the first surface is embossed with an optical diffraction pattern or a holographic image,
- b) preparing an ink which is adapted to bond to the first surface of the sheet and to form, with the first surface, an interface which approximates the light reflective properties of an interface formed by vacuum metallization, wherein the ink is a metallic effect ink formed of a binder containing metallic flakes, and in which the metallic flakes are embossed by metallizing an embossed carrier sheet, removing the metallized layer from the embossed sheet and producing finely divided embossed metallic particles used as the metallic pigment for the metallic effect ink, and
- c) applying the metallic effect ink to at least a portion of the embossed first surface of the sheet using conventional printing equipment, for enhancing the visibility of the embossed surface.
Dependencies are inferred from the claim text.