Security device and method of making thereof

Patent metadata

Field	Value
Publication number	US-11465433-B2
Application number	US-201816627252-A
Country	US
Kind code	B2
Filing date	Jun 27, 2018
Priority date	Jun 30, 2017
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

A security device is provided, comprising: a colour shifting element that exhibits different wavelengths of light at different viewing angles, and; an at least partially transparent light control layer covering at least a part of the colour shifting element and comprising a surface relief adapted to modify the angle of light from the colour shifting element, wherein; a first region of the light control layer comprises a first optical characteristic, whereby light at a first viewing angle from the first region of the light control layer is perceived to have a resultant optical effect that is the resultant of the wavelength of light exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, and the first optical characteristic, and; a second region of the light control layer either: (i) is substantially colourless such that light at the first viewing angle from the second region is perceived to have a resultant optical effect exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, or; (ii) comprises a second optical characteristic different from the first optical characteristic, whereby light at the first viewing angle from the second region of the light control layer is perceived to have a resultant optical effect that is the resultant of the wavelength of light exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, and the second optical characteristic. Methods of manufacture thereof are also disclosed.

First claim

The invention claimed is:

1. A security device comprising:
a color shifting element that exhibits different wavelengths of light at different viewing angles, and;
an at least partially transparent light control layer covering at least a part of the color shifting element and comprising a surface relief adapted to modify, by refraction, the angle of light from the color shifting element, wherein:
a first region of the light control layer comprises a first optical characteristic, whereby light at a first viewing angle from the first region of the light control layer is perceived to have a resultant optical effect that is the result of the wavelength of light exhibited at that viewing angle due to the combination of the color shifting element and the surface relief of the light control layer, and the first optical characteristic, wherein the first optical characteristic is any of: a visible color, a level of transparency, fluorescence, luminescence and phosphorescence, and;
a second region of the light control layer either:
(i) is substantially colorless and does not comprise the first optical characteristic such that light at the first viewing angle from the second region is perceived to have a resultant optical effect exhibited at that viewing angle due to the combination of the color shifting element and the surface relief of the light control layer of the second region, or
(ii) comprises a second optical characteristic different from the first optical characteristic, whereby light at the first viewing angle from the second region of the light control layer is perceived to have a resultant optical effect that is the result of the wavelength of light exhibited at that viewing angle due to the combination of the color shifting element and the surface relief of the light control layer, and the second optical characteristic, wherein the second optical characteristic is any of: a visible color, a level of transparency, fluorescence, luminescence and phosphorescence.

2. The security device of claim 1 , wherein the resultant optical effect is a perceived color.

3. The security device of claim 1 , wherein the first optical characteristic is such that, at the first viewing angle, the first region exhibits a first visible color and the second optical characteristic is such that the second region exhibits a second, different visible color.

4. The security device of claim 1 , wherein the first and second optical characteristics are such that the first region and the second region exhibit substantially the same visible color, wherein the level of transparency of the first region is different from the level of transparency of the second region such that the resultant perceived colors exhibited by the first and second regions are different.

5. The security device of claim 1 , wherein at a first viewing angle, the light from the first region of the light control layer is perceived to have a first resultant color and, at a second viewing angle, the light from said first region of the light control layer is perceived to have a second resultant color different from the first resultant color.

6. The security device of claim 1 , wherein the first and/or second regions of the light control layer define indicia.

7. A security device comprising:
a color shifting element that exhibits different wavelengths of light at different viewing angles;
an at least partially transparent light control layer covering at least a part of the color shifting element and comprising a surface relief adapted to modify the angle of light from the color shifting element, and;
an optical characteristic layer positioned between the color shifting element and the light control layer, or positioned on a distal side of the color shifting element with respect to the light control layer, wherein at least a first region of the optical characteristic layer comprises a first optical characteristic such that it exhibits a first optical effect at substantially all viewing angles;
whereby light at a first viewing angle from the first region is perceived to have a first optical effect that is the result of the wavelength of light exhibited at that viewing angle due to the combination of the color shifting element and the surface relief of the light control layer, and the first optical characteristic.

8. The security device of claim 7 , wherein the first optical characteristic is any of: a visible color, fluorescence, luminescence and phosphorescence.

9. The security device of claim 7 , wherein the optical characteristic layer comprises a second region having a second optical characteristic such that the second region exhibits a second optical effect at substantially all viewing angles different to the first optical effect.

10. The security device of claim 9 , wherein the first and second optical characteristics are such that the first region and the second region exhibit substantially the same visible color, wherein a level of transparency of the first region is different to a level of transparency of the second region.

11. The security device of claim 7 , wherein the optical characteristic layer defines indicia.

12. A security device comprising:
a color shifting element that exhibits different wavelengths of light at different viewing angles;
an at least partially transparent light control layer covering at least a part of the color shifting element and comprising a surface relief adapted to modify the angle of light from the color shifting element; and
a substantially opaque layer having a first optical characteristic positioned between the color shifting element and the light control layer and covering a first region of the color shifting element, wherein
a first region of the light control layer comprises a second optical characteristic, whereby light at a first viewing angle from the first region of the light control layer is perceived to either:
(i) have a resultant optical effect that is the result of the first optical characteristic and the second optical characteristic, when the first region of the light control layer overlaps with the opaque layer, or
(ii) have a resultant optical effect that is the result of the wavelength of light exhibited at that viewing angle due to the combination of the color shifting element and the surface relief of the light control layer, and the second optical characteristic, when the first region of the light control layer does not overlap with the opaque layer.

13. The security device of claim 12 , wherein the first and/or second optical characteristic is any one of: a visible color, fluorescence, luminescence and phosphorescence.

14. The security device of claim 12 , wherein a second region of the light control layer is substantially colorless such that light at the first viewing angle from the second region is perceived to either:
(i) have a resultant optical effect that is the result of the first optical characteristic, when the second region of the light control layer overlaps with the opaque layer, or
(ii) have a resultant optical effect that is the result of the wavelength of light exhibited at that viewing angle due to the combination of the color shifting element and the surface relief of the light control layer, when the second region does not overlap with the opaque layer.

15. The security device of claim 12 , wherein the first optical characteristic of the substantially opaque layer is a visible color substantially corresponding to the wavelength of light exhibited by the color shifting element at a first viewing angle such that, at said first viewing angle, the device exhibits a substantially uniform color and at

Assignees

• De La Rue Int Ltd

Inventors

• Godfrey John
• Locke Rebecca

Classifications

• B42D25/324 Primary

  Reliefs · CPC title

• B42D25/364 Primary

  Liquid crystals · CPC title

• B42D25/355

  Security threads · CPC title

• B42D25/328

  Diffraction gratings; Holograms · CPC title

• B42D25/23 Primary

  Identity cards · CPC title