Light control film formed with a security feature
View Patent ↗A light control film is described that is formed with at least one security feature therein. The security feature is not visible when the film is viewed at an incorrect angle. The security feature only becomes visible when the film is viewed at the correct viewing angle or range of viewing angles. A plurality of security features can be formed in the film at substantially the same location(s), but at different angles, so that each security feature only becomes visible when the film is viewed at the correct respective viewing angle or range of viewing angles. The light control film can be integrated into any type of document where resistance to counterfeiting and fraudulent alteration are important, such as plastic identification or credit cards, or passports.
1. A light control film having a plurality of micro light control structures formed in the film, and a first security feature formed in the micro light control structures, wherein the light control film is generally transparent or translucent at a first viewing angle, the first security feature is not visible when the light control film is viewed at the first viewing angle, and the first security feature is visible when the light control film is viewed at a first correct range of viewing angles, wherein the first security feature is formed in the micro light control structures at an angle that is different than the first viewing angle and wherein the angle is within the first correct range of viewing angles, and
a second security feature formed in the micro light control structures, located in generally the same area and/or adjacent to the first security feature, wherein the second security feature is not visible when the light control film is viewed at the first viewing angle or the first correct range of viewing angles, and the second security feature is visible when the light control film is viewed at a second correct range of viewing angles, and wherein the second security feature is formed in the micro light control structures at an angle that is different than the first viewing angle and wherein the angle is within the second correct range of viewing angles.
2. The light control film of claim 1 , wherein the plurality of micro light control structures: are parallel to each other, are inclined to a vertical axis, or intersect one another.
3. The light control film of claim 1 , wherein the light control film comprises a single layer or first and second layers.
4. A method of creating a security feature in a light control film having a plurality of micro light control structures formed in the film, the light control film being generally transparent or translucent when the light control film is viewed at a first viewing angle, comprising:
using a laser beam to destroy portions of the micro light control structures to form a first security feature; wherein the light control film remains generally transparent or translucent at the first viewing angle, the first security feature is not visible when the light control film is viewed at the first viewing angle, and the first security feature is visible when the light control film is viewed at a first correct range of viewing angles, wherein the laser beam contacts the micro light control structures destroyed thereby at an angle that is different than the first viewing angle, wherein the angle is within the first correct range of viewing angles, and
using a laser beam to destroy portions of the micro light control structures to form a second security feature, located in the same area and/or adjacent to the first security feature, wherein the light control film remains generally transparent or translucent at the primary viewing angle, the second security feature is not visible when the light control film is viewed at the first viewing angle or the first correct range of viewing angles, and the second security feature is visible when the light control film is viewed at a second correct range of viewing angles, wherein the laser beam that forms the second security feature contacts the micro light control structures destroyed thereby at an angle that is different than the first viewing angle, and wherein the angle is within the second correct range of viewing angles.
5. The method of claim 4 , further comprising orienting the light control film and the laser at a first relative position to one another and forming the first security feature, and thereafter moving the light control film and laser relative to one another to a second relative position to one another and forming a second security feature.
6. The method of claim 5 , wherein moving the light control film and the laser relative to one another to the second relative position comprises tilting the light control film and the laser relative to one another from the first relative position to the second relative position or rotating the light control film and the laser relative to one another from the first relative position to the second relative position about an axis vertical to a plane of the light control film.
7. The method of claim 4 , wherein the first security feature comprises a portrait image, text data, or a logo, and the second security feature comprises a portrait image, text data, or a logo.
8. The method of claim 4 , wherein the light control film comprises a single layer or first and second layers.
9. A document that includes a light control film, the light control film having a plurality of micro light control structures formed in the film, and a first security feature formed in the micro light control structures, the first security feature is not visible when the document and the light control film are viewed at a first viewing angle, and the first security feature is visible when the document and the light control film are viewed at a first correct range of viewing angles, wherein the first security feature is formed in the micro light control structures at an angle that is different than the first viewing angle, and wherein the angle is within the first correct range of viewing angles, and
a second security feature formed in the micro light control structures, located in generally the same area and/or adjacent to the first security feature, the second security feature is not visible when the light control film is viewed at the first viewing angle or the first correct range of viewing angles, and the second security feature is visible when the light control film is viewed at a second correct range of viewing angles, and wherein the second security feature is formed in the micro light control structures at an angle that is different than the first viewing angle, and wherein the angle is within the second correct range of viewing angles.
10. The document of claim 9 , wherein the document is a plastic card or a passport.
11. The document of claim 10 , wherein the document includes a first generally transparent or translucent layer overlying a first side of the light control film, and a generally transparent or translucent layer overlying a second side of the light control film.
12. The document of claim 10 , wherein the document includes a first generally transparent or translucent layer overlying a first side of the light control film, and a nontransparent/nontranslucent layer overlying a second side of the light control film.
13. The document of claim 10 , wherein the first security feature comprises a portrait image, text data, or a logo, and the second security feature comprises a portrait image, text data, or a logo.
14. The document of claim 9 , wherein the document further comprises a second light control film having a second plurality of micro light control structures, wherein the micro light control structures of the light control film and the micro light control structures of the second light control film are disposed at an angle relative to one another so that the visibility of the first security feature and the visibility of the second security feature can be switched by rotating the document around a z-axis.
15. The document of claim 9 , wherein the light control film comprises a single layer or first and second layers.