Laser marked device
An optical device projecting one or more synthetically magnified images that has been laser marked with one or more static two dimensional (2D) images is provided. The static 2D image(s) laser marked on or within this device and the synthetically magnified image(s) projected by this device help determine the authenticity of a document (e.g., passport data page) or product that employs it. Several embodiments of the inventive device also offer increased resistance to tampering or alteration and wear.
1. A method for laser marking one or more static two dimensional images on or within a device that embodies or comprises an optical film material, wherein the optical film material projects at least one synthetically magnified image, wherein the method comprises:
identifying one or more layers or interfaces within the optical film material that may be damaged by laser energy, or by heat or gas generated by laser absorption within a laser receptive layer, wherein said layers or interfaces are laser sensitive layers or interfaces;
either positioning one or more layers markable by laser energy above the laser sensitive layer or interface, positioning one or more thermal spacer layers and one or more laser markable layers below the optical film material, the one or more thermal spacer layers being located between the optical film material and the one or more laser markable layers, wherein the thermal spacer layer protects against the damage that may be caused by the laser energy, heat or gas generated during laser marking, modifying the laser sensitive interface to increase the bond strength and/or thermal resistance of the interface, or replacing the laser sensitive layer with a layer made from a material with a higher bond strength and/or a higher thermal resistance;
optionally, molding the layers together using heat and pressure to form a device that embodies the optical film material; and
exposing the device to laser energy so as to mark one or more static two dimensional images on or into the one or more laser markable layers.
2. The method of claim 1 , wherein one or more laser markable layers are positioned above the laser sensitive layer.
3. The method of claim 2 , wherein the optical film material is made up of one or more optionally encapsulated arrangements of refractive focusing elements and one or more arrangements of image icons disposed on opposing sides of an optical spacer layer, wherein the one or more arrangements of image icons constitute the one or more layers within the optical film material that may be damaged by laser energy.
4. The method of claim 2 , wherein the optical film material is made up of one or more optionally encapsulated arrangements of reflective focusing elements and one or more arrangements of image icons disposed on opposing sides of an optical spacer layer, wherein the one or more optionally encapsulated arrangements of reflective focusing elements constitute the one or more layers within the optical film material that may be damaged by laser energy.
5. The method of claim 1 , wherein the one or more layers markable by laser energy are prepared using thermoplastic polymers selected from the group of polyethersulfone, polysulfone, polycarbonate, and polyphenylene sulfide.
6. The method of claim 5 , wherein the one or more layers markable by laser energy are laser markable transparent polycarbonate films.
7. The method of claim 5 , wherein the one or more layers markable by laser energy are laser markable clear polycarbonate sheets.
8. The method of claim 1 , wherein the one or more layers markable by laser energy are prepared using one or more laser additives and one or more thermoplastic polymers selected from the group of polystyrene, styrene acrylonitrile, acrylonitrile butadiene styrene, polyethylene terephthalate, glycol-modified polyethylene terephthalate, polybutylene terephthalate and polyethylene.
9. The method of claim 8 , wherein the one or more laser additives comprise carbon black.
10. The method of claim 2 , wherein the device is exposed to an amount of laser energy sufficient to make a legible mark within a laser markable layer.
11. The method of claim 1 , wherein one or more thermal spacer layers and one or more laser markable layers are positioned below the optical film material, the one or more thermal spacer layers being located between the optical film material and the one or more laser markable layers.
12. The method of claim 11 , wherein the optical film material comprises an arrangement of encapsulated refractive focusing elements and an arrangement of image icons that are separated by an optical spacer layer.
13. The method of claim 11 , wherein the one or more thermal spacer layers are prepared using a clear thermoplastic material.
14. The method of claim 11 , wherein the one or more thermal spacer layers have a thickness ranging from about 5 to about 500 microns.
15. The method of claim 11 , wherein the device is exposed to an amount of laser energy sufficient to make a legible mark within a laser markable layer.