Optically variable film, apparatus and method for making the same
AssigneeIllinois Tool Works Inc.
InventorDean Randazzo
Life of this patent
Estimating the term…
Abstract
An apparatus for producing an optically variable film includes a laser configured to emit a beam, a telescoping lens section having a first lens and a second lens spaced apart by a first distance and an interferometer configured to direct the beam toward a workpiece. The laser may be operated at a predetermined power level and the first and second lenses are sized and spaced relative to one another to direct the beam onto the workpiece at about 200-230 dots per inch. The workpiece may include a polyethylene terephthalate (PET) layer configured to be ablated by the beam, forming a microstructure in the surface of the layer. The microstructure may be randomized and used to present non-chroma visual effects.
Claims15
1-6. (canceled)
A method of forming an optically variable film with an apparatus, the apparatus comprising a laser configured to emit a beam, a telescoping lens section having a first lens and a second lens spaced apart by a first distance and an interferometer configured to direct the beam toward a workpiece, the method comprising:
- operating the laser at a predetermined power level;
- selecting first and second lens focal lengths and determining the first distance;
- directing the beam toward the workpiece;
- and
- ablating the workpiece with the beam to form a microstructure in the workpiece,
- wherein the beam is emitted from the apparatus onto the workpiece at approximately 200-230 dpi and the workpiece includes a layer of polyethylene terephthalate (PET) exposed to the beam and in which the microstructure is formed.
A polyethylene terephthalate (PET) layer comprising:
- a surface having a microstructure formed therein in response to exposure to a beam emitted from a laser, the microstructure including a randomized section having a plurality of peaks having different heights and valleys having different depths,
- wherein the microstructure is configured to present a substantially non-chroma visual effect.
An optically variable film comprising:
- a base layer having a microstructure imprinted therein;
- and
- a reflective layer extending of the base layer and microstructure and substantially matching a profile of the microstructure,
- wherein the microstructure includes a randomized section having a plurality of peaks extending to different heights, valleys extending to different depths, and different slope magnitudes between adjacent peaks and valleys, and
- wherein the reflective layer, over the randomized section, produces a substantially non-chroma visual effect.
Dependencies are inferred from the claim text.