Method of making holographic recording materials and articles formed thereby
View Patent ↗A method of manufacturing an article for display of a holographic image is described that includes thermally fusing a holographic recording medium containing a photochemically active dye dispersed in a transparent thermoplastic polymer binder to another layer or material; and then exposing the holographic film to intersecting beams of coherent light to form a holographic image therein formed by photoreacted areas of the photochemically active dye and unreacted areas of the photochemically active dye.
1. A method of manufacturing an article for display of a volume holographic image, comprising:
co-extruding a layer having a thickness of 1 μm to 2000 μm of a holographic recording medium comprising a photochemically active dye dispersed in and not chemically attached to a transparent thermoplastic polymer binder with a thermoplastic layer to thermally fuse the holographic recording medium with the thermoplastic layer thereby forming said article comprising a holographic recording layer having a thickness of 1 μm to 2000 μm thermally fused to the thermoplastic layer; and then
exposing the holographic recording layer having a thickness of 1 μm to 2000 μm to intersecting beams of coherent light to form a volume holographic image therein formed by photoreacted areas of the photochemically active dye and unreacted areas of the photochemically active dye.
2. The method of claim 1 wherein the thermal fusion comprises the formation of an interphase at the boundary between the adjacent layers wherein the interphase is composed of a molecular mixture of the polymer chains comprising the adjacent layers to create a monolithic structure which cannot be delaminated without degradation or destruction of the individual layers.
3. The method of claim 1 , further comprising:
thermally fusing the holographic recording medium having a plurality of surfaces including a first viewing surface and a second surface, capable of recording a holographic grating therein formed by photoreacted areas of the photochemically active dye and unreacted areas of the photochemically active dye; with
a second holographic recording medium having a composition that is the same as or different than the composition of the holographic recording medium and having a plurality of surfaces including a third viewing surface and a fourth surface, comprising a second photochemically active dye dispersed in a transparent polymeric binder and capable of recording a holographic grating therein formed by photoreacted areas of the second photochemically active dye and unreacted areas of the photochemically active dye;
wherein the second holographic recording medium has a thickness between the third and fourth surfaces that is the same as or different than a thickness between the first and second surfaces of the holographic recording medium, or wherein the third surface has a surface area that is the same as or different than the surface area of the first surface.
4. The method of claim 1 , wherein the holographic image is a transmission holographic image.
5. The method of claim 4 , wherein the thermoplastic layer is reflective, such that the holographic image is viewable from the same side of the article as an illuminating light source.
6. The method of claim 4 , wherein the thermoplastic layer is a contrast-enhancing or otherwise colored layer for enhanced hologram viewability.
7. The method of claim 1 , wherein the holographic image is a reflection holographic image.
8. The method of claim 1 , wherein the thermoplastic layer is an imaging layer, and further comprising recording a non-holographic image in the imaging layer.
9. The method of claim 8 , wherein the non-holographic image is recorded by laser marking.
10. The method of claim 1 , wherein the holographic recording medium is co-extruded with said thermoplastic layer and a second thermoplastic layer, the second thermoplastic layer having a composition that is the same as or different than the thermoplastic layer, such that the holographic recording medium is surrounded by the thermoplastic layer and the second thermoplastic layer material.