Volume hologram comprising expansion agent layer or contraction agent layer for creating color patterns
AssigneeOVD Kinegram AG
InventorsAchim Hansen, Wayne Robert Tompkin, Markus Burkhardt, Michael Scharfenberg
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Abstract
The invention concerns a security element in the form of a multi-layer film body having a volume hologram layer with two different items of optical information and a process for the production of such a security element.
Claims18
A process for the production of a security element in the form of a multi-layer film body including the steps:
- providing a carrier film;
- applying a volume hologram layer formed from a photopolymer to the carrier film, the volume hologram layer having a volume hologram written into the photopolymer, the volume hologram providing a first item of information;
- applying at least one mask layer to the volume hologram layer, wherein the at least one mask layer is partially applied to the volume hologram layer in the form of a pattern;
- applying a full-area layer of at least one beam-hardenable or thermally hardenable expansion agent and/or contraction agent to the mask layer, wherein regions of the volume hologram layer not covered by the mask layer are in contact with the at least one expansion agent and/or contraction agent;
- allowing at least partial diffusion of the at least one expansion agent and/or contraction agent into the volume hologram layer with local expansion and/or contraction of the Bragg grating, thereby altering the volume hologram in the volume hologram layer to provide a second item of optical information, and
- beam hardening or thermally hardening
- the carrier film, the volume hologram layer, the mask layer, and the at least one expansion agent and/or contraction agent together to produce a multi-layer film body arranged as follows:
- carrier film,
- volume hologram layer,
- mask layer,
- expansion agent and/or contraction agent,
- wherein the mask layer is part of the multi-layer film body and is at least partially impervious to the at least one expansion agent and/or contraction agent and has openings which are pervious to the at least one expansion agent and/or contraction agent, and
- wherein different refractive indices are formed region-wise in the photopolymer of the volume hologram layer, which provide a Bragg grating with the provision of a first item of optical information, and
- wherein an adhesive layer is provided to the multi-layer film body for adhering the security element to a security document.
A process for the production of a security element in the form of a multi-layer film body including the steps:
- providing a carrier film,
- applying a full-area of at least one beam-hardenable or thermally hardenable expansion agent and/or contraction agent to the carrier film;
- applying at least one mask layer, wherein the at least one mask layer is partially applied to the at least one expansion agent and/or contraction agent in the form of a pattern;
- applying a volume hologram layer formed from a photopolymer to the at least one expansion agent and/or contraction agent and the mask layer which partially covers over the at least one expansion agent and/or contraction agent, the volume hologram layer having a volume hologram written into the photopolymer, the volume hologram providing a first item of information;
- allowing at least partial diffusion of the at least one expansion agent and/or contraction agent into the volume hologram layer with local expansion and/or contraction of the Bragg grating, thereby altering the volume hologram in the volume hologram layer to provide a second item of optical information, and
- beam hardening or thermally hardening
- the carrier film, the volume hologram layer, the mask layer, and the at least one expansion agent and/or contraction agent together to produce a multi-layer film body arranged as follows:
- carrier film,
- expansion agent and/or contraction agent,
- mask layer,
- volume hologram layer,
- wherein the mask layer is part of the multi-layer film body and is at least partially impervious to the at least one expansion agent and/or contraction agent and has openings which are pervious to the at least one expansion agent and/or contraction agent, and
- wherein different refractive indices are formed region-wise in the photopolymer of the volume hologram layer, which refractive indices provide a Bragg grating with the provision of a first item of optical information, and
- wherein an adhesive layer is provided to the multi-layer film body for adhering the security element to a security document.
A security element in the form of a multi-layer film body, wherein the security element has a volume hologram layer comprising a photopolymer, wherein different refractive indices are formed region-wise in the photopolymer to give a Bragg grating with the provision of a first item of optical information, wherein at least one beam-hardened or thermally hardened expansion agent and/or contraction agent is introduced in the form of a pattern within the volume hologram layer, which alters the lattice plane spacing of the lattice planes of the Bragg grating within the volume hologram layer, wherein a second item of optical information is provided, wherein a mask layer has been applied to the volume hologram layer in the regions in which the at least one expansion agent and/or contraction agent does not provide a pattern, wherein the mask layer is part of the multi-layer film body and is at least partially impervious to the at least one expansion agent and/or contraction agent and has openings which are pervious to the at least one expansion agent and/or contraction agent, and wherein an adhesive layer is provided to the multi-layer film body for adhering the security element to a security document.
Dependencies are inferred from the claim text.