Holographic data support and method for production thereof
AssigneeBundesdruckerei GmbH
InventorsJens Ehreke, Michael Knebel, Tomas Loeer, Oliver Muth, Rainer Seidel
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Abstract
The invention relates to a data support (1) with a core layer (15) and at least one adjacent layer (14a), laminated to the core layer and a corresponding production method, said core layer being embodied from a holographic data store in the form of a volume hologram (5). The surface (141) facing the core layer, on the layer directly adjacent to the core layer, has a roughness (19), before lamination to the core layer, which affects the wavelength shift of the image reconstructed by the volume hologram.
Claims22
A data carrier comprising,
- a holographic data memory consisting of a core layer, said core layer containing regions of different refractive index from which a holographic image may be reconstructed by exposure to incident light;
- and
- an adjacent layer laminated to said core layer, said adjacent layer having an inner surface facing said core layer, said inner surface having an average roughness before lamination to the core layer of about 5 μm to 25 μm so as to result in a wavelength shift of the holographic image reconstructed from said core layer of about 20 nm.
A method of manufacturing a data carrier with a holographic data memory, said method comprising the steps of:
- a) providing a holographic data memory consisting of a core layer, said core layer containing regions of different refractive index from which a holographic image may be reconstructed by exposure to incident light, said core layer having a first surface;
- b) providing an adjacent layer having an adjacent surface with a roughness;
- and
- c) then laminating the adjacent layer to the core layer so that the adjacent surface of the adjacent layer is in contact with the first surface of the core layer;
- wherein the adjacent surface of the adjacent layer has an average roughness of about 5 μm to 25 μm so as to produce a wavelength shift of the holographic image reconstructed from said core layer of at least 20 nm.
A data carrier comprising:
- a holographic data memory consisting of a core layer of light-sensitive material in which regions of different refractive index are inserted by exposure to coherent radiation of a certain wavelength so that a holographic image may be reconstructed by refraction of incident light at said regions and interference within reflected light;
- and
- an adjacent layer laminated to said core layer whose inner surface facing said core layer has a regular or irregular roughness a pattern so as to shift the wavelength of said holographic image reconstructed from said core layer by said incident light;
- wherein said inner surface has an average roughness before lamination to the core layer of about 5 μm to 25 μm so as to result in a wavelength shift of the holographic image reconstructed from said core layer of about 20 nm.
A method of manufacturing a data carrier comprising the steps of:
- a) providing a holographic data memory consisting of a core layer of light sensitive material in which regions of different refractive index have been inserted by exposure to coherent radiation of a certain wavelength so that a holographic image may be reconstructed by refraction of incident light at said regions and interference within reflected light;
- b) providing an adjacent layer having an adjacent surface provided with a regular or irregular roughness;
- and
- c) laminating said adjacent layer and said core layer so that said adjacent surface of said adjacent layer is firmly connected with a first surface of said core layer;
- wherein a wavelength shift of said holographic image reconstructed from said holographic data memory by exposure to the incident light is observed;
- and
- wherein the adjacent surface has an average roughness of about 5 μm to 25 μm so that said wavelength shift of said holographic image reconstructed from said core layer is about 20 nm.
Dependencies are inferred from the claim text.