Holographic security device
First Claim
1. A holographic security debice comprising first and second holographic image generating microstructure, each structure having been originated by creating an intermediate first hologram from a respective object and a first reference beam, the two first intermediate holograms then having been illuminated with respective transfer beams which were the conjugates of the corresponding first reference beams to reconstruct their respective objects as holographic images which were then used to record the first and second holographic image generating structures on a common holographic recording medium through the process if optical interference with a second reference beam, wherein the microstructures are recorded in respective sets of substantially non-overlapping regions of the recording medium, the regions of one set being interleaved with regions of the other set, whereby the dimensions and pattern of the interleaving is substantially non-resolvable to the unaided eye, whereby the holographic security device generates two visually distinct holographic images viewed from separate viewing directions around the device and normally seen by tilting the device, and whereby each particular holographic image in viewing direction is generated structure associated with one or other set of interleaved region.
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Abstract
A holographic security device comprising first and second holographic generating structures (2,3) recorded in respective sets of substantially non-overlapping regions of a record medium is disclosed. The regions of one set are interleaved with regions of the other set, whereby both interleaved line structures are substantially non-visible to the unaided eye, whereby the holographic security device generates two or more holographic images (A,B) viewed from separate viewing directions around the device and normally seen by tilting the device. Each particular holographic image in a viewing direction is generated in whole or part by the holographic structure associated with one set of interleaved lines.
101 Citations
20 Claims
- 1. A holographic security debice comprising first and second holographic image generating microstructure, each structure having been originated by creating an intermediate first hologram from a respective object and a first reference beam, the two first intermediate holograms then having been illuminated with respective transfer beams which were the conjugates of the corresponding first reference beams to reconstruct their respective objects as holographic images which were then used to record the first and second holographic image generating structures on a common holographic recording medium through the process if optical interference with a second reference beam, wherein the microstructures are recorded in respective sets of substantially non-overlapping regions of the recording medium, the regions of one set being interleaved with regions of the other set, whereby the dimensions and pattern of the interleaving is substantially non-resolvable to the unaided eye, whereby the holographic security device generates two visually distinct holographic images viewed from separate viewing directions around the device and normally seen by tilting the device, and whereby each particular holographic image in viewing direction is generated structure associated with one or other set of interleaved region.
- 15. A transfer assembly comprising a carrier and a holographic security device detachably secured to the carrier, the holographic security device comprising first and second holographic image generating microstructures, each structure having been originated by creating an intermediate first hologram from a respective object and a first reference beam, the two first intermediate holograms then illuminated with respective transfer beams which were the conjugates of the corresponding first reference beams to reconstruct their respective objects as holographic images which were then used to record the first and second holographic image generating structures on a common holographic recording medium through the process of optical interference with a second reference beam, wherein the microstructures are recorded in respective sets of substantially non-overlapping regions of the recording medium, the regions of one set being interleaved with regions of the other set, whereby the dimensions and pattern of the interleaving is substantially non-resolvable to the unaided eye, whereby the holographic security device generates tow visually distinct holographic images viewed from separate viewing directions around the device and normally seen by tilting the device, and whereby each particular holographic image in a viewing direction is generated in whole or part by the holographic image generating structure associated with one or other set of interleaved regions.
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17. A document or other article carrying a holographic security device comprising first and second holographic image generating microstructures, each structure having been originated by creating an intermediate first hologram from a respective object and a first reference beam, the two first intermediate holograms then having been illuminated with respective transfer beams which were the conjugates of the corresponding first reference beams to reconstruct their respective objects as holographic images which were then used to record the first and second holographic image generating structures on a common holographic recording medium through the process of optical interference with a second reference beam, wherein the microstructures are recorded in respective sets of substantially non-overlapping regions of the recording medium, the region of one set being interleaved with regions of the other set, whereby the dimensions and pattern of the interleaving is substantially non-resolvable to the unaided eye, whereby the holographic security device generates two visually distinct holographic images viewed from separate viewing directions around the device and normally seen by tilting the device, and whereby each particular holographic image in a viewing direction is generated in whole or part by the holographic image generating structure associated with one or other set of interleaved regions.
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18. A method of manufacturing a transfer hologram, the method comprising creating a pair of intermediate first holograms from respective objects and first reference beams;
- illuminating the two first intermediate holograms with respective transfer beams which are the conjugates of the corresponding first reference beams to reconstruct their respective objects as holographic images;
using the holographic images to record first and second holographic image generating microstructures on a common holographic recording medium through the process of optical interference with a second reference beam, wherein the microstructures are recorded in respective sets of substantially non-overlapping regions of the recording medium, the regions of one set being interleaved with regions of the other set, whereby the dimensions and pattern of the interleaving is substantially non-resolvable to the unaided eye, whereby the transfer hologram generates two visually distinct holographic images viewed from separate viewing directions around the hologram and normally seen by tilting the hologram, and whereby each particular holographic image in a viewing direction is generated in whole or part by the holographic image generating structure associated with one or other set of interleaved regions. - View Dependent Claims (19, 20)
- illuminating the two first intermediate holograms with respective transfer beams which are the conjugates of the corresponding first reference beams to reconstruct their respective objects as holographic images;
Specification