Security holograms formed using lenticular multichannel image generation device
AssigneeM R Stephenson Group Limited
InventorsPatrick Flynn, John David Wiltshire, Jonathan Henry Wiltshire
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Abstract
We describe methods of mass-producing full color, 3D holograms, potentially incorporating a personalized image, which are particularly suitable for security purposes. Broadly speaking in embodiments a method generates, electronically, an interlaced image comprising a set of different views of a 3D object from different angles. This is projected onto a diffusing screen using coherent light and mapped from the screen into an angularly encoded object beam using a lenticular array. The different views in the angularly encoded object beam are then recorded simultaneously into holographic film using a reference beam.
Claims14
A method of recording a holographic image onto holographic recording film, said holographic image comprising a hologram of a three-dimensional (3D) object from a lenticular multi-channel image generation device, the method comprising:
- forming a holographic recording stack by:
- positioning said holographic recording film over said lenticular multichannel image generation device;
- locating an optical diffuser beneath said lenticular multichannel image generation device;
- generating, electronically, an interlaced image comprising a set of different views of the 3D object from different angles;
- projecting the generated image into the diffuser;
- combining the different views of the 3D object using said lenticular multichannel image generation device by mapping from the set of different views of the 3D object from different angles into an angularly encoded object beam using the lenticular multichannel image generation device so that the views can be replayed distinct from one another;
- and
- recording said holographic image in said holographic recording film by forming a volume hologram by illuminating said stack through said holographic recording film with a laser light of at least one wavelength to record all the different angles simultaneously into the volume hologram,
- wherein said volume hologram comprises a volume reflection hologram of said lenticular multi-channel image generated by said lenticular multichannel image generation device such that a moving 3D view of the object is obtained when the hologram is replayed.
Apparatus for recording a security hologram in holographic recording film, said holographic image comprising a hologram of a three-dimensional (3D) object formed by a lenticular multi-channel holographic image, said apparatus including a stack comprising:
- said holographic recording film;
- a lenticular screen under said holographic recording film to generate a three-dimensional (3D) object;
- and
- an optical diffuser beneath a lenticular multichannel image generation device comprising the lenticular screen;
- and a reference laser beam arranged to illuminate said holographic recording film from above;
- and
- an object laser beam arranged to illuminate said optical diffuser beneath said lenticular multichannel image generation device;
- wherein an image under said lenticular screen comprises a multiplexed image containing stereographic depth or animation, and
- wherein said hologram comprises a volume reflection hologram of said lenticular multichannel holographic image.
Dependencies are inferred from the claim text.