Double Hologram Security Element with Reflection-Transmission Reconstruction
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Solution Overview
Problem
Existing security elements and methods for producing holograms lack advanced optical features that provide enhanced protection and complexity, making them susceptible to reworkability and insufficient for modern security document requirements.
Innovation Solution
A method and device for producing a double hologram that allows for reflection and transmission reconstruction, utilizing a device with a holder, coherent light source, beam splitter, and reflection device to create a volume reflection hologram that can be duplicated through contact copying, incorporating a surface pattern generator and diffuser for individualization and increased perceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single hologram is used for security elements, then the production process is simple, but the security protection level is insufficient and the element is susceptible to reworkability
Solution Approach 1:
The invention divides a single hologram into two separate holograms (first hologram and second hologram) that are superimposed on the same recording area. This segmentation allows each hologram to serve distinct security functions while maintaining individual verifiability, thereby enhancing overall security protection without requiring a completely new complex system
Solution Approach 2:
The patent implements a nested structure where one hologram is embedded within or superimposed on another hologram in the same recording area. The first hologram and second hologram are positioned such that they occupy overlapping or adjacent regions, creating a nested arrangement that maximizes security features within the constrained space of the security element
2Adaptability or versatility
If a volume reflection hologram is used, then the hologram can be reconstructed in reflection, but the angular selectivity is high which limits the range of reconstruction angles
Solution Approach 1:
The invention combines two different types of holograms (volume reflection hologram and volume transmission hologram) in the same recording area. This composite approach allows the security element to exhibit both reflection and transmission properties, effectively broadening the range of reconstruction angles and viewing conditions while maintaining the manufacturing precision required for each individual hologram type
3Productivity
If the recording area is fully utilized for one hologram, then the production efficiency is high, but the security feature complexity is insufficient
Solution Approach 1:
The patent merges two distinct holograms into a single recording area of the recording material. By superimposing the first hologram and second hologram in the same spatial region, the invention achieves enhanced security feature complexity without requiring additional recording material or increasing the overall production cycle time, thus maintaining high production efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The double hologram offers a complex security feature that can be reconstructed in both reflection and transmission, providing enhanced protection and flexibility in production and duplication, while reducing angular selectivity and increasing the range of reconstruction angles, thus improving the security and usability of security documents.
Implementation Method 1
A security feature is a feature that is used to prove the authenticity and genuineness of an object that is linked to the security element and its security feature. Security elements can be semi-finished products that are incorporated into an object, for example, or they can be finished security items. Security documents and documents of value are examples of security elements.
Implementation Method 2
a reflection device (90) is formed at a distance (91) from the object side (21) of the holder (10), which reflects back into itself the reference light (66) that has radiated through the holder (10)
Implementation Method 3
If the layer thickness is in the order of magnitude of the wavelength of the light with which the interference structures are produced or can be produced, then one speaks of a thin hologram. If, on the other hand, the material thickness of the recording material in which the interference structures are stored is in the order of magnitude of a multiple, for example ten times, the wavelength of the light with which the interference structures are produced or can be produced, one speaks of a so-called thick hologram or volume hologram.
Data Source
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AI summary
The invention relates to a method for producing a double hologram (100) comprising the steps of: providing a recording material (20); generating coherent light (40) which is divided into a reference component (60) and an object component (50); guiding the object component (50) onto an object (80) such that object light (55) emanating from the object (80) strikes a side (21) of the recording material (20) facing the object (80) and illuminates it; guiding the reference component (60) such that this reference component (60) strikes a side (22) of the recording material (20) facing away from the object (80) at a reference angle (β) and illuminates it;so that an interference pattern arising with the object light (55) is recorded in the recording material (20), characterized in that the reference component (66) emerging from the facing side (21) of the recording material (20) is reflected back into itself, so that the reflected reference component (67) acts on the interference pattern. Furthermore, the invention relates to a device for producing such a double hologram (100), a method for duplicating it, and a security document (400) with such a double hologram (100).