Holographic Marking Composite Body Photosensitive Substrate Layer

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Solution Overview

Problem

Existing methods for integrating holograms into composite security documents are complex, particularly for mass production, and prone to errors, as they require precise coordination of individualized semi-finished products, making it difficult to correct manufacturing defects without rejecting the entire document.

Innovation Solution

A method and device that integrate a photosensitive substrate layer into the composite body, allowing for subsequent holographic marking using a master film applied to the composite body, enabling exposure and development of holograms in a simple manner, with the master film adapting to the composite body's surface for high-quality production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If holograms are integrated into composite security documents using prior art methods, then holographic security features are achieved, but the process becomes complex and error-prone requiring precise coordination of individualized semi-finished products

Engineering Contradiction:
Improvehologram integration reliabilityVSAvoidmarking process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the hologram integration process by introducing a separate photosensitive substrate layer that can be individually processed and then integrated into the composite body. This allows the hologram layer to be prepared independently with standard procedures, then combined with other document layers, reducing the complexity of coordinating all elements simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The photosensitive substrate layer is prepared in advance with holographic structures before final integration into the composite security document. This preliminary preparation allows standard production procedures to be used for creating the hologram layer, which is then integrated into the final document assembly, simplifying the overall process coordination.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If individualized semi-finished products are used for hologram production, then customization is achieved, but manufacturing defects require rejection of the entire document

Engineering Contradiction:
Improveindividualization capabilityVSAvoiddefect correction ease
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By separating the hologram layer into an independent photosensitive substrate layer, the patent enables individual replacement or correction of this specific layer without affecting other document components. If a defect occurs in the hologram layer, only that layer needs to be reprocessed rather than rejecting the entire individualized document.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables creation of hologram layers through copying processes where a master template can be used to generate multiple identical or individually customized hologram layers. This allows for easy reproduction and replacement of defective layers while maintaining the individualized characteristics of each document.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If embossed and surface holograms are used, then retrospective integration is possible, but they are very difficult to use for individual marking and require complex exposure and development

Engineering Contradiction:
Improveretrospective integration capabilityVSAvoidexposure and development complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical embossing and surface modification processes with a photosensitive layer exposure system. Instead of using embossing dies and complex development procedures, the invention uses coherent light exposure to create holographic structures in a photosensitive substrate layer, which can then be thermally developed using simple heating, greatly simplifying the overall process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If volume holograms are exposed into photosensitive film, then better protection against manipulation is achieved, but the film must remain stationary during exposure requiring contact with rigid support

Engineering Contradiction:
Improveanti-manipulation protectionVSAvoidexposure process ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent uses a flexible photosensitive substrate layer that can be mounted on cylindrical or conical drums during exposure. This flexible film approach allows the substrate to conform to the drum surface while maintaining photosensitivity, enabling easier handling and exposure compared to rigid film-on-plate contact methods, while still achieving volume hologram protection.

Inventive Principle:
Principle #30Flexible shells and thin films

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

This approach simplifies the holographic marking process, reduces errors, and allows for integration with other personalization steps, enhancing the production efficiency and adaptability of holograms within the composite body, while maintaining the quality of the hologram and the composite document.

Implementation Method 1

exposing the composite body with coherent radiation that interferes in the photosensitive area of the hologram layer in order to expose holographic information in the photosensitive area of the hologram layer

Methodology Applied
Scientific EffectPhotochemical reaction: Photopolymerisation

Implementation Method 2

The master includes at least one structure that influences light propagation. This structure can preferably be a hologram

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

coherent light is shone onto the master through the film, which is positioned in close proximity to the master and, as described, in contact with it. The diffracting or reflecting structures in the master diffract or reflect the light in such a way that the diffracted or reflected light is reflected back into the holographic film. There, it interferes with the coherent light used to illuminate the master. An interference pattern is thus formed in the holographic film

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP2948273B1Method for subsequent holographic writing and device for subsequent holographic writing
Publication Date: 2020.11.11 BUNDESDRUCKEREI GMBH
  • EP2948273B1 patent drawingFigure 1~2

AI summary

The invention relates to a device (100) for the subsequent holographic marking of a composite body (1) and a corresponding method that comprises the following steps: providing or producing the composite body (1), which comprises a hologram layer (3) that is photosensitive at least in one region (7); arranging the composite body (1) on or in a retainer (101); exposing the composite body (1) to coherent radiation (162) that interferes in the photosensitive region (7) of the hologram layer (3) in order to record holographic information in the photosensitive region (7) of the hologram layer (3) by exposure; fixing the hologram recorded by exposure in the hologram layer (3). In order to be able to make high-quality contact copies, it is specified that a master (130) in the form of a film is used, said master being applied to a front side (12) of the composite body (1).