Volume Hologram Layer with Partial Opaque Decorative Layer
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Solution Overview
Problem
Existing volume holograms used in security documents require expensive preparation on dark backgrounds to maintain visibility, limiting their application to specific substrates and making them vulnerable to forgery.
Innovation Solution
A multilayer body comprising a volume hologram layer and a partial opaque layer, applied in specific areas, allowing the multilayer body to be applied to any background without compromising optical quality, and featuring a decorative layer that enhances security and difficulty in forgery through complex optical effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a volume hologram layer is made transparent to achieve high brilliance, then optical quality is improved, but the substrate requires expensive preparation on dark backgrounds
Solution Approach 1:
The substrate preparation is segmented into multiple functional layers: a dark background layer for optical contrast, a decorative layer for aesthetic purposes, and a protective layer for durability. This segmentation allows the transparent volume hologram to maintain high brilliance while the substrate preparation costs are distributed across standardized industrial layers rather than requiring expensive custom preparation.
Solution Approach 2:
A decorative layer is introduced as an intermediary between the transparent volume hologram and the substrate. This intermediate layer provides the necessary dark background for optical contrast while allowing the hologram to remain transparent and brilliant, eliminating the need for expensive direct substrate preparation.
2Adaptability or versatility
If a transparent volume hologram is applied to light backgrounds, then application versatility is improved, but visibility and brilliance of optical effects deteriorate
Solution Approach 1:
The decorative layer exhibits local quality by being transparent in regions where the volume hologram requires light transmission (maintaining brilliance) and opaque or dark in regions where background contrast is needed (maintaining visibility). This spatially varying optical property allows the structure to adapt to different background conditions while preserving hologram performance.
Solution Approach 2:
The decorative layer is constructed as a composite material combining transparent and opaque regions, or transparent regions with dark pigments/patterns. This composite structure enables the layer to simultaneously provide background contrast where needed and optical transparency where the hologram requires light transmission, resolving the contradiction between versatility and visibility.
3Device complexity
If a simple single-layer structure is used, then device complexity is reduced, but protection against forgery deteriorates
Solution Approach 1:
The security structure employs a nested configuration where the volume hologram layer is embedded within a multi-layer assembly including decorative layers and protective layers. Each layer contributes a different security function: the hologram provides optical verification, the decorative layer provides pattern complexity, and the protective layer provides physical security. This nested arrangement increases forgery resistance while maintaining manageable overall complexity.
Solution Approach 2:
The multilayer body is constructed as a composite security element combining materials with different optical and physical properties. The volume hologram layer uses photopolymer or similar materials for optical effects, the decorative layer uses pigmented or patterned materials for visual complexity, and the protective layer uses durable materials for physical security. This material composite approach creates a security system that is difficult to forge while maintaining structural coherence.
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
Simplifies the preparation process by enabling application on various backgrounds, increases protection against forgery through intricate optical interactions, and maintains high visibility and brilliance of the hologram effects.
Implementation Method 1
volume holograms, also called white-light holograms, are based on light diffraction at the Bragg planes inside a transparent layer which thereby has local differences in refractive index
Implementation Method 2
light diffraction at the Bragg planes inside a transparent layer
Implementation Method 3
by overlaying the light irradiated onto the master and the light diffracted by the master an interference pattern forms which is recorded in the photosensitive layer
Implementation Method 4
The volume hologram thus introduced into the photosensitive layer is then fixed after curing of the photosensitive layer
Data Source
AI summary
A security document having a security element including a multilayer body with a volume hologram layer and a partial opaque layer, arranged on a surface of the volume hologram layer, which is present in a first area and is not present in a second area.