Multi-layer body with diffractive optical elements
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Solution Overview
Problem
Existing security documents lack effective optically active elements that provide distinct and memorable visual effects when viewed from different angles or under varying lighting conditions, limiting their security and decorative applications.
Innovation Solution
A multi-layer body with a transparent layer containing optically active elements, featuring differently oriented partial areas with varying refractive indices, which create unique optical effects when illuminated from both sides, allowing for distinct image information to be visible from different viewing angles and lighting situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent layer is used in a window area to allow light transmission, then light can penetrate from both sides for illumination, but the window cannot display non-transparent reflecting images
Solution Approach 1:
The transparent layer is divided into multiple partial areas (first partial area, second partial area, etc.), each containing optically active elements with different refractive index variations. This segmentation allows different regions to perform different optical functions - some regions transmit light while others create reflecting images, resolving the contradiction between transparency and image display capability.
Solution Approach 2:
Different partial areas within the transparent layer have locally varied refractive indices created by different arrangements of optically active elements. The first partial area has a first arrangement of elements with first refractive index variations, while the second partial area has a second arrangement with second refractive index variations. This local quality differentiation enables the same transparent layer to provide both light transmission and image display functions in different regions.
2Reliability
If optically active elements are arranged to create distinct optical effects from different angles, then security and decorative features are enhanced, but the structure becomes more complex
Solution Approach 1:
Multiple optically active elements with different refractive index variations are combined within the same transparent layer to create a unified security feature. The first and second partial areas with their respective optically active elements work together to produce distinct optical effects from different viewing angles, enhancing security while maintaining a single integrated structure rather than separate complex components.
Solution Approach 2:
The security feature utilizes changes in the refractive index parameter of the transparent layer in different partial areas. By varying the refractive index through different arrangements of optically active elements, the structure creates angle-dependent optical effects without requiring complex mechanical or structural arrangements, thus enhancing security with relatively simple parameter-based differentiation.
3Adaptability or versatility
If different partial areas with varying refractive indices are created, then distinct image information becomes visible from different viewing angles, but the manufacturing precision requirements increase
Solution Approach 1:
The patent uses optical copying techniques to create the different refractive index arrangements in the transparent layer. The optically active elements are arranged to form refractive index patterns that replicate the desired optical effects, allowing different image information to be copied into different partial areas with controlled refractive index variations, thereby achieving viewing angle dependency while managing manufacturing precision through optical copying methods.
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 solution enables the creation of non-transparent reflecting images in a transparent window, providing unmistakable and memorable optical effects, enhancing security and decorative features by ensuring image information is only visible under specific lighting conditions, thus improving security and aesthetic appeal.
Implementation Method 1
both the light falling on the front and the back of the security element is diffracted by the optically active elements
Implementation Method 2
the transparent layer having at least a first and a second partial area with varying refractive index
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3
AI summary
The invention relates to a multi-layer body (7) having a carrier substrate (750) and having a transparent layer (720), which is arranged at least partially in a window (70) or in a transparent region of the carrier substrate (750). The transparent layer (720) comprises at least one first (71a) and one second partial region (71b) having a varying refractive index, arranged next to each other in the layer plane formed by the transparent layer (720) and at least partially in the window (7) or in the transparent region of the carrier substrate (75). Each partial region (71a, 71b) comprises a plurality of periodically arranged knots, forming an element with an optical effect and formed by refractive index variation, arranged in planes running substantially parallel to each other. The planes in the at least one first partial region (71a) are not parallel to the planes in the at least second partial region (71b). In at least one of the partial regions (71a, 71b) the planes neither run in parallel nor perpendicular to the layer plane. Thus, the incident light on the front and also on the back of the multi-layer body (7) is diffracted due to the elements with an optical effect and the elements form an optical effect that differs in the front view and in the rear view in incident light.