3D Achromatic Hologram Security Device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current achromatic holograms are difficult to distinguish from simulated versions due to their 2D nature, making them vulnerable to counterfeiting as dot-matrix systems can replicate them, and existing decorative foils and dot-matrix systems are not designed to produce effective achromatic effects.
Innovation Solution
A security device with a surface relief optically variable effect structure that combines three diffractive image generating structures to create a 3D achromatic image, providing movement when tilted, and includes a second image plane for enhanced verification, with specific spacing and symbol design criteria to ensure visibility and recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 2D achromatic hologram is used, then it is difficult to counterfeit initially, but it can soon be replicated by dot-matrix systems making it easy to counterfeit
Solution Approach 1:
The patent transitions from 2D achromatic holograms to 3D achromatic holograms by introducing a depth dimension. The diffractive structure creates images at different focal distances (front, middle, rear planes) along the optical axis, enabling pronounced parallax effects and depth perception that dot-matrix systems cannot replicate, thus maintaining counterfeit resistance while improving security reliability.
Solution Approach 2:
The patent introduces dynamic visual effects through tilting motion. When the security device is tilted, the achromatic image moves relative to the substrate edge at a rate of at least 6mm per radian of tilt. This dynamic movement behavior is difficult to replicate and enhances the ability to detect counterfeits while maintaining the achromatic effect's inherent security advantages.
2Shape
If the achromatic image is located in a plane spaced from the substrate surface, then pronounced holographic depth is achieved, but the image may be difficult to verify without movement
Solution Approach 1:
The patent uses tilting-induced motion to enable verification. When the device is tilted, the spaced achromatic image moves relative to the substrate edge at a rate of at least 6mm per radian, making the depth effect visually apparent and easy to verify. This dynamic verification method maintains the pronounced holographic depth while solving the verification difficulty.
Solution Approach 2:
The patent incorporates a second image plane containing reference features (such as non-diffractive symbols or achromatic symbols) that remain stationary or move differently when tilted. This provides visual feedback that confirms the presence of the spaced achromatic image and its depth, enabling easy verification of the holographic effect.
3Illumination intensity
If the grating pitch is increased to achieve achromatic effect, then light dispersion is reduced, but the first order diffractive image moves close to the specular reflection limiting visual effectiveness
Solution Approach 1:
The patent resolves the angle separation problem by moving the diffractive image into the depth dimension. Instead of trying to separate the first order image from the specular reflection in the 2D plane, the invention creates images at different focal distances along the optical axis. This allows the achromatic image to be spatially separated from the substrate edge in the depth direction, maintaining visual effectiveness while achieving the desired achromatic brightness through appropriate grating pitch selection.
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 provides a secure, verifiable achromatic image with pronounced holographic depth, making it difficult to counterfeit, while ensuring the symbol is recognizable and resistant to diffusion effects under various lighting conditions.
Implementation Method 1
a surface relief optically variable effect generating structure formed by the super position of three diffractive image generating structures which respond to respectively different colour components or wavelength ranges of white light to generate a first, substantially achromatic image
Data Source
AI summary
A security device including a substrate carrying a surface relief optically variable effect generating structure formed by the super position of three diffractive image generating structures (rear, surface and front planes) which respond to respectively different color components or wavelength ranges of white light to generate a first, substantially achromatic image or background pattern located in a plane spaced from the surface of the substrate.