Anisotropic Diffuser and Colorshift Layer for Security
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Solution Overview
Problem
Holographic security technologies are becoming less effective due to widespread access and ease of replication, leading to a need for new security devices that can provide distinct image flipping and colorshift effects without the limitations of traditional holograms.
Innovation Solution
Combining an anisotropic diffuser with patterned anisotropy and a colorshift layer or coating, such as a cholesteric film or interference film, to create an optical component that exhibits distinct image flipping and colorshift effects, allowing for enhanced security features like image flipping without concomitant colorshifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If holographic structures are used to provide image flipping effect, then image flipping is achieved, but concomitant colorshifts occur which are difficult to control separately
Solution Approach 1:
The patent divides the optical component into two separate functional layers: an anisotropic diffuser layer that provides image flipping effect and a colorshift layer that provides colorshift effect. This segmentation allows each layer to independently control its respective optical effect without the unwanted concomitant colorshifts that occur in holographic structures.
Solution Approach 2:
The anisotropic diffuser layer has locally varying anisotropy properties that are specifically designed to control image flipping in certain directions while being substantially non-periodic to avoid rainbow effects. This local quality control enables precise separation of image flipping from colorshift effects.
2Reliability
If traditional holographic security devices are used, then security features are provided, but they become easily replicable and lose importance in security applications
Solution Approach 1:
The patent creates a composite optical component combining two different optical mechanisms (anisotropic diffuser and colorshift layer) that work together to provide enhanced security features. This composite structure is more difficult to replicate than traditional single-mechanism holograms, thereby improving security effectiveness and resistance to counterfeiting.
3Measurement precision
If anisotropic diffuser with substantially non-periodic structure is used, then clear image flipping is achieved, but combination with colorshift effects is difficult
Solution Approach 1:
By segmenting the optical component into separate layers with distinct functions, the patent simplifies the combination of anisotropic diffuser and colorshift effects. The anisotropic diffuser layer maintains clear image flipping with non-periodic structure, while the separate colorshift layer adds colorshift functionality without interfering with the image flipping clarity.
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 combination enables a higher security level by allowing precise control over image flipping and colorshift effects, providing a clearer and more recognizable visual change when viewed from different angles, thus enhancing the security features of optical devices.
Implementation Method 1
The local orientation of the optically effective structure determines the direction into which light is diffracted
Implementation Method 2
a colourshift layer structure (40) is provided which provides a colourshift observable upon changing viewing angle and/or changing angle of incident light
Implementation Method 3
the means for providing a colourshift observable upon changing viewing angle and/or changing angle of incident light comprise a cholesteric film (20)
Data Source
AI summary
The present invention relates to a new optical component comprising an anisotropic diffuser (5,10) with patterned anisotropy; and means (9, 11, 14, 16, 17, 20, 21, 30, 32) for providing a colorshift observable upon changing viewing angle (6) and/or changing angle of incident light (2). It also relates to methods for making such an optical component and uses of such optical components as security elements with a very high level of security.