3D Security Ink Layers Using Cholesteric Liquid Crystal Segmentation
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Solution Overview
Problem
Industrial printing technologies for security elements, such as banknotes and documents, face limitations in generating three-dimensional effects using a limited number of mono-colour ink layers, leading to reduced 3-D perception due to the absence of shading and occlusion clues, which are essential for human brain interpretation of depth.
Innovation Solution
A method involving the use of a first and second ink layer with left-handed and right-handed circularly polarizing cholesteric liquid crystal pigments, applied in a way that they are superimposed or printed aside each other, forming stereoscopic projections of graphical objects composed of separate building blocks, allowing the underlying background to be visible between the blocks, thereby enhancing the 3-D appearance when viewed with circularly polarizing filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a limited number of mono-colour ink layers are used, then the device complexity is reduced, but the 3-D perception quality deteriorates due to reduced shading and occlusion clues
Solution Approach 1:
The graphical object is divided into separate building blocks, where each block can be independently rendered with different properties. This segmentation allows the use of a limited number of ink layers while maintaining 3-D perception quality, as each building block can provide distinct visual cues about depth and spatial relationships without requiring multiple colour layers.
Solution Approach 2:
The invention transitions from traditional 2-D printing to 3-D visual perception by using stereoscopic projections. The building blocks are arranged in a way that creates depth cues through spatial arrangement and occlusion relationships, enabling 3-D perception with limited ink layers by utilizing the third dimension of space rather than relying on multiple colour layers.
2Ease of manufacture
If mono-colour ink layers are used, then the manufacturing process is simplified, but the 3-D clues such as shades and occlusion are reduced or disappeared
Solution Approach 1:
By segmenting the graphical object into separate building blocks, the invention enables mono-colour printing while preserving 3-D information. Each building block can be strategically positioned to create occlusion relationships and depth cues, allowing the human brain to interpret three-dimensional structure from two-dimensional mono-colour representations through spatial arrangement rather than colour variation.
Solution Approach 2:
The invention uses stereoscopic projections that create virtual copies of the graphical object from different viewing angles. These projections are rendered as separate building blocks that, when viewed together, reconstruct the 3-D object. This copying approach allows mono-colour printing while maintaining 3-D perception through the stereoscopic effect.
3Quantity of substance
If only one or two mono-colour ink layers are available, then the quantity of substance is reduced, but the volume perception fades due to reduced 3-D clues
Solution Approach 1:
The invention compensates for the limited quantity of ink layers by utilizing spatial arrangement in the third dimension. Building blocks are positioned to create depth cues, occlusion relationships, and parallax effects that enable volume perception. This dimensional approach allows one or two ink layers to produce convincing 3-D volume by relying on spatial relationships rather than material quantity.
Solution Approach 2:
Segmenting the object into separate building blocks enables effective use of minimal ink layers. Each block can be strategically placed to provide specific 3-D cues, and the collective arrangement of these blocks creates volume perception. This segmentation allows the human brain to reconstruct three-dimensional volume from a limited number of mono-colour layers through spatial reasoning.
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 enables the creation of three-dimensional effects with a very limited number of colours, improving the perception of depth by providing necessary clues for the human brain, even with restricted printing units, and is applicable for security features in various documents and goods.
Implementation Method 1
one of said ink layers shows a first colour at a certain viewing angle and is a left-handed circularly polarizing coating or comprises left-handed circularly polarizing pigment, and the other of said ink layers shows the same or another colour at said viewing angle and is a right-handed circularly polarizing coating or comprises right-handed circularly polarizing pigment
Implementation Method 2
left-handed and right-handed circularly polarizing cholesteric liquid crystal pigments
Data Source
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AI summary
The present invention is related to a device useful as a security element comprising first and second LC ink layers representing a graphical object exhibiting, when observed with an appropriate viewing equipment, a three-dimensional appearance, wherein one of said ink layers shows a first colour at a certain viewing angle and is a left-handed circularly polarizing coating or comprises left-handed circularly polarizing pigment, and the other of said ink layers shows the same or another colour at said viewing angle and is a right-handed circularly polarizing coating or comprises right-handed circularly polarizing pigment, said first and second LC ink layers representing a first and a second image corresponding to a pair of stereoscopic projections of said object, characterized in that said first and second images are composed of separate building blocks which are superimposed or can be superimposed.