Inclined Diffractive Security Element for Wider Viewing Angles
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Solution Overview
Problem
Conventional diffractive-based security elements have limited viewing angles and are difficult to view due to diffraction orders being far removed from the direction of specular reflection, making them inconvenient for ergonomic viewing.
Innovation Solution
A security element with an array of image regions, each comprising inclined diffractive optically variable effect generating structures, arranged to display images at various viewing angles by inclining diffractive elements within 45° of a direction, ensuring diffraction orders are visible at more natural angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffractive devices with specialised diffractive grating structures and periodicities similar to or less than the mean visible wavelength are used, then the optically variable effect is enhanced, but the viewing angle range becomes narrow and restricted
Solution Approach 1:
The patent introduces a third dimension by inclining the diffractive structure relative to the security element surface. This inclination angle allows diffraction orders to be directed toward ergonomic viewing positions without compromising the optically variable effect, effectively adding a dimensional parameter to control viewing geometry.
Solution Approach 2:
The patent modifies the geometric parameters of the diffractive structure by specifying inclination angles between 10° and 45° relative to the security element surface. This parameter change enables the diffraction orders to be positioned at ergonomic viewing angles while maintaining the specialized grating periodicities for enhanced optical variability.
2Ease of operation
If diffractive structures are inclined to bring diffraction orders closer to ergonomic viewing angles, then the viewing comfort is improved, but the device thickness increases
Solution Approach 1:
The patent applies partial inclination to only the diffractive structure rather than the entire security element. The diffractive structure is inclined at 10°-45° while remaining embedded in or on the security element surface, providing ergonomic viewing without requiring the whole device to be thick or tilted.
Solution Approach 2:
The patent creates local quality by inclining only the diffractive structure in specific regions where optical variability is needed, while the rest of the security element maintains its original geometry. This localized inclination provides viewing comfort without increasing overall device thickness.
3Ease of operation
If the diffractive structure is inclined relative to the security element surface, then diffraction orders become visible at natural viewing angles, but the manufacturing complexity increases
Solution Approach 1:
The patent merges the inclination feature with the diffractive structure formation process. The inclined diffractive structure is created as an integrated feature during manufacturing, combining the optical function with the structural geometry in a single manufacturing step rather than requiring separate assembly operations.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and pre-setting the inclination angle during the design and manufacturing phase. The diffractive structure is formed with the predetermined 10°-45° inclination built-in, eliminating the need for post-manufacturing adjustment or complex assembly procedures.
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 enhances the visibility of diffraction orders at ergonomic viewing angles, maintaining a low thickness and providing continuous inclined surfaces for improved visibility and image display.
Implementation Method 1
Many conventional security elements utilise diffractive optically variable effect generating relief structures, such as diffraction gratings, to provide an optically variable effect, i.e. an appearance that changes upon tilting or rotation of the device
Data Source
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AI summary
A security element is provided comprising: a first layer having a first surface; an array of image regions across the first surface arranged along at least a second direction, each image region comprising at least a first image sub-region having an average inclination defining an angle, relative to a plane of the security element, about an image region axis extending along a first direction; a diffractive optically variable effect generating structure provided in or on the first surface across the first image sub-regions, the diffractive optically variable effect generating structure comprising diffractive elements that extend along a direction within 45° of the first direction, wherein the diffractive optically variable effect generating structure is provided across the first image sub-regions and spatially arranged and/or modulated across the first image sub-regions in accordance with a first image such that the first image is displayed by the first image sub- regions in combination at least at a first viewing angle. A method of manufacturing said security element is also provided.