Anti-Counterfeiting Display With Orthogonal Microstructures
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Solution Overview
Problem
Existing displays used to prevent counterfeiting struggle to maintain high brightness and directivity of diffracted light, especially under low light conditions, and fail to clearly differentiate between front-view and oblique views.
Innovation Solution
A display with an uneven surface structure featuring alternating protrusion and depression surfaces, where each protrusion surface tapers towards the top and each depression surface tapers towards the bottom, arranged at specific periods and heights to limit reflection and enhance diffracted light emission in the oblique view direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If microstructures are arranged at regular intervals in a grid pattern, then the display shows iridescent color in oblique view, but the diffracted light has low brightness and poor directivity
Solution Approach 1:
The invention divides the microstructure array into two distinct directional components: first microstructures extending in a first direction and second microstructures extending in a second direction perpendicular to the first. This segmentation allows independent control of diffraction properties in each direction, enabling high brightness through continuous diffraction surfaces while achieving sharp directivity through the orthogonal grid arrangement.
Solution Approach 2:
The invention transitions from considering only linear microstructure arrangements to a two-dimensional orthogonal grid system. By introducing microstructures in both the first direction and the perpendicular second direction, the system creates a four-dimensional diffraction control space (two directions × two dimensions), enabling simultaneous optimization of brightness and directivity that cannot be achieved with unidirectional structures alone.
2Adaptability or versatility
If microstructures are arranged at regular intervals, then diffracted light is emitted in multiple directions, but the display lacks sufficient directivity to differentiate from printed objects
Solution Approach 1:
The orthogonal segmentation of microstructures into two perpendicular sets creates independent diffraction control in each direction. This allows the display to maintain a specific viewing angle range through the periodic arrangement while achieving sharp directivity through the orthogonal geometry, effectively filtering diffraction angles to create a more restricted and identifiable emission pattern.
3Illumination intensity
If the amount of incident light is small, then the display shows black color in front view, but the iridescent color in oblique view is not clearly perceived
Solution Approach 1:
The continuous surfaces formed by the extending microstructures ensure that diffraction action occurs continuously across the entire surface area, maximizing light collection and diffraction efficiency even when incident light is limited. This continuous diffraction action maintains reliable counterfeiting prevention effectiveness by ensuring consistent iridescent color perception in oblique views under low light conditions.
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 increases the brightness and directivity of diffracted light, effectively differentiating the display from printed objects and enhancing its anti-counterfeiting capabilities, even under low light conditions.
Implementation Method 1
diffracts the light incident on the uneven surface to emit diffracted light in an oblique view direction of the uneven surface
Implementation Method 2
limits reflection of light that is incident on the uneven surface in a front-view direction of the uneven surface
Implementation Method 3
The uneven structure has a property of absorbing light incident on the uneven structure
Data Source
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AI summary
A display includes an uneven structure having an uneven surface, which serves as an incident surface, on which light is incident. The uneven surface includes a section in which protrusion surfaces and depression surfaces alternate in an arrangement direction. Each protrusion surface has a shape of a strip extending in an extension direction perpendicular to the arrangement direction. Each protrusion surface tapers toward a top section in a thickness direction of the uneven structure. Each depression surface has a shape of a strip extending in the extension direction. Each depression surface tapers toward a bottom section in the thickness direction of the uneven structure. The protrusion surfaces and the depression surfaces are arranged at a period that limits reflection of light that is incident on the uneven surface in a front-view direction of the uneven surface and diffracts the light incident on the uneven surface to emit diffracted light in an oblique view direction of the uneven surface. The uneven structure has a property of absorbing light incident on the uneven structure.