Refractive Plate Deflecting Light for Simultaneous Dual-Angle Authentication
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Solution Overview
Problem
Existing devices for authenticating optically variable entities with color shifts require comparisons of images under different perspectives, leading to size discrepancies and large volume requirements, and are limited to human use, making machine authentication difficult.
Innovation Solution
A device using a plate of light-refractive material with an array of protrusions or recesses to deflect light from an oblique angle to an orthogonal angle, allowing simultaneous direct and angular views of the optically variable entity, enabling efficient authentication through optical refraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mirror is used to deflect light for indirect viewing, then simultaneous viewing under two angles is achieved, but the device volume increases due to required optical path length
Solution Approach 1:
The patent replaces the mechanical mirror-based optical deflection system with a photonic crystal structure that achieves the same light deflection function through periodic refractive index modulation. This substitution eliminates the need for long optical paths and large physical space, reducing device volume while maintaining the capability to deflect light for simultaneous viewing under orthogonal and oblique angles.
Solution Approach 2:
The patent changes the fundamental parameter of light deflection from geometric optics (mirror reflection) to photonic bandgap effects (photonic crystal refraction). By changing the operating principle from mechanical/optical path-based to material property-based, the device achieves compact size while maintaining viewing functionality.
2Reliability
If images under different perspectives are compared, then authentication is performed, but size discrepancies between images complicate the comparison
Solution Approach 1:
The patent applies local quality by ensuring that the region of the optically variable entity visible through the photonic crystal plate at oblique angle corresponds exactly to the same physical region visible in direct orthogonal view. The photonic crystal structure is designed to maintain spatial registration between the two views, allowing direct comparison without size or position discrepancies.
3Ease of operation
If the device is designed for human visual authentication, then color comparison is simple, but machine authentication becomes difficult
Solution Approach 1:
The patent designs the device with universal applicability by providing both direct and angular views of the optically variable entity through the photonic crystal plate. This dual-view capability serves both human visual inspection (color comparison) and machine authentication (spectral analysis, image processing), making the device versatile for multiple authentication methods without requiring separate systems.
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 solution allows for accurate authentication of optically variable entities by comparing colors under different angles without size discrepancies and can be adapted for machine use, reducing the device's volume and enhancing authentication reliability and speed.
Implementation Method 1
a plate of light-refractive material with an array of protrusions or recesses to deflect light from an oblique angle to an orthogonal angle, allowing simultaneous direct and angular views of the optically variable entity, enabling efficient authentication through optical refraction
Data Source
AI summary
Disclosed is a device for the authentication of an optically variable entity exhibiting a color shift with changing viewing-angle, the device comprising a plate of light-refractive material, said plate having two surfaces and an array of light-refracting protrusions or recesses on at least one of said surfaces, and being disposed in said device such as to provide, aside each other, a direct view and a view through said plate onto at least parts of said optically variable entity, said view through said plate being an angularly deflected view, resulting from light refraction at said protrusions or recesses. Further disclosed is a method for authenticating an optically variable entity, as well as the use of a plate having two parallel surfaces and an array of positive or negative light-refracting protrusions or recesses on at least one of said surfaces for authenticating an optically variable entity.