Diffractive Optical Surface for Secure Authentication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image reproduction and authentication systems are prone to errors due to damage from everyday use, such as creases and scratches, and lack visually appealing and hidden features for secure identification.
Innovation Solution
A system utilizing an optical surface with a diffractive image generating structure composed of a reflective material with grooved diffractive elements, arranged in a two-dimensional array to represent images, which undergoes polarisation conversion when illuminated at a specific angle, allowing for polarisation selection and detection, enabling secure and damage-tolerant image reproduction and authentication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bar code systems are used for identification, then article distinction is achieved, but the system is easily distorted by creases and scratches causing detection errors
Solution Approach 1:
The patent uses optical properties that change with viewing angle and polarisation state. The diffractive elements cause polarisation conversion and wavelength-dependent reflection, creating colour changes and intensity variations that are inherently resistant to physical damage like creases and scratches, unlike flat bar codes
Solution Approach 2:
The system changes physical parameters of light interaction by using diffractive elements with specific periodic structures. These elements create angle-dependent and polarisation-dependent optical responses that maintain identification accuracy even when the surface is damaged, as the diffractive pattern remains intact
2Reliability
If diffractive elements with periodic wave surface profiles are used, then polarisation conversion occurs enabling secure identification, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical authentication systems with optical phenomena. The diffractive elements utilize natural polarisation conversion and diffraction effects to provide secure authentication, eliminating the need for complex mechanical verification mechanisms while maintaining high security
Solution Approach 2:
The system achieves secure authentication by changing the optical parameters of the identification mark. The periodic wave surface profiles create specific diffraction patterns and polarisation conversion characteristics that are difficult to replicate, providing security without mechanical complexity
3Ease of manufacture
If the diffractive elements are disposed in a two dimensional array to represent an image, then visual appeal and hidden features are achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent divides the identification surface into discrete diffractive elements arranged in a two-dimensional array. Each element can be independently manufactured with standard precision, and the collective array creates the desired image and hidden features, making the system manufacturable while maintaining visual appeal and security
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 system provides a secure, visually appealing, and damage-tolerant method for image reproduction and authentication, making it difficult to replicate the diffractive pattern, and is invisible under standard lighting but visible under polarised light, enhancing the identification of genuine articles.
Implementation Method 1
the diffractive elements are configured such that, in use, polarisation conversion of the incident radiation takes place
Implementation Method 2
an optical surface having a diffractive image generating structure disposed thereon, the diffractive image generating structure itself comprising a layer of reflective material incorporating a plurality of grooved diffractive elements each having a periodic wave surface profile
Data Source
AI summary
A system and method of using the same, wherein the system comprises: an optical surface having a diffractive image generating structure disposed thereon, the diffractive image generating structure itself comprising a layer of reflective material incorporating a plurality of grooved diffractive elements each having a periodic wave surface profile, the periodic wave surface profiles each having a groove alignment direction; a source of incident electromagnetic radiation arranged to illuminate the diffractive elements at an angle of incidence substantially normal to the plane of the surface of the diffractive elements; means for polarizing the radiation from the source, and means for polarizing radiation reflected from the diffractive elements; wherein the diffractive elements are configured such that, in use, polarization conversion of the incident radiation takes place, and wherein the diffractive elements are disposed in a two dimensional array of pixels to represent an image; and further wherein the means for polarizing is arranged to pass incident radiation having a polarization state of approximately 45° azimuth to the groove alignment direction, and is arranged to select a polarization, using the means for polarizing the radiation reflected from the diffractive elements, and to pass radiation of the selected polarization to a detection point.