Thin Film Optical Encryption Structure for Secure Authentication

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Solution Overview

Problem

Current optical encryption methods lack a practical and easy-to-use solution for revealing hidden information on a surface using Fabry-Perot, plasmonic, or powerful interference effects, particularly for applications requiring optical safety and identity authentication, and are vulnerable to imitation.

Innovation Solution

An optical encryption structure comprising an encryption layer with a dielectric and metal layer, and a decryption layer on a transparent substrate, utilizing key and lock compatibility to absorb specific light spectra and reflect or transmit the rest, allowing easy decryption outside a laboratory setting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional optical encryption methods are used, then hidden information can be concealed, but the decryption process requires complex laboratory equipment and is difficult to perform outside a laboratory setting

Engineering Contradiction:
Improveease of decryptionVSAvoiddecryption equipment complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by utilizing wavelength-selective optical properties of thin film layers. The encryption layer contains dielectric and metal layers with specific thicknesses and refractive indices that create wavelength-dependent reflection and transmission characteristics. By changing the optical parameters (wavelength, angle of incidence) through the decryption layer, the hidden information is revealed without requiring complex equipment, thus resolving the contradiction between ease of operation and device complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The decryption layer acts as an intermediary element that simplifies the decryption process. This layer contains dielectric and metal structures that modulate the optical properties of the encryption layer, enabling wavelength-selective transmission. The intermediary structure allows standard optical devices to perform decryption functionality that would otherwise require complex laboratory equipment, thereby improving ease of operation while maintaining security.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If thin film structures are used for optical encryption, then the structure becomes compact and can be applied on surfaces, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvestructure compactnessVSAvoidthin film thickness control
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent employs composite materials consisting of multiple dielectric and metal layers with different optical properties. The encryption layer comprises alternating dielectric and metal thin films, while the decryption layer contains similar composite structures. These composite structures provide wavelength-selective optical effects that enable encryption and decryption functions. The composite material approach allows compact integration while distributing manufacturing tolerances across multiple layers, reducing the impact of precision requirements compared to single-layer structures.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating wavelength-selective optical properties at specific locations within the thin film structure. Different regions of the encryption and decryption layers have different thicknesses and material compositions tailored to specific optical wavelengths. This localized optimization allows the structure to achieve compact dimensions while maintaining the necessary optical performance, as each local region is designed for its specific functional contribution to the overall encryption/decryption process.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If Fabry-Perot, plasmonic or interference effects are used, then colorful surfaces and hidden information can be created, but the structures are vulnerable to imitation

Engineering Contradiction:
Improvesurface coloring capabilityVSAvoidsecurity against imitation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the optical encryption function into two distinct layers: an encryption layer and a decryption layer. Each layer contains specific dielectric and metal structures with predetermined optical properties. The encryption layer creates wavelength-selective reflection and transmission characteristics, while the decryption layer provides the corresponding complementary properties. This segmentation makes the system more secure against imitation, as copying one layer does not provide the complete functional system, while still enabling easy manufacturing of each individual layer with standard thin film deposition techniques.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic optical properties through wavelength and angle-dependent responses. The thin film structures exhibit changing optical characteristics as a function of incident light wavelength and viewing angle. This dynamic behavior creates wavelength-selective visibility patterns that are difficult to replicate. The decryption layer is specifically designed to dynamically modulate the optical properties of the encryption layer, enabling controlled revelation of hidden information only with the correct decryption wavelength, thereby enhancing security while maintaining manufacturability.

Inventive Principle:
Principle #15Dynamics

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 structure effectively conceals and reveals information using thin metal and dielectric films, providing secure optical safety and authentication by changing reflection or transmission spectra with the decryption layer, making it difficult to imitate and simplifying the decryption process.

Implementation Method 1

utilizing Fabry-Perot, plasmonic or powerful interference effect

Methodology Applied
Scientific EffectFabry-Perot interference: Fabry-Perot Interferometer

Implementation Method 2

utilizing Fabry-Perot, plasmonic or powerful interference effect

Methodology Applied
Scientific EffectPlasmonic effect:

Implementation Method 3

absorb specific light spectra and reflect or transmit the rest

Methodology Applied
Scientific EffectSelective light absorption and reflection: Absorption (EM radiation)

Implementation Method 4

utilizing Fabry-Perot, plasmonic or powerful interference effect

Methodology Applied
Scientific EffectOptical interference: Interference

Data Source

PatentEP3871022B1Optical encryption and decryption structure with thin film surface coloring
Publication Date: 2024.06.12 ATILIM UNIVSI
  • EP3871022B1 patent drawingFigure 1~2
  • EP3871022B1 patent drawingFigure 3~4
  • EP3871022B1 patent drawingFigure 5

AI summary

The invention is related to an optical encryption structure which allows for creating shapes on a surface that cannot be detected with eyes or cameras and revealing these created shapes with metal or semi-conductive thin films with flat or shaped form to be covered on the surface. The invention is particularly related to an optical encryption structure which uses Fabry- Perot, plasmonic or powerful interference effect, enables revealing the hidden information on a surface with a clear substrate and has an encryption and decryption layer that have key and lock integrity between thereof.