Piezoelectric Polymer Authentication for Flexible Banknotes
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Solution Overview
Problem
Existing security document authentication methods require complementary devices, which are not suitable for high-volume transactions or undefined geographical locations, and are ineffective for flexible documents like banknotes due to the rigidity of piezoelectric films.
Innovation Solution
A flexible security document with a printed source of electrical potential using piezoelectric polymeric material, comprising vinylidene fluoride (VDF), trifluoroethylene (TrFE), and a halogenated ethylene based monomer, activated by mechanical deformation, connected to a reporter element that can switch between perceptible states, such as color or sound, to authenticate without external devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piezoelectric films are used for authentication, then authentication capability is provided, but the films are rigid and brittle when stretched, making them unsuitable for flexible documents
Solution Approach 1:
The patent replaces rigid piezoelectric films with flexible piezoelectric polymer thin films that can be integrated into flexible security documents like banknotes. The polymer material maintains piezoelectric properties while providing the necessary flexibility and bendability for flexible documents.
Solution Approach 2:
The patent uses composite piezoelectric polymer materials that combine the piezoelectric properties of crystalline materials with the flexibility of polymeric materials, creating a material that exhibits both authentication capability and mechanical flexibility suitable for flexible security documents.
2Measurement precision
If complementary devices are used for authentication, then authentication accuracy is improved, but the solution becomes unsuitable for high-volume transactions and undefined geographical locations
Solution Approach 1:
The patent implements self-service authentication where the security document itself contains all necessary authentication components (piezoelectric material, electrodes, circuitry). The document can be authenticated by simple mechanical deformation without requiring external complementary devices, enabling universal use in any location and high-volume transactions.
Solution Approach 2:
The patent extracts the authentication functionality from external complementary devices and embeds it directly into the security document itself. This integration eliminates the need for separate authentication devices while maintaining authentication capability.
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
Enables authentication of flexible security documents like banknotes without complementary devices, providing a cost-effective and geographically flexible solution for verifying authenticity through mechanical deformation.
Implementation Method 1
a printed source of electrical potential, the source of electrical potential including a piezoelectric polymeric material... the source of electrical potential being activated by mechanical deformation of the flexible security document
Data Source
AI summary
A flexible security document is provided which contains an authentication device including: a) source of electrical potential (5), the source including a piezoelectric polymeric material including at least one terpolymer of vinylidene fluoride (VDF), trifluoroethylene (TrFE) and a halogenated ethylene based monomer containing at least one non-fluorine halogen atom, the source of electrical potential being activated by mechanical deformation; b) reporter element (3) including a material capable of switching electrically between a first state and a second state, the difference between the first state and the second state being able to be perceived by an unaided human; and c) conducting elements (8) electrically connecting the source of electrical potential and the reporter element to produce an electric circuit. The reporter element (3) may take a number of different forms, such as a light emitting device which lights up or undergoes color change when activated by the source of electrical potential to provide an indication of authenticity. In a particularly preferred embodiment, the flexible security document is a banknote and the source of electrical potential is applied by printing.