Embedded Printed LEDs for Optical Authentication via Wavelength Conversion
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Solution Overview
Problem
Current methods for authenticating objects using printed LEDs lack robust security and efficient visual feedback, as they rely on expensive optical detection equipment and are susceptible to counterfeiting.
Innovation Solution
Embedding LEDs in objects like credit cards and casino chips with an induction coil or direct voltage supply for power, combined with wavelength conversion materials and light guiding, providing visual feedback and enhanced security through unique light patterns that are difficult to replicate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If visual feedback is provided using printed LEDs, then user feedback and security are improved, but expensive optical detection equipment is still required
Solution Approach 1:
The credit card itself serves as the light guide, using its own structure to distribute and emit light from the embedded LEDs. The card body acts as both the powered device and the light distribution medium, eliminating the need for separate optical detection equipment.
Solution Approach 2:
The patent removes the expensive optical detection equipment from the authentication system. Instead of requiring external detectors, the system uses the card's own structure to provide visible light emission that can be seen directly by users, extracting the detection function from the system entirely.
2Ease of manufacture
If standard credit card materials are used, then manufacturing cost is reduced, but light guiding capability is insufficient
Solution Approach 1:
The patent modifies the optical parameters of standard credit card materials by incorporating transparent or translucent sections with specific refractive indices. These material parameter changes enable light guiding functionality in conventional card materials without requiring complete material replacement.
Solution Approach 2:
The credit card uses a composite structure combining standard card materials with transparent/translucent light-guiding sections. This composite approach allows the card to maintain its basic manufacturing simplicity while adding specialized light guiding regions for the LED authentication feature.
3Reliability
If LEDs are embedded in the card, then visual authentication is improved, but power supply complexity increases
Solution Approach 1:
The induction coil serves multiple functions: it provides power to the embedded LEDs for visual authentication and simultaneously can interact with readers at point-of-sale terminals. This multi-functionality reduces the need for separate power supply components.
Solution Approach 2:
The patent replaces a mechanical/electrical power supply system with an inductive power system. Instead of requiring batteries, wires, or direct electrical connections, the LEDs are powered wirelessly through electromagnetic induction from an external coil, simplifying the card's internal structure.
4Reliability
If wavelength conversion materials are added, then security is enhanced through unique light patterns, but manufacturing complexity increases
Solution Approach 1:
The wavelength conversion materials are pre-applied to specific regions of the card during manufacturing, creating predetermined light emission patterns. This preliminary action ensures that each card has its unique authentication signature built-in before the LED embedding process, simplifying the overall manufacturing sequence.
Solution Approach 2:
The patent combines multiple security features into a single integrated system: the embedded LEDs, the wavelength conversion materials, and the light guiding structure work together as one unified authentication mechanism. This merging reduces the need for separate security components and simplifies manufacturing compared to implementing multiple independent security features.
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 provides ergonomic visual feedback and high-security authentication without the need for expensive optical detection, making it difficult for counterfeiters to duplicate the visual effect, while also allowing for additional security features like coded pulsing of LEDs.
Implementation Method 1
an induction coil that supplies power to LEDs embedded in the card to illuminate the LEDs
Implementation Method 2
the LEDs are coated with a wavelength conversion material, such as phosphor or quantum dots, prior to printing, or a wavelength conversion layer is provided over the LEDs. The wavelength conversion material absorbs some of the relatively short wavelength primary light and emits longer wavelength secondary light
Implementation Method 3
The card may act as a light guide to cause the light to be emitted from any portion of the card surface
Data Source
AI summary
In one embodiment, a printed LED area comprises a random arrangement of printed LEDs and a wavelength conversion layer. The LED area is embedded in an object to be authenticated, such as a credit card or a casino chip. The object may include a light guide for enabling the generated light to be emitted from any portion of the object. In one embodiment, when the LEDs are energized during authentication of the object, the existence of light emitted by the object is sufficient authentication and/or provides feedback to the user that the object is being detected. For added security, the emitted spectrum vs. intensity and persistence of the wavelength conversion layer is detected and encoded in a first code, then compared to valid codes stored in the database. If there is a match, the object is authenticated.