Embedded Optical Security Feature in Polymer Substrate

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Solution Overview

Problem

Existing security features in documents, such as banknotes, face challenges in maintaining high transmission contrast while avoiding increased visibility in reflection, and are susceptible to counterfeiting and durability issues due to registration errors and wear.

Innovation Solution

A security feature is created by embedding an optical security feature within a polymer substrate that is partially covered by a print layer, using particles reacting to a designated wavelength of light to form bubbles or markings, which scatter or absorb light, making the feature covert in reflection and durable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If multiple ink layers are applied to increase transmission contrast, then the shadow image becomes more visible in transmission, but the feature becomes visible in reflection which reduces its covert security capability

Engineering Contradiction:

Improvetransmission contrastVSAvoidvisibility in reflection

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different optical properties to different regions of the security feature. The shadow image area has high transmission contrast while the surrounding areas maintain low reflection visibility. This is achieved by selectively applying ink layers only where needed to create the shadow image, rather than uniformly across the entire feature, thus resolving the contradiction between transmission visibility and reflection covertness

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent transitions from a two-dimensional surface printing approach to a three-dimensional embedded structure. By embedding the shadow image within the polymer substrate using multiple ink layers at different depths and positions, the feature achieves high transmission contrast when viewed through the substrate while remaining covert in reflection when viewed from the surface, effectively using the third dimension (substrate thickness) to resolve the visibility contradiction

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If shadow images are made overt for public authentication, then ease of verification improves, but susceptibility to counterfeiting increases

Engineering Contradiction:

Improveauthentication easeVSAvoidanti-counterfeiting reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent utilizes optical variable inks that change appearance based on viewing conditions. The shadow image appears with specific contrast and characteristics in transmission mode (easy for public verification) but presents different optical properties in reflection mode (difficult for counterfeiters to replicate). This optical variability provides both ease of authentication and enhanced anti-counterfeiting reliability

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent creates a master shadow image embedded within the substrate that serves as the authentic reference. Any counterfeit attempt must replicate this embedded three-dimensional optical structure, which is extremely difficult to copy accurately. The embedded nature of the shadow image makes it a unique master template that cannot be easily reproduced, thus providing reliability against counterfeiting while maintaining authentication ease through its visible optical effects

Inventive Principle:

Principle #26Copying

3Manufacturing precision

If registration precision is increased to maintain image quality with multiple layers, then manufacturing complexity increases

Engineering Contradiction:

Improveregistration precisionVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies ink layers in a predetermined sequence and at predetermined positions within the substrate, establishing registration references before final assembly. By pre-positioning the shadow image layers during the manufacturing process with built-in registration marks and alignment features, the system achieves high registration precision without requiring complex post-manufacturing alignment procedures, thus resolving the contradiction between precision and complexity

Inventive Principle:

Principle #10Preliminary action

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 enhances the security feature's effectiveness by making it more difficult to counterfeit and durable, as it remains indelible and covert in reflection, while maintaining high contrast in transmission.

Implementation Method 1

using particles reacting to a designated wavelength of light to form bubbles or markings, which scatter or absorb light

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 2

using particles reacting to a designated wavelength of light to form bubbles or markings, which scatter or absorb light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS11453234B2Security document including an optical security feature

Publication Date: 2022.09.27 CCL SECURE PTY LTD

AI summary

A security document, including: a polymer substrate; at least one print layer disposed on one or both sides of the polymer substrate; and a security feature including an image area embodied within the polymer substrate and at least partially covered by the at least one print layer, wherein the security feature is an optical security feature formed in the image area.