Security Document Tilt Authentication Images
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Solution Overview
Problem
Existing security documents with authentication images struggle to rapidly and reliably detect unauthorized alterations, as these images can be manipulated without being easily noticed due to their complex structure and optical effects.
Innovation Solution
A security document featuring a positive authentication image and a negative authentication image with reversed brightness values, where the positive image is visible at a perpendicular viewing direction and the negative image is visible at a non-perpendicular direction, preventing simultaneous manipulation and ensuring effective detection of alterations by tilting the document.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex authentication image structure with multiple images and lenses is used, then the security document becomes resistant to unauthorized alterations, but the detection of alterations becomes difficult and time-consuming
Solution Approach 1:
The patent applies inversion by creating a negative authentication image with reversed brightness values compared to the positive identification image. When viewed at different angles, the authentication image transitions from positive to negative, allowing rapid visual detection of alterations through contrast reversal rather than requiring complex analysis of the original multi-layer structure
Solution Approach 2:
The patent utilizes brightness value changes by encoding the authentication image with reversed brightness values relative to the identification image. This brightness inversion creates a visually distinct negative image that can be quickly compared against the positive image to detect any unauthorized modifications
2Reliability
If a stereoscopic authentication image is used, then the authentication image cannot be easily altered without being noticed, but the detection of alterations is not rapid
Solution Approach 1:
The patent implements periodic action through the tilt-dependent switching between positive and negative authentication images. As the document is tilted, the authentication image periodically transitions between positive and negative states, enabling rapid back-and-forth comparison to detect alterations without prolonged inspection
Solution Approach 2:
By inverting the brightness values to create a negative image that switches with tilting, the patent enables rapid detection through visual contrast changes rather than requiring time-consuming analysis of the stereoscopic image structure
3Reliability
If multiple authentication images are placed below lenses, then the security feature prevents simultaneous manipulation, but the structure becomes complex
Solution Approach 1:
The patent merges the positive and negative authentication images into a single integrated structure below the lens array. Both images are encoded in the same layer with complementary brightness values, simplifying the manufacturing process while maintaining the security benefit of preventing simultaneous manipulation
Solution Approach 2:
The authentication image layer serves multiple functions: it provides both positive and negative images for authentication, enables tilt-dependent switching, and prevents manipulation through its complex structure. This multi-functionality reduces the need for separate components while enhancing 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
This solution allows for rapid and reliable detection of unauthorized alterations by maintaining the positive image as a visual stimulus, ensuring the authentication image corresponds with the main image, thus safeguarding against forgery attempts and maintaining the integrity of the portrait.
Implementation Method 1
The stereoscopic image consists of two or more portrait images showing the portrait at different angles. These images are laser engraved in an interlaced manner below a number of cylindrical lenses into a laser sensitive image layer. The user inspecting the security document observes below the lenses with each eye a respective portrait image such that a stereoscopic image is formed.
Implementation Method 2
These images are laser engraved in an interlaced manner below a number of cylindrical lenses into a laser sensitive image layer
Data Source
AI summary
Disclosed is a security document including an image layer with in a first image area an identification image. The document has in a second image area an authentication image that is composed of a first authentication image that is a positive version of the first image and a second authentication image that is a negative version of the first image. The authentication images can be observed at different angles and form a tilt image. Mutual comparison of the positive and negative tilt images and comparison with the identification image provides improved detection of unauthorized alterations.