Optical Skin Authentication for ID Cards

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Solution Overview

Problem

Existing authentication devices integrated into identification documents, such as ID cards or smart cards, face challenges due to their large size and low resolution, which affect the identification rate and vulnerability to presentation attacks.

Innovation Solution

An authentication device with a compact design that includes a lighting source emitting light in a predetermined wavelength range, typically nearby infrared, to illuminate a skin area, and a detector, such as a CCD sensor, to capture and compare the resulting pattern with a reference pattern stored in the device or an external memory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If capacitive or thermal semiconductor sensors are used for authentication, then the authentication device can be integrated into identification documents, but the device becomes comparatively thick and has low resolution

Engineering Contradiction:
Improveintegration into identification documentVSAvoidresolution
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical contact-based semiconductor sensors with an optical measurement system. A light source illuminates the skin area, and a detector captures the reflected light pattern, eliminating the need for thick semiconductor sensors while achieving high resolution through optical imaging principles.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from electrical properties (capacitive/thermal) to optical properties. By using light reflection patterns from skin surface topography, the system achieves higher resolution without requiring physical contact sensors, thus maintaining thin profile integration.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the authentication device is integrated into the identification document, then portability is improved, but the geometric dimensions become comparatively thick

Engineering Contradiction:
ImproveportabilityVSAvoidthickness
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent replaces thick mechanical semiconductor sensor structures with a thin optical system consisting of a light source and detector array. This substitution maintains the portability benefit of integration while dramatically reducing the thickness constraint.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from three-dimensional physical contact sensing to two-dimensional optical pattern capture. By measuring skin surface topography through light reflection rather than physical sensor contact, the system achieves authentication functionality in a thinner profile suitable for card integration.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Extent of automation

If semiconductor sensors are used, then biometric capture is enabled, but the resolution is comparatively low affecting false match and false mismatch rates

Engineering Contradiction:
Improvebiometric capture capabilityVSAvoidresolution
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent replaces low-resolution semiconductor sensors with an optical imaging system that captures detailed skin surface patterns through light reflection. This substitution enables high-resolution biometric capture, significantly improving the ability to distinguish genuine matches from false matches.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If the authentication device is integrated into the identification document, then the association between document and person is strengthened, but the device complexity increases

Engineering Contradiction:
Improveauthentication reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a light source and detector system that serves multiple functions: illuminating the skin area, capturing reflection patterns, and enabling authentication. This multi-functionality reduces overall device complexity compared to specialized semiconductor sensors while maintaining high authentication reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables efficient and accurate authentication with improved identification rates and enhanced resistance to presentation attacks, while maintaining compact geometric dimensions suitable for integration into identification documents.

Implementation Method 1

a light source (101) which is configured to illuminate a skin area of the person with light in a predetermined wavelength range, in which the light at least partially penetrates the skin area

Methodology Applied
Scientific EffectLight penetration: Absorption (EM radiation)

Implementation Method 2

a detector (103) for detecting an image of the skin area in the predetermined wavelength range

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3408790B1Authentication apparatus for authenticating a person
Publication Date: 2025.05.07 BUNDESDRUCKEREI GMBH
  • EP3408790B1 patent drawingFigure 1
  • EP3408790B1 patent drawingFigure 2
  • EP3408790B1 patent drawingFigure 3

AI summary

The invention relates to an authentication device (100) for authenticating a person, said device comprising a light source (101) which is designed to illuminate an area of the skin of the person with the light at a determined wave length range, in which the light at least partially penetrates into the area of the skin; a detector (103) for detecting a detection image of the area of the skin in the predetermined wavelength range; and a processor (105) for authenticating the person based on the detection image.