Display Fingerprint Sensor Using Luminance Comparison Against Spoofs

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Solution Overview

Problem

Existing display devices with fingerprint sensors face challenges in distinguishing between biometric and forged fingerprints without the need for additional bio or color sensors, leading to increased manufacturing costs.

Innovation Solution

The display device incorporates a fingerprint sensor that acquires both a fingerprint image and its peripheral image, determining similarity through luminance comparison, eliminating the need for separate bio or color sensors by using a comparator to analyze preprocessed images for authentication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate bio sensor or color sensor is added to determine whether a fingerprint is biometric or forged, then the authentication accuracy is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveauthentication accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The display device performs multiple functions using a single integrated system. The fingerprint sensor not only captures fingerprint images but also analyzes luminance characteristics to distinguish biometric from forged fingerprints. The display panel serves both as a visual output device and as a lighting source for fingerprint illumination, eliminating the need for separate bio sensors or color sensors while maintaining authentication accuracy

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

Solution Approach 2:

The patent combines the fingerprint sensing function, luminance analysis function, and display function into a single integrated device. The fingerprint sensor is integrated with the display panel, allowing the display to serve as both the interface for fingerprint capture and the analysis system for detecting luminance differences between real and forged fingerprints

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the fingerprint sensor simultaneously acquires fingerprint image and peripheral image for similarity analysis, then the ability to detect forged fingerprints is improved, but the device complexity increases

Engineering Contradiction:
Improveforged fingerprint detection capabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The image processing is divided into distinct segments: the fingerprint sensor captures the complete image including both the fingerprint region and peripheral region, then the processor separates these regions for independent analysis. The luminance values are extracted and compared in separate processing steps, allowing complex analysis to be broken down into manageable operations without requiring additional hardware components

Inventive Principle:
Principle #1Segmentation

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 approach effectively differentiates between biometric and forged fingerprints, reducing manufacturing costs by integrating fingerprint authentication directly into the display device without additional sensors.

Implementation Method 1

sensing light reflected by the fingerprint to acquire a fingerprint image

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3783511B1Display device including fingerprint sensor and fingerprint authentication method thereof
Publication Date: 2025.11.19 SAMSUNG DISPLAY CO LTD
  • EP3783511B1 patent drawingFigure 1A
  • EP3783511B1 patent drawingFigure 1B
  • EP3783511B1 patent drawingFigure 2

AI summary

A display device includes a fingerprint sensor including a first layer having at least one photo sensor to generate a fingerprint image corresponding to reflected light from a fingerprint contact surface, light emitting elements to transmit light reflected by the fingerprint, and a second layer including pin holes to allow reflected light to be incident upon the at least one photo sensor; and fingerprint detector to receive the fingerprint image from the fingerprint sensor, to extract a first image corresponding to a first region of the fingerprint and a second image corresponding to a second region of the fingerprint, to compare the first and second images to determine similarity, and to perform fingerprint authentication, based on similarity determination, where the fingerprint first region is in contact with the fingerprint contact surface and the fingerprint second region is not in contact with the fingerprint contact surface.