Deformable Fingerprint Sensor with Strain Compensation

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Solution Overview

Problem

Existing fingerprint recognition technologies face challenges in accurately recognizing fingerprints on flexible or stretchable electronic devices, as deformation affects the accuracy of fingerprint sensors, making it difficult to maintain reliable authentication.

Innovation Solution

A deformable fingerprint recognition device is developed, incorporating a capacitive fingerprint sensor and a strain sensor with a matrix array configuration, where the strain sensor measures deformation distribution to correct fingerprint images, ensuring accurate recognition even when the device is deformed. The device includes a shield layer and a cover film for user interaction, and can be stretchable or bendable, with a processor to standardize fingerprint information based on deformation data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional rigid fingerprint sensor is used, then fingerprint recognition accuracy is maintained, but the device cannot be made flexible or stretchable

Engineering Contradiction:
ImproveflexibilityVSAvoidfingerprint recognition accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies flexible substrate technology to create a bendable fingerprint sensor assembly. The sensor is mounted on a flexible substrate that can be bent or stretched without breaking, enabling the sensor to conform to curved surfaces or deformable device structures while maintaining functional integrity

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces a strain sensor that dynamically measures deformation in real-time. This dynamic measurement capability allows the system to detect and compensate for changes in the fingerprint sensor's geometry during bending or stretching, maintaining recognition accuracy under varying mechanical conditions

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a flexible fingerprint sensor is used, then device flexibility is achieved, but fingerprint recognition accuracy deteriorates due to deformation

Engineering Contradiction:
Improvedevice flexibilityVSAvoidfingerprint recognition accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where strain sensor data about deformation is fed back to the processor. The processor uses this feedback information to correct and compensate for distortion in the captured fingerprint image, restoring recognition accuracy despite the sensor being in a deformed state

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The strain sensor acts as an intermediary element that measures mechanical deformation and translates it into electrical signals. This intermediary provides critical information about the sensor's geometric state, enabling computational compensation algorithms to correct fingerprint image distortion

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If strain compensation is implemented, then fingerprint recognition accuracy under deformation is improved, but device complexity increases

Engineering Contradiction:
Improvefingerprint recognition accuracyVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the fingerprint sensing function and strain measurement function into a single integrated sensor assembly. Both sensors share the same flexible substrate and are processed together by a single processor, reducing overall system complexity compared to separate compensation systems

Inventive Principle:
Principle #5Merging (Combining)

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 enables accurate fingerprint recognition and authentication on flexible or stretchable devices, maintaining high accuracy despite deformation, and is suitable for use in mobile and wearable devices with reduced computational requirements.

Implementation Method 1

The fingerprint sensor may include capacitive fingerprint sensor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The strain sensor may include one of a capacitive strain sensor, a resistive strain sensor, and a piezoelectric strain sensor

Methodology Applied
Scientific EffectStrain sensing: Piezoresistive Effect

Data Source

PatentEP3644230B1Deformable fingerprint recognition device, and fingerprint authentication method and electronic apparatus using the same
Publication Date: 2023.11.08 SAMSUNG ELECTRONICS CO LTD
  • EP3644230B1 patent drawingFigure 1~2
  • EP3644230B1 patent drawingFigure 3
  • EP3644230B1 patent drawingFigure 4

AI summary

Provided are a deformable fingerprint recognition device and a fingerprint authentication method and an electronic apparatus using the deformable fingerprint recognition device. The deformable fingerprint recognition device may include a fingerprint sensor configured to be deformed in shape and a strain sensor provided on a surface of the fingerprint sensor to measure deformation distribution of the fingerprint sensor. The deformable fingerprint recognition device may recognize a fingerprint of a user by reflecting the deformation distribution of the fingerprint sensor measured by the strain sensor. The deformable fingerprint recognition device may include a plurality of first pixel regions to detect the fingerprint of the user, and the strain sensor may include a plurality of second pixel regions to measure the deformation distribution of the fingerprint sensor.