Fingerprint Sensor Stabilization in Flexible Display Devices

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Solution Overview

Problem

Existing display devices face challenges in maintaining accurate fingerprint sensing capabilities due to movement of the fingerprint sensor, which affects the reliability and precision of biometric authentication.

Innovation Solution

The implementation of a display device design that includes a fingerprint sensor positioned on a flexible area, supported by a rigid plate and an impact absorption layer, which minimizes sensor movement and enhances sensing accuracy through the use of an ultrasonic wave sensor and a support member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the fingerprint sensor is embedded in the display device, then biometric authentication capability is provided, but sensor movement occurs affecting sensing accuracy

Engineering Contradiction:

Improvebiometric authentication reliabilityVSAvoidfingerprint sensing accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies beforehand cushioning by introducing an impact absorption layer between the fingerprint sensor and the display module. This layer is positioned in advance to cushion external impacts before they reach the sensor, preventing sensor displacement and maintaining sensing accuracy during authentication.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses an intermediary approach by introducing a support member as a mediator between the fingerprint sensor and the display module. This support member specifically reinforces the area around the sensor, providing additional mechanical support and preventing sensor movement without affecting the sensor's sensing function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the fingerprint sensor is positioned on a flexible area, then sensing capability is enhanced, but sensor movement increases under external pressure

Engineering Contradiction:

Improvefingerprint sensing capabilityVSAvoidsensor position stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by providing differential support to different areas of the display device. The support member is specifically positioned to reinforce only the area around the fingerprint sensor, while other areas maintain their flexibility. This localized reinforcement stabilizes the sensor position without compromising the overall flexibility of the display.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining the flexible display module with a rigid support member and impact absorption layer. This composite structure creates a hybrid system that provides both flexibility for sensing and rigidity for stability, allowing the sensor to maintain its position under external pressure while the display retains its flexible characteristics.

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If support structures are added to minimize sensor movement, then sensing accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvesensing accuracyVSAvoidstructural complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the support structure into distinct functional components: an impact absorption layer for cushioning external forces and a support member for providing structural reinforcement. This segmentation allows each component to perform its specific function efficiently while keeping the overall design modular and manageable.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The support member acts as an intermediary element that bridges the fingerprint sensor and the display module. Rather than directly coupling the sensor to the rigid display structure, the support member provides a dedicated interface that simplifies the connection while ensuring sensor stability, thereby reducing overall structural complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 design significantly improves the fingerprint sensing ability by reducing sensor movement, enhancing accuracy, and maintaining reliable biometric authentication, even under external pressure or bending conditions.

Implementation Method 1

a fingerprint sensor positioned on a flexible area, supported by a rigid plate and an impact absorption layer

Methodology Applied

Scientific EffectImpact absorption: Damping

Implementation Method 2

the use of an ultrasonic wave sensor

Methodology Applied

Scientific EffectUltrasonic wave detection: Ultrasound

Data Source

PatentEP3771960B1Display device

Publication Date: 2025.03.05 SAMSUNG DISPLAY CO LTD

Figure 1A
Figure 1B
Figure 2A

AI summary

A display device includes a display module. An impact absorption layer is disposed under the display module and includes a first opening exposing a lower surface of the display module. A rigid plate is disposed under the impact absorption layer. A sensor is disposed between the display module and the rigid plate within the first opening and is coupled to a lower surface of the rigid plate. A support member is disposed between the impact absorption layer and the sensor within the first opening, and contacts the display module and the rigid plate.