Segmented Light Shielding Layer for Foldable Display Fingerprint Accuracy

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Solution Overview

Problem

Current display devices with fingerprint recognition capabilities face challenges in accurately sensing fingerprints due to issues with light interference and stress distribution during folding, which affect the accuracy and sensitivity of fingerprint recognition.

Innovation Solution

Incorporating a light shielding layer with strategically placed holes and cut portions in the display panel to control the incident angle of light to the fingerprint sensor, reducing stress and enhancing the flexibility of the device while maintaining image quality and improving fingerprint recognition accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a light shielding layer is added to control light incidence for fingerprint recognition, then fingerprint recognition accuracy is improved, but device structure becomes more complex

Engineering Contradiction:
Improvefingerprint recognition accuracyVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The light shielding layer is segmented with multiple holes and cut portions strategically distributed across the layer. These segments allow selective light transmission to the fingerprint sensor while maintaining overall light shielding functionality, improving fingerprint recognition accuracy without requiring a completely opaque structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the light shielding layer have different properties: areas with holes and cut portions allow light transmission for fingerprint sensing, while other areas maintain light shielding for display quality. This local differentiation optimizes both fingerprint recognition accuracy and image quality

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the display panel is made flexible for folding, then adaptability is improved, but stress distribution during folding affects fingerprint recognition accuracy

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

Solution Approach 1:

The light shielding layer is divided into multiple segments through holes and cut portions, which act as stress relief points. This segmentation allows the layer to flex during device folding without generating excessive stress that would compromise fingerprint sensor performance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light shielding layer is designed as a thin, flexible film structure that can accommodate bending and folding. The holes and cut portions in this thin film reduce stress concentration during folding, maintaining the layer's ability to function as both a light shield and a flexible component

Inventive Principle:
Principle #30Flexible shells and thin films

3Stress or pressure

If holes and cut portions are added to the light shielding layer, then stress is reduced during folding, but light transmission control becomes more complex

Engineering Contradiction:
Improvestress during foldingVSAvoidlight transmission control
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The light shielding layer is segmented with holes and cut portions that serve dual purposes: reducing stress during folding and controlling light transmission. The segmentation simplifies stress management while the strategic placement of segments maintains light transmission control for both display and fingerprint sensing

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

The solution enhances the accuracy and sensitivity of fingerprint recognition by controlling light incidence and reducing stress on the light shielding layer during folding, thereby improving the overall performance of the display device's biometric authentication capabilities.

Implementation Method 1

Inclining the plurality of holes to a first direction and the cut portion to a second direction in a light shielding layer, thereby controlling an incident angle of light incident to the fingerprint sensor

Methodology Applied
Scientific EffectLight incidence control: Reflection

Data Source

PatentEP3882752B1Display device
Publication Date: 2023.08.02 SAMSUNG DISPLAY CO LTD
  • EP3882752B1 patent drawingFigure 1A
  • EP3882752B1 patent drawingFigure 1B
  • EP3882752B1 patent drawingFigure 2A

AI summary

Provided is a display device including a display panel defining a folding area and a non-folding area and including a base layer, a circuit layer on the base layer, and a display element layer on the circuit layer, an input sensor below the display panel and defining a sensing area overlapping the non-folding area, and a light shielding layer between the display element layer and the input sensor, where the light shielding layer defines a plurality of holes in a first portion of the light shielding layer at the non-folding area, and a cut portion in a second portion of the light shielding layer at the folding area.