Display Panel Filter Layer for Reduced Leakage in Fingerprint Sensing

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Solution Overview

Problem

Existing display devices with optical fingerprint recognition face issues such as light leakage and warpage due to insufficient sealing at component edges, leading to reduced assembly yield and increased overall thickness, which affect the accuracy and reliability of fingerprint recognition.

Innovation Solution

Integrate a filter layer with a filtering function on the backside of the display panel, stacking the photosensitive imaging device away from the display side, eliminating the need for additional attachment of a filtering function layer on the prism, thereby reducing assembly complexities and thickness while enhancing recognition accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a filtering function layer is separately attached on the prism, then fingerprint recognition accuracy is improved, but device complexity and assembly steps increase

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

Solution Approach 1:

The patent merges the filtering function into the display panel structure itself by forming a filter layer at the backside of the display panel. This integration eliminates the need for separately attaching a filtering function layer on the prism, thereby reducing assembly complexity while maintaining fingerprint recognition accuracy through effective light filtering.

Inventive Principle:
Principle #5Merging (Combining)

2Object-affected harmful factors

If multiple components are attached separately, then filtering function is achieved, but overall thickness increases

Engineering Contradiction:
Improvelight leakageVSAvoidoverall thickness
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The patent combines multiple functional layers into an integrated structure where the filter layer is formed at the backside of the display panel. This merging approach achieves effective light filtering to prevent light leakage while minimizing overall thickness by eliminating redundant separate components.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If insufficient sealing at component edges is used, then assembly is easier, but light leakage occurs reducing recognition accuracy

Engineering Contradiction:
Improveassembly easeVSAvoidrecognition accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent integrates the filtering function into the display panel's backside structure, creating a unified component that eliminates interfaces between separate filtering layers and the prism. This integration inherently improves sealing at edges, preventing light leakage while maintaining ease of assembly through reduced component count.

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

This configuration improves assembly yield, reduces light leakage, and minimizes overall thickness, resulting in enhanced fingerprint recognition accuracy and reliability by effectively filtering interference light.

Implementation Method 1

a filter layer having a filtering function, and a photosensitive imaging device stacked with the display panel and located at a side of the filter layer facing away from the display side

Methodology Applied
Scientific EffectLight filtering: Filter (optical)

Data Source

PatentEP3890026B1Display apparatus and preparation method therefor
Publication Date: 2025.08.13 BOE TECHNOLOGY GROUP CO LTD
  • EP3890026B1 patent drawingFigure 1A~1B
  • EP3890026B1 patent drawingFigure 1C~2
  • EP3890026B1 patent drawingFigure 3~4

AI summary

A display device and a manufacturing method thereof are provided. The display device (100) includes a display panel (110) and a photosensitive imaging device (130). The display panel (110) includes a display side (111) and a backside (111) opposite to the display side (112), and the display panel (110) further includes a filter layer (120) disposed at the back side (112) of the display panel (110). The photosensitive imaging device (130) is stacked with the display panel (110) and located at a side of the filter layer (120) facing away from the display side (111), and the photosensitive imaging device (130) is configured to detect a skin texture image of a user touching the display panel. The display device (100) reduces attaching processes between components and improves the assembly yield of each component.