Display Device Fingerprint Sensing Light Blocking

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Solution Overview

Problem

Current display devices lack effective methods for accurately sensing fingerprints and other biometric information while minimizing external light interference, which affects the accuracy of fingerprint detection and recognition.

Innovation Solution

The display device incorporates a touch sensing layer with a sensing conductive layer that overlaps with light receiving pixels, including openings to allow light from a sub-pixel to be reflected from a finger and sensed, and a light blocking layer to prevent external light from interfering with the sensing process, along with a driving circuit for calibration to enhance fingerprint detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a sensing conductive layer is added to enable fingerprint sensing, then fingerprint detection capability is improved, but external light interference increases affecting sensing accuracy

Engineering Contradiction:

Improvefingerprint sensing capabilityVSAvoidexternal light interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The sensing conductive layer is segmented into multiple regions: a first region with higher transparency positioned over the display area to allow light transmission for fingerprint sensing, and a second region with lower transparency positioned over the non-display area to block external light. This spatial segmentation enables the same layer to perform dual functions of facilitating sensing while blocking harmful light.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the sensing conductive layer are assigned different optical properties (transparency levels) according to their specific functional requirements. The first region has higher transparency to enable light passage for fingerprint detection, while the second region has lower transparency to prevent external light interference, creating local quality variations optimized for each area's purpose.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If the sensing conductive layer has high transparency to allow light transmission for fingerprint sensing, then fingerprint detection accuracy is improved, but external light blocking capability deteriorates

Engineering Contradiction:

Improvefingerprint detection accuracyVSAvoidexternal light interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The sensing conductive layer is divided into functionally distinct regions with different transparency characteristics. The first region maintains high transparency to ensure sufficient light transmission for accurate fingerprint sensing, while the second region reduces transparency to block external light, thereby resolving the contradiction between light transmission and light blocking requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solution transitions from a uniform sensing layer to a spatially differentiated structure where transparency varies across different regions. This dimensional approach allows simultaneous optimization of light transmission (first region) and light blocking (second region) within a single layer structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If a light blocking layer is added to prevent external light interference, then sensing accuracy is improved, but device structure complexity increases

Engineering Contradiction:

Improvesensing accuracyVSAvoidlayer structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The light blocking function is merged into the sensing conductive layer itself by creating a second region with lower transparency. This integration eliminates the need for a separate light blocking layer, thereby reducing overall device structure complexity while maintaining sensing accuracy through the differentiated transparency regions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The sensing conductive layer is designed to perform multiple functions: it provides fingerprint sensing capability through its conductive properties while simultaneously providing light blocking functionality through its differentiated transparency regions. This multi-functionality reduces the need for additional dedicated components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 the accuracy of fingerprint detection by blocking external light and using calibration to refine the sensing process, resulting in enhanced fingerprint recognition capabilities.

Implementation Method 1

a first light sensing pixel in a display area... configured to sense light emitted from the sub-pixel, as reflected from a finger, to detect a fingerprint

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

the at least one sensing conductive layer is positioned to block external light from being received by the light receiving layer of the second light sensing pixel

Methodology Applied

Scientific EffectLight blocking/absorption: Absorption (EM radiation)

Data Source

PatentUS12262621B2Display device

Publication Date: 2025.03.25 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a light emitting sub-pixel disposed in a display area, a light receiving pixel disposed in one of the display area or a non-display area, and a touch sensing layer including a sensing conductive layer overlapping with the light receiving pixel.