Fingerprint Sensing Display Dual Light Shielding Layers

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Solution Overview

Problem

Current fingerprint sensing display technologies face challenges in accurately detecting fingerprint information due to interference from diffusedly reflected light, which prevents clear image capture by photosensors.

Innovation Solution

A fingerprint sensing display apparatus featuring a counter substrate and an array substrate with a first and second light shielding layer, where the light shielding layers have alternating absorbing and transmitting regions that cross over to block diffusedly reflected light, allowing only totally reflected light to pass through and form a signal-enriched light beam for detection by photosensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light shielding layers are added to block diffusedly reflected light, then measurement precision of fingerprint detection is improved, but device complexity increases

Engineering Contradiction:

Improvefingerprint detection accuracyVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The light shielding function is segmented into two separate layers: a first light shielding layer with first light absorbing barriers arranged in a first direction, and a second light shielding layer with second light absorbing barriers arranged in a second direction. This segmentation allows each layer to target specific directions of diffusedly reflected light, improving fingerprint detection accuracy while maintaining manageable structural complexity through modular design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The light shielding layers are designed with spatially varying properties: the first light absorbing barriers are positioned to block diffusedly reflected light in the first direction, while the second light absorbing barriers are positioned to block diffusedly reflected light in the second direction. This local quality differentiation enables precise control of light paths from different directions, enhancing measurement precision without requiring uniform complex structures throughout

Inventive Principle:

Principle #3Local quality

2Measurement precision

If light shielding layers are added to block diffusedly reflected light, then measurement precision of fingerprint detection is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvefingerprint detection accuracyVSAvoidalignment precision

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The first and second light shielding layers are designed with predetermined patterns of light absorbing barriers before assembly. The first light absorbing barriers are pre-positioned to block diffusedly reflected light in the first direction, and the second light absorbing barriers are pre-positioned to block diffusedly reflected light in the second direction. This preliminary arrangement of light shielding structures simplifies the overall manufacturing process by allowing each layer to be fabricated and positioned independently with standard precision tolerances

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The two light shielding layers are designed with asymmetric orientations: the first light absorbing barriers are arranged in a first direction while the second light absorbing barriers are arranged in a second direction. This asymmetric design allows each layer to address specific light paths from different directions, improving fingerprint detection accuracy while enabling independent optimization of each layer's manufacturing process

Inventive Principle:

Principle #4Asymmetry

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 solution ensures clear detection of fingerprint information by filtering out diffusedly reflected light, allowing photosensors to accurately capture the signal-enriched light beam and distinguish between fingerprint ridges and valleys.

Implementation Method 1

at least a portion of the light being totally reflected by a surface of the counter substrate away from the array substrate

Methodology Applied

Scientific EffectTotal reflection: Total Internal Reflection

Implementation Method 2

the first light shielding layer comprises a plurality of first light transmitting regions and a plurality of first light absorbing barriers alternatively arranged

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS11495044B2Fingerprint sensing display apparatus, method of using fingerprint sensing display apparatus, and method of fabricating fingerprint sensing display apparatus

Publication Date: 2022.11.08 BEIJING BOE TECH DEV CO LTD

AI summary

A fingerprint sensing display apparatus having a plurality of subpixel regions spaced apart by an inter-subpixel region is provided. The fingerprint sensing display apparatus includes a counter substrate; an array substrate facing the counter substrate, wherein the array substrate includes a plurality of light emitting elements configured to emit light toward the counter substrate, at least a portion of the light being totally reflected by a surface of the counter substrate away from the array substrate; a plurality of photosensors on a side of the array substrate away from the counter substrate; and a first light shielding layer and a second light shielding layer between the plurality of photosensors and the plurality of light emitting elements, the second light shielding layer is on a side of the first light shielding layer away from the plurality of light emitting elements.