Optical Fingerprint Detection Calibration for Distance Fluctuations

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Solution Overview

Problem

The existing under-screen optical fingerprint detection systems face challenges in maintaining detection and identification effectiveness due to fluctuations in the installation distance between the optical fingerprint detection apparatus and the display screen, caused by bending or displacement of the middle frame under strong impacts or manufacturing tolerances, leading to deteriorated user experience.

Innovation Solution

The implementation of a fingerprint detection apparatus with a pixel array and processing unit that can automatically calibrate the reconstructed image when the installation distance changes, ensuring clear image formation and improved detection and identification efficacy by adjusting the moving distances of multiple images based on quality parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the optical fingerprint detection apparatus is installed on the middle frame during mass production, then the detection system can be calibrated according to the installation distance, but the middle frame may bend or displace under strong impact, causing the installation distance to change and deteriorating the detection effect

Engineering Contradiction:
Improvedetection effectVSAvoidinstallation distance
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies the Dynamics principle by making the installation distance adjustable rather than fixed. The optical fingerprint detection apparatus can dynamically adapt to different installation distances through automated calibration that adjusts the distance between the optical component and the display screen, allowing the system to maintain optimal performance despite frame bending or displacement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements Parameter changes by automatically adjusting the installation distance parameter based on detected image quality. The system measures the actual installation distance and modifies it to optimize the fingerprint detection image quality, thereby maintaining reliable detection效果 even when the middle frame deforms.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the optical fingerprint detection apparatus is installed on the middle frame, then the system can be assembled during mass production, but manufacturing tolerance causes fluctuations in installation distance, resulting in deteriorated detection and identification effect

Engineering Contradiction:
Improveassembly processVSAvoidinstallation distance
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies the Feedback principle by implementing an automated calibration process that measures the actual installation distance and uses this information to adjust the optical component position. The system continuously monitors and adjusts the installation distance to compensate for manufacturing tolerances, ensuring optimal detection performance without requiring extremely precise initial assembly.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements Self-service through the automated calibration function that allows the fingerprint detection system to self-adjust its installation distance. The system autonomously measures the actual distance and performs necessary adjustments without requiring manual intervention, thereby compensating for manufacturing variations and maintaining detection precision.

Inventive Principle:
Principle #25Self-service

3Reliability

If the installation distance between the optical fingerprint detection apparatus and the display screen changes, then the system must be recalibrated, but manual recalibration is time-consuming and affects user experience

Engineering Contradiction:
Improvedetection and identification effectVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements Self-service by enabling the fingerprint detection system to automatically recalibrate when installation distance changes. The automated calibration process autonomously detects the new distance, adjusts the optical component position, and optimizes detection parameters without requiring manual intervention, thereby maintaining reliable detection效果 while minimizing time loss.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies Preliminary action by performing automated calibration adjustments in advance or in real-time when distance changes are detected. The system proactively adjusts the installation distance parameters before detection quality deteriorates significantly, ensuring continuous optimal performance without requiring time-consuming manual recalibration.

Inventive Principle:
Principle #10Preliminary action

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 enhances the detection and identification effectiveness and user experience by maintaining clear image quality and signal-to-noise ratio even when the installation distance between the fingerprint detection apparatus and the display screen fluctuates, thereby improving the overall performance of the fingerprint detection system.

Implementation Method 1

receiving light signals in multiple directions, which are light signals reflected or scattered by a finger above the display screen

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

receiving light signals in multiple directions, which are light signals reflected or scattered by a finger above the display screen

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 3

The processing unit is configured to move the multiple images for combination to form a reconstructed image, and adjust moving distances of the multiple images according to a quality parameter of the reconstructed image

Methodology Applied
Scientific EffectImage processing: Image Processing

Data Source

PatentEP3809315B1Fingerprint detection method
Publication Date: 2022.12.07 SHENZHEN GOODIX TECH CO LTD
  • EP3809315B1 patent drawingFigure 1
  • EP3809315B1 patent drawingFigure 2
  • EP3809315B1 patent drawingFigure 3~4a

AI summary

Provided are a fingerprint detection apparatus (30) and method and an electronic device, which can improve the detection and identification effect of fingerprint detection when a distance between the optical fingerprint detection apparatus (30) and a display screen changes, thereby improving user experience. The fingerprint detection apparatus (30) is configured to be disposed below a display screen of an electronic device, and includes: a pixel array (320) including a plurality of groups of pixels, the plurality of groups of pixels being configured to respectively receive light signals in multiple directions to obtain multiple images, where the light signals in the multiple directions are light signals in multiple specific directions reflected or scattered by a finger above the display screen, and directed by a light path of an optical component; and a processing unit (330) configured to move the multiple images for combination to form a reconstructed image, and adjust moving distances of the multiple images according to a quality parameter of the reconstructed image to form a target reconstructed image, the target reconstructed image being a fingerprint image of the finger for fingerprint identification.