Under-Display Fingerprint Sensing for Ambient-Light Adaptation

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Solution Overview

Problem

The accuracy of under-screen fingerprint identification is affected by external environmental changes, leading to increased false rejection and acceptance rates.

Innovation Solution

An optical fingerprint identification apparatus with a pixel array and color filter layer that determines the environmental lighting conditions to adjust capturing parameters, such as exposure time and gain, for improved fingerprint image capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If under-screen fingerprint identification is performed using optical imaging, then fingerprint identification functionality is integrated into the display, but identification accuracy deteriorates under varying external lighting conditions

Engineering Contradiction:
Improveintegration of fingerprint identification into displayVSAvoidfingerprint identification accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent dynamically adjusts capturing parameters (exposure time, gain, illumination intensity) based on detected environmental lighting conditions. The processing circuitry modifies these parameters in real-time to compensate for varying ambient light, thereby maintaining fingerprint identification accuracy while preserving the integrated under-screen design.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates a feedback mechanism where the processing circuitry continuously monitors environmental lighting conditions and uses this information to adjust capturing parameters. This closed-loop control ensures that the fingerprint sensor adapts to changing light conditions, resolving the accuracy issue while maintaining the integrated display design.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If capturing parameters are dynamically adjusted according to environmental lighting, then fingerprint identification accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvefingerprint identification accuracyVSAvoidparameter adjustment mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the light sensing capability and fingerprint capturing function into a single integrated system. The same optical sensor array used for fingerprint imaging also detects ambient lighting conditions, and the processing circuitry performs both environmental assessment and fingerprint image processing. This merging reduces device complexity while maintaining improved accuracy through dynamic parameter adjustment.

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

Enhances fingerprint identification accuracy by adapting to varying lighting conditions, reducing false rejection and acceptance rates.

Implementation Method 1

imaging is performed according to the difference of reflection abilities of a ridge and a valley of a fingerprint to light

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

An optical fingerprint identification apparatus with a pixel array and color filter layer that determines the environmental lighting conditions

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentEP3920087B1Fingerprint identification method and apparatus, and electronic device
Publication Date: 2025.10.08 SHENZHEN GOODIX TECH CO LTD
  • EP3920087B1 patent drawingFigure 1A~1B
  • EP3920087B1 patent drawingFigure 2A~2B
  • EP3920087B1 patent drawingFigure 3~4

AI summary

Embodiments of the present application provide a fingerprint identification method, a fingerprint identification apparatus and an electronic device, which could effectively improve the accuracy of fingerprint identification. The fingerprint identification method is applied to a fingerprint identification apparatus disposed under a display screen of an electronic device, the fingerprint identification apparatus includes a pixel array and a colour filter layer, the colour filter layer includes at least one filter unit, and the at least one filter unit is disposed above at least one first type pixel of the pixel array, respectively, and the method includes: capturing a first light signal transmitting through the at least one filter unit and sensed by the first type pixel; determining a fingerprint identification environment according to an intensity of the first light signal; and determining, based on the fingerprint identification environment, a target capturing parameter of capturing a fingerprint light signal returned by reflection or scattering of a finger above the display screen, the fingerprint light signal being used for fingerprint identification.