Fingerprint Sensing Module Photosensitive Region Area Optimization

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Solution Overview

Problem

Under-screen fingerprint sensing modules face challenges in maintaining consistent sensing sensitivity across different colored lights due to varying quantum efficiency of photosensitive materials, affecting image sensing quality.

Innovation Solution

The fingerprint sensing module incorporates a photosensitive element layer with multiple photosensitive regions and a color filter layer, where the percentage of second photosensitive pixels is less than 30%, and the orthographic projection areas of photosensitive regions differ, along with a light shielding pattern layer and infrared light cut-off filter patterns, to adjust quantum efficiency and sensitivity for different colored lights.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If photosensitive pixels with the same structural design are used for different colored lights, then manufacturing is simplified, but sensing sensitivity varies significantly across different wavelengths

Engineering Contradiction:

Improvestructural design consistencyVSAvoidsensing sensitivity uniformity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies local quality by making different parts of the photosensitive element layer have different photosensitive region areas. Specifically, photosensitive pixels corresponding to different color filter patterns (R, G, B) have different photosensitive region areas, allowing each pixel to be optimized for its specific wavelength range while maintaining the same overall structural design. This resolves the contradiction by enabling uniform sensitivity across different colors without requiring completely different structures.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of photosensitive region area to compensate for varying quantum efficiency across wavelengths. By adjusting the area of photosensitive regions based on the specific wavelength range they detect, the patent achieves uniform sensing sensitivity. This is done while keeping the basic structural design consistent, thus maintaining ease of manufacture through parameter optimization rather than structural redesign.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the percentage of second photosensitive pixels is kept low (less than 30%), then sensitivity differences are reduced, but device complexity increases due to multiple photosensitive patterns

Engineering Contradiction:

Improvesensing sensitivity uniformityVSAvoidphotosensitive pixel configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses local quality by creating different types of photosensitive pixels (first, second, and third photosensitive pixels) with different photosensitive region areas, each optimized for specific wavelength ranges. By limiting second photosensitive pixels to less than 30% of the total, the patent achieves sensitivity uniformity without excessive complexity. The different pixel types are strategically distributed to match the color filter pattern arrangement, optimizing performance while controlling device complexity.

Inventive Principle:

Principle #3Local quality

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 reduces the sensitivity difference between photosensitive pixels for different colored lights, thereby enhancing the image sensing quality of the fingerprint sensing module.

Implementation Method 1

The color filter layer has multiple openings and multiple first color filter patterns. The openings respectively overlap the first photosensitive pixels. The first color filter patterns respectively overlap the second photosensitive pixels.

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

quantum efficiency (QE %) of a photosensitive material that is used to convert the ray into an electrical signal is different at different wavelength ranges

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11495048B2Fingerprint sensing module

Publication Date: 2022.11.08 AU OPTRONICS CORP

AI summary

A fingerprint sensing module, including a photosensitive element layer and a color filter layer, is provided. The photosensitive element layer has multiple photosensitive regions, and includes a substrate and multiple photosensitive pixels. The photosensitive pixels have multiple photosensitive patterns overlapping the photosensitive regions. The photosensitive pixels include multiple first photosensitive pixels overlapping multiple first photosensitive regions and multiple second photosensitive pixels overlapping multiple second photosensitive regions. A percentage value of a number of the second photosensitive pixels to a number of the photosensitive pixels is less than 30%. An orthographic projection area of each of the first photosensitive regions is different from an orthographic projection area of each of the second photosensitive regions. The color filter layer has multiple openings overlapping the first photosensitive pixels and multiple first color filter patterns overlapping the second photosensitive pixels.