Piezoelectric Fingerprint Sensor Void Region Diaphragm

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Solution Overview

Problem

Existing TFT-driven fingerprint sensors with piezoelectric thin films face issues of high power consumption and damage to piezoelectric elements due to void formation during the manufacturing process.

Innovation Solution

Incorporating a void region under the vibration region of the thin-film transistor layer to create a diaphragm structure, which reduces process damage and lowers power consumption by enhancing piezoelectric element amplitude.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional manufacturing process is used to form voids, then void formation is achieved, but piezoelectric elements are damaged

Engineering Contradiction:

Improvevoid formationVSAvoidpiezoelectric element integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The manufacturing process is segmented into distinct stages: first forming the piezoelectric element layer with its electrodes and piezoelectric film, then separately forming the void region in the seat layer. This segmentation allows the piezoelectric element to be completed and protected before the void formation process, preventing damage while achieving the desired void structure for diaphragm operation.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If the piezoelectric element operates with high frequency, then sensing performance is improved, but power consumption increases

Engineering Contradiction:

Improvesensing performanceVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The void region creates a diaphragm structure that enhances mechanical vibration amplitude of the piezoelectric element. This increased vibration amplitude improves the coupling between the piezoelectric element and the object being sensed, thereby improving sensing performance at high frequencies while the diaphragm structure itself helps manage the energy requirements through enhanced mechanical efficiency.

Inventive Principle:

Principle #18Mechanical vibration

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

The void region configuration reduces process damage to piezoelectric elements and lowers power consumption while maintaining high-frequency operation, improving the efficiency and durability of the sensors.

Implementation Method 1

a piezoelectric element layer including a piezoelectric element... The piezoelectric element includes an upper electrode, a lower electrode, and a piezoelectric film between the upper electrode and the lower electrode

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

receives ultrasound reflected off an object and converts the received ultrasound into an electric signal

Methodology Applied

Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentUS20250205736A1Piezoelectric device

Publication Date: 2025.06.26 SHANGHAI TIANMA MICRO ELECTRONICS CO LTD

AI summary

A piezoelectric device has a multilayer structure on a support member and includes a piezoelectric element layer including a piezoelectric element, a thin-film transistor layer located between the piezoelectric element layer and the support member, and a seat disposed between the support member and the thin-film transistor layer. The piezoelectric element includes an upper electrode, a lower electrode, and a piezoelectric film between the upper electrode and the lower electrode. The seat includes a void region inside the seat, the void region overlapping the piezoelectric element in a layering direction.