Piezoelectric Acoustic Sensor Membrane for Higher SPL and Vibration

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Solution Overview

Problem

Existing acoustic sensors face limitations in vibrational displacement and performance due to fully filled polymer membranes, and manufacturing difficulties with dry film materials.

Innovation Solution

An acoustic sensor design with a base structure that includes a back cavity, piezoelectric unit, and an additional membrane that is partially filled in a slit but not in a second slit or back cavity, using vapor deposition to form a membrane with sections that reduce restrictions on vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If liquid or paste polymer is used to fully fill the membrane structure, then the structural gap is fully filled, but the vibrational displacement and performance are limited

Engineering Contradiction:

Improvestructural gap fillingVSAvoidvibrational displacement

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies local quality by creating different filling states in different regions of the membrane structure. The additional membrane is filled into the first slit (local region) but intentionally left unfilled in the second slit and back cavity regions. This localized filling approach allows the membrane to maintain structural integrity where needed while preserving vibrational freedom in other areas, thus resolving the contradiction between gap filling and vibrational performance.

Inventive Principle:

Principle #3Local quality

2Reliability

If dry film type material is used to cover the structure without filling, then the vibrational performance is maintained, but the manufacturing difficulties and handling concerns increase significantly

Engineering Contradiction:

Improvevibrational performanceVSAvoidmanufacturing difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the membrane structure into multiple slits (first slit and second slit) with different filling requirements. The additional membrane is selectively filled only in the first slit region, while the second slit remains unfilled. This segmentation allows the structure to benefit from both filled and unfilled regions, achieving a balance between manufacturing ease (partial filling) and vibrational performance (unfilled regions).

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by filling the additional membrane only in specific regions (first slit) rather than completely filling all structural gaps. This partial filling approach reduces manufacturing complexity compared to complete filling, while still providing structural support where needed. The unfilled regions (second slit, back cavity) maintain vibrational performance, thus resolving the contradiction between manufacturing ease and vibrational performance.

Inventive Principle:

Principle #16Partial or excessive action

3Power

If the additional membrane is filled in the first slit, then the sound pressure is increased, but the vibrational displacement may be restricted

Engineering Contradiction:

Improvesound pressureVSAvoidvibrational displacement

Core Design Contradiction:

PowerVSLength of moving object

Solution Approach 1:

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

Enhances vibrational displacement, increases sound pressure, and improves structural reliability while eliminating material limitations on dry film types, achieving higher sound pressure level (SPL) and improved reliability.

Implementation Method 1

a piezoelectric unit formed on the second oxide layer and including a first electrode layer, a piezoelectric layer and a second electrode layer that are stacked in sequence from bottom to top

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

using vapor deposition to form a membrane with sections that reduce restrictions on vibration

Methodology Applied

Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentUS12532129B2Acoustic sensor and manufacturing method therefor

Publication Date: 2026.01.20 AAC TECHNOLOGIES PTE LTD

AI summary

Acoustic sensor and manufacturing method. The acoustic sensor includes: a base including a first silicon layer, a first oxide layer and a second silicon layer stacked, and a back cavity; a second oxide layer formed on the base; a piezoelectric unit formed on the second oxide layer and including a first electrode layer, a piezoelectric layer and a second electrode layer stacked; a first slit formed at a middle portion of the second electrode layer and passing the second electrode layer, the piezoelectric layer and the first electrode layer; a second slit formed at a middle portion of the second silicon layer and passing the second silicon layer and the second oxide layer; an additional membrane filled in the first slit and not filled in the second slit. The SPL and structural reliability are effectively improved, and the material type is not limited by dry film type materials.