Directional Acoustic Sensor With Capacitive Air-Gap Resonators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing directional acoustic sensors face challenges in designing small-sized devices due to difficulties in controlling the thickness of piezoelectric layers and electrode layers, which affects the resonant frequency and overall design complexity.
Innovation Solution
The proposed directional acoustic sensor incorporates a support member with a plurality of resonators, including a driver and a sensor that senses capacitance changes based on air gap movements, utilizing a spacer layer and electrodes with different thicknesses and configurations to achieve precise frequency tuning and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric sensing unit with stacked layers is used, then sensing capability is achieved, but device thickness increases and resonant frequency control becomes difficult
Solution Approach 1:
The patent replaces the mechanical piezoelectric sensing unit with an electrical sensing mechanism. The driver unit's movement is detected by measuring capacitance changes between the driver (first electrode) and the support member (second electrode), eliminating the need for piezoelectric material layers and their associated thickness constraints.
Solution Approach 2:
The patent transitions from a three-dimensional stacked structure (piezoelectric layers with upper and lower electrodes) to a two-dimensional planar structure where the driver moves laterally relative to the support member. This dimensional change allows thickness reduction while maintaining sensing functionality through capacitance measurement.
2Manufacturing precision
If piezoelectric layer thickness is determined, then resonator thickness is constrained, but resonant frequency tuning becomes difficult
Solution Approach 1:
The patent enables resonant frequency tuning by changing the capacitance parameter through adjustable air gap distance. The driver unit's lateral movement relative to the support member changes the capacitance, allowing resonant frequency adjustment without being constrained by fixed layer thicknesses.
Solution Approach 2:
The patent introduces dynamic adjustability to the resonator system. The air gap between the driver and support member can be dynamically changed to tune the resonant frequency, transforming a static structure with fixed frequency characteristics into a dynamic system with adjustable parameters.
3Ease of manufacture
If resonant frequency is adjusted using only length and width, then thickness control is simplified, but device miniaturization becomes difficult
Solution Approach 1:
The patent replaces mechanical dimension-based frequency adjustment with an electrical capacitance-based sensing mechanism. This substitution allows for more compact device design as the sensing function is achieved through electrical field interaction rather than requiring large mechanical dimensions.
Solution Approach 2:
The patent employs thin-film electrode structures (first electrode on driver, second electrode on support member) that enable miniaturization. These thin film structures maintain electrical functionality while significantly reducing device thickness and overall size.
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 enables the design of smaller directional acoustic sensors with improved sensitivity and frequency response, allowing for more efficient sound direction detection and voice recognition applications.
Implementation Method 1
a directional acoustic sensor using the principle of a resonator that responds to sound pressure difference has been developed
Implementation Method 2
a sensor configured to sense a capacitance change based on an air gap that changes based on a movement of the driver
Data Source
AI summary
Provided is a directional acoustic sensor including a support member, and a plurality of resonators extending in a longitudinal direction with respect to the support member, wherein each of the plurality of resonators includes a driver configured to move based on an input sound signal, and a sensor configured to sense a capacitance change based on an air gap that changes based on a movement of the driver.