Ultrasonic Sensor Acoustic Matching Layer Resonance

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Solution Overview

Problem

Conventional ultrasonic sensors face challenges in downsizing while maintaining detection sensitivity, as bulky piezoelectric materials struggle to resonate with acoustic matching layers, affecting the balance between size reduction and sensitivity improvement.

Innovation Solution

An ultrasonic sensor design featuring an acoustic matching layer with a deformable surface that generates a standing wave, coupled with a vibration member that resonates with the repeat deformation, increasing vibration amplitude and detection sensitivity independently of the matching layer's surface area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If bulky piezoelectric material is used for the ultrasonic detection element, then the detection sensitivity is improved, but the size of the ultrasonic sensor increases

Engineering Contradiction:

Improvedetection sensitivityVSAvoidsize of ultrasonic sensor

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent utilizes mechanical vibration resonance between the acoustic matching layer and the ultrasonic detection element. The acoustic matching layer is designed to vibrate at a specific resonance frequency, and the ultrasonic detection element is tuned to match this frequency, creating a resonant coupling that amplifies the detection signal without requiring a larger element size. This resolves the contradiction by using vibrational resonance to enhance sensitivity while maintaining compact dimensions.

Inventive Principle:

Principle #18Mechanical vibration

Solution Approach 2:

The patent changes the physical parameters of the ultrasonic detection element, specifically its resonance frequency, to match the resonance frequency of the acoustic matching layer. By adjusting the thickness, material properties, and geometric parameters of the detection element, the system achieves optimal resonant coupling. This parameter matching allows compact-sized elements to achieve high detection sensitivity through resonant amplification rather than relying on bulk material size.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the area of the acoustic matching layer is diminished, then the downsizing of the ultrasonic sensor is achieved, but the detection sensitivity deteriorates

Engineering Contradiction:

Improvesize of ultrasonic sensorVSAvoiddetection sensitivity

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent employs mechanical vibration resonance to concentrate the ultrasonic energy interaction within a small volume. By designing the acoustic matching layer and detection element to resonate at matching frequencies, the system achieves high detection sensitivity even with a reduced-area acoustic matching layer. The resonant vibration amplifies the interaction between the ultrasonic wave and the detection element, compensating for the reduced surface area.

Inventive Principle:

Principle #18Mechanical vibration

Solution Approach 2:

The patent utilizes periodic vibration at the resonance frequency of the acoustic matching layer and ultrasonic detection element. This periodic action creates a buildup of vibrational energy through constructive interference, allowing the system to achieve high detection sensitivity with repeated cycles of vibration. The periodic resonant oscillation enables compact components to accumulate sufficient vibrational amplitude for sensitive detection despite their small size.

Inventive Principle:

Principle #19Periodic action

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 enhances detection sensitivity by increasing vibration amplitude and allows for the downsizing of the acoustic matching layer, improving the ultrasonic sensor's ability to detect ultrasonic waves efficiently.

Implementation Method 1

The acoustic matching layer is repeatedly deformable in accordance with a standing wave, which is generated in the acoustic matching layer by the received ultrasonic wave

Methodology Applied

Scientific EffectStanding wave:

Implementation Method 2

The vibration member resonates with the repeat deformation of the acoustic matching layer

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

The sending and receiving of the ultrasonic wave is done by an element capable of sending and receiving the ultrasonic wave

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS7612485B2Ultrasonic sensor

Publication Date: 2009.11.03 DENSO CORP

AI summary

An ultrasonic sensor for detecting an ultrasonic wave, which is output from an ultrasonic generator and reflected by an object to be detected, the ultrasonic sensor includes: an acoustic matching layer having a first surface and a second surface, the first surface which receives the ultrasonic wave, and the second surface which is opposite to the first surface; and an ultrasonic detection element including a vibration member. The vibration member is coupled with the second surface of the acoustic matching layer. The acoustic matching layer is repeatedly deformable in accordance with a standing wave, which is generated in the acoustic matching layer by the received ultrasonic wave. The vibration member resonates with the repeat deformation of the acoustic matching layer.