Ultrasonic Sensor Deflecting Element for Directional Acoustic Coupling

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Solution Overview

Problem

Current ultrasonic sensors face challenges in efficiently emitting and receiving acoustic signals in a primary direction due to complex designs, unwanted sound propagation, and inefficient damping methods, which affect their energy efficiency and directional characteristics, especially in close-range measurements.

Innovation Solution

The device employs a deflection element and decoupling means to redirect acoustic signals, minimizing rearward sound emission and enhancing energy efficiency by creating a constructive superimposition of sound waves, allowing for targeted transmission and reception of acoustic signals in a specific direction through carefully designed acoustic paths and membrane structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the electroacoustic transducer is positioned close to the membrane for compact design, then the device size is reduced, but sound radiation in the primary direction is attenuated due to proximity to the supporting wall

Engineering Contradiction:
Improvedevice sizeVSAvoidsound radiation efficiency
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

An acoustic coupling element is introduced between the electroacoustic transducer and the membrane. This intermediary component transmits acoustic signals from the transducer to the membrane while allowing the transducer to be positioned close to the membrane for compact design, thus resolving the contradiction between device size and sound radiation efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The acoustic coupling element extends in the thickness direction (third dimension) to bridge the gap between the transducer and membrane. By utilizing the dimensional space between these components, the system achieves both close positioning for compactness and effective acoustic coupling for efficient sound radiation

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the electroacoustic transducer is positioned close to the membrane, then the device is more compact, but vibrations are transmitted to the supporting wall causing unwanted sound propagation

Engineering Contradiction:
Improvedevice sizeVSAvoidunwanted sound propagation
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The acoustic coupling element serves as a mediator that decouples the electroacoustic transducer from the supporting wall. It transmits acoustic signals to the membrane while blocking the transmission of vibrations to the wall, thus reducing unwanted sound propagation while maintaining compact device size

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The acoustic coupling element converts the potentially harmful vibration transmission path into a beneficial acoustic signal transmission path. By designing the coupling element to transmit only acoustic signals to the membrane while blocking vibration transmission to the wall, the system turns what would be a source of unwanted sound into a component that actively prevents harmful vibrations

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If the transducer is positioned at a distance from the membrane, then sound radiation in the primary direction is improved, but the device complexity and size increase

Engineering Contradiction:
Improvesound radiation efficiencyVSAvoidstructural complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The acoustic coupling element acts as a mediator that enables the transducer to be positioned at an optimal distance from the membrane. It maintains the necessary spacing for effective sound radiation while providing a simple, integrated structure that does not significantly increase device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The acoustic coupling element performs multiple functions: it transmits acoustic signals from the transducer to the membrane, provides mechanical support, and acts as a vibration isolator. This multi-functionality allows the transducer to be positioned at the optimal distance without increasing overall device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach significantly increases the energy efficiency of ultrasonic sensors by minimizing unwanted sound emission, maximizing the ratio of emitted sound power, and improving directional characteristics, enabling precise acoustic signal transmission and reception.

Implementation Method 1

one to a contact on a contact carrier and the other to a corresponding contact on a piezoceramic disc, the so-called electroacoustic transducer

Methodology Applied
Scientific EffectElectroacoustic transduction: Piezoelectric Effect

Implementation Method 2

the acoustic signals emitted by the electroacoustic transducer, which are not directly transmitted in the primary direction, are deflected into this direction via the deflecting element

Methodology Applied
Scientific EffectAcoustic reflection: Reflection

Implementation Method 3

The pot-shaped structure of the ultrasound transducer, the so-called transducer pot, often contains a foam to shorten reverberation and diaphragm vibration and to reduce sound radiation against the primary direction by damping the foam

Methodology Applied
Scientific EffectAcoustic damping: Damping

Implementation Method 4

The leads are welded to the electroacoustic transducer, preferably using a thermocompressive welding process. The electroacoustic transducer is bonded to the bottom of a cup-shaped aluminum structure, which tapers to a membrane

Methodology Applied
Scientific EffectAcoustic transmission: Sound

Data Source

PatentEP3286755B1Device for transmitting acoustic signals in a primary direction and/or receiving acoustic signals from the primary direction
Publication Date: 2019.11.06 ROBERT BOSCH GMBH
  • EP3286755B1 patent drawingFigure 1
  • EP3286755B1 patent drawingFigure 2
  • EP3286755B1 patent drawingFigure 3

AI summary

The invention relates to a device (1) for transmitting acoustic signals in a primary direction (2) and/or receiving acoustic signals from the primary direction (2), in particular in order to sense a vehicle environment, comprising an electroacoustic transducer (3) and a deflecting element (4). The electroacoustic transducer (3) is designed, when acoustic signals are transmitted, to transmit the acoustic signal in the primary direction (2) and a backward direction (5) and/or, when acoustic signals are received, to be excited by the acoustic signal from the primary direction (2) and from the backward direction (5). The deflecting element (4) is designed, when acoustic signals are transmitted, to deflect the acoustic signal output in the backward direction (5) into the primary direction (2) over a first acoustic path (6) in such a way that said acoustic signal passes the electroacoustic transducer (3) to the side thereof and/or, when acoustic signals are received, to deflect the acoustic signal, which arrives from the primary direction and passes the electroacoustic transducer (3) to the side thereof, over the first acoustic path (6) in such a way that said acoustic signal hits the electroacoustic transducer (3) from the backward direction (5).