Lateral Contact Acoustic Sensor for Compact Ultrasonic Design

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Solution Overview

Problem

The complexity and cost of acoustic sensor structures, particularly in ultrasonic sensors, are hindered by the need for intricate electrical connections and large structural sizes due to traditional contacting methods of piezoceramic discs, which limit the miniaturization and efficiency of these devices.

Innovation Solution

The acoustic sensor employs a lateral contacting method using a conductor track and a membrane, allowing the electroacoustic transducer to be positioned flatly, with the electrical conductor oscillating with the membrane for reliable contact, and a printed circuit board for simplified electronics integration, minimizing signal attenuation and maximizing sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional contacting methods are used for piezoceramic discs, then reliable electrical connections are achieved, but the structural size increases and complexity increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidsensor housing volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent transitions from traditional vertical contacting (through the piezoceramic disc thickness) to lateral contacting (at the edge/circumference of the disc). This dimensional change allows the electrical connections to be made at the side surface of the piezoceramic element rather than requiring conductors to pass through the housing structure, thereby reducing the overall sensor housing volume while maintaining reliable electrical connection.

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

Solution Approach 2:

Instead of contacting the piezoceramic disc from the top and bottom surfaces (traditional method), the patent inverts the contacting approach by making electrical contact at the lateral edge/circumference of the disc. This inversion of the contacting geometry eliminates the need for complex internal wiring structures and reduces the housing volume required to accommodate traditional contacting arrangements.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If traditional contacting methods are used for piezoceramic discs, then electrical connections are established, but the device complexity increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidcomponent placement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By moving the contact point from the top/bottom surfaces to the lateral edge of the piezoceramic disc, the patent simplifies the overall device architecture. The lateral contact configuration reduces the number of wiring paths required and simplifies the assembly process, as contacts can be made at the perimeter rather than requiring precise placement of conductors through the housing structure.

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

3Reliability

If the active area of the piezoceramic disc is increased, then sensitivity is improved, but the structural size increases

Engineering Contradiction:
Improvesensor sensitivityVSAvoidsensor housing volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The lateral contacting method frees up the top and bottom surfaces of the piezoceramic disc, allowing the entire surface area to be utilized as active sensing area. Since contacts are made at the edge rather than occupying surface area, the active area is maximized without increasing the disc diameter or housing volume, thereby improving sensitivity within the same footprint.

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

Solution Approach 2:

The patent applies local quality by concentrating the electrical contact function at the lateral edge/circumference of the piezoceramic disc, while the main body surfaces are dedicated entirely to acoustic sensing. This functional separation allows maximum active area on the sensing surfaces without compromising electrical connection reliability.

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

This design enables a compact, flat, and efficient acoustic sensor structure with increased active area and sensitivity, while ensuring reliable electrical connections and protection from electromagnetic radiation.

Implementation Method 1

a plate-shaped transducer element (2) which is set up to emit an acoustic signal when it is excited by the electrical signal and to emit an electrical signal when it is excited by an acoustic signal

Methodology Applied
Scientific EffectElectroacoustic conversion: Piezoelectric Effect

Data Source

PatentEP3298799B1Acoustic sensor for transmitting and receiving acoustic signals
Publication Date: 2021.06.09 ROBERT BOSCH GMBH
  • EP3298799B1 patent drawingFigure 1~2
  • EP3298799B1 patent drawingFigure 3~4
  • EP3298799B1 patent drawingFigure 5

AI summary

The present invention relates to an acoustic sensor (1) comprising an electroacoustic transducer and an electrical conductor (4). The electroacoustic transducer comprises a plate-shaped transducer element (2) which is configured to emit an acoustic signal when it is excited by the electrical signal. The electroacoustic transducer furthermore comprises a first contacting (3) which is arranged on at least one of the surfaces of the plate-shaped transducer element (2) in such a way that it has at least one portion which terminates flush with the outer circumference of the first or second surface (2a, 2b) of the plate-shaped transducer element (2) or extends at least in part outside of the outer circumference of the first or second surface (2a, 2b) of the plate-shaped transducer element (2). The electrical conductor (4) has a contact region (5) which is in contact with an outer circumference of the first contacting (3), wherein the contact region (5) of the electrical conductor (4) is arranged in a plane, defined by the first surface (2a), outside of a region which overlaps with the electroacoustic transducer.