Integrated Polymer Transducer Diaphragm for Ultrasonic Sensors

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing ultrasonic sensors face manufacturing challenges and reliability issues due to the failure-prone adhesive join between the piezoceramic element and the diaphragm, which complicates the production and operation of acoustic transducers.

Innovation Solution

An acoustic transducer design that integrates an electroacoustic transducer element with an electrically active polymer directly into the diaphragm cup, eliminating the need for an adhesive join and allowing for a one-piece configuration of the functional group and housing, using materials like carbon fiber-reinforced epoxy resins, and employing geometric configurations for specific vibration shapes and frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a piezoceramic element is attached to the diaphragm using an adhesive process, then the transducer element can be joined to the diaphragm, but the adhesive join fails during production and operation

Engineering Contradiction:

Improvereliability of adhesive joinVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The transducer element is integrated directly into the diaphragm cup as a single piece, eliminating the separate adhesive joining process. The functional group comprising the diaphragm cup and transducer element is produced as one integrated component, removing the failure-prone interface between separate parts.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The diaphragm cup is made from composite plastic materials such as carbon fiber-reinforced epoxy resins or glass fiber-reinforced epoxy resins, providing both structural integrity and acoustic performance while integrating the transducer element without requiring adhesive bonds.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the functional group and housing are produced as separate individual parts, then assembly is possible, but the production process becomes complex and time-consuming

Engineering Contradiction:

Improveassembly flexibilityVSAvoidproduction efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The functional group (diaphragm cup with transducer element) and the housing are produced as a single integrated piece through injection molding or resin transfer molding. This one-piece configuration eliminates multiple assembly steps, reduces production time, and increases manufacturing efficiency while maintaining design flexibility.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If multiple separate components are assembled to form the acoustic transducer, then functional requirements can be met, but the number of components increases manufacturing cost

Engineering Contradiction:

Improvefunctional capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The acoustic transducer is designed as an integrated one-piece component where the diaphragm cup, transducer element, and housing are formed together. This integration reduces the total number of parts, eliminates assembly operations, and significantly decreases manufacturing costs while preserving all necessary acoustic and electromechanical functions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated functional group serves multiple functions simultaneously: the diaphragm cup provides acoustic coupling and structural support, the embedded transducer element performs electromechanical transduction, and the integrated housing provides protection and mounting. This multi-functionality in a single component reduces overall system complexity and cost.

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 simplifies the manufacturing process, reduces costs, enhances robustness against environmental influences, and improves the transducer's sensitivity and signal-to-noise ratio, making it suitable for both airborne and liquid-based ultrasound applications, including automotive use.

Implementation Method 1

The transducer element is, for example, a piezoceramic element that causes the diaphragm to vibrate after application of an electrical voltage

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

for the reception of ultrasonic echoes, converts the vibrations on the diaphragm, which are excited by the acoustic pressure in front of the diaphragm, into an electrical signal

Methodology Applied

Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentUS11590533B2Sound transducer, having a transducer element integrated in a vibration-capable diaphragm including an electrically active polymer

Publication Date: 2023.02.28 ROBERT BOSCH GMBH

AI summary

An acoustic transducer, in particular for an ultrasonic sensor, is proposed. The acoustic transducer has a functional group, the functional group encompassing a diaphragm cup and at least one electroacoustic transducer element. The acoustic transducer furthermore has a housing. The diaphragm cup encompasses a vibration-capable diaphragm and an encircling wall, as well as at least one electroacoustic transducer element, the transducer element being embodied to excite the diaphragm to vibrate and/or to convert vibrations of the diaphragm into electrical signals. The diaphragm cup is constituted from a plastic material, the at least one transducer element being integrated into the vibration-capable diaphragm, the transducer element having an electrically active polymer.