Acoustical Stack Formation for Ultrasound Probes

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Solution Overview

Problem

The fragility and brittleness of single crystal piezoelectric materials in ultrasound probes require specific handling conditions, making it challenging to dice them without losing piezoelectric properties or developing cracks, especially when combined with other materials like graphite or epoxy, which necessitates optimized dicing parameters that increase manufacturing costs and complexity.

Innovation Solution

A method involving partial dicing of single crystal piezoelectric material with kerfs, filling these kerfs with a kerf filling material, attaching matching layers and flex circuits, and using multiple dicing operations with varying parameters to form acoustical stacks without compromising the single crystal material's quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If standard dicing saw is used to dice single crystal piezoelectric material, then manufacturing throughput is improved, but material cracks propagate and piezoelectric properties are lost

Engineering Contradiction:

Improvemanufacturing throughputVSAvoidpiezoelectric properties

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The dicing process is divided into two distinct stages: a first dicing operation that creates initial kerfs through the single crystal material, and a second dicing operation that completes the separation. This segmentation allows each operation to be optimized independently - the first operation can use parameters optimized for single crystal (lower speed, specific blade) while the second operation can use parameters optimized for the stacked materials (higher speed, different blade), thereby resolving the contradiction between maintaining material integrity and achieving high throughput.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first dicing operation performs preliminary cutting to create kerfs that extend partway through the single crystal material before stacking. This preliminary action prepares the structure for subsequent stacking and final dicing, allowing the fragile single crystal to be processed under optimized conditions first, then protected during later high-speed dicing operations.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If dicing parameters are optimized for single crystal piezoelectric material, then material quality is maintained, but manufacturing cost increases due to reduced feeding speed

Engineering Contradiction:

Improvematerial qualityVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The manufacturing process is segmented into two dicing operations with different parameter optimizations. The first operation uses optimized parameters for single crystal quality (lower feeding speed, specific blade material) only where needed to create initial kerfs. The second operation uses faster, more cost-effective parameters for completing the dicing through the stacked materials, thereby reducing overall manufacturing cost while maintaining material quality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different dicing parameters are applied to different regions and stages of the process. The first dicing operation applies quality-optimized parameters locally to the single crystal portion to create precise initial kerfs. The second operation applies cost-optimized parameters to the remaining stacked materials, achieving local quality where critical while reducing cost in less critical areas.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If blade material is optimized for dicing single crystal piezoelectric material, then cutting precision is improved, but the blade is not appropriate for dicing stacked materials

Engineering Contradiction:

Improvecutting precisionVSAvoidblade compatibility

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The dicing process is segmented into two operations using different blades. The first operation uses a blade specifically optimized for single crystal material, achieving high cutting precision for the critical initial kerfs. The second operation uses a different blade optimized for the stacked materials (graphite, epoxy, flex materials), achieving adaptability and versatility across different material types without compromising overall precision.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8978216B2Method for forming an acoustical stack for an ultrasound probe

Publication Date: 2015.03.17 GE PRECISION HEALTHCARE LLC

AI summary

A method for forming an acoustical stack for an ultrasound probe comprises partly dicing a single crystal piezoelectric material to form single crystal pieces that are partly separated by a plurality of kerfs. The single crystal piezoelectric material comprises a carrier layer. The kerfs are filled with a kerf filling material to form a single crystal composite and the carrier layer is removed. At least one matching layer is attached to the single crystal composite, and dicing within the kerfs is accomplished to form separate acoustical stacks from the single crystal composite.