Ultrasonic Probe Rear Surface Acoustic Isolation
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Solution Overview
Problem
Two-dimensional array ultrasonic probes face challenges in reducing acoustic radiation to the rear surface, leading to false images and increased manufacturing costs due to the use of materials with high acoustic impedance and the complexity of air gap structures, which are difficult to implement and prone to mechanical damage.
Innovation Solution
The use of a flexible printed circuit with an air gap layer or resin layer on the rear surface, combined with high-impedance layers and columnar connecting members, effectively suppresses acoustic radiation to the rear surface, improving sensitivity and reducing manufacturing costs by simplifying the structure and eliminating the need for acoustic absorbing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If materials with very high acoustic impedance (e.g., tungsten or its carbide) are made to tightly adhere to the rear surface of the piezoelectric transducer to reduce acoustic radiation, then acoustic radiation to the rear surface is reduced, but manufacturing complexity and cost increase due to the need for specialized materials and processes
Solution Approach 1:
The patent introduces an air gap as an intermediary layer between the piezoelectric transducer and the rear surface structure. This air gap acts as a mediator that provides acoustic isolation without requiring complex high-impedance material adherence processes, thereby reducing acoustic radiation to the rear surface while simplifying manufacturing
Solution Approach 2:
The patent replaces expensive and complex high-impedance materials (tungsten or its carbide) with a simpler, more cost-effective air gap structure. This substitution achieves the same acoustic isolation function using a less complex, more manufacturable solution
2Loss of energy
If an air gap structure is provided on the rear surface of each transducer to reduce acoustic radiation, then acoustic radiation is reduced, but the structure becomes mechanically unstable and prone to damage
Solution Approach 1:
The patent combines the air gap structure with a support member to create a hybrid structure that maintains both acoustic isolation and mechanical stability. The support member provides structural reinforcement to the air gap, preventing mechanical damage while preserving the acoustic radiation reduction function
Solution Approach 2:
The patent creates a composite structure consisting of the air gap and support member working together. This composite design integrates the acoustic isolation properties of the air gap with the mechanical strength of the support member, achieving both acoustic and mechanical performance requirements
3Ease of operation
If a cut groove is formed to separate each transducer after underfill hardening, then individual transducer separation is achieved, but mechanical damage to the IC and difficulty in inspecting acoustic quality occur
Solution Approach 1:
The patent performs transducer separation before the underfill hardening step, rather than after. This preliminary separation allows for safe cutting and inspection of acoustic quality while the transducers are still mounted on the support member, avoiding damage to the IC that would occur if cutting were performed after underfill hardening when the structure becomes more rigid and fragile
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 acoustic separation performance, improves sensitivity by reducing backward radiation, and simplifies the manufacturing process, while maintaining structural stability and reducing the influence of acoustic radiation on ultrasonic images.
Implementation Method 1
the air gap portions suppress acoustic radiation to the rear surface side of the piezoelectric elements
Implementation Method 2
A plurality of piezoelectric elements transmit and receive ultrasonic waves
Data Source
AI summary
According to one embodiment, an ultrasonic probe includes piezoelectric elements, a flexible printed circuit, and one of an air gap layer and a resin layer. The piezoelectric elements transmit and receive ultrasonic waves. The flexible printed circuit located on a rear surface side of the piezoelectric elements and electrically connected to the piezoelectric elements. The air gap layer locates on a rear surface side of the flexible printed circuit and has air gaps. The resin layer is obtained by filling the air gap layer with a resin and locates on the rear surface side of the flexible printed circuit.