Strain Gauge Pressure Sensor Miniaturization via Nested PCB
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Solution Overview
Problem
Pressure transducers with microfused silicon strain gauge technology face challenges in miniaturization and component packaging, leading to size constraints and potential reliability issues due to the configuration of internal components.
Innovation Solution
A transducer assembly with a pressure port having an integral base and neck, where the neck forms a thin elastic diaphragm that flexes with fluid pressure changes, and an electronics package supported by a conductive lead frame and nonconductive support frame, allowing wire bonding pads on the printed circuit board to be parallel to the diaphragm and strain gauges for secure and efficient electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the transducer is miniaturized to reduce size, then space limitations are addressed, but component packaging becomes more difficult and reliability may be compromised
Solution Approach 1:
The patent implements nesting by placing the printed circuit board inside the hollow interior of the pressure port assembly. The PC board is positioned within the space created by the pressure port's internal cavity, allowing electronic components to be housed within the structural volume of the pressure port itself rather than requiring separate external packaging space. This nested arrangement reduces overall transducer volume while maintaining component accessibility and reliability.
Solution Approach 2:
The patent merges the pressure port structure with the electronic component mounting structure by integrating the PC board support directly into the pressure port assembly. The pressure port serves dual functions as both the pressure transmission pathway and the housing for electronic components. This consolidation eliminates the need for separate component packages and reduces the number of discrete parts, thereby simplifying packaging while maintaining reliability.
2Volume of moving object
If wire bonding pads are oriented perpendicular to the diaphragm plane, then compact packaging is achieved, but wire bonding becomes more difficult and connections are less secure
Solution Approach 1:
The patent resolves the orientation conflict by utilizing the third dimension (depth/height) rather than forcing a two-dimensional perpendicular arrangement. The PC board is positioned at an offset distance from the diaphragm plane, creating a parallel plane configuration separated by vertical spacing. This dimensional approach allows wire bonding pads to remain parallel to the diaphragm while maintaining compact overall packaging through optimized vertical space utilization. The parallel orientation enables straightforward wire bonding with pads facing each other, improving connection reliability while the vertical offset maintains compact form factor.
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 enables reduced transducer size without compromising performance, simplifies assembly, and provides a secure mechanical and electrical connection, reducing the risk of wire damage during bonding.
Implementation Method 1
a portion of the neck will define a thin elastic diaphragm along the side of the neck that can flex elastically in response to variations of fluid pressure within the fluid passageway
Implementation Method 2
One or more strain gauges are secured to the outer face of the diaphragm and are adapted to respond to the strain on the diaphragm as a function of the fluid pressure of the pressure environment
Data Source
AI summary
A pressure transducer assembly that includes a pressure-responsive diaphragm to which a sensing element is mounted and an electronic package that includes wire-bonding pads adapted be electrically connected to the sensing element by wire bonding equipment. The diaphragm and wire bonding pads are supported within the transducer so that they lie in proximity to each other and in non-intersecting planes.