LGA/Mold Premold Pressure Sensor with Incompressible Oil Buffer
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Solution Overview
Problem
Existing pressure sensor systems face reliability issues when exposed to corrosive media, such as exhaust gases, due to the gel or oil used for media insulation, which can impair the MEMS pressure sensor and ASIC, and may cause bubbling or foaming at high pressures, necessitating a robust and cost-effective solution for protection and temperature compensation.
Innovation Solution
A pressure sensor system with a sensor unit embedded in a land grid array/mold premold structure (LGA/MPM) support, integrated signal processing, and an incompressible fluid filling, providing protection against aggressive media and allowing for temperature adjustment, with the option of using a lead frame and advanced porous silicon MEMS sensor elements, and passive electrical structures for enhanced reliability and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gel is used for media insulation to protect the MEMS pressure sensor and ASIC, then protection against dust, particles, moisture and corrosive media is improved, but the gel may still be attacked by aggressive gases and may bubble or foam at pressures above 5 bar
Solution Approach 1:
The patent replaces the gel buffer with an oil buffer that is less susceptible to degradation and bubbling. The oil serves as a stable, incompressible medium that does not foam under pressure, effectively solving the reliability issue without requiring complex additional structures.
Solution Approach 2:
The patent changes the physical-chemical parameters of the insulation medium from gel to oil, specifically selecting an oil with appropriate viscosity and compressibility characteristics. This parameter change eliminates the bubbling and foaming issue while maintaining protection against corrosive media.
2Reliability
If oil is used instead of gel for media insulation, then gel bubbling and foaming at high pressure is prevented, but temperature adjustment to compensate for oil influence becomes necessary
Solution Approach 1:
The patent incorporates a temperature compensation mechanism that automatically adjusts for the oil's temperature-dependent properties. The system self-regulates by measuring temperature and applying compensation algorithms, eliminating the need for manual adjustment while maintaining measurement accuracy.
Solution Approach 2:
The patent implements a feedback loop where temperature sensors monitor the oil temperature and the system automatically compensates for thermal expansion and viscosity changes. This feedback mechanism maintains stable operation across varying temperatures without adding significant complexity.
3Reliability
If a robust module structure is formed to protect against aggressive media, then protection is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the sensor element, ASIC, and buffer medium into a single integrated module housed in a compact housing. This merging of components simplifies the manufacturing process by reducing assembly steps while maintaining robust protection against aggressive media through the sealed housing design.
Solution Approach 2:
The patent designs a universal housing structure that provides both mechanical protection and environmental sealing functions. The housing serves multiple purposes: protecting the sensor elements, containing the oil buffer, providing thermal management, and enabling electrical connections, thereby simplifying the overall device architecture and manufacturing.
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
The solution provides robust protection against aggressive media, allows for simple temperature adjustment, and is cost-effective, ensuring reliable operation across a wide pressure range without mechanical damage, making it suitable for industrial and automotive applications.
Implementation Method 1
surrounded by an incompressible oil for relaying the pressure force
Implementation Method 2
at least one sensor element which is situated in a cavity of a support structure
Data Source
AI summary
A pressure sensor system including at least one pressure sensor unit, the pressure sensor unit being configured with at least one sensor element which is situated in a cavity of a support structure, signal processing elements being integrated into support structure, the at least one sensor element being embeddable into the support structure to form the pressure sensor unit, and the support structure being formed by a land grid array/mold premold structure (LGA/MPM). The pressure sensor unit is introduced into a sensor housing to be provided with a diaphragm and is supported therein, a residual volume of the sensor housing, which is provided with at least one diaphragm and to the wiring of which the pressure sensor unit is electrically connected, being filled with an incompressible fluid. Also described is a method for manufacturing such a pressure sensor system and a measuring device.