Pressure Sensor Module Recessed PCB Encapsulation
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Solution Overview
Problem
Existing pressure sensor modules face durability issues due to exposure of the connection area between the pressure cell and printed circuit board to aggressive media, which can lead to damage or contamination.
Innovation Solution
A pressure sensor module design where the pressure cell is attached to the rear side of a printed circuit board with a recessed area, encapsulated by injection molding compound, ensuring the connection area remains protected from the medium, using a recess larger than the measuring opening and funnel-shaped measuring opening for effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure cell is encapsulated by injection molding compound, then the connection area is protected from aggressive media, but the measuring opening must remain accessible creating a complex sealing requirement
Solution Approach 1:
The patent divides the encapsulation space into two distinct regions: a protected connection area encapsulated by injection molding compound, and an accessible measuring opening region. This segmentation allows the connection area to be sealed while the measuring opening remains accessible for pressure medium input, resolving the contradiction between protection and accessibility.
Solution Approach 2:
The injection molding compound provides selective protection only to the connection area between the pressure cell and printed circuit board, while leaving the measuring opening area exposed. This local application of sealing properties protects vulnerable areas without compromising the functional opening, addressing the contradiction between comprehensive sealing and measurement accessibility.
2Ease of manufacture
If a recess larger than the measuring opening is created in the printed circuit board, then sufficient space is available for molding compound to join directly at the pressure cell, but the overall device size increases
Solution Approach 1:
The recess in the printed circuit board is pre-formed to create sufficient space for the injection molding compound to join directly at the pressure cell. This preliminary structural preparation facilitates the encapsulation process and ensures proper sealing, making the manufacturing easier despite the increased footprint.
3Ease of manufacture
If the measuring opening is formed funnel-shaped, then it is particularly simple to produce, but the sealing interface with injection molding compound becomes more complex
Solution Approach 1:
The measuring opening is formed with a funnel shape, changing the geometric parameters from a simple cylindrical opening to a tapered structure. This parameter change simplifies the production process while the injection molding compound adapts to this shape, creating an effective seal at the interface between the tapered opening and the encapsulating material.
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 design enhances the durability and longevity of the pressure sensor module by preventing medium contact with the attachment area, allowing for the use of soft adhesives and effective sealing with injection molding compound, particularly in harsh environments like engine oil applications.
Implementation Method 1
the pressure cell is encapsulated by injection molding compound in such a manner that a measuring opening of the pressure cell is open
Data Source
AI summary
For a pressure sensor module comprising a printed circuit board and a pressure cell, wherein the pressure cell has a measuring opening, and the pressure cell is encapsulated by injection molding compound in such a manner that the measuring opening is kept open, the pressure cell, as viewed from the measuring opening, is attached on the rear side of the printed circuit board. The printed circuit board has a recess in the area of the measuring opening, and the injection molding compound encloses the attachment area of the pressure cell on the printed circuit board. Thereby, the use of different adhesives, also soft adhesives, for the connection of the pressure cell with the printed circuit board is possible without this attachment area being attacked by the surrounding media.