PCB Humidity Sensing Via Layout for Multi-Zone Corrosion Detection
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Solution Overview
Problem
Existing humidity sensors for printed circuit boards are limited in detecting humidity in multiple zones and are not efficient, often requiring significant space and providing only local readings.
Innovation Solution
A humidity sensing module that includes a ground plane, signal layer, transistor layer, and pairs of vias connected to resistors, allowing for detection of humidity in multiple zones with adjustable sensitivity, and a hydrolysis prevention module to disconnect current flow when humidity exceeds a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional humidity sensors are used to detect humidity on printed circuit boards, then local humidity detection is provided, but the ability to detect humidity in multiple zones is limited and device complexity increases
Solution Approach 1:
The patent merges multiple humidity detection zones into a single integrated printed circuit board structure. Multiple vias are arranged in pairs across different zones of the PCB, all connected to a common evaluation unit. This combines what would traditionally require multiple separate sensors into one unified system, reducing device complexity while maintaining multi-zone detection capability.
Solution Approach 2:
The printed circuit board itself is designed to serve multiple functions: it provides structural support, electrical connections, and integrated humidity sensing across multiple zones. The via pairs act as universal sensing elements that can detect humidity in any zone where they are placed, eliminating the need for zone-specific sensor designs.
2Measurement precision
If multiple humidity sensors are placed to detect humidity in different zones, then measurement coverage is improved, but space requirements and manufacturing costs increase
Solution Approach 1:
Multiple sensing functions are merged into the PCB structure itself. The via pairs, which are standard PCB features, are repurposed as humidity sensing elements. This eliminates the need for additional sensor components and the space they would occupy, while still providing multi-zone detection coverage.
Solution Approach 2:
The PCB serves as both the structural platform and the sensing system. The same PCB that supports electronic components also contains the humidity sensing functionality through its via structure, eliminating the need for separate sensor housing and reducing overall space requirements.
3Reliability
If humidity detection sensitivity is increased to detect early humidity levels, then hydrolysis prevention is improved, but false alarms and detection accuracy are affected
Solution Approach 1:
The evaluation unit continuously monitors the electrical properties of the via pairs and provides feedback about humidity levels. By measuring changes in electrical characteristics (such as capacitance or resistance) of the via structure, the system can detect humidity accumulation trends and provide early warning before hydrolysis occurs, while the continuous monitoring helps distinguish real threats from transient conditions.
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
Enables earlier detection of humidity in multiple zones, reducing the risk of electrochemical corrosion and extending the lifespan of printed circuit boards while minimizing costs and resource requirements.
Implementation Method 1
When humidity from various sources reaches any outer surface of the outer layer or both outer layers of a printed circuit boards PCB, hydrolysis occurs, creating the condition of electrochemical corrosion.
Data Source
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AI summary
This invention refers to a humidity sensing module for detecting humidity on at least one pre-determined humidity-prone zone of at least one of the outer surfaces of the two outer layers of a printed circuit board, connected to a voltage source, comprising at least two layers, the first being the ground plane and the other (s) being electrically conductive and further comprising a transistor layer, said transistor layer and said ground plane being connected to said voltage source by two resistors configured to work as a voltage divider, a plurality of vias arranged in pairs, each pair comprising a positive via and a negative via and an external decision taking module, the plurality of vias being configured as sensing elements such that, when the humidity threshold is exceeded on at least one humidity sensing areas from the at least one pre-determined humidity-prone zone, the negative via and the positive via become electrically connected, determining a different voltage between the resistors, the external decision taking module reading the specific signal between the resistances and interpreting it depending on the different voltage between the resistors.