Pressure Sensor Detection Electrodes for Water Droplet Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pressure sensors face reliability issues in harsh environments due to water droplets adhering to membranes, which can cause short circuits and abnormal readings, as existing protective films cannot fully cover electrodes connected to Wheatstone bridge circuits.
Innovation Solution
Incorporating detection electrodes between bridge electrodes on the membrane surface, with a resistance change detection unit to detect changes in resistance, allowing for the early detection of water droplets before they spread across the bridge electrodes, thereby preventing circuit damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective film is provided for the Wheatstone bridge circuit, then reliability is improved, but the electrodes cannot be completely covered due to connection wires
Solution Approach 1:
The invention divides the electrode system into two functional parts: bridge electrodes for signal output and detection electrodes for water droplet detection. This segmentation allows the protective film to cover the Wheatstone bridge circuit while leaving the detection electrodes exposed for their specific function.
Solution Approach 2:
The detection electrodes serve as intermediary elements between the protected Wheatstone bridge circuit and the external environment. They detect water droplets before they can reach the bridge electrodes, acting as a first line of defense without requiring full coverage of the entire electrode system.
2Difficulty of detecting and measuring
If the distance between bridge electrodes is increased to allow detection electrode placement, then water droplet detection capability is improved, but the membrane area available for other functions is reduced
Solution Approach 1:
The invention applies local quality by placing detection electrodes in specific peripheral regions of the membrane where they can effectively monitor for water droplets without interfering with the central Wheatstone bridge circuit. This localized placement optimizes detection capability while preserving membrane area for pressure sensing.
3Reliability
If detection electrodes are provided separately from bridge electrodes, then water droplet adhesion can be detected early, but the device structure becomes more complex
Solution Approach 1:
The detection electrodes, while structurally separate from the bridge electrodes, utilize the same conductive material and integration process. They serve a specialized detection function but are manufactured using the same universal electrode fabrication techniques, minimizing added complexity.
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 effectively detects water droplet adhesion on the membrane surface before it becomes a problem, preventing abnormal readings and circuit damage by using detection electrodes and resistance change detection units to monitor resistance changes between bridge electrodes and detection electrodes.
Implementation Method 1
A pressure sensor is known that detects the distortion of a membrane (also referred to as a diaphragm) from a change in resistance, using a piezoresistive effect.
Implementation Method 2
a resistance change detection unit detecting a change in resistance between the detection electrode and at least one of the bridge electrodes
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Adhesion of a water droplet or the like on a membrane is detected before an abnormality occurs in a detection value of a Wheatstone bridge circuit. A pressure sensor includes: a Wheatstone bridge circuit formed by a plurality of resistors on a membrane; a plurality of bridge electrodes which are electrically connected to the Wheatstone bridge circuit and constitute a portion of an outer surface of the membrane and to which wires for connecting the Wheatstone bridge circuit to an outside are connected; a detection electrode which is disposed between one bridge electrode and another bridge electrode on the membrane, constitutes another portion of the outer surface, and is provided separately from any of the bridge electrodes; and a resistance change detection unit detecting a change in resistance between the detection electrode and at least one of the plurality of bridge electrodes.