Pressure Sensing Module With Diagonal Wheatstone Bridge
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Solution Overview
Problem
Conventional pressure sensing units face accuracy issues due to temperature-induced resistance changes, requiring complex multi-layered structures that complicate fabrication and increase costs, while also suffering from signal distortion caused by ambient noise.
Innovation Solution
A pressure sensing module with a simplified structure featuring a sensing layer on a substrate, comprising four resistors with the same resistance values forming a Wheatstone bridge, where two resistors with the same extending directions are diagonally disposed, and a touch control sensing unit is integrated to eliminate temperature influences and enhance sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a multi-layered structure with reference electrode layer is adopted for temperature compensation, then temperature-induced resistance change is suppressed, but device complexity and fabrication difficulty increase
Solution Approach 1:
The patent merges the temperature compensation function with the pressure sensing function by integrating the reference electrode layer into the same layer as the pressure sensing unit, forming a unified multi-layered structure. This combination allows simultaneous achievement of pressure sensing and temperature compensation without requiring separate independent components, thereby reducing overall device complexity while maintaining measurement precision.
Solution Approach 2:
The patent implements nesting by placing the reference electrode layer beneath the pressure sensing unit within the same multi-layered structure. The reference electrode is nested within the structural framework of the pressure sensing module, allowing it to serve as both a structural component and a functional temperature compensation element. This nested arrangement eliminates the need for external reference components and simplifies the overall device architecture.
2Measurement precision
If conventional piezoresistive material is used for pressure sensing, then pressure detection is achieved, but temperature variation causes resistance change that decreases sensing accuracy
Solution Approach 1:
The patent converts the harmful temperature-induced resistance change into a beneficial compensation mechanism. By introducing the reference electrode layer that experiences identical temperature effects, the patent creates a bridge circuit where the temperature-induced resistance change in the reference electrode exactly compensates for the temperature-induced resistance change in the pressure sensing unit. This transforms the harmful temperature effect into a useful self-compensation mechanism, maintaining pressure detection accuracy across temperature variations.
Solution Approach 2:
The patent introduces the reference electrode layer as an intermediary element between the pressure sensing unit and the measurement system. This intermediary experiences the same temperature effects as the pressure sensing unit but does not respond to pressure, thereby serving as a mediator that isolates the measurement system from temperature disturbances. The reference electrode acts as a control variable that compensates for temperature-induced drift in the pressure sensing measurement.
3Measurement precision
If multi-layered structure with reference electrode is implemented, then temperature compensation is achieved, but fabrication process becomes complicated and costs increase
Solution Approach 1:
The patent merges multiple functions (pressure sensing and temperature compensation) into a single integrated multi-layered structure, reducing the number of separate fabrication processes required. By combining the pressure sensing unit and reference electrode layer into one cohesive structure, the patent eliminates the need for separate assembly steps and reduces manufacturing complexity while maintaining temperature compensation performance.
Solution Approach 2:
The patent designs the multi-layered structure to serve multiple functions simultaneously: the reference electrode layer serves both as a structural support element and as a temperature compensation component. This multi-functionality reduces the total number of components and assembly operations required, thereby simplifying the fabrication process and reducing manufacturing costs while achieving effective temperature compensation.
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 achieves high accuracy and sensitivity in pressure and touch control sensing with a simpler fabrication process, reducing noise interference and costs, and allowing for effective differentiation of strains to enhance output voltage.
Implementation Method 1
the pressure sensing unit includes four resistors with the same resistance values, the four resistors form a Wheatstone bridge
Implementation Method 2
two of the four resistors with the pattern shapes having the same extending directions are not disposed adjacent to each other
Data Source
AI summary
A pressure sensing module and a pressure sensing touch control system are provided. The pressure sensing module includes a sensing layer formed on a surface of a substrate. The sensing layer includes at least one pressure sensing unit including four resistors with the same resistance values. The four resistors form a Wheatstone bridge. Pattern shapes of two of the four resistors have the same extending directions, and the two of the four resistors are not disposed adjacent to each other. The pressure sensing touch control system includes a touch control sensing unit. The touch control sensing unit is disposed between the four resistors to achieve pressure sensing and position sensing of pressing action. In the present disclosure, a bridge circuit is disposed on a single surface to prevent the sensing for pressing with a finger from being affected by temperature and other noise.