Force Sensing Module Groove Substrate Assembly Yield
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Solution Overview
Problem
The existing force sensing modules face issues with low yield in the assembly process due to the poor stress resistance of force sensing resistors, which can lead to them being pulled off during assembly.
Innovation Solution
A force sensing module design that includes a substrate with a first groove, where the first flexible circuit board and the second flexible circuit board are stacked on this substrate, forming a Wheatstone bridge structure with force sensing resistors across the groove, thereby improving structural strength and reducing the likelihood of resistor detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If force sensing resistors are disposed on flexible circuit boards at intervals to form a Wheatstone bridge structure, then the sensing function is achieved, but the resistors are easily pulled off due to poor stress resistance and stiffness difference between circuit boards
Solution Approach 1:
A substrate is introduced as an intermediary component between the first and second flexible circuit boards. The substrate provides a stable mounting surface with grooves that securely hold the force sensing resistors, acting as a mediator that prevents direct stress concentration on the resistors while maintaining the Wheatstone bridge structure. This intermediary structure resolves the contradiction by providing mechanical support without interfering with the sensing function.
Solution Approach 2:
The structure is segmented into three distinct layers: the first flexible circuit board, the substrate, and the second flexible circuit board. The force sensing resistors are divided into two sets (first and second force sensing resistors) mounted on opposite surfaces of the substrate. This segmentation allows each component to perform its specific function optimally while distributing mechanical stress across the entire structure rather than concentrating it on the resistors.
2Device complexity
If the distance between two steel sheets is increased to accommodate force sensing resistors, then the Wheatstone bridge structure can be formed, but the resistors are more likely to be pulled off during assembly
Solution Approach 1:
The substrate serves as a mediator that enables the Wheatstone bridge structure to be formed without increasing the distance between flexible circuit boards. By mounting resistors on opposite surfaces of the substrate, the structure achieves the necessary complexity while the substrate's mechanical strength prevents resistor detachment, resolving the contradiction between structural requirements and attachment reliability.
3Ease of manufacture
If force sensing resistors are mounted directly on flexible circuit boards, then assembly is simplified, but the resistors have poor stress resistance and low assembly yield
Solution Approach 1:
The assembly is segmented into modular components: flexible circuit boards for electrical connection, a substrate for mechanical support and resistor mounting, and detection circuits for signal processing. This segmentation allows each component to be optimized independently - the substrate provides stress resistance while the flexible circuit boards maintain ease of assembly, resolving the contradiction between manufacturing simplicity and assembly yield.
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
This design enhances the assembly yield of the force sensing module by preventing resistor detachment and improving structural integrity, while also increasing the sensitivity of the module by optimizing the groove dimensions.
Implementation Method 1
One side of the first flexible circuit board facing the first surface is disposed with a first force sensing resistor and a second force sensing resistor... both the first force sensing resistor and the second force sensing resistor are across the first groove and attached to the first surface
Data Source
AI summary
A force sensing module is provided. The force sensing module includes: a first flexible circuit board, a substrate, and a second flexible circuit board stacked in sequence. The substrate includes a first surface and a second surface opposite to the first surface, and the first surface is provided with a first groove. A first force sensing resistor and a second force sensing resistor are disposed on a first side of the first flexible circuit board facing the first surface. A third force sensing resistor corresponding to the first force sensing resistor and a fourth force sensing resistor corresponding to the second force sensing resistor are disposed on a second side of the second flexible circuit board facing the second surface. The four resistors form a Wheatstone bridge structure. The force sensing module includes a detection circuit, configured to detect a differential voltage of the Wheatstone bridge structure.