Foldable Force Sensor With Back-Folded Electrodes
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Solution Overview
Problem
Conventional frameless or seamless array devices face challenges in designing a compact structure due to the need for signal lines that occupy space at the side regions, making it difficult to achieve a seamless integration of sensor arrays and controllers.
Innovation Solution
A foldable force sensing device is designed with a sensor array and substrates that include foldable electrodes on both substrates, allowing the side regions to be folded back, creating a seamless structure while maintaining the sensor pitch and signal delivery, enabling the devices to be tiled without increasing size or affecting operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If signal lines are placed at the side regions to connect sensor array and controller, then signal delivery is ensured, but the device cannot achieve a frameless or seamless structure due to occupied space
Solution Approach 1:
The patent moves signal lines from the lateral dimension (side regions) to the vertical dimension (through-substrate vias and folded-back connections on the back side). This dimensional transition eliminates the need for side region occupancy, achieving a seamless front surface while maintaining signal connectivity through three-dimensional routing paths.
Solution Approach 2:
The signal lines are nested within the substrate structure itself, using through-substrate vias that pass through the substrate thickness and folded-back connections that route signals along the back side. This nesting approach integrates signal routing within the device's own structure rather than requiring external side regions.
2Shape
If side regions are folded back to create seamless structure, then frameless design is achieved, but bending stress may affect device reliability
Solution Approach 1:
The patent employs flexible substrate materials that can accommodate the folding action without fracturing. These flexible substrates and thin film structures distribute bending stresses throughout the material, preventing stress concentration at fold lines and maintaining device reliability during the folding process.
Solution Approach 2:
The substrate is divided into multiple regions including foldable side regions and a central sensor region. This segmentation allows the side regions to be independently folded back without affecting the integrity of the sensor array, isolating bending stresses to specific flexible zones.
3Area of stationary object
If multiple force sensing devices are tiled together, then larger seamless device is created, but controller placement and signal routing become more complex
Solution Approach 1:
The back side of each tiled device serves multiple functions: it hosts the controller for that device and also provides the folded-back signal routing path. This multi-functional use of the back side simplifies the overall system architecture when multiple devices are tiled together, as each device's back side is already configured for both control and signal routing.
Solution Approach 2:
The controller and signal routing infrastructure are merged into the same back-side region of each device. This consolidation reduces the number of separate components and connection points needed when tiling multiple devices, simplifying the interconnection architecture compared to separate front-side routing approaches.
Data Source
AI summary
A force sensing device includes a sensor array, a first substrate, a second substrate and a plurality of electrodes. The first substrate has a sensor region and a side region. The second substrate has a sensor region and a side region. The sensor array is formed above the sensor region of the first substrate. The plurality of electrodes are formed on the sensor region and the side region of the first substrate and below the sensor region and the side region of the second substrate, and coupled to the sensor array. The side region of the first substrate, the side region of the second substrate and the plurality of electrodes on the side region are foldable to a back side of the sensor array.