Equipotential Shielding for Piezoresistive Sensor Detection Accuracy
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Solution Overview
Problem
Array piezoresistive sensors face inaccuracies in force detection due to loop interference among contact elements, leading to incorrect resistance value measurements.
Innovation Solution
A detection circuit employing equipotential shielding, which includes row and column control circuits, shielding circuits with inverse adders and row pull-up resistors, and an ADC module, ensures equal potentials at unselected contact elements, preventing current flow and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If contact elements are connected to form a resistance network for detection, then the sensor can detect force magnitude through resistance changes, but loop interference among contact elements causes inaccurate detection results
Solution Approach 1:
The patent applies equipotential shielding by connecting unselected contact elements to a common potential (ground or reference potential) through shielding circuits. This creates equal potential at both ends of unselected contact elements, preventing current flow through them and eliminating loop interference. The shielding circuit includes resistors and switches that establish equipotential conditions for non-active contact elements during measurement, thereby improving measurement precision while maintaining the resistance network structure for force detection
2Ease of operation
If row and column control circuits are used to select contact elements, then specific contact elements can be individually detected, but current may still pass through unselected contact elements causing interference
Solution Approach 1:
The shielding circuit actively maintains unselected contact elements at equipotential by connecting them to a common potential through resistors and switches. When a specific contact element is selected for detection, all other contact elements in the same row and column are connected to the shielding potential, ensuring no current flows through them. This eliminates loop interference while preserving the ability to individually select and detect specific contact elements through the row and column control circuits
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 enhances the accuracy of force detection by isolating unselected contact elements, reducing interference and ensuring precise resistance value calculations for selected contact elements.
Implementation Method 1
An array piezoresistive sensor is used for detecting the magnitude of a force applied thereupon and includes a plurality of contact elements. Once the contact elements are forced, a corresponding change in a resistance value is observed, and the magnitude of the force applied upon the contact elements may be derived from the change in the resistance value.
Implementation Method 2
the shielding circuit is configured to provide a potential for unselected contact elements so that equal potentials are enabled at both ends of the unselected contact elements
Data Source
AI summary
Disclosed are a detection circuit and apparatus based on equipotential shielding. A first connection end of a row control circuit, configured to be connected to a row lead of an array piezoresistive sensor; a control end of the row control circuit, connected to a main control chip for outputting a control signal; a second connection end of the row control circuit, connected to a first power supply terminal; and a row pull-up resistor, with an end connected to the row lead and another end connected to a second power supply terminal. Herein, each row lead corresponds to one row pull-up resistor; each column lead of the array piezoresistive sensor is connected to an input end of an inverse adder; an output end of the inverse adder is connected to a first connection end of the column control circuit.