Interlinked Impedance Touch Sensor Array for High-Resolution Sensing
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Solution Overview
Problem
Existing touch sensor systems require complex electronics and significant power consumption to achieve high spatial sensing resolutions, are not compatible with standard PCB manufacturing processes, and struggle with accuracy and linearity, especially in larger formats and non-rectangular shapes.
Innovation Solution
The implementation of interlinked impedance columns and rows within a touch sensor array, which reduces the number of drive and sense lines needed, allowing for lower resolution electronics to achieve high tracking resolution through interpolation, and enables scanning at varying resolutions while maintaining accuracy and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual column drive and row sense circuitry is used for each row/column in the sensing array, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The sensing array is segmented into multiple zones or regions, each handled by shared drive and sense circuitry. Instead of dedicating individual circuitry to each row and column, the system divides the large sensing array into smaller segments that can be managed by fewer electronics components, reducing overall device complexity while maintaining measurement precision through coordinated scanning of segments.
Solution Approach 2:
The drive and sense circuitry is designed to be multi-functional, where the same electronics components serve multiple rows and columns across different time periods. The circuitry can be dynamically configured to drive different columns and sense different rows during sequential scanning operations, allowing a smaller number of electronics to handle a larger sensing array.
2Measurement precision
If individual column drive and row sense circuitry is used for each row/column in the sensing array, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The sensing array is divided into segments that are scanned sequentially rather than all at once. This allows the system to activate only the necessary drive and sense circuitry for the current segment being scanned, reducing the total number of active electronics components at any given time and thereby lowering dynamic power consumption while still achieving high spatial sensing resolution through the coordinated scanning of all segments.
Solution Approach 2:
The system employs periodic scanning of different segments of the sensing array in a sequential manner. Each segment is scanned at intervals rather than continuously, allowing electronics to be activated and deactivated in a periodic fashion. This reduces the average power consumption of the drive and sense circuitry while maintaining the ability to detect touches with high precision across the entire array.
3Ease of manufacture
If standard PCB manufacturing processes are used, then ease of manufacture is improved, but manufacturing precision worsens
Solution Approach 1:
The sensing array uses local sensing elements at row/column intersections that can be manufactured using standard PCB techniques. Each intersection point has localized sensing capability, allowing the system to achieve high spatial resolution through the distribution of many small, locally-manufactured sensing points rather than requiring precision across the entire array. This local quality approach enables standard PCB manufacturing processes to produce the sensor while maintaining high manufacturing precision at each sensing location.
4Area of stationary object
If the sensing array is made larger, then area is improved, but device complexity increases
Solution Approach 1:
The large sensing array is divided into multiple smaller segments or zones that can be managed by shared drive and sense circuitry. This segmentation allows the system to cover a large touch screen area without requiring proportionally more electronics, as the same drive and sense components can be reused across different segments through sequential scanning operations.
Solution Approach 2:
The system adds the time dimension to the spatial scanning process by sequentially activating different columns and sensing different rows at different time periods. This temporal dimension allows a smaller number of drive and sense electronics to effectively manage a larger sensing array, as the electronics can be dynamically reconfigured for different regions of the array over time rather than requiring simultaneous support for all rows and columns.
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 approach results in a low-cost, high-resolution touch sensor system that can be manufactured using traditional methods, reducing electronics complexity and power consumption, and supports large area sensing with improved accuracy and interactivity.
Implementation Method 1
a force sensing element (FSM) having a fourth terminal electrically connected to the second row electrode and configured to vary an impedance of the force sensing element in response to a force applied to the force sensing element
Data Source
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AI summary
A resistive touch sensor system and method incorporating an interpolated sensor array is disclosed. The system and method utilize a touch sensor array (TSA) configured to detect proximity/contact/pressure (PCP) via a variable impedance array (VIA) electrically coupling interlinked impedance columns (IIC) coupled to an array column driver (ACD), and interlinked impedance rows (IIR) coupled to an array row sensor (ARS). The ACD is configured to select the IIC based on a column switching register (CSR) and electrically drive the IIC using a column driving source (CDS). The VIA conveys current from the driven IIC to the IIC sensed by the ARS. The ARS selects the IIR within the TSA and electrically senses the IIR state based on a row switching register (RSR). Interpolation of ARS sensed current/voltage allows accurate detection of TSA PCP and/or spatial location.