Memristor Sensor Array Sneak-Path Resistance Utilization

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Solution Overview

Problem

The reliability of memristor-based gas sensors is compromised by 'sneak-paths' - unintended conductive routes that lead to erroneous resistance measurements, especially in larger arrays, degrading sensing margin and limiting array size.

Innovation Solution

A crossbar array of nanoscale memristors with sneak-path resistance leveraged to enhance sensing, using a circuit design where unselected rows and columns are shorted to ensure uniform current distribution, allowing for accurate resistance measurement by capturing total array resistance in a single reading cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple measurements are taken from a single sensor, then measurement errors can be reduced statistically, but the reliability of measurement cannot be ascertained

Engineering Contradiction:
Improvemeasurement error reductionVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The sensor system is segmented into multiple independent sensor elements arranged in an array configuration. Each element provides independent measurement capability, allowing both statistical error reduction through multiple readings and reliability verification through cross-validation across elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the parameter of sensor quantity from single to multiple elements. By deploying an array of sensor elements rather than relying on repeated measurements from a single sensor, the system simultaneously achieves statistical error reduction and reliability verification through diverse elemental responses.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If redundant sample measurements are taken from multiple sensors, then measurement reliability can be ensured, but device complexity increases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsensor array complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple sensor elements are merged into a unified array structure with shared readout circuitry and control mechanisms. This combining approach ensures measurement reliability through redundant elements while managing complexity through integrated architecture that shares common resources.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor array employs universal readout circuitry and control logic that serves all sensor elements. This multi-functionality ensures reliable measurements from multiple sensors while minimizing complexity by using shared infrastructure rather than dedicated circuitry for each element.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If memristive elements are used in sensor arrays, then sensing capability is enhanced, but sneak-paths cause erroneous resistance measurements

Engineering Contradiction:
Improvesensing capabilityVSAvoidresistance measurement accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The sneak-paths in bidirectional memristive elements, which traditionally cause measurement errors, are converted into a beneficial feature. The system utilizes the conductive properties of sneak-paths as part of the sensing mechanism, transforming what was previously a harmful interference into an enhanced sensing capability that maintains measurement accuracy.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system changes the operational parameter approach by applying voltage in a specific sequence and direction. By controlling the voltage application pattern across the memristive array, the system enables accurate resistance measurements while accounting for the bidirectional conductive nature of the elements, thereby resolving the sneak-path interference issue.

Inventive Principle:
Principle #35Parameter changes

4Area of stationary object

If array size is increased to improve sensing coverage, then sensing margin is degraded by sneak-paths

Engineering Contradiction:
Improvesensor array sizeVSAvoidsensing margin
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The system converts the harmful effect of sneak-paths in large arrays into a beneficial contribution to sensing. By utilizing the conductive paths that were previously considered interference, the system maintains sensing margin even as array size increases, enabling large-scale deployment without degradation of measurement precision.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system changes the voltage application parameters and measurement sequence to accommodate larger array sizes. By optimizing the voltage sweep pattern and reading sequence, the system maintains accurate resistance measurements across expanded arrays, preventing sensing margin degradation that would normally occur with increased array dimensions.

Inventive Principle:
Principle #35Parameter changes

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 improves measurement accuracy and reliability by utilizing sneak-path resistance, enabling larger array sizes and precise gas concentration detection, while minimizing the impact of sneak-paths on sensing margin.

Implementation Method 1

a chemically sensitive top layer

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

Memristors are known in the art as devices whose electrical resistance is changed by the electrical current that flows through the device

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3523638B1Memristor based sensor array and corresponding sensor reading method
Publication Date: 2023.06.07 OXFORD BROOKES UNIVERSITY
  • EP3523638B1 patent drawingFigure 1~2
  • EP3523638B1 patent drawingFigure 3~4
  • EP3523638B1 patent drawingFigure 5~7

AI summary

A sensor comprises a plurality of sensor elements arranged in an array. Each sensor element is memristive and has an electrical resistance characteristic related to exposure to a species to be sensed. The sensor elements are arranged to be connectable such that at least one sensor element is connected in parallel with at least one other sensor element. By using appropriate connections, the array of sensor elements can be read.