Integrated Gas Sensor with Built-in Resistor

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Solution Overview

Problem

Gas sensors face challenges with high energy consumption, operational risks, and errors due to external resistors, which increase costs and introduce environmental noise, especially when dealing with high-resistance sensing materials.

Innovation Solution

A stacked type resistance-integrated gas sensor is developed, where external resistors are integrated into the device, allowing direct integration with voltage followers or analog-to-digital converters, reducing environmental noise and external circuit usage, and utilizing a substrate with a first metal oxide layer as an internal resistor and a second metal oxide layer for sensing, eliminating the need for additional external resistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If external resistors are used for resistance matching, then the gas sensor can be applied to life, but environmental noise increases and usage area of external circuits increases

Engineering Contradiction:

Improveapplication capabilityVSAvoidenvironmental noise

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent merges the external resistor function into the gas sensor body by fabricating a resistor layer integrated with the sensing film. This integration eliminates the need for separate external resistors, thereby reducing environmental noise and minimizing the usage area of external circuits while maintaining the resistance matching capability necessary for practical application.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If external resistors are used for resistance matching, then the gas sensor can be applied to life, but the usage area of external circuits increases

Engineering Contradiction:

Improveapplication capabilityVSAvoidusage area of external circuits

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent combines the resistor and sensing film into a single integrated structure within the gas sensor body. By fabricating the resistor layer and sensing film layer in the same device structure, the usage area of external circuits is significantly reduced, allowing for more compact device design and integration.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If high-resolution ADC is used to compensate for unmatched resistors, then measurement precision is improved, but cost of use increases

Engineering Contradiction:

ImproveresolutionVSAvoidcost of use

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The integrated resistor structure serves itself by providing built-in resistance matching functionality. This self-matching capability eliminates the need for high-resolution ADCs to compensate for resistor mismatches, thereby reducing device complexity and cost of use while maintaining adequate measurement precision.

Inventive Principle:

Principle #25Self-service

4Measurement precision

If sensing thin film material with high resistance value is used, then sensitivity is improved, but resistance matching becomes difficult

Engineering Contradiction:

ImprovesensitivityVSAvoidresistance matching

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the resistor layer and sensing film layer into an integrated structure where both layers are fabricated using the same material system (metal oxide). This integration allows for simplified manufacturing processes and easier resistance matching, as the resistor and sensing elements can be fabricated simultaneously with controlled resistance ratios through material composition and geometric design rather than requiring separate high-precision resistor fabrication.

Inventive Principle:

Principle #5Merging (Combining)

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 solution reduces the area and noise of external circuits, lowers costs, and minimizes judgment errors by integrating resistors within the gas sensor, enabling direct integration with ADCs and reducing the need for external components.

Implementation Method 1

the sensing thin film material of the gas sensor has a higher resistance value... the upper second metal oxide layer is used for sensing

Methodology Applied

Scientific EffectGas adsorption: Adsorption

Implementation Method 2

the first metal oxide layer and the second metal oxide layer are made of the same material... used for sensing

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS11573193B2Resistance-integrated gas sensor

Publication Date: 2023.02.07 NUVOTON

AI summary

A resistance-integrated gas sensor is provided, including a substrate, a first metal oxide layer, an insulating layer, a contact metal layer, a contact hole, a second metal oxide layer, and an interdigitated electrode layer. The first metal oxide layer is disposed in the substrate. The insulating layer is disposed on the substrate and the first metal oxide layer. The contact metal layer and the contact hole are disposed in the insulating layer. The second metal oxide layer is disposed on the insulating layer. A portion of the interdigitated electrode layer is disposed on the insulating layer, and another portion is disposed in the second metal oxide layer. The contact metal layer and the contact hole connect the first metal oxide layer and the interdigitated electrode layer.