Conductive Sensor Sidewall Insulation for Stray Current Prevention
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Solution Overview
Problem
Existing pH sensors fail under high pressure and repeated pressure cycling due to the failure of O-rings or epoxy seals, allowing conductive fluid leaks and stray currents to flow into the sensor's circuit, leading to inaccurate measurements.
Innovation Solution
A sensor design featuring a conductive substrate with a dielectric layer and a sensing layer, where an insulating layer, such as an atomic-layer-deposition (ALD) layer, conformally coats the sidewalls to prevent stray currents, maintaining integrity and adhesion even under high pressure and cycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If O-rings or epoxy are used to seal the conductive fluid from the sidewalls, then the sensor can prevent stray currents under normal conditions, but the seal fails under high pressure and repeated pressure cycling
Solution Approach 1:
The patent replaces mechanical sealing systems (O-rings, epoxy) with a conformal insulating layer deposited directly on the sidewalls. This eliminates mechanical seals that fail under pressure by using a thin-film deposition process that creates a pressure-resistant insulating barrier integrated with the substrate structure.
Solution Approach 2:
The patent uses a conformal insulating layer (thin film) deposited on the sidewalls to provide sealing and insulation. This thin film structure maintains integrity under high pressure and pressure cycling, replacing rigid mechanical seals with a flexible, adherent coating that conforms to the substrate geometry.
2Measurement precision
If the sensing layer is coated on the gate dielectric, then the sensor can detect pH accurately, but the insulating layer must not cover the sensing layer surface to maintain sensitivity
Solution Approach 1:
The patent applies the insulating layer selectively to specific regions (sidewalls and gate dielectric) while deliberately leaving the sensing layer surface uncoated. This localized insulation approach provides stray current prevention on the sidewalls while maintaining sensing functionality on the exposed sensing layer surface.
Solution Approach 2:
The patent segments the insulating layer application into distinct regions: the insulating layer covers the sidewalls and gate dielectric but is excluded from the sensing layer surface. This segmentation allows different functional requirements (insulation vs. sensing) to be satisfied in different spatial zones.
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 sensor effectively prevents stray currents and maintains accurate measurements by ensuring the insulating layer adheres to the sidewalls, preventing conductive fluid leaks and maintaining sensor functionality in high-pressure environments.
Implementation Method 1
an insulating layer conformally coating at least the side-walls of the conductive substrate
Implementation Method 2
an insulating layer, such as an atomic-layer-deposition (ALD) layer, conformally coats the sidewalls
Data Source
AI summary
A sensor is provided. The sensor includes a conductive substrate having side-walls; a dielectric layer overlaying a first surface of the conductive substrate, the dielectric layer including a gate dielectric having a first thickness and a field dielectric having a second thickness; a sensing layer overlaying a first surface of the gate dielectric; a non-conductive carrier wherein a second surface of the conductive substrate overlays a portion of the non-conductive carrier; and an insulating layer conformally coating at least the side-walls of the conductive substrate, wherein a first surface of the sensing layer is uncoated by the insulating layer.