Tuning Fork Sensor Packaging with Selective Protective Coating
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Solution Overview
Problem
There is a need for sensor assemblies that can withstand harsh operating conditions, including extreme temperatures and corrosive environments, while maintaining the exposed sensing surface for fluid condition monitoring in applications such as engines, aerospace, and oil refining, and can be efficiently assembled using automated materials handling equipment.
Innovation Solution
The method involves attaching a coated or uncoated sensor element with an exposed sensing surface to a platform, maintaining the sensing surface's exposure, and optionally applying a protective layer to shield the components from harsh conditions while allowing the sensing surface to remain exposed, using techniques like Faraday cages and consumable barriers for selective protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is applied over the sensor components, then the sensor is protected from harsh operating conditions, but the sensing surface may be blocked
Solution Approach 1:
The patent applies protective layers selectively to specific areas of the sensor assembly. The protective layer is applied to the platform and non-sensing portions of the sensor element, while the sensing surface is deliberately excluded from coating. This localized protection approach shields vulnerable components from harsh conditions without blocking the sensing surface, resolving the contradiction between protection and functionality.
2Measurement precision
If the sensing surface is exposed for fluid monitoring, then accurate sensing is achieved, but the sensor components are vulnerable to harsh environments
Solution Approach 1:
The sensor element is designed with differentiated zones: the sensing surface remains exposed and uncoated for accurate fluid interaction, while other portions of the sensor element and the platform receive protective coating. This spatial differentiation allows the sensing surface to maintain measurement precision while surrounding components gain environmental protection.
Solution Approach 2:
The platform serves as an intermediary structure that supports the sensor element. By applying protective layer to the platform rather than the entire sensor assembly, the system provides indirect protection to the sensor element's vulnerable components while leaving the sensing surface accessible to the fluid medium.
3Productivity
If automated materials handling equipment is used for assembly, then manufacturing efficiency is improved, but precise positioning of small sensor components is difficult
Solution Approach 1:
The patent designs the sensor assembly with a flat platform and planar surfaces that provide stable, level positioning for the sensor element. This equipotential design creates uniform surfaces that are easier for automated pick-and-place equipment to grasp and position accurately, reducing the difficulty of handling small components while maintaining manufacturing precision.
Data Source
AI summary
An improved method of packaging a sensor is provided. The method includes the step of affixing a tuning fork to a platform. The tuning fork includes tines comprising one or more surfaces, with each tine further comprising an electrode and a piezoelectric material. An application specific integrated circuit (ASIC) is affixed to the platform. Electrical communication between the ASIC and the electrode of each tine is established for providing stimulus to the tuning fork and for receiving a response signal from the tuning fork. A protective layer is applied to cover the platform and a portion of the tuning fork while maintaining a portion of a surface of each tine free from the protective layer such that the surface can displace the fluid in contact therewith.