Implantable Sensor Calibration via Optical Coefficient Transfer
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Solution Overview
Problem
Implantable pressure sensors face challenges in maintaining accuracy due to mechanical stress from temperature gradients during hermetic sealing, and conventional two-way wireless communication is costly and wasteful after initial calibration.
Innovation Solution
A calibration protocol using RF communication for data transmission and optical communication for coefficient transfer, allowing for efficient one-way communication post-calibration, with a processor, RF circuitry, optical components, and memory within a hermetically sealed glass housing, enabling accurate pressure readings adjustment using stored coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hermetic sealing is performed using heat treatment to protect sensor components from harsh biological environments, then reliability is improved, but manufacturing precision deteriorates due to mechanical stress from temperature gradients affecting sensor accuracy
Solution Approach 1:
The patent applies preliminary calibration after hermetic sealing to compensate for the mechanical stress-induced accuracy changes. The calibration process measures the actual sensor output under known pressure conditions and calculates correction coefficients that are stored in memory. These coefficients are then applied during operation to correct the sensor readings, effectively compensating for the manufacturing precision loss caused by heat treatment.
2Ease of operation
If two-way wireless communication components are included for calibration to improve ease of operation, then device complexity increases and cost increases
Solution Approach 1:
The patent extracts the optical communication components from the implant after calibration is complete. The system uses optical communication only during the initial calibration phase to transfer correction coefficients from the external calibration device to the implant's memory. Once calibration is done, these optical components are removed or deactivated, leaving only the essential RF telemetry components for ongoing operation. This reduces device complexity and cost while maintaining full calibration capability.
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 reduces component costs and complexity, ensuring accurate sensor readings while minimizing power consumption and eliminating unnecessary telemetry components, enhancing the implant's operational efficiency and longevity.
Implementation Method 1
optical communication wherein modulated light is transmitted through the transparent window or part of the housing to the photo-detector
Implementation Method 2
Sensor readings are transmitted by RF using the RF communication circuitry to a remote reader
Data Source
AI summary
An implant includes a processor, RF communication circuitry, optical communication circuitry, a power source and a memory, all of which being hermetically sealed within a housing having a transparent window. Sensor readings are transmitted by RF using the RF communication circuitry to a remote reader after receiving interrogation signals from the reader. During calibration of the sensor, corrective coefficients are calculated by comparing actual sensor pressure readings with known pressure readings. The corrective coefficients are transmitted to the memory of the control circuitry using optical communication wherein modulated light is transmitted through the transparent window of the housing to the photo-detector.