Opaque Nonconductive Sensor Region for Pulse Oximetry
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Solution Overview
Problem
Pulse oximetry measurements are prone to errors due to external light infiltration and shunted light, which can cause incorrect readings of blood constituents, and existing solutions like reflective coatings can introduce electrical interference.
Innovation Solution
The use of an opaque, electrically nonconductive material on the tissue-contacting surface of pulse oximetry sensors to absorb and prevent external and shunted light from reaching the detector, reducing measurement errors and electrical interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reflective coating is applied to the tissue contacting surface to reflect shunted light away from the detector, then measurement accuracy is improved, but electrical interference and capacitive coupling between emitter and detector increase
Solution Approach 1:
The patent introduces an opaque nonconductive layer as an intermediary between the tissue contacting surface and the detector. This layer absorbs shunted light (preventing it from reaching the detector) while simultaneously blocking electrical interference and capacitive coupling between the emitter and detector. The nonconductive property of the layer is critical, as it prevents electrical pathways while maintaining optical functionality.
Solution Approach 2:
The patent extracts the harmful conductive property from the reflective coating by using an opaque nonconductive material instead. The solution removes the electrical interference problem while retaining the light-blocking function through the opaque property of the material, separating the optical and electrical functions into distinct characteristics.
2Measurement precision
If the sensor is fitted snugly against the patient's tissue to avoid outside light infiltration, then measurement accuracy is improved, but local exsanguination of tissue occurs causing shunted light and measurement errors
Solution Approach 1:
The patent converts the harmful effect of shunted light into a beneficial measurement by using the opaque nonconductive layer to selectively block only the unwanted shunted light paths while allowing the sensor to maintain a relaxed fit. This enables the sensor to avoid tissue compression and exsanguination while still preventing measurement errors from external and shunted light sources.
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 opaque nonconductive regions effectively minimize the impact of external and shunted light, leading to more accurate physiological measurements by reducing unwanted light detection and electrical crosstalk, thereby enhancing the reliability of pulse oximetry readings.
Implementation Method 1
at least one opaque region disposed on a tissue-contacting surface of the sensor body, the opaque region including a substantially electrically nonconductive material
Implementation Method 2
a detector disposed on the sensor body, wherein the detector is adapted to detect the light
Data Source
AI summary
A medical sensor may be adapted to prevent unwanted light and electrical interference from corrupting physiological measurements. Sensors are provided with features that reduce the amount of outside light or shunted light that impinge the detecting elements of the sensor. The sensor is adapted to reduce crosstalk between electrical signals, increasing the accuracy of measurements. The sensor is also adapted to reduce the effect of outside light or shunted light on pulse oximetry measurements.