Capacitive Proximity Sensor for Pulse Oximeter Positioning
Solution Overview
Problem
Standard pulse oximeter sensors lack accurate positioning feedback, leading to improper alignment with the measurement site, which can result in inaccurate physiological measurements due to movement or displacement during use.
Innovation Solution
Incorporating capacitive proximity sensors within the oximeter housing to detect the distance between the sensor electrodes and the skin, providing feedback for correct positioning and repositioning of the sensor, and determining probe off conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If physical stop is used to indicate desired placement, then ease of operation is improved, but measurement precision deteriorates because the physical stop does not ensure proper finger positioning
Solution Approach 1:
The patent applies feedback by using capacitive sensors to continuously monitor the distance between the sensor and measurement site, providing real-time information about positioning accuracy. This feedback mechanism allows the system to detect when the finger is properly positioned and alert users to repositioning needs, thereby resolving the contradiction between ease of application and measurement precision.
Solution Approach 2:
The patent replaces the mechanical physical stop system with an electrical sensing system using capacitive sensors. This substitution eliminates the limitations of mechanical indicators while maintaining ease of operation, as the capacitive sensors can precisely detect finger position without physical contact, thereby improving measurement precision while preserving ease of use.
2Measurement precision
If sensor is initially placed correctly, then measurement precision is improved, but reliability deteriorates due to movement during artificial pulsing that can displace the finger
Solution Approach 1:
The patent implements continuous monitoring of sensor-position relationship through capacitive sensors that operate throughout the measurement period. This continuous action ensures that any displacement caused by artificial pulsing or patient movement is immediately detected, maintaining measurement precision and reliability throughout the entire measurement process rather than only at the initial placement stage.
Solution Approach 2:
The system uses feedback from capacitive sensors to continuously monitor whether the finger remains properly positioned during artificial pulsing. When displacement is detected, the system can alert users to reposition, thereby maintaining measurement reliability despite the dynamic conditions created by artificial pulsing.
3Measurement precision
If capacitive sensor electrodes are positioned at various locations within the oximeter housing, then measurement precision is improved through accurate proximity feedback, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the sensing function into multiple capacitive sensor electrodes positioned at different locations within the housing. Each electrode monitors a specific region, and their combined data provides comprehensive positioning information. This segmentation approach improves measurement precision by enabling detailed spatial awareness while managing complexity through modular sensor placement.
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
Ensures accurate and reliable physiological measurements by ensuring proper alignment of the sensor with the measurement site, reducing the impact of movement and improving data confidence through proximity sensing technology.
Implementation Method 1
one or more capacitive sensor electrodes can provide an indication to a processor of the oximeter regarding whether the sensor is correctly positioned by sensing proximity to the skin of the measurement site
Data Source
AI summary
Systems and methods are disclosed for proximity sensing in physiological sensors, and more specifically to using one or more proximity sensors located on or within a physiological sensor to determine the positioning of the physiological sensor on a patient measurement site. Accurate placement of a physiological sensor on the patient measurement site is a key factor in obtaining reliable measurement of physiological parameters of the patient. Proper alignment between a measurement site and a sensor optical assembly provides more accurate physiological measurement data. This alignment can be determined based on data from a proximity sensor or sensors placed on or within the physiological sensor.