Wearable Sensor Deformable Protrusion Constant Pressure
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Solution Overview
Problem
Current wearable sensor devices for continuous vital sign monitoring face challenges in maintaining consistent contact pressure to avoid skin irritation and motion-induced noise, which affects the accuracy and reliability of measurements like blood oxygen saturation and perfusion levels.
Innovation Solution
A wearable sensor device featuring a flexibly deformable protrusion with a sensor module, designed to maintain constant pressure through deformation, minimizing skin irritation and motion-induced noise, using a hollow cushion or balloon-shaped protrusion with a base and apex, and a fixating structure that ensures the sensor remains in contact with the skin without increasing pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is pressed against the skin with sufficient force to ensure reliable contact, then measurement precision is improved, but skin irritation occurs due to prolonged pressure exposure
Solution Approach 1:
The sensor device incorporates a spring mechanism that dynamically adjusts the contact pressure between the sensor and skin. The spring allows the sensor to maintain consistent contact pressure while accommodating skin movement and deformation, ensuring reliable measurements without excessive force that would cause irritation during prolonged wear
Solution Approach 2:
The invention changes the pressure parameter from a fixed high value to a dynamically adjusted value through the spring mechanism. The spring constant and pre-load force are optimized to provide sufficient contact pressure for accurate optical measurements while remaining below the threshold that causes skin irritation during extended monitoring periods
2Measurement precision
If the sensor is fixed rigidly to the skin to prevent motion artifacts, then measurement precision is improved, but motion-induced noise increases due to skin movement and deformation
Solution Approach 1:
The spring-loaded sensor design allows the sensor to move dynamically with skin deformation while maintaining constant contact pressure. This dynamic adaptation reduces motion-induced noise by preventing the sensor from becoming dislodged or creating air gaps during patient movement, while the spring mechanism absorbs deformation forces that would otherwise cause measurement artifacts
Solution Approach 2:
The spring acts as an intermediary element between the sensor housing and the skin surface. It mediates the interaction by providing a compliant connection that maintains optical contact while isolating the sensor from direct mechanical coupling to skin movements, thereby reducing motion artifacts in the optical measurements
3Object-affected harmful factors
If the contact area of the sensor is increased to reduce pressure, then skin irritation is reduced, but device complexity increases due to larger sensor housing
Solution Approach 1:
The invention applies local quality by concentrating the pressure-reducing effect specifically at the sensor-skin interface through the spring mechanism, rather than uniformly increasing the entire device size. The contact area is optimized locally to distribute pressure appropriately, allowing the rest of the device to remain compact and simple in design
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 solution provides reliable and accurate vital sign monitoring over extended periods by maintaining constant contact pressure, reducing skin irritation, and minimizing motion-induced noise, allowing for comfortable and long-term wear without compromising signal quality.
Implementation Method 1
a wearable sensor device featuring a flexibly deformable protrusion with a sensor module, designed to maintain constant pressure through deformation
Data Source
AI summary
A wearable sensor assembly for contacting skin, the sensor assembly comprises a hollow, flexibly deformable protrusion, a sensor module, and a sensor device fixating structure. The protrusion is preferably a cushion- or a balloon-shaped protrusion. The protrusion comprises a base and an apex, preferably a substantially flat apex. At least part of the apex forms a contact area for contacting the skin. The sensor module is mounted on or inside the protrusion, preferably on or against the contact area. The sensor device fixating structure is configured to press the contact area with a substantially constant pressure against the skin. When the contact area is pressed against the skin, an increase, respectively decrease of a force exerted on the sensor device deforms, e.g. deflects and/or compresses, the protrusion such that the contact area that is in contact with the skin increases, respectively decreases, while the pressure stays substantially the same.