PPG Sensor Housing With Flexible Membrane for Stable Skin Attachment
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Solution Overview
Problem
Existing photoplethysmography (PPG) sensor housings face challenges in providing flexible placement options and effective pressure application on the skin, leading to movement artifacts and reduced probe amplitude, particularly in reflection mode.
Innovation Solution
A sensor housing with a flexible membrane attachment system that allows rotational movement and controlled pressure application, using a combination of clips and adhesive tabs to secure the device to the skin while minimizing torque and providing a physical barrier for reusability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clip-based sensor housing is used for photoplethysmography, then the sensor can be attached to the skin, but movement artifacts increase and signal quality decreases due to lack of controlled pressure
Solution Approach 1:
The attachment member is divided into two distinct components: a first component that attaches to the sensor housing and a second component (flexible membrane) that attaches to the patient's skin. This segmentation allows each component to be optimized for its specific function - the first component provides structural support while the second component provides flexible, conformable attachment with controlled pressure distribution.
Solution Approach 2:
The second component is specifically designed as a flexible membrane that can conform to the contours of the patient's skin. This flexible membrane distributes the attachment force evenly across the skin surface, providing controlled pressure that enhances signal quality while reducing movement artifacts, unlike rigid clip-based attachments.
2Stability of the object's composition
If a rigid attachment member is used to secure the sensor housing, then attachment stability improves, but torque is applied to the skin causing discomfort and movement artifacts
Solution Approach 1:
The flexible membrane second component acts as a compliant interface between the rigid sensor housing and the skin. It absorbs and distributes mechanical stresses, preventing torque transmission to the skin while maintaining stable attachment. The flexibility of the membrane allows it to deform with skin movement rather than transmitting rigid forces.
Solution Approach 2:
The attachment member combines rigid and flexible materials in a composite structure. The first component provides rigid structural support for secure attachment to the sensor housing, while the second component (flexible membrane) provides soft, compliant contact with the skin. This composite approach balances stability with comfort.
3Reliability
If the sensor housing is made disposable to ensure hygiene, then infection risk decreases, but cost increases and environmental impact worsens
Solution Approach 1:
The system is segmented into a reusable sensor housing and a disposable attachment member. This allows the expensive, complex sensor housing containing electronic components to be reused, while only the simpler attachment member (flexible membrane with adhesive) is disposed of after single use, minimizing waste and cost.
Solution Approach 2:
The attachment member is designed as a low-cost, single-use component that can be easily manufactured and disposed of. By making only the attachment member disposable rather than the entire sensor housing, the system achieves hygiene safety while minimizing waste of valuable electronic components and materials.
4Stability of the object's composition
If adhesive is used to attach the flexible membrane to the skin, then attachment stability improves, but skin irritation increases
Solution Approach 1:
The flexible membrane itself serves as the attachment interface, distributing adhesive forces over a large surface area. This reduces the adhesive stress concentration on any single point of skin, minimizing irritation while maintaining stable attachment. The membrane acts as a barrier between the adhesive and direct skin contact.
Solution Approach 2:
The adhesive properties of the flexible membrane can be optimized by adjusting parameters such as adhesive strength, viscosity, and curing characteristics. By carefully selecting adhesive parameters, the system achieves sufficient attachment stability while minimizing skin irritation through controlled adhesion levels.
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 ensures secure fixation to the skin, minimizes torque, applies controlled pressure, and reduces movement artifacts, enabling effective PPG measurements with reusability of the sensor housing.
Implementation Method 1
the attachment member is adapted to allow passage of non-ionising radiation from the sensor housing to the patient
Implementation Method 2
the first component configured to receive the sensor housing therein and to permit rotational movement between the attachment member and the sensor housing and to restrict relative movement between the attachment member and the sensor housing in the axial direction
Implementation Method 3
The attachment means may comprise an adhesive surface at least to the side of the flexible membrane that is distal from the first component
Data Source
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AI summary
A sensing device comprises a sensor housing mounting sensor elements and an attachment member, the attachment member comprising first and second components. The first component is configured to receive the sensor housing therein and to permit rotational movement between the attachment member and the sensor housing and to restrict relative movement between the attachment member and the sensor housing in the axial direction of the sensor housing. The second component comprises a flexible membrane that is attachable to an underside of the first component attached to an underside of the first component, the flexible membrane extending at least in part beyond an outer edge of the first component. The flexible membrane comprises attachment means for attachment of the attachment member to a patient, and the attachment member is adapted to allow passage of non-ionising radiation from the sensor housing to the patient.