Medical Sensor Cable-to-PCB Joint Wrapping for Flex and Water Resistance

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Solution Overview

Problem

Medical sensors, such as pulse oximeters, are prone to damage due to flexing, water ingress, and pull forces, leading to malfunction or failure, including wire breakage and short circuits.

Innovation Solution

A patient monitoring sensor with a secure joint between the cable and PCB or optics, featuring a heat shrinkable adhesive joint wrap, injection molded joint, or over-molded joint to provide water resistance and flex/pull resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional cable-to-PCB connection is used in medical sensors, then the device structure remains simple, but the connection becomes susceptible to damage from flexing, water ingress, and pull forces

Engineering Contradiction:

Improveconnection reliabilityVSAvoidjoint structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite material structures in the joint wrap assembly, combining heat shrinkable material, adhesive layers, and protective wrapping materials to create a multi-layered protective joint that resists flexing, water ingress, and pull forces while maintaining connection reliability

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The joint wrap is pre-applied to the cable-to-PCB connection before final assembly, creating a pre-protected joint structure that is subsequently sealed and secured. This preliminary protective action ensures the connection is safeguarded against environmental factors before the sensor is put into service

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the sensor joint is made more robust to resist flexing and pull forces, then reliability improves, but manufacturing complexity increases

Engineering Contradiction:

Improvesensor reusabilityVSAvoidjoint assembly ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The joint wrap assembly is designed as a disposable protective component that is applied to each sensor during manufacturing and does not require complex retrieval or reuse processes. This approach maintains sensor reusability while keeping the manufacturing process straightforward and cost-effective

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent utilizes parameter changes in the heat shrinkable material, which undergoes thermal contraction when heated to form a tight, secure wrap around the joint. This phase change from relaxed to contracted state provides robust protection without requiring complex mechanical fastening systems

Inventive Principle:

Principle #35Parameter changes

3Reliability

If protective measures are added to prevent water ingress and wire breakage, then sensor reliability improves, but device complexity increases

Engineering Contradiction:

Improvewater resistanceVSAvoidprotective layer complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The joint wrap employs flexible, thin-film materials that conform to the cable and PCB connection, creating a water-resistant barrier without adding significant bulk or complexity. The flexible nature of these films allows them to accommodate movement while maintaining the water seal

Inventive Principle:

Principle #30Flexible shells and thin films

4Strength

If the joint is secured with multiple protective layers, then resistance to flex forces and pull forces improves, but manufacturing time increases

Engineering Contradiction:

Improvejoint strengthVSAvoidassembly speed

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent combines multiple protective functions into a single integrated joint wrap assembly that applies thermal contraction, adhesive bonding, and mechanical wrapping simultaneously. This merging of functions maintains high joint strength while reducing the number of separate manufacturing steps required

Inventive Principle:

Principle #5Merging (Combining)

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

Enhances sensor reliability and reusability by preventing damage from flexing, water ingress, and pull forces, ensuring consistent performance.

Implementation Method 1

heat shrinkable adhesive joint wrap

Methodology Applied

Scientific EffectHeat shrinkage: Thermal Contraction

Implementation Method 2

adhesive joint wrap

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Implementation Method 3

injection molded joint installed over the cable and secured with a base sealing component

Methodology Applied

Scientific EffectInjection molding:

Implementation Method 4

over-molded joint

Methodology Applied

Scientific EffectOver-molding:

Data Source

PatentUS12440129B2Sensor joint wrapping in a medical sensor

Publication Date: 2025.10.14 COVIDIEN LP

AI summary

A patient monitoring sensor having a communication interface, through which the patient monitoring sensor can communicate with a monitor is provided. The patient monitoring sensor includes a light-emitting diode (LED) communicatively coupled to the communication interface and a detector, communicatively coupled to the communication interface, capable of detecting light. The patient monitoring sensor includes a cable to flexible printed circuit board (PCB) connection that provides a reliable connection resistant to flex forces, water ingress and pull forces.