Folded Flex Circuit Assembly for Low-Noise Optical Probes

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Solution Overview

Problem

Existing optical probes face challenges in efficiency and cost-effectiveness in the field of non-invasive physiological monitoring of the field of non-invasive physiological monitoring of bodily functions, such as blood pressure and oxygen saturation, require low-noise optical probes that are both disposable and reusable, but current technologies face difficulties in providing these at low cost and minimizing motion-induced noise.

Innovation Solution

A method of assembling a physiological optical sensor using a flexible circuit assembly with a nested configuration to maximize material usage, allowing for efficient manufacturing of low-cost, low-noise optical probes that can be folded into various configurations, reducing waste and increasing production yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If traditional optical probe designs are used, then functional performance is achieved, but material waste increases and manufacturing cost increases

Engineering Contradiction:
Improvematerial wasteVSAvoidmanufacturing cost
Core Design Contradiction:
Loss of substanceVSEase of manufacture

Solution Approach 1:

The flexible circuit board is configured in a nested arrangement where multiple circuit traces are layered and positioned to maximize material utilization. The circuit board nesting allows efficient packing of electrical pathways within the probe structure, reducing overall material consumption while maintaining functional integrity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from traditional linear or planar circuit layouts to a three-dimensional nested configuration. By utilizing vertical layering and spatial optimization, the design maximizes material usage efficiency without compromising electrical performance or probe functionality

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If optical probes are designed for low cost, then manufacturing efficiency improves, but motion-induced noise increases

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmotion-induced noise
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent employs a flexible circuit board with a thin-film structure that can accommodate motion while maintaining electrical connections. The flexible nature of the circuit board allows it to deform with probe movement without generating excessive noise or failing, thus reducing motion-induced noise while keeping manufacturing costs low

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The circuit board design incorporates dynamic flexibility to adapt to probe motion. The flexible traces and connections are engineered to move with the probe rather than resist motion, reducing mechanical stress and noise generation during dynamic operation

Inventive Principle:
Principle #15Dynamics

3Loss of substance

If flexible circuit board nesting is implemented, then material usage is maximized, but assembly complexity increases

Engineering Contradiction:
Improvematerial usage efficiencyVSAvoidassembly complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The nested flexible circuit board is divided into distinct segments or modules that can be independently positioned and connected. This segmentation allows for systematic assembly where each nested layer can be installed in a standardized sequence, reducing overall assembly complexity despite the nested configuration

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4329439B1Fold flex circuit for lnop
Publication Date: 2025.12.17 MASIMO CORP
  • EP4329439B1 patent drawingFigure 1A~1B
  • EP4329439B1 patent drawingFigure 2A
  • EP4329439B1 patent drawingFigure 2B~2C

AI summary

The present invention discoses a method of assembling a physiological sensor, the method comprising: obtaining an individual flexible circuit configured to be attached to a plurality of components, the individual flexible circuit comprising: a connector end, and a detector end (206) comprising an emitter (226), a detector (228), and a hook portion (227a, 227b, 227d), wherein the hook portion is configured to form an opening (227c) that the emitter (226) can attach to; covering the physiological sensor on both top and bottom with a layer of foam (646), wherein the foam covering covers the individual flexible circuit and forms a covering which extends from the emitter and the detector to the connector end; providing an applicator tape (668); and applying the applicator tape to a portion of the individual flexible circuit.