Flexible Strain Gauge Layout Without Lead Wires

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Solution Overview

Problem

The use of lead wires for electrical connection in strain gauges results in a larger device size, which is undesirable for compact designs.

Innovation Solution

A strain gauge with a flexible substrate, a resistor formed from chromium and/or nickel materials, and integrated wiring patterns and electrodes, allowing for direct electrical connection to an electronic component mounted on the substrate, reducing the need for external lead wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If lead wires are used for electrical connection between electrodes and electronic component, then electrical connection is achieved, but the device size becomes larger

Engineering Contradiction:
Improvestrain gauge sizeVSAvoidconnection structure
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent merges the electrodes and electronic component onto a single flexible substrate, eliminating the need for separate lead wires. The wiring patterns are directly formed on the substrate and electrically connected to both the resistor and electrodes, integrating multiple functions into one compact structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from a three-dimensional connection structure using lead wires to a two-dimensional planar configuration where all components (resistor, wiring patterns, electrodes, electronic component) are arranged on the surface of the flexible substrate, significantly reducing overall device volume.

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

2Reliability

If lead wires are used for electrical connection, then electrical connection is achieved, but connection reliability and noise resistance are reduced

Engineering Contradiction:
Improveconnection reliabilityVSAvoidnoise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the lead wires from the system, removing the source of connection reliability issues and noise interference. The electrical connection is achieved through integrated wiring patterns formed directly on the substrate, which provide more stable and reliable connections.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible substrate with integrated wiring patterns serves as an intermediary between the resistor and electronic component, providing a stable, low-noise electrical connection path that eliminates the need for external lead wires and their associated reliability and noise problems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3702722B1Strain gauge and sensor module
Publication Date: 2023.10.11 MINEBEAMITSUMI INC
  • EP3702722B1 patent drawingFigure 1
  • EP3702722B1 patent drawingFigure 2
  • EP3702722B1 patent drawingFigure 3

AI summary

The present strain gauge includes a substrate having flexibility; a resistor formed from a material containing at least one of chromium and nickel, on the substrate; a pair of wiring patterns formed on the substrate and electrically connected to both ends of the resistor; and a pair of electrodes formed on the substrate and electrically connected to the pair of wiring patterns, respectively. The wiring patterns include a first layer extending from the resistor, and a second layer having a lower resistance than the first layer and layered on the first layer. On the substrate, an electronic component mounting area is demarcated, on which an electronic component electrically connected to the electrodes is mounted.