Microprobe With Pivotable Wall Elements For Linear Measurement

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Solution Overview

Problem

Existing microprobes face challenges in generating linear measurement signals over a large deflection range with a simple and cost-effective production method, while maintaining isotropic mechanical behavior.

Innovation Solution

A microprobe design featuring orthogonally connected force sensors with pivotable wall elements and integrally formed solid-state joints, where piezoresistive resistors generate a linear measurement signal, and a manufacturing method involving silicon wafers and etching processes to produce flexible hinges and conductive tracks, allowing for efficient production of multiple identical sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional force sensors with parallel silicon leaf springs are used, then the structure is well-established, but the measurement signal linearity deteriorates over large deflection ranges

Engineering Contradiction:
Improvemeasurement signal linearityVSAvoiddeflection range
Core Design Contradiction:
Measurement precisionVSLength of moving object

Solution Approach 1:

The patent applies dynamics by making the wall elements pivotable at solid-state joints, allowing the structure to dynamically adapt to large deflections while maintaining measurement linearity. The pivotable joints enable the wall elements to rotate relative to each other, providing dynamic response capability over large angular ranges while the piezoresistive sensors continuously track the deformation state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the structural parameters from fixed parallel leaf springs to pivotable wall elements with variable orientation. The solid-state joints allow the wall elements to change their angular parameters during deflection, enabling large range of motion while the piezoresistive resistors maintain linear measurement through their positioning on the pivotable joints.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If complex microprobe structures are designed to achieve large deflection range, then the measurement capability is improved, but the production cost and complexity increase

Engineering Contradiction:
Improvedeflection rangeVSAvoidstructure complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the wall elements and solid-state joints structure. The wall elements serve as both structural components and measurement carriers, while the solid-state joints provide both mechanical pivoting and sensor mounting functions. This integration reduces the number of separate components needed to achieve large deflection range capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the sensing function from complex sensor assemblies and integrates piezoresistive resistors directly into the solid-state joints. This extraction simplifies the overall structure by eliminating separate sensor housings and mounting mechanisms, achieving large deflection capability through the pivotable joint design itself rather than through complex external sensing systems.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If high precision manufacturing processes are used to achieve good measurement linearity, then the measurement precision is improved, but the production cost increases

Engineering Contradiction:
Improvemeasurement signal linearityVSAvoidproduction cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies self-service by using self-aligning pivotable joints that automatically maintain proper geometric relationships during assembly. The solid-state joints with integrated piezoresistive resistors self-position during the manufacturing process, reducing the need for high-precision alignment procedures and expensive manual adjustment operations while maintaining measurement linearity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical sensor mounting systems with integrated piezoresistive resistors fabricated directly into the solid-state joints using semiconductor processing techniques. This substitution eliminates the need for precision mechanical assembly of separate sensor components, reducing manufacturing costs while maintaining measurement precision through the inherent stability of the integrated sensor structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If multiple force sensors are connected orthogonally to form a microprobe, then the measurement capability is improved, but the device complexity increases

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidsensor arrangement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the wall element assembly as a universal module that can be oriented in any orthogonal direction. Each wall element pair forms a complete force sensor unit that can be arranged along x, y, or z axes using the same basic structure, simplifying the design of multi-axis measurement capability while maintaining measurement versatility through identical modular components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 microprobe achieves linear measurement signals over a large deflection range with isotropic mechanical behavior, ensuring high rigidity and cost-effective production, suitable for attachment to coordinate measuring machines.

Implementation Method 1

Each force sensor has two wall elements which are parallel and spaced apart and has two integrally formed solid state joints on which the wall elements are pivotable parallel to one another. At least one piezoresistive resistor is integrated in at least one flexure joint

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 2

The solid-state joints are produced in a silicon wafer, e.g. by removal, in particular etching processes. It has been shown that wet etching processes can be used to produce solid-state hinges in a silicon wafer that have a uniform thickness

Methodology Applied
Scientific EffectWet etching:

Implementation Method 3

each force sensor having two wall elements which are parallel and spaced apart has, each having two integrally formed solid state joints on which the wall elements are pivotable parallel to one another

Methodology Applied
Scientific EffectFlexural deformation: Elasticity

Data Source

PatentEP3388778B1Microbutton and method for manufacturing the same
Publication Date: 2020.03.11 TECH UNIV BRAUNSCHWEIG
  • EP3388778B1 patent drawingFigure 1
  • EP3388778B1 patent drawingFigure 2
  • EP3388778B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a microswitch having at least one force sensor, preferably two or three force sensors arranged orthogonally to each other and connected in a row, each force sensor having two parallel wall elements spaced apart, each having two integrally formed solid joints on which the wall elements can be pivoted parallel to each other.