Microactuator Extender Structure for Fast, Low-Power Deflection

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Solution Overview

Problem

Existing microactuators are not fast enough, difficult to miniaturize, and require high electrical voltage, which is a challenge for applications like optical coherence tomography.

Innovation Solution

A thermally-actuated microactuator with an extender comprising voids to reduce thermal mass and length, allowing for faster deflection with lower electrical power consumption, and a bimorph structure with layers of different thermal expansion coefficients for enhanced actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If existing microactuator designs are used, then structural integrity is maintained, but deflection speed is insufficient and device size cannot be miniaturized

Engineering Contradiction:
Improvedeflection speedVSAvoidmicroactuator length
Core Design Contradiction:
SpeedVSLength of moving object

Solution Approach 1:

The microactuator is divided into two functional segments: a heated bimorph section for actuation and a cold extender section for deflection amplification. This segmentation allows the heated portion to be short and fast-responding while the extender provides additional deflection leverage without requiring heat, thereby increasing deflection speed and enabling miniaturization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The extender section is positioned at an angle (e.g., 90 degrees) relative to the bimorph section, creating a L-shaped configuration. This dimensional change allows the extender to amplify deflection in a direction perpendicular to the heating section, increasing effective deflection without increasing the thermal response path length.

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

2Speed

If high electrical voltage is applied to achieve fast deflection, then deflection speed improves, but power consumption increases

Engineering Contradiction:
Improvedeflection speedVSAvoidelectrical power consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The cold extender section acts as a mechanical intermediary that amplifies the small deflection of the heated bimorph section into a larger overall deflection. This mechanical leverage allows fast deflection to be achieved with lower heating power, reducing electrical energy consumption while maintaining high deflection speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By changing the geometric parameters of the extender (length, cross-sectional area, position), the mechanical advantage is optimized to amplify deflection. This allows the system to achieve fast deflection with reduced thermal input power by maximizing the leverage effect of the extender section.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If the microactuator length is increased to improve deflection, then deflection range increases, but thermal mass increases and response time decreases

Engineering Contradiction:
Improvedeflection rangeVSAvoidresponse time
Core Design Contradiction:
Length of moving objectVSLoss of time

Solution Approach 1:

The microactuator is segmented into a short heated bimorph section and a longer cold extender section. The heated section remains short to minimize thermal mass and maintain fast response time, while the cold extender provides additional deflection range without requiring heat, thus avoiding the penalty of increased thermal mass and response time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The extender is positioned at an angle to the bimorph section, creating a L-shaped configuration. This dimensional arrangement allows the extender to contribute to deflection range in a perpendicular direction without adding to the thermal path length, thereby increasing deflection range while maintaining fast thermal response.

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

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 enables rapid deflection with reduced power requirements, suitable for applications like optical coherence tomography, facilitating the development of portable and efficient systems.

Implementation Method 1

The microactuator comprises a bimorph, wherein the bimorph comprises a first layer and a second layer, and wherein the first layer and the second layer have different coefficients of thermal expansion.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The first layer and/or the second layer is configured as a resistive heater.

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 3

an extender configured to increase deflection of the component by the microactuator, wherein the extender comprises one or more voids

Methodology Applied
Scientific EffectThermal mass reduction:

Data Source

PatentEP4066040B1Microactuator apparatus
Publication Date: 2025.09.03 NOKIA TECHNOLOGIES OY
  • EP4066040B1 patent drawingFigure 1~3B
  • EP4066040B1 patent drawingFigure 4A~4C
  • EP4066040B1 patent drawingFigure 5

AI summary

An apparatus comprising: a thermally-actuated microactuator configured to deflect a component in dependence on an applied stimulus; and an extender having a length configured to increase deflection of the component by the microactuator, wherein the extender comprises one or more voids.