Electrostatic Micro-Pump Electrode Spacing to Prevent Stiction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing electrostatic micro-pumps face instability due to high operating voltages, small stroke volumes, and the risk of electrical short circuits, making them impractical for applications requiring larger strokes and compressible media like air, and they are not commercially available despite their advantages over piezo-driven pumps.

Innovation Solution

The design incorporates a diaphragm arrangement with varying electrode spacing, anti-stiction bumps, and a stator structure to minimize sticking and short circuits, allowing for larger strokes and reduced energy consumption, while enabling wafer-level production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If electrostatic actuation is used to drive the micro-pump, then energy consumption is reduced and manufacturing is simplified, but the stroke volume remains small and the system becomes unstable at high voltages

Engineering Contradiction:

Improveenergy consumptionVSAvoidstroke volume

Core Design Contradiction:

Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The pump chamber is divided into multiple segments or compartments, allowing the electrostatic actuator to achieve larger effective displacement through sequential or coordinated movement of multiple diaphragms, thereby increasing overall stroke volume while maintaining low energy consumption per actuator

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from single-point electrostatic actuation to distributed electrode arrangements across the diaphragm surface, utilizing area-based electrostatic forces to generate larger strokes without proportionally increasing energy consumption

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If high supply voltage is applied to achieve larger strokes, then stroke volume increases, but the risk of electrical short circuits and instability increases

Engineering Contradiction:

Improvestroke volumeVSAvoidrisk of short circuits

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

An insulating layer is introduced as an intermediary between the electrostatic actuator electrodes and the pump chamber, providing electrical isolation that prevents short circuits while allowing the actuator to operate at higher voltages for larger strokes

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The diaphragm is pre-deflected or pre-positioned to an optimal starting position before actuation, allowing the electrostatic force to efficiently generate large strokes without requiring excessive voltage that would risk electrical breakdown

Inventive Principle:

Principle #10Preliminary action

3Power

If electrode spacing is reduced to increase electrostatic force, then actuation efficiency improves, but the risk of electrical breakdown and stiction increases

Engineering Contradiction:

Improveactuation efficiencyVSAvoidelectrical breakdown risk

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The electrode spacing is optimized locally in different regions of the actuator, with tighter spacing in areas requiring high force and larger spacing in areas prone to breakdown, achieving overall high efficiency while minimizing electrical breakdown risk

Inventive Principle:

Principle #3Local quality

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 achieves higher stroke volumes, reduced energy usage, and prevents short circuits, making the micro-pump practical for compressible media and enabling efficient, cost-effective mass production.

Implementation Method 1

a second electrode structure arranged so as to form an electrostatic drive with the first electrode structure, the electrostatic drive configured to deflect the diaphragm

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS12473904B2Electrostatic micro-pump and a process to produce an electrostatic micro-pump

Publication Date: 2025.11.18 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

An embodiment is an electrostatic micro-pump including a diaphragm arrangement including a diaphragm and a first electrode structure. The electrostatic micro-pump further includes a valve arrangement, including an inlet check valve and an outlet check valve, wherein the diaphragm arrangement and the valve arrangement at least partially enclose a pump chamber. The electrostatic micro-pump further includes a second electrode structure arranged so as to form an electrostatic drive with the first electrode structure. The electrostatic drive is configured to deflect the diaphragm. The electrostatic micro-pump further includes at least one anti-stiction bump arranged between the first electrode structure and the second electrode structure, wherein in an inactive state of the micro-pump, a spacing between the first electrode structure and the second electrode structure varies towards a center region of the pump chamber when starting from a peripheral region of the pump chamber, wherein the peripheral region encloses the center region.