Corrugated Piezoelectric MEMS Mirror Suspension for Larger Tilt

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Solution Overview

Problem

Existing MEMS mirrors with cantilever beams for piezoelectric actuation are limited by maximum tilt angle and prone to reliability issues, such as breakage and failure, which restricts their performance in 2D scanning applications.

Innovation Solution

A MEMS mirror system utilizing a piezoelectric corrugated structure with concentric rings of alternating peaks and valleys, coupled to a frame via a suspension assembly, enables improved tilting and scanning capabilities by using piezoelectric actuators to drive the reflective structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cantilever beams are used as piezoelectric actuators, then the MEMS mirror can be actuated, but the maximum tilt angle is limited and reliability deteriorates due to breakage and failure

Engineering Contradiction:

Improveactuator reliabilityVSAvoidmaximum tilt angle

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The actuator is segmented into multiple parallel piezoelectric beam elements instead of using a single cantilever beam. This segmentation distributes the mechanical stress across multiple elements, reducing the risk of complete actuator failure and enabling greater tilt angles through cumulative displacement

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs thin piezoelectric film layers deposited on flexible substrate structures. These thin films provide the necessary actuation while maintaining flexibility and reducing mechanical stress concentrations that lead to breakage in traditional cantilever beams

Inventive Principle:

Principle #30Flexible shells and thin films

2Force

If cantilever beams are used as actuators, then piezoelectric actuation is achieved, but the reachable force is limited

Engineering Contradiction:

Improvereachable forceVSAvoidactuator structure

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

Multiple piezoelectric beam actuators are merged and connected in parallel configurations, combining their individual force outputs to achieve greater total reachable force while sharing the mechanical load across the structure

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The actuator structure uses composite materials combining piezoelectric ceramics or polymers with flexible substrate materials. This composite construction enhances both the force generation capability and the mechanical durability of the actuator

Inventive Principle:

Principle #40Composite materials

3Productivity

If traditional piezoelectric actuators are used, then scanning function is achieved, but scanning performance is limited

Engineering Contradiction:

Improvescanning performanceVSAvoidresonance frequency

Core Design Contradiction:

ProductivityVSSpeed

Solution Approach 1:

The actuator design incorporates dynamic compliance and mass optimization to tune the resonant frequency of the MEMS mirror system. The flexible thin-film structure allows for higher resonance frequencies while maintaining adequate actuation force for effective scanning

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent optimizes key parameters including piezoelectric material selection, film thickness, beam geometry, and suspension spring constants to achieve desired resonance frequencies and scanning speeds. By adjusting these parameters, the system achieves enhanced scanning performance

Inventive Principle:

Principle #35Parameter changes

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 system achieves greater tilting amplitudes and resonance frequencies, enhancing the scanning performance and reliability of MEMS mirrors in 2D scanning systems, suitable for applications like LIDAR and extended reality technologies.

Implementation Method 1

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS12461358B2Piezoelectric micro mirror with corrugated actuator and suspension system

Publication Date: 2025.11.04 INFINEON TECHNOLOGIES AG

AI summary

A light steering system includes: a reflective structure configured to tilt about a first axis; a frame that includes a frame recess over which the reflective structure is suspended; and a suspension assembly that includes a piezoelectric corrugated structure coupled to and between the reflective structure and the frame. The piezoelectric corrugated structure includes a first corrugated surface including concentric rings of alternating peaks and valleys; a second corrugated surface arranged opposite to the first corrugated surface; a plurality of peak electrodes, each peak electrode being coupled to a respective peak of the first corrugated surface; a plurality of valley electrodes, each valley electrode being coupled to a respective valley of the first corrugated surface; and a common electrode layer coupled to the second corrugated surface, wherein the common electrode layer is arranged counter to the plurality of peak electrodes and to the plurality of valley electrodes.