Piezoelectric MEMS Rotation via Segmented Pillar Actuation

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Solution Overview

Problem

Microelectromechanical devices with piezoelectric actuation require high actuation force and voltage, leading to high power consumption and large die area, making them unsuitable for compact and cost-effective production.

Innovation Solution

A microelectromechanical device with a semiconductor body and a piezoelectric-actuation system that includes deformable elements and pillars, allowing for controlled rotation of a mobile structure with reduced voltage requirements and compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If piezoelectric actuation is used to achieve precise rotation control, then rotation precision is improved, but power consumption increases

Engineering Contradiction:

Improverotation precisionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The mobile structure is divided into a supporting region and a pillar region that can rotate relative to each other. The piezoelectric actuator is integrated at the interface between these regions, allowing precise rotation control of the pillar region while the supporting region remains stable, thus improving rotation precision without requiring excessive power across the entire structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes the piezoelectric effect where electrical voltage parameters are converted into mechanical deformation. By applying controlled voltage changes to the piezoelectric actuator, precise rotation is achieved with lower power consumption compared to traditional electromagnetic actuators that require continuous power to maintain position.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If piezoelectric actuation system is implemented, then rotation control is achieved, but die area increases

Engineering Contradiction:

Improverotation controlVSAvoiddie area

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

The piezoelectric actuator is merged with the mobile structure itself, forming an integrated unit where the actuator, supporting region, and pillar region work together as a single component. This integration eliminates the need for separate actuator housings and mounting structures, significantly reducing the die area while maintaining full rotation control functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The piezoelectric actuator is nested within the mobile structure's supporting region. The actuator occupies the space between the supporting region and the pillar region, allowing the rotation mechanism to be compact and nested within the overall device footprint, thereby minimizing die area consumption.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Force

If high actuation force is required for piezoelectric actuation, then rotation capability is improved, but device complexity increases

Engineering Contradiction:

Improveactuation forceVSAvoiddevice complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The pillar region is designed with a curved or angled geometry relative to the supporting region. This curved configuration provides mechanical leverage and force multiplication, allowing the piezoelectric actuator to generate the required rotation torque with lower actuation force, thereby simplifying the overall device design.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The actuation force is applied in a direction that exploits the geometric configuration of the pillar region. By orienting the piezoelectric actuator to apply force at an optimal angle, the system leverages mechanical advantage through dimensional positioning, reducing the magnitude of force required while maintaining rotation capability.

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 reduces power consumption and die area, enabling the production of compact and cost-effective microelectromechanical devices with precise control over the mobile structure's rotation.

Implementation Method 1

a piezoelectric-actuation system configured to be controlled so as to deform said first deformable element and cause a consequent rotation of the mobile structure

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11086122B2Microelectromechanical device having a structure tiltable through an actuation of the piezoelectric type

Publication Date: 2021.08.10 STMICROELECTRONICS SRL

AI summary

A microelectromechanical device includes a body of semiconductor material, which forms a cavity, a mobile structure, and an actuation structure. The actuation structure includes at least one first deformable element which faces the cavity and is mechanically coupled to the body and to the mobile structure, and a piezoelectric-actuation system which can be controlled so as to deform the first deformable element and cause a consequent rotation of the mobile structure. The mobile structure includes a supporting region and at least one first pillar region, the first pillar region being mechanically coupled to the first deformable element, the supporting region being set on the first pillar region and overlying at least part of the first deformable element.