Dual-Hinge MEMS Mirror for Comb Misalignment and Vibration Resistance

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Solution Overview

Problem

MEMS devices face challenges in maintaining deflection angles due to unwanted lateral linear forces and in-plane torques caused by misalignment in comb actuator teeth, leading to reduced functionality in solid-state LIDAR systems.

Innovation Solution

Incorporating a dual hinge structure with a first set of twisting hinges to resist lateral linear forces and a second set of serpentine hinges to counteract in-plane torques, ensuring the pivot center aligns with the mirror's mass center, thereby enhancing resistance to operational vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single hinge structure is used to tilt the mirror, then the device complexity is low, but the device cannot effectively resist unwanted lateral linear forces and in-plane torques

Engineering Contradiction:

Improveresistance to unwanted forces and torquesVSAvoidhinge structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The hinge structure is segmented into two distinct sets: a first set of hinges configured to resist lateral linear forces, and a second set of hinges configured to resist in-plane torques. This segmentation allows each hinge set to specialize in counteracting specific unwanted forces, improving overall device reliability without requiring a single complex hinge mechanism to handle all force types simultaneously.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If comb actuator teeth are used for driving, then the actuation mechanism is simple, but misalignment causes unwanted lateral linear forces and in-plane torques

Engineering Contradiction:

Improveactuator fabrication simplicityVSAvoidcomb actuator teeth alignment

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The dual hinge structure provides preliminary anti-action by being pre-configured to counteract the specific types of forces (lateral linear forces and in-plane torques) that arise from comb actuator teeth misalignment. Rather than attempting to achieve perfect alignment, the design anticipates the misalignment-induced forces and incorporates hinge structures specifically oriented to resist these predetermined unwanted forces.

Inventive Principle:

Principle #9Preliminary anti-action

3Adaptability or versatility

If the mirror is allowed to tilt freely about the axis, then the deflection angle can change, but operational vibrations cause unwanted movement and reduce functionality

Engineering Contradiction:

Improvedeflection angle adjustmentVSAvoidoperational vibrations

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The hinge structure exhibits local quality by providing different mechanical properties in different directions: it allows free tilting movement about the primary axis (maintaining adaptability for deflection angle adjustment) while providing rigid resistance to lateral linear forces and in-plane torques (counteracting harmful vibrations). This directional selectivity enables the mirror to perform its intended function while being protected from vibration-induced unwanted movements.

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

This configuration increases the likelihood of maintaining preferred deflection angles and improves the robustness of MEMS devices and solid-state LIDAR systems by reducing the impact of operational vibrations and misalignment-induced forces.

Implementation Method 1

a driving torque to tilt the mirror structure about a first axis of the MEMS device via a first set of hinges and a second set of hinges is caused by a stator comb actuator, of a set of stator comb actuators, engaging with a rotor comb actuator, of a set of rotor comb actuators

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

the first set of hinges is configured to resist a lateral linear force on the mirror structure in a direction associated with the first axis caused by the stator comb actuator engaging with the rotor comb actuator

Methodology Applied

Scientific EffectMechanical force resistance: Friction

Implementation Method 3

the second set of hinges is configured to resist an in-plane torque on the mirror structure about a second axis of the MEMS device caused by the stator comb actuator engaging with the rotor comb actuator

Methodology Applied

Scientific EffectTorque resistance: Friction

Data Source

PatentUS12007555B2MEMS device with a dual hinge structure

Publication Date: 2024.06.11 WELLS FARGO BANK NA

AI summary

A micro-electro-mechanical system (MEMS) device may comprise a first layer that includes a stator comb actuator; a second layer that includes a rotor comb actuator; a mirror structure that includes a mirror; and a first set of hinges and a second set of hinges configured to tilt the mirror structure about a first axis of the MEMS device based on a driving torque caused by the stator comb actuator engaging with the rotor comb actuator. The first set of hinges may be configured to resist a lateral linear force on the mirror structure in a direction associated with the first axis caused by the stator comb actuator engaging with the rotor comb actuator. The second set of hinges may be configured to resist an in-plane torque on the mirror structure about a second axis of the MEMS device caused by the stator comb actuator engaging with the rotor comb actuator.