Non-contact Micro Mirrors Using Electrostatic Hinges

Solution Overview

Problem

Conventional micro mirror devices require mechanical stops to define tilt angles, leading to stiction issues and mechanical breakdowns, limiting their operational lifetime and material selection flexibility.

Innovation Solution

A micro mirror device with a hinge-supported mirror plate that uses electrostatic forces to tilt and hold the mirror plate at predetermined angles without mechanical stops, utilizing materials like titanium-nickel alloys and aluminum titanium nitride to achieve elastic restoration and reduced angular deflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mechanical stops are used to define tilt angles, then tilt angle definition is achieved, but stiction issues and mechanical breakdown occur

Engineering Contradiction:

Improvetilt angle definitionVSAvoiddevice lifetime

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent removes mechanical stops from the micro mirror device entirely. Instead of using physical mechanical stops to define tilt angles, the invention uses electrostatic forces to achieve precise angular positioning of the mirror plate without any mechanical contact, thereby eliminating stiction and mechanical breakdown while maintaining tilt angle definition

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical stop system with an electrostatic field-based positioning system. The controller applies electrostatic forces to the mirror plate to achieve precise angular positioning without mechanical contact, substituting mechanical angle definition with electrical field control to eliminate stiction and extend device lifetime

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If mechanical stops are used to define tilt angles, then tilt angle definition is achieved, but mechanical breakdown limits operational lifetime

Engineering Contradiction:

Improvetilt angle definitionVSAvoidoperational lifetime

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent removes mechanical stops from the micro mirror device entirely. Instead of using physical mechanical stops to define tilt angles, the invention uses electrostatic forces to achieve precise angular positioning of the mirror plate without any mechanical contact, thereby eliminating stiction and mechanical breakdown while maintaining tilt angle definition

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical stop system with an electrostatic field-based positioning system. The controller applies electrostatic forces to the mirror plate to achieve precise angular positioning without mechanical contact, substituting mechanical angle definition with electrical field control to eliminate stiction and extend device lifetime

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional materials are used for hinge, then fabrication is simple, but material selection flexibility is limited

Engineering Contradiction:

Improvefabrication simplicityVSAvoidmaterial selection flexibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the material parameters of the hinge by using materials with high elastic restoration capability and low stiction properties, such as titanium-nickel alloys and aluminum titanium nitride. These material parameter changes enable both simplified fabrication processes and expanded material selection flexibility while reducing angular deflection and eliminating stiction

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

This design simplifies the micro mirror structure, reduces stiction, extends device lifetime, allows for a wider range of materials, and enables higher operational frequencies by eliminating mechanical stops and minimizing hinge rotation.

Implementation Method 1

the hinge is configured to produce an elastic restoring force on the mirror plate when the mirror plate is tilted

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a controller that can produce an electrostatic force to overcome the elastic restoring force to tilt the mirror plate from the un-tilted position to an 'on' position or an 'off' position. The electrostatic force is configured to counter the elastic restoring force to hold the mirror plate at the 'on' position or the 'off' position

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS7586669B2Non-contact micro mirrors

Publication Date: 2009.09.08 SPATIAL PHOTONICS INC

AI summary

A micro mirror device includes a hinge supported by a substrate and a mirror plate tiltable around the hinge. The hinge is configured to produce an elastic restoring force on the mirror plate when the mirror plate is tilted away from an un-tilted position. The micro mirror device also includes a controller that can produce an electrostatic force to overcome the elastic restoring force to tilt the mirror plate from the un-tilted position to an “on” position or an “off” position. The electrostatic force can counter the elastic restoring force to hold the mirror plate at the “on” position or the “off” position.