Active Hinge Rack and Pinion for Micromirror Tilting

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Solution Overview

Problem

Existing micromechanical devices lack a practical method to precisely raise or tilt structures to arbitrary angles relative to a supporting substrate, especially for volume production, as current approaches are either batch-fabricated or require individualized assembly using mechanical forces.

Innovation Solution

An active hinge apparatus with an axle, teeth, and a rack system operated by an actuator, such as an electrostatic or thermal actuator, allows for the compact and precise tilting of micromechanical structures like plates or micromirrors on a substrate, enabling them to be raised to arbitrary angles, including 90 degrees, using conventional surface micromachining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional batch-fabrication methods are used to erect micromechanical structures, then volume production is achieved, but the structures cannot be raised to arbitrary angles with respect to the substrate

Engineering Contradiction:

Improvevolume productionVSAvoidability to raise to arbitrary angles

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The invention transforms static batch-fabricated structures into dynamically adjustable configurations by introducing an active hinge mechanism with a rack and pinion system. The micromechanical structures can be dynamically raised to arbitrary angles while maintaining volume production capabilities through integrated actuation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The active hinge apparatus serves as an intermediary mechanism between the substrate and the micromechanical structures. It provides the functional linkage that enables angle adjustment, mediating between the fixed substrate and the movable structures to achieve both volume production and angular versatility.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If individualized assembly using micromanipulator probes is used to erect micromechanical structures, then arbitrary angles can be achieved, but the approach is not suitable for volume production

Engineering Contradiction:

Improveability to raise to arbitrary anglesVSAvoidvolume production

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention enables self-service assembly by integrating the actuation mechanism directly onto the substrate. The active hinge apparatus with its rack and pinion system allows structures to be raised to arbitrary angles through integrated actuators, eliminating the need for external micromanipulator probes and enabling scalable volume production.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention merges the assembly function and the actuation function into a single integrated apparatus. The active hinge mechanism combines the structural support function with the angle-adjustment function, allowing both volume production and arbitrary angle positioning to be achieved through a unified system.

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If an active hinge apparatus with rack and pinion system is used, then precise tilting to arbitrary angles is achieved, but the device complexity increases

Engineering Contradiction:

Improveprecise tilting to arbitrary anglesVSAvoidstructure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention segments the tilting function into discrete rotational steps through the rack and pinion mechanism. The pinion gear divides the continuous rotation into controlled angular increments, achieving precise positioning while maintaining a relatively simple mechanical structure that can be integrated into the micromechanical system.

Inventive Principle:

Principle #1Segmentation

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 active hinge apparatus enables precise and efficient tilting of micromechanical structures, facilitating volume production by allowing for the compact fabrication and operation of micromechanical devices like tiltable plates or micromirrors, which can be locked in desired positions, enhancing the versatility of micromechanical systems.

Implementation Method 1

The active hinge apparatus can be operated by an electrostatic actuator

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

The active hinge apparatus can be operated by a thermal actuator

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS7421924B1Apparatus for raising or tilting a micromechanical structure

Publication Date: 2008.09.09 NATIONAL TECHNOLOGY & ENGINEERING SOLUTIONS OF SANDIA LLC

AI summary

An active hinge apparatus is disclosed which can be used to raise a micromechanical structure (e.g. a plate or micromirror) on a substrate. The active hinge apparatus utilizes one or more of teeth protruding outward from an axle which also supports the micromechanical structure on one end thereof. A rack is used to engage the teeth and rotate the axle to raise the micromechanical structure and tilt the structure at an angle to the substrate. Motion of the rack is provided by an actuator which can be a mechanically-powered actuator, or alternately an electrostatic comb actuator or a thermal actuator. A latch can be optionally provided in the active hinge apparatus to lock the micromechanical structure in an “erected” position.