Micro-mirror Array with Segmented Electrodes and Stoppers

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current micro-mirror array devices face challenges in achieving high accuracy and resolution due to identical micro-mirror elements, which require complex manufacturing and suffer from asymmetrical performance, charge build-up, and compromised sensitivity due to shared electrodes for actuation and measurement.

Innovation Solution

A micro-mirror array device with sections of varying properties, featuring distinct tilt angle ranges defined by stoppers of different heights and separate actuation and measurement electrodes, allowing for optimized performance and simplified electronics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If all micro-mirror elements are made identical to simplify manufacturing, then manufacturing complexity is reduced, but manufacturing precision and tilt angle accuracy deteriorate

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidtilt angle accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by making each micro-mirror element unique with customized tilt axes and actuation electrode configurations tailored to specific tilt angle requirements. Different sections of the array have different properties, allowing each element to be optimized for its specific function while maintaining overall manufacturing feasibility through systematic design approaches.

Inventive Principle:
Principle #3Local quality

2Device complexity

If electrodes are used for both actuation and measurement to reduce device complexity, then device complexity is reduced, but measurement precision and sensitivity deteriorate

Engineering Contradiction:
Improveelectrode configuration simplicityVSAvoidtilt angle measurement sensitivity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the electrode functions by providing separate actuation electrodes and separate measurement electrodes for each micro-mirror element. This segmentation allows each electrode type to be optimized for its specific function - actuation electrodes for precise tilt control and measurement electrodes for accurate tilt angle detection - thereby improving measurement precision while the systematic arrangement keeps overall device complexity manageable.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If electrodes are shaped as stoppers to limit micro-mirror movement, then device complexity is reduced, but reliability deteriorates due to charge build-up

Engineering Contradiction:
Improvestructure simplicityVSAvoidoperational stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the stopper function from the electrode structures by introducing separate mechanical stoppers that are decoupled from the actuation and measurement electrodes. This separation eliminates the charge build-up problem that occurs when electrodes serve as stoppers, as the mechanical stoppers can be designed with conductive coatings or grounding to dissipate charges, thereby improving reliability while keeping the overall structure simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces mechanical stoppers as intermediary elements that mediate between the electrostatic actuation system and the micro-mirror movement limits. These stoppers provide the physical movement limits without being part of the electrical actuation system, eliminating the charge build-up issue while maintaining the ability to limit micro-mirror movement effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If segmented electrodes are used to control each micro-mirror portion, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvesurface profile controlVSAvoidelectronic circuit complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing separate actuation electrodes on each side of the tilt axis that can be independently controlled to achieve desired surface profiles and tilt angles. This localized control allows precise manipulation of each micro-mirror element's orientation and shape, with the electronic circuit complexity managed through systematic addressing schemes and control strategies.

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 enables precise control of tilt angles, improved sensitivity, and reduced complexity in electronics, enhancing the accuracy and flexibility of micro-mirror arrays for applications like variable focal length lenses.

Implementation Method 1

at least one actuation electrode arranged on each side of said at least one tilt axis

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

at least one measurement electrode decoupled from said at least one actuation electrode and from said at least one stopper, which at least one measurement electrode is arranged on each side of said at least one tilt axis for measuring a capacitance induced by a change in tilt angle

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

each micro-mirror element further comprises at least one stopper having a conductive coating

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2805199B1Improvements in or relating to micro-mirror arrays
Publication Date: 2017.05.03 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP2805199B1 patent drawingFigure 1
  • EP2805199B1 patent drawingFigure 2
  • EP2805199B1 patent drawingFigure 3

AI summary

Described herein is a variable focal length lens comprising a polar grid micro-mirror array (100) having a plurality of micro-mirror elements arranged in a plurality of radii (110, 120, 130, 140, 150, 160, 170, 180) around a central micro-mirror element (190). The grid is divided into an inner section comprising micro-mirror elements in the three innermost radii (160, 170, 180) together with the central micro-mirror element (190) and an outer section comprising micro-mirror elements in the five outermost radii (110, 120, 130, 140, 150). Each micro-mirror element in the inner section (160, 170, 180, 190) has a different tilt angle to the micro-mirror elements in the outer section (110, 120, 130, 140, 150). The difference in tilt angles is provided by different stoppers of different heights.