Curved Reflector MEMS Scanner for Ultra-Wide Angle Beam Rotation

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Solution Overview

Problem

Conventional optical microscanners using rotating micromirrors are limited to rotation angles of ±10 degrees, restricting their application in achieving wide rotation angles required for advanced imaging and scanning technologies.

Innovation Solution

The development of an optical microscanner with a moveable mirror and a curved reflector, where the linear displacement of the mirror is transformed into angular rotation of the reflected beam, enabling wide rotation angles up to 180 degrees or more, using MEMS technology and silicon on insulator (SOI) wafer fabrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional rotating micromirrors are used, then the device structure is simple and easy to manufacture, but the rotation angle is limited to ±10 degrees

Engineering Contradiction:

Improveease of manufactureVSAvoidrotation angle

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent employs a curved reflector with a spherical or elliptical surface instead of a flat mirror. This curvature enables the conversion of linear mirror displacement into angular beam rotation, achieving wide scanning angles (±45 degrees or more) while maintaining a simple linear actuation mechanism. The curved surface geometry is specifically designed to transform the linear motion of the MEMS mirror into the desired angular deflection of the reflected beam.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The curved reflector acts as an intermediary element between the linearly actuated MEMS mirror and the optical beam. It mediates the transformation from linear displacement to angular rotation, enabling the system to achieve wide scanning angles without requiring complex rotational mechanisms or special materials. This intermediary component simplifies the overall system architecture while expanding the operational range.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If special materials like polyamides or magnetic materials are used to achieve wide rotation angles, then the rotation angle can reach 45 or 50 degrees, but the device complexity and fabrication difficulty increase

Engineering Contradiction:

Improverotation angleVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical rotational mechanisms with a simpler linear actuation system combined with a curved reflector. Instead of using special materials (polyamides, magnetic materials) that require complex fabrication processes, the invention uses standard MEMS linear actuators with a geometrically curved reflecting surface. This substitution maintains the desired wide scanning angles while dramatically simplifying the device structure and fabrication process, using conventional semiconductor manufacturing techniques.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the rotation angle is increased to achieve wide scanning coverage, then the application range expands, but the manufacturing precision requirements increase

Engineering Contradiction:

Improverotation angleVSAvoidmanufacturing precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent achieves wide scanning angles by changing the geometric parameters of the curved reflector (radius of curvature, surface profile) rather than increasing the rotation amplitude of the mirror itself. This parameter transformation allows the system to achieve ±45 degrees or more scanning coverage with small, precise linear displacements of the MEMS mirror, thereby reducing the manufacturing precision requirements compared to achieving the same angular range through large rotational movements.

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 solution allows for the creation of ultra-wide angle optical scanners suitable for applications like bar code readers, laser projection systems, and imaging devices, reducing the need for arrays of detectors and enabling cost-effective, high-resolution imaging and spectrometry.

Implementation Method 1

Different actuation forces have also been suggested, such as utilizing electrothermal force through structure bending or electrostatic force through a comb drive actuator

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

the curved reflector transforms the lateral displacement of the reflected beam into an angular rotation of the second reflected beam

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS8411340B2Ultra-wide angle MEMS scanner architecture

Publication Date: 2013.04.02 SI WARE SYSTEMS INC(EG)

AI summary

An optical microscanner achieves wide rotation angles utilizing a curved reflector. The optical microscanner includes a moveable mirror for receiving an incident beam and reflecting the incident beam to produce a reflected beam and a Micro Electro-Mechanical System (MEMS) actuator that causes a linear displacement of the moveable mirror. The curved reflector produces an angular rotation of the reflected beam based on the linear displacement of the moveable mirror.