MEMS MMA Optical Sensor Eliminates Gimbal Volume

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Solution Overview

Problem

Conventional gimbaled optical sensors face inefficiencies in active transmit and receive capabilities due to signal loss, mechanical fragility, and limited wavelength support, particularly with fiber-based and free-space coupling methods, which restrict their volume, weight, and power constraints in constrained environments.

Innovation Solution

The implementation of a Micro-Electro-Mechanical System (MEMS) Micro-Mirror Array (MMA) that scans a narrow laser beam over a larger field of regard, eliminating the need for dual-axis gimbals and enabling compact, lightweight, and low-power optical sensors with adaptive beam correction and spectral diversity, allowing for both active illumination and detection within restricted volumes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fiber-based coupling is used to transmit laser beam through gimbal, then active transmit capability is provided, but signal loss occurs and mechanical fragility increases

Engineering Contradiction:

Improveactive transmit capabilityVSAvoidsignal loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the fiber coupling mechanism from the gimbal system and replaces it with direct free-space optical coupling. The laser beam is transmitted directly through the gimbal axes without being routed through fragile fiber optics, eliminating signal loss and mechanical fragility while maintaining active transmit capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical fiber-based coupling system with a free-space optical transmission system. Instead of using physical fiber optics that require precise mechanical alignment and are susceptible to damage, the system uses direct laser beam propagation through the gimbal, substituting a fragile mechanical system with a more robust optical path.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If dual-axis gimbal is used to scan laser beam and sensor FOV, then field-of-regard is extended, but device complexity and weight increase

Engineering Contradiction:

Improvefield-of-regardVSAvoidgimbal structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the scanning function from the traditional dual-axis gimbal mechanism. Instead of using complex mechanical gimbals to scan both the laser beam and sensor FOV, the system separates these functions: the laser beam is transmitted through the gimbal axes without mechanical scanning, while the sensor maintains its own FOV, achieving extended field-of-regard with reduced complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical dual-axis gimbal scanning system with a simplified optical path where the laser beam passes through the gimbal axes. The scanning capability is maintained through the gimbal's inherent ability to rotate, but the complexity of additional scanning mechanisms is eliminated, reducing device weight and complexity while preserving field-of-regard.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If off-gimbal laser transmitter is positioned behind bulkhead, then active illumination is provided, but volume and weight constraints are worsened

Engineering Contradiction:

Improveactive illumination capabilityVSAvoidsensor volume

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent merges the laser transmitter with the sensor volume by positioning it within the sensor compartment rather than behind a bulkhead. This integration eliminates the need for bulkheads and external positioning, reducing the overall volume and weight of the system while maintaining active illumination capability. The laser beam is routed through the sensor volume to achieve transmission without requiring additional space.

Inventive Principle:

Principle #5Merging (Combining)

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 approach significantly reduces the volume and weight of optical sensors while enhancing active illumination and detection capabilities, minimizing power consumption and avoiding the drawbacks of fiber-based systems, enabling robust and versatile operation in various platforms and environments.

Implementation Method 1

A micro-electro-mechanical system (MEMS) micro-mirror array is provided to scan a laser beam

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS11644542B2Optical sensor with MEMS MMA steered transmitter and staring detector

Publication Date: 2023.05.09 RAYTHEON CO

AI summary

An optical sensor uses a MEMS MMA to scan a narrow laser beam over a transmit FOR to provide active illumination and to correct the beam profile (e.g., collimate the beam, reduce chromatic aberrations, correct the beam profile or wavefront). A staring detector senses light within a receive FOR that at least partially overlaps the transmit FOR. By completely eliminating the dual-axis gimbal, this sensor architecture greatly reduces the volume and weight of the optical sensor while avoiding the deficiencies of known systems associated with either fiber or free-space coupling of the laser beam into an existing receiver.