Digital Micro-Mirror Device for Dual-Wavelength Imaging

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Solution Overview

Problem

Traditional imaging systems face challenges in capturing images in two distinct wavelength ranges without parallax error, requiring separate apertures or beam splitters, which can be cumbersome and prone to calibration issues.

Innovation Solution

An imaging system with a single aperture and a digital micro-mirror device (DMD) that selectively reflects light between two focal plane arrays (FPAs) for long-wave infrared (LWIR) and short-wave infrared (SWIR) ranges, allowing for adjustable mirror states to direct light to either FPA, reducing the need for mechanical shutters and minimizing light reflection back into the aperture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two separate apertures are used to capture light in two distinct wavelength ranges, then each FPA can be optimized for its specific wavelength range, but the device complexity increases and parallax error occurs

Engineering Contradiction:

Improvewavelength detection precisionVSAvoidaperture structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines two separate aperture systems into a single aperture that serves both wavelength ranges. The DMD device acts as a dynamic beam splitter, directing different wavelength ranges to respective FPAs through electronic control rather than physical separation, thereby reducing structural complexity while maintaining dual-wavelength detection capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single aperture is designed to be universal for both LWIR and SWIR wavelength ranges. The DMD device enables the single aperture to function for multiple wavelength ranges by dynamically routing light to appropriate FPAs, eliminating the need for separate apertures optimized for specific wavelengths

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a beam splitter is used to separate light into two wavelength ranges, then dual wavelength detection is achieved, but calibration issues arise and device complexity increases

Engineering Contradiction:

Improvedual wavelength detection capabilityVSAvoidcalibration stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the mechanical beam splitter system with an electronically controlled DMD device. The DMD uses electrostatic actuation to tilt mirrors, providing dynamic wavelength routing without mechanical moving parts that require calibration, thereby improving reliability while maintaining dual-wavelength detection versatility

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system transitions from a static beam splitter to a dynamic DMD device that can electronically reconfigure light routing in real-time. The mirrors can be tilted to different angles to direct different wavelength ranges to appropriate FPAs, providing adaptive wavelength selection without mechanical calibration requirements

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If mechanical shutters are used to direct light to different FPAs, then wavelength selection is achieved, but the system becomes cumbersome and calibration is difficult

Engineering Contradiction:

Improvewavelength switching capabilityVSAvoidshutter mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces mechanical shutters with a DMD device that uses electrostatic fields to control mirror tilting. This electronic control mechanism eliminates cumbersome mechanical shutter assemblies while providing precise wavelength selection capability through voltage control of mirror angles

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system controls wavelength routing by changing the electrical voltage parameter applied to the DMD mirrors. By adjusting the voltage, mirrors tilt to different angles, dynamically switching which wavelength range is directed to which FPA, replacing mechanical shutter position changes with electrical parameter changes

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 configuration enables reduced parallax error, quicker calibration, and improved image quality by allowing simultaneous capture of images in multiple wavelength ranges with reduced noise and light detection issues.

Implementation Method 1

A digital micro-mirror device (DMD) is angled with respect to the optical axis and optically coupled to the primary lens to selectively reflect light entering the primary aperture to at least one of the first FPA or the second FPA

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS9671281B2Imaging systems with digital micromirror devices (DMD)

Publication Date: 2017.06.06 SENSORS UNLIMITED INC

AI summary

An imaging system includes an imager housing having a primary aperture defining an optical axis. A primary lens is disposed over the primary aperture. A first focal plane array (FPA) is within the imager housing. A second FPA is within the imager housing. A digital micro-mirror device (DMD) is angled with respect to the optical axis and optically coupled to the primary lens to selectively reflect light entering the primary aperture to at least one of the first FPA or the second FPA.