Mm-wave Schmidt Imager Using Planar Correctors

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing millimeter-wave optical imaging systems are weight-sensitive due to heavy lenses, which hinder their application in weight-critical imaging applications while maintaining performance in wide fields of view, fast optical speed, and low aberrations.

Innovation Solution

The implementation of a lightweight millimeter-wave optical imaging system utilizing a catadioptric design with a planar corrector configured as a diffraction grating or Fresnel lens, coupled with a highly curved primary mirror and an immersion lens, which reduces weight while maintaining performance by using a two-dimensional array sensor and a transceiver for efficient radiation focusing and direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional lenses are used in mm-wave imaging systems, then imaging performance (wide field of view, fast optical speed, low aberrations) is achieved, but system weight increases significantly

Engineering Contradiction:

Improveimaging performanceVSAvoidsystem weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the physical state and properties of optical elements by using metamaterials with negative refractive index and transforming traditional lenses into planar structures (diffraction gratings and Fresnel lenses). This parameter transformation maintains the optical functionality while dramatically reducing the weight and physical volume of the imaging system.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces heavy mechanical lens structures with planar optical elements including diffraction gratings and Fresnel lenses. These planar structures achieve the same optical focusing and directing functions without the bulk and weight of traditional curved lenses, effectively substituting mechanical optical systems with lighter planar alternatives.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Weight of moving object

If lens weight is reduced for weight-sensitive applications, then system weight decreases, but imaging performance (field of view, optical speed, aberration control) may deteriorate

Engineering Contradiction:

Improvesystem weightVSAvoidimaging performance

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent employs composite optical systems combining multiple elements: a primary mirror, immersion lens, diffraction grating, and Fresnel lens. This composite approach distributes the optical functions across different components, allowing each element to be optimized for weight reduction while maintaining collective imaging performance through synergistic interaction of the composite system.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent segments the optical system into distinct functional components: a primary mirror for initial radiation collection, an immersion lens for focusing, a diffraction grating for wavelength-based direction, and a Fresnel lens for additional focusing. This segmentation allows each component to be independently optimized for minimal weight while preserving overall system performance through proper functional distribution.

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 system achieves significant weight reduction while maintaining a wide field of view, compact optical form, and fast optical speed, enabling robust imaging with reduced aberrations and distortion, suitable for weight-sensitive applications.

Implementation Method 1

a diffraction grating configured to receive and direct the electromagnetic radiation towards the primary mirror

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

a Fresnel lens configured to receive and direct the electromagnetic radiation towards the primary mirror

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

a positive power primary mirror configured to reflect the electromagnetic radiation towards the immersion lens

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 4

an immersion lens directly coupled to the imaging detector and configured to focus the electromagnetic radiation onto the imaging detector

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS11431921B2Mm-wave short flat-field Schmidt imager using one or more diffraction grating(s) and/or Fresnel lens(s)

Publication Date: 2022.08.30 RAYTHEON CO

AI summary

A millimeter-wave optical imaging system including an imaging detector located at a focal plane of the optical imaging system, the imaging detector being responsive to electromagnetic radiation in wavelength range of approximately 5-50 millimeters, an immersion lens directly coupled to the imaging detector and configured to focus the electromagnetic radiation onto the imaging detector, wherein the focal plane is located on a planar surface of the immersion lens and the imaging detector is directly coupled to the planar surface, a positive power primary mirror configured to reflect the electromagnetic radiation towards the immersion lens, and one of a Fresnel lens or a diffraction grating configured to receive and direct the electromagnetic radiation towards the primary mirror.