MWIR Orthoscopic Lens Aberration Correction
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Solution Overview
Problem
Current mid-wave infrared (MWIR) lenses for airborne applications suffer from distortion issues, inability to correct for monochromatic and chromatic aberrations, and lack of cold shield efficiency, which affects image quality and compatibility with high-resolution infrared detectors.
Innovation Solution
A lens assembly with a low F-number and long focal length, utilizing two types of optical glass materials, specifically Germanium and Silicon, to minimize complexity, weight, and cost, while correcting for both monochromatic and chromatic aberrations over the 4900 nm to 3300 nm wavelength range, and incorporating a cold shield for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If current MWIR lenses are used to achieve wide field of view, then the field of view is improved, but image distortion occurs (pincushion or barrel distortion)
Solution Approach 1:
The lens assembly is divided into multiple optical elements (at least three elements) with different optical powers and material properties. Each element contributes to correcting specific types of distortion, allowing the system to achieve wide field of view while maintaining orthoscopy through cumulative correction effects
Solution Approach 2:
The patent employs optical elements made from different materials (such as Germanium and Silicon) with distinct refractive indices and dispersion characteristics. This composite material approach enables correction of both monochromatic and chromatic aberrations simultaneously while maintaining wide field of view and minimizing distortion
2Device complexity
If lens complexity is reduced to minimize weight and cost, then manufacturing simplicity is improved, but ability to correct aberrations deteriorates
Solution Approach 1:
The patent optimizes specific parameters including F-number (low F-number design), focal length, and the distribution of optical power among elements. By carefully selecting these parameters, the system achieves effective aberration correction with a streamlined design that minimizes complexity while maintaining correction capability
Solution Approach 2:
The invention extracts and addresses only the essential aberration correction requirements for MWIR applications, focusing on the most critical corrections (monochromatic and chromatic aberrations) rather than attempting to correct all possible optical defects, thereby achieving adequate correction with reduced complexity
3Measurement precision
If focal length is increased to improve spatial resolution, then resolution is improved, but lens size and weight increase
Solution Approach 1:
The patent employs a low F-number design that allows for a shorter physical lens structure while maintaining the effective focal length needed for high spatial resolution. This parameter optimization enables achieving resolution requirements without proportionally increasing lens weight
Solution Approach 2:
By using lightweight infrared-transparent materials such as Germanium and Silicon with optimized thicknesses, the lens achieves the necessary focal length for high resolution while minimizing weight through material selection rather than simply reducing focal length
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 solution provides an orthoscopic lens assembly with residual distortion less than 0.03% over a full field of view, achieving high resolution and wide field of view, suitable for aerial reconnaissance and surveillance, and compatible with high-resolution infrared detectors.
Implementation Method 1
lenses of optical systems must have a specific focal length to entrance pupil diameter ratio (F #) to obtain fine spatial resolution while also providing a suitable energy flux to image plane detectors
Implementation Method 2
In order to have an imaging without stray light or narcissus, MWIR projection lens should include approximately 100% cold shield efficiency
Data Source
AI summary
A mid-wave infrared (MWIR) lens assembly that may include a first set of optical elements, wherein each optical element of the first set of optical elements is a positive optical power. MWIR lens assembly may also include a second set of optical elements, wherein each optical element of the second set of optical elements is a negative optical power. MWIR lens assembly may also include that at least one optical element of the first set of optical elements is formed of a first optical glass material, at least another optical element of the first set of optical elements is formed of a second optical glass material, and at least one optical element of the second set of optical elements is formed of a third optical glass material wherein the second optical glass material is different than the first optical glass material and the third optical glass material.