Cold Shield Design for Stray Light Reduction
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Solution Overview
Problem
Existing cold shields in heat-seeking missiles are inadequate in reducing stray light transmission due to non-optimal surface orientations, scattering from curved surfaces, and large internal edges, which affect detector sensitivity and performance.
Innovation Solution
A cold shield design featuring alternating curved and linear profile regions coaxially aligned along the optical axis, with concave curved surfaces facing inward and linear surfaces facing outward, manufactured as a monolithic structure with sharp transitions to minimize scattering, and optionally coated with low-emissivity materials for enhanced thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple components are used to fabricate the cold shield, then manufacturing flexibility is improved, but internal edges between components become large and cause significant unpredictable scattering
Solution Approach 1:
The patent merges multiple separate cold shield components into a single monolithic structure. This eliminates the internal edges and interfaces between components that caused unpredictable scattering, while maintaining the functional benefits of a multi-region design through integrated curvature variations along the optical path.
2Object-affected harmful factors
If curved surfaces are added to reduce first-order scattering, then stray light reduction is improved, but scattering from curved surfaces increases
Solution Approach 1:
The patent applies different surface curvatures in different regions along the optical path. Specific curved surfaces are strategically positioned and shaped to redirect first-order scattered light away from the detector, while other regions maintain appropriate surface characteristics to minimize overall scattering. This localized optimization resolves the contradiction by making curvature serve the stray light reduction function without creating excessive scattering.
3Measurement precision
If detector sensitivity is increased, then heat-seeking performance is improved, but detector becomes more susceptible to stray light interference
Solution Approach 1:
The patent implements preliminary anti-action by designing the cold shield structure to preemptively block and redirect stray light paths before they can reach the detector. The alternating curved and linear profile regions are configured to intercept first-order scattered light and redirect it away from the detector field of view, thereby protecting the high-sensitivity detector from stray light interference before the interference can occur.
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 design effectively reduces first-order scattering and stray light transmission, improving detector sensitivity and heat-seeking performance by optimizing the shape and alignment of internal surfaces within the shield.
Implementation Method 1
cold shields primarily focus on reducing zero and first-order paths
Implementation Method 2
optionally coated with low-emissivity materials for enhanced thermal conductivity
Implementation Method 3
the placement and shape of curved surfaces within typical shields are often non-optimal with respect to reducing first-order scattering
Data Source
AI summary
A shield for use with a detector includes a first opening adjacent the detector, a second opening opposite the first opening along an optical axis intersecting the detector, and a field of view defined by the detector and the second opening. A shield body includes alternating curved profile regions and linear profile regions coaxially aligned along the optical axis. The curved profile regions have respective curved interior surfaces concave facing toward the second opening, and the linear profile regions have respective interior surfaces facing toward the first opening. In this way, specular reflections associated with stray light may be greatly reduced.