Convex-Concave Mirror Assembly for Rocket Homing Abrasion Protection
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Solution Overview
Problem
Self-propelled vehicle homing devices' optical inputs are prone to malfunction due to exposure to high-speed air flows and dense particles, which cause abrasion, and existing solutions like using sapphire windows are not transparent to all thermal radiation wavelengths or are costly and increase mass.
Innovation Solution
A radiation collection optical assembly featuring a convex mirror and a concave mirror with a central opening, where the convex mirror is exposed to the external fluid and reflects radiation through a transparent porthole, while the concave mirror is protected from abrasion and the fluid is deflected, allowing for a robust and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sapphire window is used in front of the optical input, then abrasion resistance and thermal resistance are improved, but transparency to thermal radiation at 10 μm wavelength is lost
Solution Approach 1:
The optical input is divided into two separate components: a convex mirror for protection and a porthole for radiation transmission. This segmentation allows each component to be optimized for its specific function without compromise.
Solution Approach 2:
Instead of placing a transparent window in front of the optical input, the patent inverts the approach by placing a reflective convex mirror in front. This mirror serves as the protective element rather than a transparent window, fundamentally changing the protective mechanism.
2Reliability
If an ejection cap or formwork is used during transport, then protection during carrier aircraft transport is improved, but cost and total mass transported increase
Solution Approach 1:
The convex mirror serves multiple functions simultaneously: it protects the optical input from particles during high-speed flight, reflects thermal radiation onto the detector, and provides structural support. This eliminates the need for separate protective caps or formworks during transport.
Solution Approach 2:
The protective function and the optical function are merged into a single component - the convex mirror. This integration eliminates the need for separate protective elements that would increase mass and cost.
3Reliability
If a convex mirror is exposed to high-speed air flow and particles, then abrasion protection for internal components is improved, but the mirror itself becomes subject to degradation
Solution Approach 1:
The convex mirror is designed as a replaceable protective element that can be easily replaced if degraded by particle abrasion. This is economically acceptable because the mirror is simpler and less expensive than the internal optical components it protects.
Solution Approach 2:
The convex mirror acts as an intermediary element between the harsh external environment and the sensitive internal optical components. It absorbs the harmful effects of particle impact, protecting the more valuable internal components from damage.
4Temperature
If the optical input is exposed to high-speed air flow, then cooling effect is improved, but particle impact causes malfunction
Solution Approach 1:
The patent converts the harmful high-speed air flow into a beneficial cooling mechanism for the internal components. The air flow passing through the optical assembly provides passive cooling, while the convex mirror protects against particle damage.
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 ensures proper operation of the homing device by protecting optical components from abrasion and maintaining spectral transparency, reducing weight and manufacturing costs, while effectively collecting electromagnetic radiation across various wavelengths.
Implementation Method 1
a convex mirror (1), which has a reflective face and an optical axis
Implementation Method 2
a concave mirror (2), which is arranged in front of the reflective face of the convex mirror and facing the latter
Data Source
Figure 1~2
AI summary
An optical radiation-collecting assembly (10) comprising a convex mirror (1), a concave mirror (2) with a central opening (O) and a window (3), which are arranged such that light passes through the opening in the concave mirror, is reflected first by the convex mirror and then by the concave mirror, and subsequently passes through the window. The optical assembly is suitable for use in a homing device for guiding a rocket, preventing an optical input component of such a device from being damaged and rendered inoperative from abrasion when exposed to a high-speed air flow containing dense particles. The optical assembly also includes an image-forming function.