Auxetic Optical Structure for Passive Thermal Focus Compensation
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Solution Overview
Problem
Conventional methods for addressing thermal stresses in optical systems, particularly in severe environments, are complex and expensive, leading to performance degradation due to thermal expansion and contraction of components.
Innovation Solution
Incorporation of auxetic structures within optical devices that passively counteract thermal expansion by physically reacting in a manner opposite to the thermal stress, maintaining the distance between optical components constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active compensation systems with motors and rails are used to adjust optics for thermal stress, then focus retention under thermal stress is improved, but device complexity and cost increase
Solution Approach 1:
The optical device uses passive athermalization where the optical elements and housing automatically compensate for thermal expansion through their inherent material properties and geometric design, eliminating the need for external active compensation systems. The system self-regulates focus under thermal stress without motors or rails.
Solution Approach 2:
The patent replaces the mechanical active compensation system (motors and rails) with a passive athermalization design that uses material science and optical geometry to achieve automatic focus retention. This substitutes complex mechanical actuation with inherent physical properties of the optical components.
2Device complexity
If conventional optical devices are used without athermalization, then device simplicity is maintained, but performance degrades under thermal stress
Solution Approach 1:
The patent applies passive athermalization by changing physical parameters such as the coefficients of thermal expansion of different optical elements and housing materials, and optimizing geometric parameters like element spacing and curvature. These parameter optimizations enable the system to maintain focus under thermal stress while remaining relatively simple in design.
3Device complexity
If passive athermalization through auxetic structures is implemented, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent incorporates athermalization design considerations during the preliminary design and manufacturing stages by selecting materials with specific thermal expansion properties and optimizing optical element geometries. This preliminary optimization of manufacturing parameters ensures that the passive athermalization works effectively without requiring complex assembly or adjustment procedures.
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
Achieves athermalization by minimizing or canceling out physical changes in optical systems, thereby maintaining optimal performance without the complexity and failure points of active compensation systems.
Implementation Method 1
the at least one optical device expands under the thermal load and increases the distance between at least one glass portion and at least one optical sensor plane
Implementation Method 2
The at least one auxetic structure expands under the thermal load and reduces the distance between at least one glass portion and at least one optical sensor plane
Data Source
AI summary
A method and device for passive athermalization in optical systems including at least one auxetic structure in at least one optical device. The at least one auxetic structure functions to counter or completely negate the increase in distance of at least one glass portion and at least one optical sensor plane of the optical device which results from expansion of the optical device when under a thermal load.