Hindle Lens Array Alignment for Large Telescope Mirror Testing
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Solution Overview
Problem
Traditional Hindle-based optical test systems for large telescopes face challenges with high cost, weight, and limited flexibility due to the use of fixed concave mirrors, which hinder accurate wavefront testing and alignment.
Innovation Solution
A Hindle lens array comprising a plurality of individually adjustable lenses, supported by a frame structure and hexapod mounting mechanism, allows for real-time adjustability and adaptive corrections, replacing the traditional Hindle concave mirror for precise wavefront measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional Hindle concave mirror is used for optical testing, then wavefront measurement capability is achieved, but the system suffers from high cost, excessive weight, and limited flexibility
Solution Approach 1:
The patent divides the traditional monolithic Hindle mirror into an array of multiple smaller lens elements. Each lens element independently contributes to wavefront measurement, allowing the system to achieve the required measurement precision while significantly reducing the weight and complexity of individual components. The segmented structure enables modular assembly and easier handling compared to a single large mirror.
Solution Approach 2:
The patent replaces the traditional mechanical/optical Hindle mirror system with a lens array that uses refraction instead of reflection. This substitution fundamentally changes the optical mechanism from mechanical reflection off a heavy mirror to optical refraction through lighter lens elements, achieving the same wavefront measurement function with reduced weight and increased flexibility.
2Device complexity
If a fixed Hindle mirror is used, then optical test setup is simplified, but adaptability to different optical configurations is limited
Solution Approach 1:
The patent transforms the static, fixed Hindle mirror into a dynamic, adjustable lens array. Each lens element can be independently positioned and oriented, allowing the system to adapt to different optical configurations and testing requirements. This dynamic adjustability maintains operational simplicity while dramatically increasing versatility compared to a fixed mirror system.
Solution Approach 2:
The lens array is designed to perform multiple functions: it can test different optical configurations, accommodate various mirror types, and provide adjustable measurement parameters. This universal design allows a single system to replace multiple specialized fixed mirror setups, achieving adaptability without proportionally increasing overall system complexity.
3Measurement precision
If a large Hindle mirror is fabricated to reduce segmentation, then measurement accuracy improves, but manufacturing cost and difficulty increase significantly
Solution Approach 1:
Instead of fabricating one large, complex Hindle mirror, the patent segments the optical function across multiple smaller, simpler lens elements. Each lens can be manufactured using standard optical fabrication techniques with tighter tolerances, which is more feasible and cost-effective than creating a single large precision mirror. The collective array achieves the required overall measurement accuracy.
Solution Approach 2:
The patent changes the fundamental optical parameter from reflection (mirror) to refraction (lens). This parameter change allows the use of different manufacturing processes and materials that are more accessible and less costly than large precision mirror fabrication. The lens array achieves equivalent measurement precision through refractive optics with more manageable manufacturing requirements.
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 Hindle lens array provides enhanced flexibility, precision, and efficiency in wavefront testing by allowing for modular assembly and real-time optical alignment, ensuring high-precision optical performance in large-scale telescope applications.
Implementation Method 1
a plurality of lens assemblies having a central lens assembly and a plurality of peripheral lens assemblies, where the plurality of lens assemblies is configured to direct a test wavefront toward the secondary mirror system
Implementation Method 2
reflecting the test wavefront back through the Hindle lens array after interaction with the secondary mirror system
Implementation Method 3
analyzing the reflected test wavefront using an interferometer to measure optical aberrations in the secondary mirror system
Data Source
AI summary
A Hindle lens array for performing a Hindle test on a secondary mirror system of a telescope includes a plurality of lens assemblies, each housed within a frame structure that supports the lenses in an optically aligned configuration. The lens assemblies include a central lens and a plurality of peripheral lenses. The frame structure is secured using an adjustable hexapod, providing six degrees of freedom for fine alignment with the secondary mirror system. The Hindle lens array is an alternative to a single large Hindle mirror, mitigating weight-induced sagging and providing improved optical performance through modular alignment capabilities. In a method of performing a Hindle test using the Hindle lens array, a test wavefront is introduced, reflected, and analyzed to measure and correct wavefront distortions.