Bendable Lap Apparatus for Aspheric Optic Polishing
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Solution Overview
Problem
The manufacturing of aspheric optics is challenging due to the lack of surface symmetry, leading to mismatch issues between rigid laps and optics, which results in increased fabrication cycle time, reduced localized figure quality, and adverse edge effects, especially in segmented primary mirror designs.
Innovation Solution
A bendable lap apparatus with a shell and torque actuators that can be deformed into desired bending profiles using a control system, allowing for efficient removal of high spatial frequency errors and improved edge quality by applying bending moments and tensioning systems to match the aspheric shape of the optic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid full-aperture lap is used for grinding and polishing aspheric optics, then the lap can maintain constant shape and provide rigidity, but it creates a mismatch in shape between the lap and the optic leading to increased fabrication cycle time and reduced localized figure quality
Solution Approach 1:
The patent applies dynamics by transforming the rigid, static lap into a dynamic, adaptable structure. The lap is divided into multiple independently controllable segments that can be actuated to change their shape and position in real-time, allowing the lap to dynamically conform to the aspheric optic surface while maintaining rigidity where needed.
Solution Approach 2:
The patent divides the full-aperture lap into multiple smaller segments or petals. This segmentation allows each segment to be independently actuated and positioned, enabling the lap to match the complex aspheric surface geometry while maintaining overall structural rigidity and reducing shape mismatch errors.
2Manufacturing precision
If smaller laps are used to reduce mismatch error between the lap and optic, then the localized figure quality may improve, but the fabrication cycle time increases and adverse edge effects occur
Solution Approach 1:
The patent merges the advantages of small laps (reduced mismatch error) with the advantages of large laps (full aperture coverage, reduced edge effects). By segmenting and independently actuating multiple small segments across the full aperture, the system achieves the precision of small laps while maintaining the productivity and edge quality of large laps.
3Manufacturing precision
If the lap is made more rigid to remove high spatial frequency errors, then the amplitude of surface errors can be reduced, but the lap cannot adapt to aspheric shapes leading to mismatch issues
Solution Approach 1:
The patent applies local quality by giving different segments of the lap independent control capabilities. Each segment can be locally actuated to achieve the precise rigidity and shape needed for that specific region of the optic, allowing high spatial frequency errors to be removed while adapting to the overall aspheric geometry.
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 apparatus effectively addresses the symmetry mismatch by allowing the lap to be deformed to match the optic's shape, improving the removal of high spatial frequency errors and edge quality, reducing cycle time, and enhancing the overall polishing process.
Implementation Method 1
The plurality of torque actuators apply bending moments to the edge of the shell
Implementation Method 2
The apparatus also includes a tensioning system attached to the top surface of the shell at the outer edge such that the tensioning system applies further bending moments to the edge of the shell
Implementation Method 3
a shell having known structural parameters and adapted to be bent into desired bending profiles
Data Source
AI summary
An apparatus, system and method for grinding or polishing an optic is provided. The apparatus includes a shell adapted to a bending profile, torque actuators attached at an outer edge of the shell and coupled to each other, a tensioning system attached at the outer edge of the shell, and a control system for computing the bending profile and controlling the torque actuators and tensioning system. The torque actuators and tensioning system apply bending moments to the edge of the shell to adapt the shell according to the bending profile provided by the control system. A calibration system further corrects errors in a measured bending profile.