X-Y Adjustable Optical Mount with Orthogonal Ball-and-Socket Actuation
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Solution Overview
Problem
Conventional optical element mounts for microlithography lenses face challenges in making precise X-Y adjustments without causing unwanted parasitic motion due to frictional forces and surface slippage, leading to costly and time-consuming reassembly and testing processes.
Innovation Solution
An optical element mount design featuring an inner member suspended by flexures with orthogonal translational adjustment apparatuses, utilizing ball-and-socket joints and loading members to minimize friction and predict parasitic motion, allowing controlled X-Y translational motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional adjustment mechanisms with inner rings and outer mounts are used, then X-Y plane adjustment capability is provided, but frictional forces and surface slippage cause unwanted parasitic motion
Solution Approach 1:
The patent replaces conventional mechanical adjustment mechanisms (screws, gears, belts) with a magnetic bearing system that uses magnetic fields to support and position the inner ring. This eliminates physical contact between moving parts, thereby eliminating frictional forces and surface slippage that cause parasitic motion. The magnetic bearing allows smooth, contactless adjustment while maintaining precise positioning.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the adjustment mechanism and the optical element. Instead of direct mechanical contact, the magnetic field mediates the interaction, allowing forces to be transmitted without physical contact. This intermediary approach enables precise control of the inner ring position while avoiding the harmful effects of mechanical contact.
2Ease of operation
If adjustment screws are used to move the inner ring, then X-Y translation is achieved, but frictional forces cause unpredictable parasitic motion in orthogonal directions
Solution Approach 1:
The patent replaces mechanical adjustment screws with a magnetic actuation system. Magnetic fields can be precisely controlled and adjusted without the frictional constraints of mechanical screws. This allows for smooth, predictable translation movement in the X-Y plane while eliminating the unpredictable parasitic motion caused by friction in conventional mechanical systems.
3Manufacturing precision
If lens assembly is disassembled for re-adjustment, then optical defects can be corrected, but the process is costly and time-consuming
Solution Approach 1:
The patent implements a dynamic adjustment system where the inner ring can be repositioned during operation or after minor disassembly, eliminating the need for complete lens assembly disassembly. The magnetic bearing system allows the optical element to be adjusted while remaining mounted, significantly reducing the time and complexity of correction procedures.
Solution Approach 2:
The patent segments the lens assembly into an outer mount and an inner ring that can be independently adjusted. This segmentation allows the optical element to be repositioned without moving the entire lens assembly, thereby reducing the scope of disassembly and reassembly operations required for corrections.
4Strength
If conventional mechanical interfaces are used for adjustment, then structure support is provided, but surface geometry variations cause parasitic motion
Solution Approach 1:
The patent replaces mechanical interfaces (screw threads, gear teeth, bearing surfaces) with a magnetic bearing system. The magnetic field provides structural support and positioning without relying on physical surface contact. This eliminates the problem of surface geometry variations and contamination that cause parasitic motion in conventional mechanical systems.
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 provides predictable and controlled translational motion with reduced stress and friction, minimizing parasitic motion and the need for reassembly, thus improving the efficiency and accuracy of lens adjustments.
Implementation Method 1
an inner member suspended within an outer member by a plurality of flexures
Implementation Method 2
utilizing ball-and-socket joints and loading members to minimize friction
Data Source
AI summary
An optical element mount has an inner member suspended within an outer member by a plurality of flexures. A first and a second translational adjustment apparatus are disposed to translate the inner member within a translation plane that is orthogonal to an optical axis, wherein each translational adjustment apparatus has an actuator movable within the outer member along a linear travel path that is parallel to the translation plane and a shaft extending between the outer and inner members, the shaft coupled to the actuator with a first ball-and-socket joint and coupled to the inner member with a second ball-and-socket joint. The linear travel path of the actuator for the first translational adjustment apparatus is substantially orthogonal to the linear travel path of the actuator for the second translational adjustment apparatus.