Projection Exposure Optical System with Decoupling Bushing
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Solution Overview
Problem
The misalignment of optical elements in projection exposure apparatuses due to unfavorable friction conditions and production deviations leads to unwanted deformation, which can be caused by parasitic forces and torques generated by spherical-cap-shaped spacers, resulting in angular errors and misalignment between the optical element and the sensor frame.
Innovation Solution
An optical system with a decoupling bushing featuring a decoupling groove that mechanically decouples the optical element from the sensor frame, reducing rigidity and preventing the transfer of forces or torques, thereby compensating for angular errors and ensuring optimal positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spherical-cap-shaped spacers are used to compensate for angular errors, then angular error compensation is improved, but frictional forces and production deviations cause misalignment and unwanted deformation
Solution Approach 1:
The patent introduces a decoupling bushing as an intermediary element between the optical element and the sensor frame. This bushing mechanically decouples the two components, allowing the spherical-cap-shaped spacers to compensate for angular errors without transmitting parasitic forces and torques to the optical element. The decoupling bushing acts as a mediator that preserves the error compensation function while eliminating the harmful mechanical coupling that causes misalignment and deformation.
2Strength
If the decoupling bushing has high rigidity, then mechanical support is improved, but parasitic forces and torques are transferred to the optical element causing deformation
Solution Approach 1:
The patent changes the rigidity parameter of the decoupling bushing by introducing a decoupling groove that reduces the bushing's rigidity. This parameter change allows the bushing to provide sufficient mechanical support while simultaneously reducing its ability to transmit parasitic forces and torques to the optical element. The reduced rigidity enables the bushing to accommodate misalignment without generating harmful mechanical coupling forces.
3Ease of operation
If the decoupling groove reduces the rigidity of the decoupling bushing, then torque-free screwing is achieved, but the mechanical coupling is weakened
Solution Approach 1:
The decoupling groove changes the rigidity parameter of the decoupling bushing, enabling torque-free screwing by reducing the bushing's resistance to rotational forces. This parameter change allows the optical element to be mounted without generating parasitic torques, while the bushing maintains sufficient mechanical coupling to provide structural support and alignment.
4Stability of the object's composition
If the optical element is rigidly mounted, then positioning stability is improved, but angular errors and misalignment cause unwanted deformation
Solution Approach 1:
The decoupling bushing serves as an intermediary that allows the optical element to be mounted with angular errors without transmitting misalignment to the optical element itself. The bushing absorbs the misalignment through its reduced rigidity, maintaining positioning stability while preventing the formation of parasitic forces that would cause deformation.
Solution Approach 2:
By changing the rigidity parameter of the decoupling bushing through the decoupling groove, the system achieves a state where the optical element can be mounted with angular errors without compromising alignment accuracy. The reduced rigidity of the bushing allows it to accommodate misalignment while maintaining sufficient mechanical support to ensure positioning stability.
Data Source
AI summary
An optical system for a projection exposure apparatus, comprising a first component, a second component, and a fastening device used to attach the second component to the first component. The fastening device has a decoupling bushing for mechanically decoupling the second component from the first component. The decoupling bushing has a decoupling groove reducing the rigidity of the decoupling bushing.