Wedge Assembly Optical Path Compensation for Focal Plane Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical path compensation methods for semiconductor measurement systems face challenges such as positional adjustments causing errors in other directions and the time-consuming process of selecting suitable flat plates for high-resolution adjustments.
Innovation Solution
An optical path compensation apparatus comprising a wedge assembly with a movable and fixed wedge, a driving mechanism, and a preload unit, allowing for precise adjustment of the focal plane without affecting other directions, using a wedge assembly with equal wedge angles and opposite orientations, and a preload unit for stable movement, enabling smooth and accurate correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the position of the object plane is adjusted for optical path compensation, then the focal plane position is corrected, but errors in other measurement directions are introduced
Solution Approach 1:
The optical path compensation function is segmented from the object plane adjustment. Instead of moving the object plane directly, the patent uses a separate wedge-shaped optical component that can be independently adjusted to compensate optical path length without affecting the object plane position, thus resolving the coupling between focal plane correction and measurement accuracy
Solution Approach 2:
A wedge-shaped optical component serves as an intermediary element between the light source and the object plane. This mediator allows optical path compensation to be achieved through the wedge's adjustable thickness, which modifies the light path length without physically moving the object plane or affecting the measurement system's reference frame
2Manufacturing precision
If multiple flat plates with different thicknesses are used for optical path compensation, then high-resolution adjustment is achieved, but the selection process becomes time-consuming
Solution Approach 1:
The static selection of discrete flat plates is replaced with a dynamic, continuous adjustment mechanism. The wedge-shaped component can be rotated or translated to continuously vary the effective optical path length, providing high-resolution adjustment without the need to manually select from multiple discrete components
Solution Approach 2:
Instead of changing the discrete parameter of plate thickness by selecting different components, the patent changes the optical path length parameter continuously by adjusting the position or orientation of the wedge-shaped component. This transforms a discrete selection process into a continuous adjustment process, improving both resolution and efficiency
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 achieves effective position correction of the focal plane with minimal error in other directions and facilitates high-resolution adjustments efficiently, ensuring stable and smooth operation.
Implementation Method 1
a wedge assembly, a driving mechanism and a preload unit, the wedge assembly comprising a movable wedge and a fixed wedge
Implementation Method 2
the preload unit configured to elastically press the movable wedge on the fixed wedge
Data Source
AI summary
An optical path compensation apparatus includes a wedge assembly, a driving mechanism and a preload unit. The wedge assembly includes a movable wedge and a fixed wedge. The movable wedge and the fixed wedge having equal wedge angles and respective wedge surfaces inclined in opposite directions. The preload unit is configured to elastically press the movable wedge on the fixed wedge, and the driving mechanism is configured to cause relative movement between the wedge surface of the movable wedge and the wedge surface of the fixed wedge. This optical path compensation apparatus is capable of achieving effective position correction of a focal plane of a measurement system for focusing and leveling in a smooth, convenient and precise way while not causing any error in other directions.