Optical Integrator Illuminance Uniformity via Segmented Array
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical integrators face challenges in maintaining uniform illuminance distribution, particularly in the orthogonal-to-scanning direction during scanning exposure, leading to illuminance nonuniformity and suboptimal imaging performance.
Innovation Solution
The optical integrator features a plurality of wavefront dividing elements with curved optical faces inclined around an axis perpendicular to the optical axis, allowing light to pass through different regions with varying surface shape errors, thereby minimizing illuminance nonuniformity through the averaging effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional fly's eye lens with biconvex lens elements are used, then the structure is simple and easy to manufacture, but surface shape errors in exit faces cause significant illuminance nonuniformity on the target surface
Solution Approach 1:
The patent divides the conventional single lens element into multiple lens elements arranged in an array. Each lens element processes a portion of the incident light, and the segmented structure allows light to pass through different regions with varying surface shape errors, achieving an averaging effect that reduces overall illuminance nonuniformity on the target surface.
Solution Approach 2:
The patent introduces a two-dimensional array arrangement of lens elements, transforming the conventional single-element structure into a multi-element system with spatial distribution. This dimensional expansion enables light to traverse multiple optical paths with different surface errors, thereby averaging out the illuminance distribution and reducing nonuniformity caused by manufacturing imperfections.
2Manufacturing precision
If the number of micro lens elements is increased to enhance uniformity, then illuminance uniformity improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs segmentation by dividing the optical system into multiple discrete lens elements arranged in a regular array. This segmentation achieves illuminance uniformity through the averaging effect of multiple optical paths while maintaining relatively simple individual element designs, thus balancing performance improvement with manageable device complexity.
Solution Approach 2:
The patent optimizes parameters such as the number of lens elements, their arrangement pattern, and individual element dimensions to achieve the desired illuminance uniformity. By carefully selecting and adjusting these parameters, the system attains high uniformity performance without excessive complexity, finding an optimal balance between the two competing requirements.
3Adaptability or versatility
If movable optical members are used to adjust illumination, then adaptability improves, but variation in incident angles and ranges causes illuminance nonuniformity
Solution Approach 1:
The patent uses a segmented array of lens elements that maintains its averaging effect even when incident light angles and ranges vary due to movable optical members. The multiple discrete elements ensure that variations in illumination conditions are averaged out, preserving illuminance uniformity while allowing the system to maintain adaptability through the movable components upstream.
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
This configuration ensures a desired illuminance distribution on the target surface, enhancing imaging performance and reducing nonuniformity, especially in the orthogonal-to-scanning direction during scanning exposure.
Implementation Method 1
a plurality of wavefront dividing elements two-dimensionally arrayed, wherein the wavefront dividing elements are so configured that a ray group obliquely incident to a center on an optical axis of an entrance face of each wavefront dividing element is emitted in parallel with the optical axis from the wavefront dividing element
Data Source
AI summary
An optical integrator has a plurality of wavefront dividing elements two-dimensionally arrayed, and is so configured that a ray group obliquely incident to an optical-axis center of an entrance face of each wavefront dividing element is emitted in parallel with the optical axis from the wavefront dividing element. In each of a required number of wavefront dividing elements out of the plurality of wavefront dividing elements, at least one curved optical face of the wavefront dividing element is formed as inclined around an axis along a predetermined direction passing an optical-axis center of an entrance face of the wavefront dividing element and being perpendicular to the optical axis AXe.