Offset Axis Rotating Diffuser Windows for Beam Homogenization
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Solution Overview
Problem
Existing optical diffuser systems, such as those used in lithography, face challenges in achieving consistent smearing of light beam inhomogeneities due to varying surface velocities across the diffuser, leading to reduced effective useable surface area and inconsistent diffusion patterns.
Innovation Solution
A system comprising at least two transmissive diffuser windows that rotate continuously around distinct, parallel, and offset axes, with partially overlapping subareas to ensure consistent relative movement and compensation of surface velocities, thereby enhancing homogenization and reducing material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single transmissive diffuser window is used to diffuse the light beam, then the device complexity is reduced, but the homogeneity of the diffusive pattern deteriorates due to varying surface velocities across the diffuser surface
Solution Approach 1:
The patent divides a single diffuser window into multiple segments (first and second diffuser windows) that rotate around distinct parallel axes. Each segment covers a specific rotating subarea, and the segments are positioned such that their rotating subareas partially overlap. This segmentation allows each segment to operate at optimized velocities, improving the overall homogeneity of the diffusive pattern while managing device complexity through modular design.
Solution Approach 2:
The patent introduces a new dimensional aspect by rotating multiple diffuser windows around distinct parallel axes rather than a single common axis. This creates a multi-dimensional rotation system where the offset between axes enables different linear velocities at corresponding positions, allowing compensation of velocity variations across the beam profile and achieving more uniform diffusion homogeneity.
2Stability of the object's composition
If the diffuser window rotates at high angular velocity to sufficiently smear out inhomogeneities, then the homogeneity of the light distribution improves, but the effective useable surface area decreases due to lower velocities at the center of rotation
Solution Approach 1:
The patent applies different rotation characteristics to different parts of the diffuser system. By positioning multiple diffuser windows around distinct parallel axes, each location in the beam path experiences optimized local velocity conditions. The offset axes ensure that areas with previously lower velocities (near centers) benefit from the rotational motion of adjacent diffuser segments, creating locally optimized velocity distribution across the entire beam cross-section.
Solution Approach 2:
The patent creates a dynamic system where multiple diffuser windows rotate around distinct parallel axes, generating time-varying velocity profiles across the beam path. This dynamic configuration allows the system to adapt the effective velocity at different spatial locations, ensuring sufficient smearing of inhomogeneities across the entire beam cross-section while maximizing the useable surface area of each diffuser window.
3Quantity of substance
If a single large diffuser window is used to cover the entire beam area, then the material usage is optimized, but the manufacturing precision and consistency of diffusion patterns deteriorate due to varying surface velocities
Solution Approach 1:
The patent segments the diffuser function into multiple smaller windows rotating around distinct parallel axes. This segmentation allows each individual diffuser window to be manufactured with higher precision and more consistent optical properties, as smaller components are easier to manufacture uniformly. The segmented design maintains adequate material usage while achieving superior manufacturing precision and diffusion consistency through the combined action of multiple precision-manufactured segments.
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 provides a more consistent and effective diffusion pattern across the light beam, improving the usable area and material efficiency while minimizing vibrations and edge effects, resulting in improved beam homogeneity and reduced material costs.
Implementation Method 1
at least two transmissive diffuser windows (11, 21) are provided, which are arranged to sequentially diffuse a light beam (L1, L2) transmitted through the diffuser windows
Data Source
AI summary
A diffuser system (100) and method for optically diffusing a light beam (L1,L2). At least two transmissive diffuser windows (11,21) are provided. The diffuser windows (11,21) are arranged to sequentially diffuse the light beam (L1,L2) transmitted there through. The diffuser system (100) is configured to continuously rotate the diffuser windows (11,21) at an angular velocity (ω1,ω2) for homogenizing a diffusive pattern of the transmitted light beam (L1,L2). The diffuser windows (11,21) are configured to rotate around distinct rotation axes (C1,C2). The distinct rotation axes (C1,C2) are parallel and offset with respect to each other by a radial center distance (d12). A rotating subarea of the first diffuser window (11) partially overlaps a rotating subarea of the second rotating diffuser window (12) The partially overlapping rotating subareas define a beam window (W12) for homogenizing and diffusing the transmitted light beam (L1,L2).