Split Illumination Optics for Rectangular Field Alignment
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Solution Overview
Problem
Existing illumination systems struggle to efficiently illuminate non-square geometries and align detector fields of view with illuminated regions, particularly when using low spatial coherent illumination and rectangular detector arrays.
Innovation Solution
An optical system with first and second field splitting stages that divide and shift illumination beams along orthogonal axes, using optical elements like transparent plates, periscopes, and diffractive gratings to create tailored illumination regions and align them with detector arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If typical light sources and illumination systems are configured to provide illumination of a field of a selected geometrical/spatial shape, then efficient illumination of square regions is achieved, but alignment with rectangular detector arrays and non-square geometries becomes difficult
Solution Approach 1:
The illumination field is divided into multiple sub-fields using beam splitting optics. The first beam splitter divides the input beam into multiple beams, and the second beam splitter further divides these beams into multiple sub-beams. This segmentation allows the illumination system to cover rectangular and non-square regions by arranging multiple square sub-fields in specific geometric patterns, thereby aligning with rectangular detector arrays while maintaining efficient illumination of each region.
2Device complexity
If a single illumination field is used, then simple illumination is achieved, but simultaneous illumination of multiple regions with aligned detector fields is not possible
Solution Approach 1:
The system introduces spatial dimensionality by creating multiple illumination beams at different angular orientations. The first beam splitter creates multiple beams at different angles, and the second beam splitter further separates these beams into distinct angular directions. This angular separation in the optical domain translates to spatial separation at the sample plane, enabling simultaneous illumination of multiple regions while maintaining alignment with rectangular detector arrays through the conjugate optical relationship.
3Ease of manufacture
If illumination field shape is fixed, then manufacturing is simple, but adaptation to different sample geometries and detector arrangements is limited
Solution Approach 1:
The illumination system is made dynamically reconfigurable through the use of adjustable beam splitters and optical elements that can be positioned and oriented to create different illumination patterns. The system can dynamically adapt the number, arrangement, and orientation of illumination beams to match different sample geometries and detector array configurations, while maintaining the simplicity of the basic optical components used in each configuration.
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
Enables efficient illumination of non-square regions and simultaneous collection of light, aligning detector fields of view with illuminated areas, enhancing inspection efficiency.
Implementation Method 1
The first field splitting stage is configured to divide the input illumination field to a selected number of sub-regions along a first axis, and optionally, to laterally shift the number of illumination sub-regions with respect to each other along a second axis
Implementation Method 2
The optical system comprises at least first and second light splitting stages for receiving input illumination field and divide the input illumination field to a selected number of illumination regions
Implementation Method 3
The second field splitting stage is configured to generate a selected number of field duplications along a selected axis (being parallel to the first or second axis)
Implementation Method 4
The optical arrangement may operate as an optical relay and may define at least first and second optical planes each conjugated to at least one of input pupil of the optical system and illumination region on the sample
Data Source
AI summary
An optical system is described. The optical system comprises an input pupil for input of illumination radiation, and first and second field splitting stages. The first field splitting stage is configured to divide input illumination radiation into a first selected number of illumination beams along a selected first axis. The second field splitting stage is configured for receiving the first selected number of illumination beams and dividing said first selected number of illumination beam into a second selected number of illumination beams along a selected second axis. The optical system thus provides a selected number of illumination beams exiting through said output pupil and providing illumination of a region of a selected spatial shape.