Prism Beam Combiner for Wide-Angle Illumination
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Solution Overview
Problem
Conventional illuminators face challenges in achieving high radiant intensity and irradiance over large numerical apertures and fields, especially when the field's diagonal dimension is much larger than the working distance, and inserting a beamsplitter complicates meeting these design targets.
Innovation Solution
The design incorporates an extended radiation source with a controllable spatial distribution, condensing optics, and a prism combiner to achieve high uniformity and efficiency, allowing for a telecentric configuration that ensures uniform illumination across a large field with a numerical aperture exceeding 0.3, and includes a radiation source controller for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a beamsplitter is inserted in the illumination path to enable imaging, then the imaging function is achieved, but the illumination uniformity and intensity distribution become difficult to control
Solution Approach 1:
The illumination system is segmented into multiple independent light sources (first light source for bright-field, second light source for dark-field) that can be controlled separately. This segmentation allows each source to be optimized for its specific function without interfering with the other, resolving the contradiction between achieving imaging versatility and maintaining illumination uniformity.
Solution Approach 2:
A beam combiner is introduced as an intermediary component that merges the optical paths of multiple light sources while maintaining their individual characteristics. The beam combiner enables the beamsplitter to function for imaging while preserving the uniformity and intensity control of each illumination source through its specific optical design.
2Area of stationary object
If the field diagonal dimension is made much larger than the working distance to expand the field of view, then the field coverage is improved, but the numerical aperture and illumination intensity decrease
Solution Approach 1:
Multiple light beams are merged using a beam combiner to illuminate the same large field area simultaneously. By combining the radiant intensity from multiple sources, the system achieves both large field coverage and high illumination intensity, resolving the contradiction between field size and intensity.
Solution Approach 2:
The illumination system is designed with multi-functional light sources that can provide both wide-field illumination and high numerical aperture illumination. The first light source provides uniform broad illumination for large fields, while the second light source provides concentrated illumination for high NA, allowing the system to achieve both objectives simultaneously.
3Adaptability or versatility
If multiple light sources are used to provide both bright-field and dark-field illumination, then the versatility is improved, but the device complexity increases
Solution Approach 1:
The beam combiner serves as a universal optical component that handles multiple light sources and directs them through a single imaging path. This multi-functional design allows the system to achieve versatile illumination modes (bright-field, dark-field, and combinations) without proportionally increasing the complexity of the imaging system, as the beam combiner integrates multiple functions in one component.
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 solution enables illumination with irradiance varying by no more than 10% across the field and received radiant intensity varying by no more than 20% across the numerical aperture, achieving high uniformity and wide field angles, suitable for applications requiring both bright-field and dark-field illumination.
Implementation Method 1
a first beam combiner reflecting the first and second light beams onto a common optical path
Implementation Method 2
a second beam combiner transmitting the first and second light beams along a common optical path
Data Source
AI summary
Provided is an optical apparatus that includes an illumination assembly which include an extended radiation source emitting radiation with a controllable spatial distribution and telecentric condensing optics, configured to receive and project the emitted radiation with a numerical aperture exceeding 0.3 along a first optical axis onto a field and an imaging assembly that includes a sensor and objective optics configured to image the field along a second optical axis onto the sensor and also a prism combiner positioned between the field and the condensing and objective optics which is configured to combine the first and second optical axes, while reflecting at least one of the optical axes multiple times within the prism combiner.