Reflective Microscopy Objective with Multiple Reflections
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Solution Overview
Problem
Optical imaging devices face challenges in achieving high magnification and numerical aperture with minimal aberrations, particularly in broadband wavelength ranges, due to chromatic aberrations associated with refractive and catadioptric systems, which often require multiple mirrors or compromise on magnification or aperture size.
Innovation Solution
The use of a system with at least three optical elements, where at least one element is reused, specifically a configuration with reflective surfaces that allows multiple reflections to reduce individual refractive power without compromising magnification, achieving high numerical aperture and minimizing aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If refractive optical elements are used for imaging, then the imaging device can process light of different wavelengths, but chromatic aberrations occur which worsen with broader wavelength ranges
Solution Approach 1:
The patent replaces refractive optical elements with reflective optical elements (mirrors) to eliminate chromatic aberrations. Reflective surfaces do not disperse light by wavelength, allowing the imaging device to process the broad wavelength range (193 nm to 436 nm) without the chromatic aberrations that plague refractive systems.
Solution Approach 2:
The patent changes the fundamental optical parameter from refraction to reflection. By using mirrors instead of lenses, the system maintains broadband capability while eliminating the wavelength-dependent focal length variations that cause chromatic aberration in refractive systems.
2Measurement precision
If catoptric systems with multiple mirrors are used to achieve high magnification, then magnification increases, but the device complexity increases with more than four mirrors
Solution Approach 1:
The patent combines multiple reflective surfaces onto fewer optical elements. The objective lens comprises only three mirrors, with at least one mirror having multiple reflective surfaces. This merging approach achieves the required high magnification while reducing the total mirror count to three or fewer, thereby reducing device complexity.
Solution Approach 2:
The patent makes individual mirrors serve multiple functions by incorporating multiple reflective surfaces on single optical elements. One mirror performs the work of what would traditionally require multiple separate mirrors, reducing the overall component count while maintaining the optical path needed for high magnification.
3Device complexity
If catoptric systems use comparatively large individual refractive powers to achieve high magnification with fewer mirrors, then the number of mirrors decreases, but aberrations increase
Solution Approach 1:
The patent applies different surface characteristics to different regions of the mirrors. By optimizing the local reflective properties and curvatures of specific mirror surfaces, the system achieves high magnification with fewer mirrors while controlling aberrations through localized surface quality optimization rather than requiring uniformly high power across all elements.
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 enables high magnification and numerical aperture with reduced aberrations, allowing for efficient imaging across a broad wavelength range, such as 193 nm to 436 nm, while maintaining acceptable optical element size and minimizing chromatic aberrations.
Implementation Method 1
The first optical element group (107) comprises a first optical element (111) with a reflective first optical surface (111.1) and a second optical element (112) with a reflective second optical surface (112.1), wherein the first optical element (111) and the second optical element (112) are formed and arranged such that on formation of the image of the object point, in each case a multiple reflection of at least one imaging ray takes place on the first optical surface (111.1) and on the second optical surface (112.1)
Data Source
AI summary
The present invention relates to an optical imaging device, in particular for microscopy, with a first optical element group and a second optical element group, wherein the first optical element group and the second optical element group, on an image plane, form an image of an object point of an object plane. The first optical element group includes a first optical element with a reflective first optical surface and a second optical element with a reflective second optical surface. The second optical element group includes a third optical element with a reflective third optical surface. The first optical element and the second optical element are formed and arranged such that on formation of the image of the object point, in each case a multiple reflection of at least one imaging beam takes place on the first optical surface and the second optical surface.