Oblique Illumination Optical System for Microscopy Vignetting
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Solution Overview
Problem
Existing observation devices face challenges in achieving high-contrast images without brightness unevenness and vignetting when observing samples like cells, especially when the container height varies, due to limitations in illuminating light angles and lens interactions.
Innovation Solution
An observation device with an illuminating optical system that emits obliquely upward illuminating light, using a light source, a mask to restrict light to a specific emission region, and a collimating optical system to convert light into substantially parallel light, ensuring the emission region partially overlaps the peripheral pupil area, thereby maintaining image contrast and reducing vignetting across varying container heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional illuminating optical systems are used with varying container heights, then the device structure becomes simple, but brightness unevenness and vignetting occur in the images
Solution Approach 1:
The patent changes the illumination angle parameter from vertical (0 degrees) to oblique (specifically designed angle), which fundamentally alters how light interacts with the sample and container interfaces. This parameter change enables the system to maintain consistent illumination characteristics across varying container heights, eliminating brightness unevenness and vignetting effects while preserving optical system simplicity
Solution Approach 2:
The patent introduces asymmetric illumination by emitting light at an oblique angle rather than symmetrically from the vertical axis. This asymmetric illumination geometry creates optimal light paths that avoid problematic reflections and refractions at container interfaces, thereby maintaining image brightness uniformity without increasing device complexity
2Manufacturing precision
If the illuminating light angle is changed to improve image contrast, then brightness unevenness is reduced, but the device requires more adjustments and becomes less robust
Solution Approach 1:
The patent performs preliminary optimization by designing the illuminating optical system with a specifically configured oblique emission angle that is predetermined to work optimally across varying container heights. This preliminary design decision eliminates the need for runtime adjustments, as the system is pre-configured to maintain both high image contrast and brightness uniformity without requiring operator intervention
Solution Approach 2:
The patent creates a universal illuminating optical system design where the oblique emission geometry enables the system to function effectively across a range of container heights without requiring reconfiguration. The single optimized illumination angle serves multiple functions: maintaining contrast, eliminating brightness unevenness, and accommodating height variations, thereby reducing adjustment requirements
3Device complexity
If vertical illuminating light is used, then the optical path is simple, but vignetting occurs and image contrast decreases
Solution Approach 1:
The patent modifies the illumination angle parameter from vertical to oblique, which fundamentally changes the optical path geometry. This parameter change simultaneously achieves two objectives: maintaining optical path simplicity while eliminating vignetting effects. The oblique angle creates light paths that better utilize the objective lens aperture, improving image contrast without adding complex optical components or path configurations
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
The solution enables high-contrast imaging without brightness unevenness, even when container heights change, by maintaining the illuminating light angle and reducing the need for adjustments, thus enhancing the robustness and clarity of sample observation.
Implementation Method 1
a collimating optical system that converts the light restricted by the mask into substantially parallel light
Implementation Method 2
an objective optical system that images transmitted light, which is the illuminating light emitted from the illuminating optical system, reflected above the sample, and passed through the sample
Data Source
AI summary
An observation device includes an illuminating optical system that emits illuminating light obliquely upward from below a sample; and an objective optical system that images transmitted light, which is the illuminating light emitted from the illuminating optical system, reflected above the sample, and passed through the sample, the objective optical system imaging the transmitted light below the sample and via a different path from that of the illuminating optical system. The illuminating optical system includes a light source, a mask that restricts light, which is emitted from the light source, to a particular emission region, and a collimating optical system that converts the light restricted by the mask into substantially parallel light, and the illuminating optical system is arranged so that when the region is projected onto a pupil plane of the objective optical system, a projected image of the region partially overlaps a peripheral portion of the pupil.