Scanning Microscope Oblique Illumination Light Sheet
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Solution Overview
Problem
Conventional scanning microscopes face challenges in achieving collision-free light microscopic imaging, especially under difficult geometric conditions, and are limited in their ability to vary the spatial distribution of light intensity for oblique illumination, which can result in shadowing and poor resolution when imaging spherical objects like tissue cultures.
Innovation Solution
The scanning microscope directs the illuminating light beam to a partial area of the entrance pupil offset from the center, tilting the illumination focus relative to the optical axis and moving it to generate a light sheet, using a spatially separate observation lens with an acute angle to the illumination optics, allowing for variable inclination and alignment with the object plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cylindrical lens is used to generate a light sheet for oblique illumination, then the illumination geometry is fixed and cannot be varied, but the ability to vary spatial distribution of light intensity is lost
Solution Approach 1:
The patent replaces the static cylindrical lens with a dynamic scanning system that uses a point scanner (galvanometer-controlled mirror) to sweep a focused light beam across the entrance pupil of the illumination objective. This dynamic scanning approach allows the spatial distribution of light intensity to be varied by changing the scanning parameters, while still generating the desired light sheet geometry for oblique illumination.
Solution Approach 2:
The patent enables variation of the spatial distribution of light intensity by changing the scanning parameters (scan angle, scan speed, beam position) and the position of the focused light beam within the entrance pupil. By adjusting these parameters, different illumination patterns and light sheet characteristics can be achieved without requiring physical changes to the optical components.
2Measurement precision
If the illumination objective has high numerical aperture to generate a thin light sheet, then the optical resolution along the optical axis is improved, but the free working distance must be large to avoid collision with the observation objective
Solution Approach 1:
The patent employs oblique illumination geometry where the light sheet is generated at an angle to the optical axis of the observation objective. By using a point scanner to direct the illuminating light beam to a partial area of the entrance pupil offset from the center, the light sheet is tilted relative to the optical axis, allowing the observation objective to be positioned closer to the sample without collision while maintaining thin light sheet thickness and high axial resolution.
3Ease of manufacture
If conventional right-angled lens arrangement is used, then the setup is simple, but shadowing occurs when imaging spherical objects like tissue cultures
Solution Approach 1:
The patent uses an asymmetric illumination geometry where the light sheet is directed obliquely onto the sample at an angle to the optical axis, rather than using symmetric perpendicular illumination. This asymmetric arrangement allows light to illuminate spherical objects from the side, preventing shadowing effects while the observation objective maintains its perpendicular detection path for optimal image quality.
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-resolution sectional imaging of objects, including spherical ones, by generating a thin and variable light sheet that can illuminate target areas without collision, improving imaging quality and flexibility in microscopy applications.
Implementation Method 1
The illumination optics transform the illumination light beam entering its entrance pupil into a focused light distribution, which is referred to below as the illumination focus
Implementation Method 2
a scanning device for moving the illuminating focus over a target area to be illuminated of the object to be imaged by changing the direction of incidence in which the illuminating light beam enters a Entrance pupil of the illumination optics falls
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
A scanning microscope (100, 200, 300, 400, 500) comprises a light source (20, 61, 64) for emitting an illumination beam (12), an illumination optic (10) for generating an elongated illumination focus (16, 84) in an object to be imaged (36) and a scanning device (33) for moving the illumination focus (16, 84) over a target area of the object to be imaged (36) by changing the direction of incidence in which the illumination beam (12) falls into an entrance pupil (14) of the illumination optic (10).The scanning device (33) directs the illumination light beam (12) to tilt the illumination focus (16, 84) relative to the optical axis (O1) of the illumination optics (10) onto a portion of the entrance pupil (14) of the illumination optics (10) that is offset from the center of the pupil. To move the illumination focus (16, 84) over the target area to be illuminated, the scanning device changes the direction of incidence of the illumination light beam (36) within this portion. An observation objective (38), spatially separate from the illumination optics (10), is provided. Its optical axis (O3) is arranged substantially perpendicular to the illuminated target area and at an acute angle (α) to the optical axis (O1) of the illumination optics (10).