Scanning microscope illumination control via entrance pupil offset
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Solution Overview
Problem
Existing scanning microscopes, particularly confocal and selective plane illumination microscopy (SPIM) systems, face limitations in flexible illumination and the inability to vary light intensity distribution, making them unsuitable for applications requiring both point-by-point confocal scanning and inclined illumination.
Innovation Solution
A scanning microscope design that directs the illumination light beam onto a sub-region offset from the center of the entrance pupil, modifying its incidence direction to create an inclined and expandable illumination focus, which is then moved to generate a light sheet, allowing for flexible and efficient illumination with adjustable intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cylindrical lens is used to generate an inclined light sheet in SPIM, then the light sheet can be formed, but the system cannot perform point-by-point confocal scanning and the light intensity distribution cannot be varied
Solution Approach 1:
The patent makes the scanning apparatus serve dual functions: it can perform traditional point-by-point confocal scanning by directing the beam through the center of the entrance pupil, and generate inclined light sheets for SPIM by directing the beam to an offset sub-region. This multi-functionality eliminates the need for separate cylindrical lenses while maintaining both illumination modes.
Solution Approach 2:
The patent removes the cylindrical lens from the optical system entirely, extracting this component that limited versatility. The light sheet generation function is achieved through the scanning apparatus alone by controlling beam direction to an offset sub-region of the entrance pupil, simplifying the system while maintaining functionality.
2Shape
If the illumination light beam is directed onto a sub-region offset from the center of the entrance pupil, then an inclined illumination focus is generated, but the illumination area is reduced
Solution Approach 1:
The patent applies local quality by directing illumination to a specific sub-region of the entrance pupil rather than the entire pupil. This localized illumination creates the desired inclined focus shape while the system compensates by scanning across different sub-regions to cover the full field of view, ensuring complete specimen coverage despite reduced instantaneous illumination area.
3Productivity
If the illumination focus is moved by modifying the direction of incidence, then a light sheet can be generated, but the scanning complexity increases
Solution Approach 1:
The patent makes the scanning apparatus self-serving by utilizing its existing beam deflecting capability to generate light sheets. The same mirrors or prisms used for point scanning are repurposed to direct the beam to offset sub-regions for light sheet generation, eliminating the need for additional light sheet-specific scanning mechanisms and reducing overall system complexity.
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 high-resolution sectional imaging and efficient generation of light sheets, accommodating various microscopy applications with the same microscope configuration, including point-type illumination, by utilizing existing optical elements and allowing for modulated illumination.
Implementation Method 1
The microscope objective shapes the illumination light beam incident into its entrance pupil into a focused light distribution that is referred to hereinafter as an 'illumination focus.'
Implementation Method 2
a scanning apparatus for moving the illumination focus over a target region of the specimen to be illuminated by modifying the direction of incidence in which the illumination light beam is incident into an entrance pupil of the objective
Implementation Method 3
in fluorescence microscopy to excite dyes with laser light to emit fluorescent radiation that is then sensed by a detector
Data Source
AI summary
A scanning microscope is described, having an illumination unit for emitting an illumination light beam, an objective for generating an elongated illumination focus in a specimen to be imaged, and a scanning apparatus for moving the illumination focus over a target region of the specimen to be illuminated by modifying the direction of incidence in which the illumination light beam is incident into an entrance pupil of the objective. The scanning apparatus directs the illumination light beam onto a sub-region of the entrance pupil offset from the pupil center in order to incline the illumination focus relative to the optical axis of the objective, and modifies the direction of incidence of the illumination light beam within that sub-region in order to move the illumination focus over the target region to be illuminated.