Asymmetric SPIM Optical System for High-Resolution Imaging

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Solution Overview

Problem

Conventional Selective Plane Illumination Microscopy (SPIM) techniques face limitations in resolution due to mechanical constraints and the symmetrical design of optical systems, which restrict the numerical aperture and detection angle spectrum, leading to suboptimal imaging of samples.

Innovation Solution

The design incorporates an asymmetric detection angle spectrum by positioning the object and intermediate image planes at angles smaller than the detection aperture cone, allowing for a larger detectable fluorescence angle range, and using optical media with varying refractive indices to enhance the numerical aperture of the optical imaging system, thereby increasing resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a symmetrical optical transmission system is used for SPIM, then the system is mechanically simple and easy to align, but the numerical aperture is restricted and resolution is reduced

Engineering Contradiction:
Improveease of alignmentVSAvoidresolution
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by designing an optical transmission system where the detection angle spectrum is deliberately made asymmetric rather than symmetrical. The object plane is positioned at an angle θ1 to the optical axis, and the intermediate image plane is positioned at a different angle θ2, creating an asymmetric detection geometry that expands the numerical aperture and improves resolution while maintaining mechanical simplicity

Inventive Principle:
Principle #4Asymmetry

2Manufacturing precision

If the detection angle spectrum is expanded to improve resolution, then imaging quality improves, but image blurring increases requiring deconvolution

Engineering Contradiction:
ImproveresolutionVSAvoidimage blurring
Core Design Contradiction:
Manufacturing precisionVSLoss of information

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing the asymmetric point spread function (PSF) that results from the expanded detection angle spectrum. This PSF is saved in a lookup table during system calibration, allowing for rapid deconvolution processing during image acquisition without requiring real-time complex calculations, thus reducing processing time while maintaining improved resolution

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If optical media with varying refractive indices are used to enhance numerical aperture, then resolution improves, but system complexity increases

Engineering Contradiction:
ImproveresolutionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by utilizing optical media with different refractive indices (n1 and n2) on either side of the intermediate image plane. By varying these refractive index parameters, the numerical aperture of the optical imaging system is enhanced, allowing for expanded detection angles and improved resolution. The system complexity is managed by carefully selecting standard optical materials with known refractive indices

Inventive Principle:
Principle #35Parameter changes

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 approach results in improved resolution by expanding the detectable angle range and allowing for better correction of image blurring, providing higher-resolution images without the need for deconvolution, while maintaining an asymmetrical point spread function.

Implementation Method 1

an optical transmission system (3) which images a region of the sample (2) from the object plane (1) into an intermediate image plane (4), wherein the object plane (1) and the intermediate image plane (4) form an angle other than 90° with an optical axis (5) of the transmission system (3), wherein the transmission system (3) is composed of several lenses

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

an optical imaging system (6) with a lens whose optical axis (7) is perpendicular to the intermediate image plane (4) and which is focused on the intermediate image plane (4), so that the object plane (1) can be imaged onto a detector (8) without distortion

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 3

an illumination unit (10) for illuminating the sample (2) with a light sheet (11), wherein illumination light is coupled into the beam path of the transmission system (3) in the intermediate image plane (4) or in a pupil plane and directed onto the sample (2) by the transmission system (3)

Methodology Applied
Scientific EffectLight propagation: Light

Implementation Method 4

a first optical medium is arranged between the optical transmission system (3) and the intermediate image plane (4), and a second optical medium is arranged between the intermediate image plane (4) and the optical imaging system (6). The intermediate image plane (4) lies at the interface between the first and second optical media

Methodology Applied
Scientific EffectRefraction at interface: Refraction

Data Source

PatentEP3198323B2Device for imaging a sample
Publication Date: 2023.03.08 CARL ZEISS MICROSCOPY GMBH
  • EP3198323B2 patent drawingFigure 1
  • EP3198323B2 patent drawingFigure 2
  • EP3198323B2 patent drawingFigure 3

AI summary

The invention relates to a device and to a method for imaging a sample (2) arranged in an object plane (1). Such a device comprises an optical transmission system (3), which images a region of the sample (2) from the object plane (1) into an intermediate image plane (4). The object plane (1) and the intermediate image plane (4) together with an optical axis (5) of the transmission system (3) enclose an angle different from 90°. The optical transmission system (3) is constructed of a plurality of lenses. The device additionally comprises an optical imaging system (6), which has a lens, the optical axis (7) of which is perpendicular to the intermediate image plane (4) and which is focused at the intermediate image plane (4) such that the object plane (1) can be imaged onto a detector (8) without distortion. Finally, the device also comprises an illuminating apparatus (10) for illuminating the sample (2) by means of a light sheet (11), wherein the light sheet (11) lies substantially in the object plane (1) and defines an illumination direction, and wherein the normal of the object plane (1) defines a detection direction. In the case of such a device, the object plane (1) encloses an angle together with the optical axis (5) of the transmission system (3), the magnitude of which angle is less than the opening angle of an object-side detection aperture cone (12) of the transmission system (3), and the object plane (1) lies at least partially within the object-side detection aperture cone (12). In addition, the intermediate image plane (4) encloses an angle together with the optical axis (5) of the transmission system (3), the magnitude of which angle is less than the opening angle of an intermediate-image-side detection aperture cone (13) of the transmission system (3), and the intermediate image plane (4) lies at least partially within the intermediate-image-side detection aperture cone (13).