Optical Beam Splitter Assembly for Multi-Spectral Microscopy

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Solution Overview

Problem

Current optical beam splitter assemblies for microscopes, particularly in surgical microscopes, face challenges in achieving high image quality when recording images in multiple spectral portions, especially when dealing with fluorophores, as they often result in overlapping spectral portions and reduced sensitivity due to the use of Bayer filters.

Innovation Solution

The optical beam splitter assembly employs a configuration with multiple beam splitters and cameras, including a black-and-white camera without a Bayer filter, and cameras with Bayer filters, to guide and separate light into distinct spectral portions, allowing for the recording of images from different fluorophores like fluorescein and ICG, with optimized subfilters for high transmittance and minimal cross-talk between color channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple spectral portions are recorded using conventional beam splitter assemblies with Bayer filters, then images can be captured in different spectral ranges, but spectral portions overlap and sensitivity is reduced

Engineering Contradiction:
Improvespectral recording capabilityVSAvoidspectral separation and sensitivity
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent divides the spectral recording task into three separate spatial locations (first, second, and third light output sections) that are spaced apart from each other. Each location captures a distinct spectral portion without overlap, eliminating the spectral confusion that occurs with conventional Bayer filter approaches. This segmentation allows each camera to specialize in detecting specific spectral ranges with high sensitivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of attempting to separate spectral portions within a single camera plane using color filters (2D approach), the patent distributes three separate light output sections in space (3D arrangement). The output sections are positioned at different locations relative to the beam splitters, creating spatial separation that corresponds to spectral separation. This dimensional transformation resolves the spectral overlap problem by mapping spectral information to spatial positions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of information

If Bayer filters are used to capture color information, then color images can be recorded, but cross-talk between color channels increases and signal intensity decreases

Engineering Contradiction:
Improvecolor information captureVSAvoidsignal intensity and transmittance
Core Design Contradiction:
Loss of informationVSLoss of energy

Solution Approach 1:

The patent assigns different spectral portions to different spatial locations and cameras, eliminating the need for Bayer filters that cause cross-talk between color channels. Each camera receives light within a specific spectral range defined by the beam splitter configuration, allowing for high transmittance without the energy loss associated with filtering approaches.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the color filtering function from the camera sensors and relocates it to the optical beam splitter assembly. The beam splitters selectively direct different spectral portions to different cameras, effectively performing the spectral separation function before the light reaches the sensors. This extraction eliminates the need for Bayer filters on the cameras themselves.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If conventional beam splitter configurations are used, then light can be split into different paths, but spectral portions overlap and image quality deteriorates

Engineering Contradiction:
Improvebeam splitter configurationVSAvoidimage quality and spectral separation
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent arranges three light output sections at different spatial locations that are spaced apart from each other, creating a three-dimensional optical path configuration. This spatial arrangement ensures that spectral portions directed to different output sections do not overlap, maintaining high image quality while using a relatively simple beam splitter configuration with only two beam splitters.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 enhances image quality by allowing for the separation of distinct fluorescence emission bands, increasing signal intensity, and providing high sensitivity for weak signals, while minimizing cross-talk between color channels, thereby improving the overall recording of images in surgical microscopes.

Implementation Method 1

the first beam splitter reflects light of the first spectral portion along the first light path

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The first beam splitter transmits light of the second spectral portion

Methodology Applied
Scientific EffectTransmission:

Implementation Method 3

the second beam splitter reflects light of the second spectral portion along the second light path

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

The second beam splitter may transmit light of the first spectral portion

Methodology Applied
Scientific EffectTransmission:

Implementation Method 5

an optical beam splitter assembly for guiding light of three different spectral portions from a light entrance section to three light output sections

Methodology Applied
Scientific EffectOptical beam splitting:

Data Source

PatentEP3779554B1Optical beam splitter assembly, camera head, and microscope assembly
Publication Date: 2024.01.17 LEICA INSTRUMENTS (SINGAPORE) PTE LTD
  • EP3779554B1 patent drawingFigure 1
  • EP3779554B1 patent drawingFigure 2
  • EP3779554B1 patent drawingFigure 3

AI summary

The documents show an optical beam splitter assembly (100) for recording images in at least three different spectral portions (110, 120, 130), comprising a first and a second beam splitter (151, 152), and a first, second and third light path (171, 172, 173), the first light path (171) being configured to guide light of a first spectral portion (110) from a light entrance section (160) to a first light output section (161), the second light path (172) being configured to guide light of a second spectral portion (120) from the light entrance section (160) to a second light output section (162), the second light output section (162) being spaced apart from the first light output section (161), and the third light path (173) being configured to guide light of a third spectral portion (130) from the light entrance section (160) to a third light output section (163), the third light output section (163) being spaced apart from the first light output section (161) and the second light output section (162), wherein the second light path (172) traverses the first beam splitter (151), and the third light path (173) traverses the first and the second beam splitter (151, 152).