Surgical Microscope Dichroic Beam Splitter Infrared Fluorescence

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Solution Overview

Problem

Conventional surgical microscopes require complex camera systems to detect both normal light and fluorescence images, often with inefficient infrared light handling, leading to suboptimal signal-to-noise ratios, especially when dealing with low-intensity infrared fluorescence.

Innovation Solution

A surgical microscope with a simplified camera system utilizing a dichroic beam splitter to direct infrared light to a single camera chip, combined with selective blocking filters to switch between normal and infrared imaging modes, enhancing signal-to-noise ratios by optimizing light distribution and blocking irrelevant wavelengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional camera system with multiple camera chips is used to detect both normal light and fluorescence images, then both types of images can be obtained, but the device complexity increases and the signal-to-noise ratio for infrared light detection deteriorates

Engineering Contradiction:
Improvecapability to detect both normal light and fluorescence imagesVSAvoidcamera system structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the detection function by wavelength ranges using a dichroic beam splitter that divides incoming light into different spectral bands (visible light for normal imaging and infrared for fluorescence), directing each band to appropriate camera chips. This segmentation allows a single camera system to perform multiple detection functions without requiring completely separate imaging systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The camera system is designed with multi-functionality to detect both normal visible light images and infrared fluorescence images using the same optical path and camera housing. The dichroic beam splitter enables the system to universally handle different wavelength ranges, making the camera system adaptable for dual-purpose imaging without increasing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If infrared light is directed to multiple camera chips, then redundancy is provided, but the signal-to-noise ratio for low-intensity infrared fluorescence detection deteriorates

Engineering Contradiction:
Improvedetection redundancyVSAvoidsignal-to-noise ratio
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by directing infrared light primarily to one specific camera chip optimized for infrared detection, while other camera chips are dedicated to their respective visible light wavelength ranges. This specialized allocation ensures that each camera chip operates at its optimal performance level for its designated wavelength, maximizing the signal-to-noise ratio for infrared fluorescence detection without unnecessary distribution to suboptimal detectors.

Inventive Principle:
Principle #3Local 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

The solution allows for high-quality detection of both normal light and infrared fluorescence images with improved signal-to-noise ratios, enabling effective visualization of tissues using dyes like indocyanine green, even with low-intensity infrared signals.

Implementation Method 1

a dichroic beam splitter and first, second and third camera chips, wherein the dichroic beam splitter is configured to direct red light received at the input port mainly towards the first camera chip

Methodology Applied
Scientific EffectDichroic beam splitting: Dichroic Filter

Implementation Method 2

A conventional camera has a dichroic beam splitter configured to direct red, green and blue light to respective camera chips. The conventional camera further includes an infrared blocking filter to prevent detection of infrared light

Methodology Applied
Scientific EffectInfrared blocking: Filter (optical)

Implementation Method 3

One example of a fluorescent dye is indocyanine green (ICG) having a fluorescence spectrum in the range of infrared light

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP2199842B1Surgical microscope for observing an infrared fluorescence and corresponding method
Publication Date: 2015.12.16 CARL ZEISS MEDITEC AG
  • EP2199842B1 patent drawingFigure 1
  • EP2199842B1 patent drawingFigure 2~3
  • EP2199842B1 patent drawingFigure 4

AI summary

A surgical microscope for observing an infrared fluorescence comprises a camera system 25 having three chips 35, 36, 37, wherein infrared light emanating from an object 9 is supplied to only one of the three camera chips via a dichroic beam splitter 33.