Surgical Microscopy Illumination Spectral Filter

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Solution Overview

Problem

Conventional surgical microscopes for ophthalmology often require a choice between xenon or metal halogenide illumination light sources, limiting their ability to image structures with different optical characteristics effectively during surgeries.

Innovation Solution

A surgical microscopy system incorporating a xenon gas discharge lamp with a spectral filter that adjusts the light spectrum between 400 nm and 700 nm, allowing for variable illumination characteristics similar to xenon or halogen light, enhancing imaging of eye structures by reducing blue light scattering and ultraviolet radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a xenon gas discharge lamp is used for illumination, then blue light scattering is reduced and imaging of certain eye structures is improved, but ultraviolet radiation increases causing potential damage to eye tissues

Engineering Contradiction:

Improveimaging qualityVSAvoidultraviolet radiation damage

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A spectral filter is introduced as an intermediary element in the illumination path between the xenon light source and the eye structures. This filter selectively transmits visible light wavelengths while blocking harmful ultraviolet radiation, allowing the benefits of xenon illumination to be realized without the associated risks of UV damage to ocular tissues

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful ultraviolet component of xenon light into a beneficial filtering action. By using a spectral filter with specific transmission characteristics, the system eliminates the harmful UV wavelengths while preserving the useful visible spectrum, effectively transforming a harmful aspect of xenon illumination into a controlled and beneficial imaging modality

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If a spectral filter is added to the illumination system, then harmful ultraviolet radiation is reduced, but device complexity increases

Engineering Contradiction:

Improveultraviolet radiationVSAvoidillumination system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The spectral filter is designed to perform multiple functions simultaneously: it blocks harmful ultraviolet radiation, maintains appropriate visible light transmission for imaging, and can be integrated into existing surgical microscopy systems without requiring complete system redesign. This multi-functionality justifies the added component by delivering multiple benefits from a single element

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If blue light fraction is increased in illumination, then scattering structures become more observable, but blue light scattering increases reducing image contrast

Engineering Contradiction:

Improvevisibility of scattering structuresVSAvoidimage contrast

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The spectral filter is designed with wavelength-specific transmission characteristics that create local quality differences in the illumination spectrum. It selectively enhances transmission in certain visible wavelength ranges that improve visibility of specific eye structures while maintaining appropriate transmission in other ranges to preserve overall image contrast, thereby optimizing different spectral regions for different imaging needs

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

Enables improved visualization of eye structures with optimized illumination, reducing stray light and radiation damage, and allowing for flexible adjustment of spectral characteristics to suit different imaging needs during ophthalmologic surgeries.

Implementation Method 1

a spectral filter optionally positionable into the illumination beam path and removable from the same, wherein the spectral filter has a filter characteristics satisfying for a wavelength range between 400 nm and 700 nm, the relations f*(m*λ+b−Δb)≦A(λ)≦f*(m*λ+b+Δb)

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

the illumination system comprises a xenon gas discharge lamp for generating at least the illumination light

Methodology Applied

Scientific EffectGas discharge: Electric Glow Discharge

Implementation Method 3

Due to the large fraction of blue light of the xenon light scattering structures or variations in the cornea, the anterior and posterior eye chamber of the lens and in the vitreous body are better observable

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS7839566B2Surgical microscopy system and imaging method

Publication Date: 2010.11.23 CARL ZEISS SURGICAL

AI summary

A surgical microscopy system having an illumination system is provided. The illumination system comprises a xenon gas discharge lamp and a spectral filter which is optionally positionable into an illumination beam path of the surgical microscopy system and removable from the same. The spectral filter substantially exhibits, in a wavelength range between 400 nm and 700 nm, a transmission increasing from about 0.12 to 1 having a gradient between 0.025/nm and 0.0035/nm, in particular 0.00293/nm. Thus, the illumination system is enabled to provide light having two different spectral characteristics which is advantageous in particular for imaging structures in the human eye scattering to a different degree.