Surgical Microscope Illumination Control for Thermal Tissue Damage Prevention

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Solution Overview

Problem

Current surgical microscopes lack an automated mechanism to optimize light power levels at the object plane, leading to potential thermal tissue damage and inadequate control over stray light, which can result in reduced contrast and increased risk of thermal effects during surgeries beyond ophthalmology.

Innovation Solution

An automated method that adjusts light output based on device parameters such as illumination magnification, working distance, and diaphragm settings to maintain constant brightness at the eyepiece while minimizing thermal risks, using algorithms and correction tables to account for light source aging, and allowing for temporary manual override with alarms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the light output is increased to maintain constant brightness at the eyepiece with increasing magnification, then the brightness at the eyepiece is maintained, but thermal tissue damage risk increases

Engineering Contradiction:
Improvebrightness at the eyepieceVSAvoidthermal tissue damage
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the parameter of light spot size dynamically with magnification. Instead of keeping light output constant, the system reduces the light spot size proportionally to the increase in magnification, which concentrates the same light energy into a smaller area, thereby maintaining eyepiece brightness without increasing total light output to the tissue.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the control unit continuously monitors the magnification setting and automatically adjusts the illumination parameters (light spot size and light output) accordingly. This closed-loop control ensures that brightness at the eyepiece remains constant while preventing excessive light output that could cause thermal damage.

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If manual diaphragms are introduced to reduce the illuminated field size, then the illuminated field size is reduced, but the intensity in the remaining area is not increased

Engineering Contradiction:
Improveilluminated field sizeVSAvoidintensity in illuminated area
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The patent dynamically changes the parameter of light spot size in proportion to the visual field size at different magnifications. By reducing the light spot size as magnification increases, the system concentrates the light energy into a smaller area, thereby increasing the illumination intensity in the illuminated region while maintaining appropriate overall lighting levels.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If the illuminated spot size is reduced below the minimum diameter achievable with illumination zoom, then further reduction is possible, but only through manual diaphragm control

Engineering Contradiction:
Improveilluminated spot sizeVSAvoidautomatic control
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The patent implements an automatic control system that self-adjusts the illumination parameters based on the microscope's zoom and magnification settings. The control unit automatically calculates and adjusts the light spot size and light output without requiring manual intervention, making the system serve itself and eliminating the need for manual diaphragm control.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent merges the functions of illumination zoom and diaphragm control into a single automated system. Instead of having separate manual controls for light spot size and light output, the control unit integrates both functions and automatically adjusts them in coordination based on the magnification setting, simplifying the operation for the user.

Inventive Principle:
Principle #5Merging (Combining)

4Illumination intensity

If xenon light sources with high color temperature are used to provide sufficient illumination, then the illumination intensity is increased, but photochemical light damage occurs

Engineering Contradiction:
Improveillumination intensityVSAvoidphotochemical light damage
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent dynamically changes the parameter of light spot size to concentrate the available light energy. By reducing the light spot size proportionally with magnification, the system maximizes the utilization of light from the xenon source, achieving sufficient illumination intensity at the tissue level without increasing the total light output or color temperature that would cause photochemical damage.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS7505201B2Method for optimized setting of light power at the object plane in the case of reflected light microscopes
Publication Date: 2009.03.17 MOLLER WEDEL BETEILIGUNGEN GMBH

AI summary

The invention relates to a method for optimized setting of light power at the object plane in the case of reflected light microscopes, surgical microscopes in particular. In accordance with the invention, a check is performed as to whether or to what extent thermal danger or damage to the illuminated sections is relevant in order to regulate, in particular limit, the light output of a light source upon a threshold being reached.