Surgical Microscope Illumination with Variable Aperture Diaphragm

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Solution Overview

Problem

Existing surgical microscope illumination devices face challenges in achieving optimal lighting quality across different variants due to issues with aperture adjustment, scattered light, and high control effort, especially with small light sources, leading to reduced imaging quality and increased complexity.

Innovation Solution

A surgical microscope with independently controllable individual light sources arranged in a two-dimensional array, coupled with a diaphragm device featuring aperture openings matching each light source, allowing for quick adjustment of lighting variants and minimizing image errors, thereby achieving high imaging quality with adaptable and cost-effective optics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the light source size is reduced to improve illumination precision, then the image of the light source becomes blurred at the edges and stray light increases, but reducing the light source size further limits light output

Engineering Contradiction:
Improvelight source image sharpnessVSAvoidlight output
Core Design Contradiction:
Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The illumination light source is divided into multiple independently controllable individual light sources arranged in a two-dimensional array. Each light source can be controlled separately, allowing optimization of illumination quality and light output independently for different regions and applications.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The diaphragm device features variable aperture openings that can be dynamically adjusted in size to match the dimensions of the illumination light source. This dynamic adjustment allows the system to adapt to different light source configurations and maintain optimal imaging quality while maximizing light output.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If a rigid diaphragm is inserted into the illumination beam path to control light distribution, then the aperture can be set to maximum size for sharp imaging, but this causes stray light and reflected light to project into the object area

Engineering Contradiction:
Improveimage sharpnessVSAvoidstray light
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The diaphragm device employs variable aperture openings instead of rigid fixed apertures. The aperture size can be dynamically adjusted to precisely match the light source dimensions, allowing the system to minimize stray light by reducing aperture size when needed while maintaining sharp imaging when the aperture is enlarged to match the light source.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The diaphragm aperture parameters (size, shape) are changed to match the illumination light source parameters. This parameter matching allows optimal control of light distribution, enabling the system to achieve both sharp imaging and stray light reduction by adjusting the aperture to the appropriate size for each lighting variant.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a variable aperture is used to adjust aperture size to the light source size to improve imaging quality, then imaging quality improves, but the complexity of creating and controlling the variable aperture increases significantly

Engineering Contradiction:
Improveimage sharpnessVSAvoidaperture control complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The diaphragm device with variable aperture openings serves multiple functions: it controls light distribution, matches aperture size to different light source configurations, reduces stray light, and maintains imaging quality across various illumination variants. This multi-functionality reduces the need for separate complex control systems for each function.

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

Solution Approach 2:

The diaphragm aperture parameters are adjusted to match the illumination light source parameters. This parameter matching approach simplifies control by establishing a direct relationship between light source characteristics and aperture settings, reducing the complexity of creating and controlling the variable aperture system.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If transmissive apertures are used in the diaphragm device to adjust aperture size, then aperture adjustment is possible, but light loss occurs which is disadvantageous for small light sources with limited light output

Engineering Contradiction:
Improveaperture adjustment capabilityVSAvoidlight loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The diaphragm device uses variable aperture openings that can be dynamically adjusted to match the size of the illumination light source. This dynamic adjustment allows the system to maximize light transmission by setting the aperture size optimally for each light source configuration, minimizing light loss while maintaining adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The aperture parameters are changed to match the light source parameters, optimizing the aperture size for maximum light transmission. This parameter matching ensures that the aperture is neither too large (causing stray light) nor too small (causing light loss), achieving optimal balance for small light sources with limited light output.

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 solution enables high-quality lighting with minimal image errors and reduced complexity, allowing for efficient adaptation to various lighting scenarios and ergonomic performance, even with small light sources, by independently controlling each light source and matching aperture openings to their images, resulting in improved imaging performance and reduced manufacturing costs.

Implementation Method 1

The array of individually controllable individual light sources is imaged by illumination optics into a plane conjugate to the first plane

Methodology Applied
Scientific EffectOptical imaging: Lens

Implementation Method 2

Stray or reflected light caused by the illumination optics or the edges of the mounts of optical elements is effectively blocked out or significantly reduced by the aperture device

Methodology Applied
Scientific EffectLight blocking: Filter (optical)

Data Source

PatentEP2960705B1Illuminating device for an optical observation unit
Publication Date: 2024.03.06 CARL ZEISS MEDITEC AG
  • EP2960705B1 patent drawingFigure 1
  • EP2960705B1 patent drawingFigure 2
  • EP2960705B1 patent drawingFigure 3

AI summary

Illumination device (1) for an optical observation device, comprising an illumination light source (2, 50) with independently controllable individual light sources (3a, 3b, 3c) arranged in a first plane in a two-dimensional array (3, 100), and an illumination beam path with an illumination optic (10) and an optical axis (4). The illumination optic (10) forms a plane conjugate to the first plane. An aperture device (14, 200) is arranged in the plane conjugate to the first plane. The aperture device (14, 200) has a number of aperture openings (210), each aperture opening (210) being associated with an individual light source (3a, 3b, 3c).