Surgical Microscope Variable Working Distance Objective
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Solution Overview
Problem
Surgical microscopes have an unsatisfactory range of working distances, which limits their versatility and requires the simultaneous use of two different tools - a surgical microscope and an overview camera, increasing complexity and cost.
Innovation Solution
A surgical microscope with an objective system comprising two lens groups, where one group has a negative optical power and is moveable along the optical axis, allowing for a variable working distance from 200 mm to 5,000 mm, enabling a wider range of magnification and field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional surgical microscope objective is used, then the microscope provides a stable focal plane for surgical imaging, but the working distance range is limited and unsatisfactory
Solution Approach 1:
The patent applies the dynamics principle by making the first lens group moveable along the optical axis. This allows the working distance to be varied dynamically between 200 mm and 5,000 mm, transforming a static objective into a dynamic system that can adapt to different surgical requirements. The moveable lens group enables continuous adjustment of the focal plane position without changing the entire microscope system.
Solution Approach 2:
The objective is segmented into multiple lens groups (first lens group with negative optical power and second lens group with positive optical power) that can be moved independently. This segmentation allows the first lens group to be adjusted for working distance variation while the second lens group maintains image quality, resolving the contradiction between adaptability and complexity by distributing functions across separate modules.
2Adaptability or versatility
If the working distance is increased beyond conventional ranges, then the microscope can function as both surgical microscope and overview camera, but the optical system becomes more complex
Solution Approach 1:
The patent achieves universality by designing an objective that can serve dual functions: as a surgical microscope objective at shorter working distances (200-500 mm) and as an overview camera objective at longer working distances (up to 5,000 mm). The moveable first lens group enables the same optical system to cover both applications, eliminating the need for separate tools and reducing overall system complexity despite the extended functional range.
Solution Approach 2:
The patent changes the optical parameters by using a lens group with negative optical power that can be positioned at different distances from the focal plane. By varying the position of the first lens group, the effective focal length and working distance are adjusted, enabling the system to transition between microscopic and overview imaging modes without changing the fundamental optical design.
3Adaptability or versatility
If a lens group with negative optical power is added to extend working distance, then the working distance variation is enhanced, but the objective structure becomes more complex
Solution Approach 1:
The first lens group with negative optical power acts as an intermediary element between the object and the second lens group. This intermediate lens group enables the extension of working distance by creating a virtual image that the second lens group then focuses. The negative power lens group mediates the optical path, allowing working distance variation without requiring complete redesign of the entire objective structure.
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 design allows for a significant variation in working distance, enhancing the microscope's versatility, allowing it to function as both a surgical microscope and an overview camera, reducing the need for multiple tools and improving operational efficiency.
Implementation Method 1
The first lens group of the objective, which is along the at least one imaging path located directly adjacent to the focal plane, consists altogether of at least three optical lenses and has a negative optical power
Data Source
AI summary
A surgical microscope 1 comprises an imaging system 2 providing a magnified multidimensional image of an object 3 disposable in a focal plane 4 of the imaging system 2 along at least one optical imaging path 2a, 2b. The imaging system 2 comprises an objective 5 having at least two lens groups 6, 7, through which the at least one optical imaging path 2a, 2b passes consecutively, and which define the focal plane 4 of the imaging system 2. At least one lens group 6 of the objective is moveable along its optical axis relative to the at least one other lens group 7 of the objective. The objective's first lens group 6 located directly adjacent to the focal plane 4 along the at least one optical imaging path 2a, 2b consists of at least three optical lenses 61, 62, 63 and has altogether a negative optical power.