Endoscope Objective Optical System Halation Prevention
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Solution Overview
Problem
Endoscope objective optical systems face challenges in minimizing size for minimally invasive procedures while maintaining durability for autoclave sterilization and preventing halation due to laser light, which affects image quality and assembly complexity.
Innovation Solution
The endoscope objective optical system is designed with a planoconcave negative lens, an absorption-type filter, an aperture stop, and a planoconvex positive lens, adhering to specific conditional expressions to ensure mechanical durability, prevent halation, and facilitate compact and easy assembly, including the use of an infra-red absorption filter to reduce halation from laser light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the optical system is reduced to minimize inserting portion dimensions, then the outer diameter and overall length are reduced, but the workability of optical elements and assembly difficulty increase
Solution Approach 1:
The optical system is divided into separate components (objective lens, relay lens, cut filter) that can be manufactured independently with standard tolerances and then assembled. This segmentation allows each element to be optimized for manufacturability while the overall system achieves compact dimensions suitable for minimally invasive procedures.
2Reliability
If autoclave sterilization is performed to ensure thorough sterilization, then sterilization effectiveness is improved, but thermal stress damages optical elements due to differential thermal expansion
Solution Approach 1:
The cut filter is designed with specific material properties and thickness parameters that allow it to withstand autoclave sterilization temperatures. By carefully selecting the filter material and optimizing its thickness, the system achieves both thorough sterilization capability and thermal durability, with the filter maintaining its optical function after repeated sterilization cycles.
3Object-affected harmful factors
If a reflection-type cut filter is used to block laser light, then light blocking is achieved, but reflected light causes halation which degrades image quality
Solution Approach 1:
The patent converts the potentially harmful reflected light from a cut filter into a beneficial outcome by using an absorption-type filter that eliminates reflection. The absorption mechanism prevents halation while maintaining effective laser light blocking, thereby improving image quality without sacrificing sterilization capability or requiring increased system size.
4Object-generated harmful factors
If an absorption-type cut filter with adequate thickness is used to prevent halation, then halation is reduced, but the overall length of the optical system increases
Solution Approach 1:
The cut filter thickness is optimized to the minimum value required to achieve adequate halation prevention while maintaining compact system dimensions. By carefully controlling the filter thickness parameter and selecting appropriate material properties, the system achieves effective halation reduction without excessive increase in overall length, balancing image quality with minimally invasive requirements.
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 system achieves resistance to temperature changes during autoclave sterilization, prevents halation from laser light, and maintains a short overall length, making it suitable for minimally invasive procedures with improved assembly and processing ease.
Implementation Method 1
the absorption-type cut filter absorbs light of a predetermined band by a filter
Implementation Method 2
comprising in order from an object side, a planoconcave negative lens, an absorption-type filter, an aperture stop, and a planoconvex positive lens
Data Source
AI summary
An endoscope objective optical system that is to be combined with a solid image pickup element includes, in order from an object side, a planoconcave negative lens, an absorption-type filter, an aperture stop, and a planoconvex positive lens.