Endoscope Optical Path Separation With Autoclave-Resistant Cemented Lenses
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Solution Overview
Problem
Conventional endoscope systems fail to consider the temperature characteristics of cemented lenses, leading to issues with high-temperature resistance during sterilization processes like autoclaving, which can cause delamination and affect image capture.
Innovation Solution
An optical system with a specific configuration of cemented lenses and a movable lens group, satisfying certain conditional formulas to ensure high temperature resistance and maintain high resolution performance, including a separation optical system to handle visible and infrared light paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cemented lenses are used in the image forming optical system, then manufacturing precision and resolution are improved, but temperature resistance deteriorates due to thermal expansion differences between bonded lenses
Solution Approach 1:
The patent applies parameter changes by carefully selecting lens materials with specific refractive indices, Abbe numbers, and thermal expansion coefficients that satisfy predetermined conditional formulas. This ensures that the cemented lenses maintain both manufacturing precision and high-temperature resistance by controlling thermal expansion differences between bonded lenses through material parameter optimization
Solution Approach 2:
The patent uses composite materials by bonding lenses made of different glass materials with complementary properties. The positive lens and negative lens are constructed from specific glass compositions that, when combined, achieve both optical performance and thermal stability, creating a composite lens structure that resolves the contradiction between precision and temperature resistance
2Measurement precision
If high-resolution imaging is achieved, then observation accuracy of fine structures is improved, but susceptibility to thermal damage during sterilization increases
Solution Approach 1:
The patent changes material parameters by selecting glass materials with specific thermal expansion coefficients and optical properties that satisfy conditional formulas. This allows the high-resolution imaging system to resist thermal expansion damage during sterilization, maintaining both image quality and thermal durability through optimized material selection
3Ease of manufacture
If conventional cemented lenses are used without considering thermal expansion, then ease of manufacture is improved, but reliability under sterilization conditions deteriorates
Solution Approach 1:
The patent applies parameter changes by establishing specific conditional formulas for thermal expansion coefficients and optical properties. These parameter constraints guide material selection and lens design, enabling manufacturers to produce reliable sterilization-resistant cemented lenses through systematic material parameter optimization rather than trial and error
Solution Approach 2:
The patent applies preliminary action by pre-calculating and specifying the required thermal expansion coefficients and optical parameters before manufacturing begins. The conditional formulas are established in advance to guide material selection and lens design, preventing thermal expansion issues before they occur during sterilization, thus maintaining both manufacturability and reliability
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 enhances manufacturability and reliability by reducing thermal expansion effects, ensuring high resolution and minimizing image degradation during sterilization, supporting high-speed autofocus and stable image capture.
Implementation Method 1
The separation optical system separates an optical path of light passing through the image forming optical system into an optical path of visible light to the visible light imaging element and an optical path of infrared light to the infrared light imaging element
Implementation Method 2
when αp is an average linear expansion coefficient at 100° C. to 300° C. in the lens having the positive refractive power, and αn is an average linear expansion coefficient at 100° C. to 300° C. in the lens having the negative refractive power, the following conditional formula |1−αp/αn|<0.05 is satisfied
Data Source
AI summary
An optical system includes an image forming optical system with a first and a second lens group, and forms an image of light from a subject on each of a visible light imaging element and an infrared light imaging element. The system also includes a separation optical system that separates an optical path of light passing through the image forming optical system into at least two optical paths. The first lens group includes a plurality of cemented lenses formed by bonding a lens having positive refractive power and a lens having negative refractive power, in which when αp is an average linear expansion coefficient of the lens having positive refractive power at 100° C. to 300° C. and αn is an average linear expansion coefficient of the lens having negative refractive power at 100° C. to 300° C., the following conditional formula |1−αp/αn|<0.2 is satisfied.