Endoscope Objective Optical System Aberration Correction
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Solution Overview
Problem
Current nasal endoscopes with small diameters face challenges in achieving high image quality and effective focusing, as existing objective optical systems are limited in size and performance, leading to issues with aberrations and focal length constraints.
Innovation Solution
The endoscope objective optical system is designed with a configuration of a first group having negative refractive power, a second group with a meniscus lens of positive refractive power, and a third group including a cemented lens, where the second group moves to focus, satisfying specific conditional expressions to optimize focal length and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a small diameter objective optical system is used in nasal endoscopes, then the scope size is reduced, but the observation performance and focusing capability are degraded
Solution Approach 1:
The objective optical system is divided into three distinct groups: a first group with negative refractive power, a second group with positive refractive power, and a third group with positive refractive power. This segmentation allows each group to perform specific functions, enabling the system to achieve both compact size and high observation performance through coordinated operation of specialized lens elements.
Solution Approach 2:
The second group is designed as a movable lens group that can be positioned along the optical axis to adjust focus. This dynamic positioning capability enables the compact system to achieve effective focusing at both far points and near points, resolving the contradiction between small size and focusing capability.
2Adaptability or versatility
If a focusing function is added to a small diameter endoscope, then near-field observation is enabled, but aberrations increase and image quality deteriorates
Solution Approach 1:
Each lens group is designed with specific refractive power characteristics tailored to its function. The first group with negative refractive power corrects certain aberrations, while the second and third groups with positive refractive power contribute to focusing and image quality. This localized optimization of optical properties enables the system to maintain high image quality while providing focusing capability.
Solution Approach 2:
The system uses conditional expressions to precisely control the refractive powers and positions of the lens groups. By optimizing parameters such as the refractive power ratios and lens spacing, the system achieves effective focusing across different distances while minimizing aberrations and maintaining high image quality.
3Length of moving object
If the overall length of the optical system is reduced for compactness, then the scope size decreases, but the focusing range and image plane adjustment are constrained
Solution Approach 1:
The three lens groups are arranged in a nested configuration along the optical axis, with the second group positioned between the first and third groups. This compact nesting arrangement enables the system to achieve an extended focusing range within a reduced overall length, as the movable second group can adjust its position to accommodate both far-point and near-point focus 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
This configuration enables a compact, high-performance optical system with improved focusing capabilities and reduced aberrations, suitable for both far-point and near-point observations, while maintaining a small size and efficient image plane adjustment.
Implementation Method 1
a second group having a positive refractive power... a lens which is a meniscus lens having a positive refractive power
Implementation Method 2
focusing from an object point at a long distance to an object point at a short distance is carried out by moving the second group
Data Source
AI summary
An endoscope objective optical system includes, in order from an object side, a first group having a negative refractive power, a second group having a positive refractive power, and a third group having a positive refractive power. Focusing from an object point at a long distance to an object point at a short distance is carried out by moving the second group from the object side to an image side. The first group includes a lens having a negative refractive power, the second group includes a lens which is a meniscus lens having a positive refractive power of which a convex surface is directed toward the image side, and the third group includes, in order from the object side, a lens having a positive refractive power, and a cemented lens composed of a lens having a positive refractive power and a lens having a negative refractive power.