Endoscope Optical System with Cemented Lens Groups
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Endoscope optical systems face challenges in switching between normal and magnified observation states while maintaining low aberration variation and being robust against manufacturing errors, with existing systems either requiring high manufacturing costs or excessive lens curvature to correct chromatic and Seidel aberrations.
Innovation Solution
The endoscope optical system includes a fixed negative first lens group, a movable positive second lens group, a fixed aperture stop, and a fixed positive third lens group with specific cemented lenses, adhering to certain refractive index and curvature conditions to allow switching between observation states while minimizing aberration correction needs and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing objective optical systems use high curvature lenses to correct chromatic and Seidel aberrations, then aberration correction is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent changes the refractive index parameters of the lens materials to achieve aberration correction without relying on high curvature. By selecting specific refractive index ranges for the lens groups, the system corrects chromatic and Seidel aberrations while using lenses with moderate curvature that are easier and cheaper to manufacture.
Solution Approach 2:
The patent employs composite lens structures with different refractive indices arranged in specific groups. The first lens group has a first refractive index range, the second lens group has a second refractive index range, and the third lens group has a third refractive index range, creating a composite optical system that corrects aberrations through material composition rather than excessive curvature.
2Adaptability or versatility
If the second lens group moves along the optical axis for switching between observation modes, then functionality is improved, but aberration variation increases
Solution Approach 1:
The patent designs the lens groups with specific refractive index ranges that are optimized for minimal aberration variation during movement. The refractive index parameters are selected to ensure that when the second lens group moves along the optical axis for switching between normal and magnified observation modes, the aberrations remain controlled and stable.
Solution Approach 2:
The patent accommodates the dynamic movement of the second lens group along the optical axis while maintaining optical performance. The lens groups are designed with flexible parameters that allow this movement without causing excessive aberration variation, enabling smooth switching between observation modes with consistent image quality.
3Manufacturing precision
If lens curvature is increased to correct aberrations, then optical performance is improved, but robustness against manufacturing errors decreases
Solution Approach 1:
The patent changes from using high curvature lenses to using lenses with moderate curvature but optimized refractive indices. This parameter change makes the system more robust against manufacturing errors because moderate curvature lenses are less sensitive to manufacturing tolerances and defects, while still achieving the necessary aberration correction through careful selection of refractive index ranges.
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 effective switching between normal and magnified observation states with reduced aberration variation, improved robustness against manufacturing errors, and favorable correction of chromatic and Seidel aberrations, while maintaining a long back focus and preventing lens shift due to low impact.
Implementation Method 1
a cemented lens consisted of three lenses; and a cemented lens consisted of two lenses... in the cemented lens consisted of three lenses, three lenses of a positive lens, a negative lens, and a positive lens are cemented
Implementation Method 2
an objective optical system for endoscopes... a fixed negative first lens group; a movable positive second lens group; a fixed aperture stop; and a fixed positive third lens group
Data Source
AI summary
An endoscope optical system includes, in order from an object side: a fixed negative first lens group; a movable positive second lens group; a fixed aperture stop; and a fixed positive third lens group, the endoscope optical system being capable of switching between a normal observation state and a magnified observation state by moving the second lens group along an optical axis, in which the third lens group includes, in order from the object side: a cemented lens consisted of three lenses; and a cemented lens consisted of two lenses. In the cemented lens consisted of three lenses, three lenses of a positive lens, a negative lens, and a positive lens are cemented. In the cemented lens consisted of two lenses, two lenses of a positive lens and a negative lens are cemented. The following conditional expressions (1) and (2) are satisfied: 1.70<(nd3G1+nd3G2+nd3G3)/3<2.0 (1); and 1.72<(nd3G4+nd3G5)/2<2.0 (2).