Endoscope Objective Optical System with Moving Middle Lens Group
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Solution Overview
Problem
Existing endoscope objective optical systems face challenges in achieving high image quality due to reduced sensitivity and contrast caused by smaller pixels and diffraction, particularly when using progressive read-out types or multi-plate image pickup units, and require a balance of optical specifications that is difficult to maintain with pan focusing.
Innovation Solution
The objective optical system for an endoscope incorporates a front lens group with negative refractive power, a middle lens group with positive refractive power consisting of multiple lens components, and a rear lens group with positive refractive power, where only one lens component from the middle lens group moves for focusing, optimizing the optical power arrangement to correct field curvature and aberrations while maintaining a compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the f-number is decreased to ensure sufficient image brightness for high precision imaging, then image brightness is improved, but depth of field becomes insufficient
Solution Approach 1:
The patent implements a focusing function by enabling lens movement within the objective optical system. This dynamic adjustment allows the system to maintain sufficient depth of field while preserving the low f-number configuration needed for high image brightness, resolving the contradiction between brightness and depth of field for high precision endoscopic imaging
2Adaptability or versatility
If a lens moving mount is added to provide focusing function, then focusing capability is improved, but device complexity and size increase
Solution Approach 1:
The patent integrates the focusing function directly into the existing lens barrel structure by enabling lens movement, rather than adding a separate lens moving mount. This merging approach provides the necessary focusing capability while minimizing increases in device complexity and size, suitable for compact endoscope designs
3Manufacturing precision
If multiple lens components are used in the middle lens group, then aberration correction is improved, but manufacturing complexity increases
Solution Approach 1:
The patent assigns specific refractive power characteristics to different lens groups: the front lens group has negative refractive power while the middle and rear lens groups have positive refractive power. This localized optimization of optical properties across different sections enables effective aberration correction through the coordinated action of multiple lens components, balancing manufacturing precision requirements with assembly feasibility
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 ensures high precision imaging with improved sensitivity and reduced aberrations, allowing for a wide field of view and effective focus adjustment with minimal fluctuations in image quality, while maintaining a compact and lightweight structure suitable for endoscope applications.
Implementation Method 1
a front lens group having negative refractive power
Implementation Method 2
a middle lens group having positive refractive power and a rear lens group having positive refractive power
Data Source
AI summary
An objective optical system is disclosed that is suitable for a high-precision endoscope that performs focusing by moving a single lens component. The objective optical system includes, in order from the object side, a front lens group, a middle lens group, and a rear lens group. The middle lens group is composed of two or more lens components, at least two of which have positive refractive power, and the lens component that is moved for focusing is in the middle lens group. Additionally, the objective optical system satisfies two specified conditions, and other conditions may apply.