Endoscope Optical System Wide Angle Aberration Control
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Solution Overview
Problem
Conventional endoscope optical systems have a narrow angle of view, making them unsuitable for wide-angle observations, and increasing negative refractive power leads to aberration issues, while adding more lenses increases size and complexity.
Innovation Solution
An endoscope optical system with a first positive lens group, an aperture diaphragm, and a second negative lens group, where focusing is achieved by the second lens group moving along the optical axis, satisfying specific conditional equations to maintain a wide angle of view while correcting aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the negative refractive power is increased to widen the angle of view, then the angle of view is improved, but off-axis aberration occurs
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive indices and curvatures of lens surfaces through conditional equations. Specifically, it sets constraints on the refractive index of the first lens (1.6 ≤ nd1 < 1.75) and the shape factor (H(76)*(1-nd01)/r2r1+r2)/(r1-r2)) to achieve wide angle of view while maintaining aberration correction.
Solution Approach 2:
The patent uses composite materials by combining multiple lens groups with different refractive properties. The optical system includes a first positive lens group, second negative lens group, and third positive lens group, where each group is designed with specific refractive index ranges to collectively achieve both wide field of view and aberration correction.
2Adaptability or versatility
If the second negative lens is disposed to widen the angle of view, then the angle of view is improved, but the diameter of the lens becomes large
Solution Approach 1:
The patent controls lens diameter by setting specific parameter ranges including the refractive index of the first lens (1.6 ≤ nd1 < 1.75) and the shape factor. These parameter constraints allow the optical system to achieve wide angle of view without requiring excessively large lens diameters.
Solution Approach 2:
The patent segments the optical system into three distinct lens groups (first positive, second negative, and third positive groups). This segmentation allows each group to be optimized independently for specific functions, enabling wide field of view while keeping individual lens sizes manageable.
3Reliability
If more lenses are added to correct aberration, then aberration correction is improved, but the device complexity and size increase
Solution Approach 1:
The patent achieves multi-functionality by designing each lens group to perform multiple functions simultaneously. For example, the first positive lens group not only corrects aberration but also contributes to achieving wide angle of view. This universal design reduces the total number of lenses needed while maintaining comprehensive optical performance.
Solution Approach 2:
The patent uses composite materials by combining three lens groups with different refractive properties (first positive, second negative, and third positive groups). Each group is designed with specific refractive index ranges that work synergistically to correct aberrations while maintaining a compact overall structure.
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 solution enables a smaller, cost-effective endoscope optical system with a wide angle of view and corrected aberrations, reducing the number of lenses and overall length.
Implementation Method 1
a first lens group having positive refractive power
Implementation Method 2
a second lens group having negative refractive power... focusing being performed by the second lens group moving along an optical axis
Implementation Method 3
an aperture diaphragm
Data Source
AI summary
An endoscope optical system has a first lens group having positive refractive power, an aperture diaphragm, a second lens group having negative refractive power and a third lens group having positive refractive group, the second lens group moving along an optical axis to perform focusing, the first lens group having a first lens having negative refractive power and a second lens having positive refractive power, and the optical system satisfying the following conditional equation:−5.0<H(76)*(1−nd01)/r2<−0.2 (1)0.5<(r1+r2)/(r1−r2)<1.2 (2)where H(76) is a height at which a principal ray having an incidence angle of view of 76 degrees during normal observation passes through a surface on an image side of the first lens, nd01 is a refractive index of the first lens with respect to a line d, and r1 and r2 are respectively curvature radii of surfaces on the object side and the image side of the first lens.