Wide Angle Lens Cemented Group Aberration Correction
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Solution Overview
Problem
Wide angle lenses with cemented lenses positioned to the image side of a diaphragm face challenges in reducing aberrations and maintaining stable manufacturing due to small radius of curvature, leading to deteriorated resolution and increased chromatic aberration.
Innovation Solution
A wide angle lens configuration with five groups of six lenses, where the fourth lens with positive power is placed to the rear side of the diaphragm, forming a cemented lens with a plastic fifth and sixth lens, and specific refracting power and Abbe number conditions are met to correct chromatic and other aberrations, allowing for a larger radius of curvature and stable manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cemented lens is disposed to the rear side of a diaphragm, then chromatic aberration is improved, but the absolute value of the radius of curvature of the cemented faces becomes extremely small making manufacturing unstable
Solution Approach 1:
The patent changes the spatial dimension by moving the cemented lens from the rear side of the diaphragm to the object side of the diaphragm. This dimensional repositioning in the optical path allows the cemented lens to correct chromatic aberration while maintaining a manufacturable radius of curvature, as the object-side position provides greater design flexibility for curvature parameters.
Solution Approach 2:
The patent applies parameter changes by adjusting the radius of curvature of the cemented lens faces and the position of the cemented lens relative to the diaphragm. By changing these parameters, the design achieves both effective chromatic aberration correction and manufacturing stability, avoiding the extremely small radius of curvature that occurs when the cemented lens is placed at the rear side of the diaphragm.
2Ease of manufacture
If a cemented lens is disposed to the rear side of a diaphragm, then cost is reduced, but other aberrations remain and resolution is deteriorated
Solution Approach 1:
The patent repositions the cemented lens to the object side of the diaphragm, changing its spatial dimension in the optical path. This new position allows the cemented lens to effectively correct not only chromatic aberration but also other aberrations such as spherical aberration and coma, thereby improving resolution while maintaining cost-effectiveness through the use of a cemented lens structure.
3Manufacturing precision
If the absolute value of the radius of curvature of cemented faces is extremely small, then chromatic aberration is corrected, but manufacturing and cementing are not performed stably
Solution Approach 1:
The patent changes the radius of curvature parameter of the cemented lens faces from extremely small values to moderate values that are manufacturable. By adjusting this parameter along with the lens position, the design achieves effective chromatic aberration correction without compromising manufacturing reliability, as moderate curvature values are more stable during lens fabrication and cementing processes.
4Adaptability or versatility
If a wide angle lens is designed with viewing angle of 90° or more, then viewing angle is improved, but aberration increases and resolution is deteriorated
Solution Approach 1:
The patent segments the optical system into multiple lens groups with specific functions: the first and second lens groups for wide angle coverage, the third lens group for aberration correction, and the fourth cemented lens group for chromatic aberration correction. This segmentation allows each group to be optimized for its specific function, enabling the overall system to achieve both wide viewing angle and high resolution.
Solution Approach 2:
The patent uses a composite lens structure where the fourth group consists of two different lenses cemented together with different refractive indices and Abbe numbers. This composite structure enables effective correction of chromatic aberration across the wide viewing angle, allowing the lens to maintain high resolution while providing 90° or more viewing angle.
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 effectively reduces magnification chromatic aberration, field curvature, distortion, and astigmatism, enabling high-pixel imaging and stable manufacturing of the cemented lens, while maintaining a wide viewing angle and suppressing temperature-related resolution changes.
Implementation Method 1
a cemented lens obtained by cementing plastic lenses together is disposed as the fourth group to a rear side (image side) of the diaphragm... improvement of chromatic aberration
Implementation Method 2
a first lens which is a first lens from an object side whose convex surface is directed to the object side and its concave surface is directed to an image side
Data Source
AI summary
A wide angle lens may include a first lens having a negative power with a convex surface on an object side and a concave surface on an image side, a second lens having a negative power with a concave surface on the image side, a third lens having a positive power with a convex surface on the image side, a fourth lens having a positive power with a convex surface on the image side, a fifth lens being a plastic lens with a negative power with a concave surface on the object side and a concave surface on the image side, a sixth lens being a plastic lens with a positive power with a convex surface on the object side and a convex surface on the image side, and a diaphragm disposed between the third and fourth lenses. The fifth and sixth lenses constitute a cemented lens.