Zoom Lens First Unit Aberration Correction
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Solution Overview
Problem
Existing zoom lenses with high zoom ratios struggle to achieve a wide angle of view, high optical performance, and reduced size while effectively correcting chromatic aberration and spherical aberration across the entire zoom range, particularly at the telephoto end.
Innovation Solution
A zoom lens design featuring a first lens unit with a specific configuration of at least six lenses, including a negative refractive power lens closest to the object side, and a second lens unit with a negative refractive power, optimized by conditional expressions for refractive power, Abbe number, and partial dispersion ratio to correct chromatic aberration and spherical aberration, allowing for a wide angle of view, high zoom ratio, and reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the zoom lens is designed to achieve a wider angle of view and higher magnification, then the angle of view and zoom ratio are improved, but chromatic aberration at the telephoto end becomes undercorrected
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive powers and glass materials of the lenses in the first lens unit. Specifically, it sets the refractive power of the negative lens closest to the object side and the Abbe numbers of positive lenses to satisfy specific conditional expressions, which corrects chromatic aberration at the telephoto end while maintaining wide angle of view and high zoom ratio capabilities
Solution Approach 2:
The patent uses composite materials by selecting specific glass materials with appropriate Abbe numbers for the lenses in the first lens unit. The combination of positive and negative lenses with different glass materials (different dispersion properties) creates a composite optical system that corrects chromatic aberration while achieving the desired wide angle of view and high magnification
2Device complexity
If the first lens unit uses conventional refractive powers and glass materials, then the lens structure is simple, but chromatic aberration at the telephoto end is undercorrected when designed for wide angle of view and high magnification
Solution Approach 1:
The patent changes the optical parameters by defining specific conditional expressions for the refractive powers and Abbe numbers of lenses in the first lens unit. This optimized parameter selection corrects chromatic aberration without requiring additional lens elements, thus maintaining structural simplicity while achieving high optical performance
3Device complexity
If existing zoom lens designs are used, then the basic structure is established, but optical performance from the center to the periphery of the field is insufficient at high zoom ratios
Solution Approach 1:
The patent applies local quality by optimizing the specific lenses within the first lens unit, particularly the negative lens closest to the object side and the positive lenses with specific Abbe numbers. This localized optimization of refractive powers and glass materials in critical positions improves optical performance uniformity from center to periphery while maintaining the basic zoom lens 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 design achieves high optical performance and reduced size with improved correction of chromatic and spherical aberrations across the entire zoom range, enhancing the lens's ability to maintain image quality from the center to the periphery.
Implementation Method 1
a first lens unit having a positive refractive power configured not to be moved for zooming
Implementation Method 2
correct chromatic aberration and spherical aberration
Implementation Method 3
correct chromatic aberration and spherical aberration
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
A zoom lens consists of, in order from the object side to the image side, a first lens unit having a positive refractive power and configured not to be moved for zooming, a second lens unit having a negative refractive power and configured to be moved for zooming, and a rear lens group including at least one lens unit. The first lens unit includes at least six lenses, a lens closest to the object side included in the first lens unit is a negative lens, and the zoom lens satisfies conditional expressions −1.65<fln/fl<−1.10, 37<vln<48, and 87<vpave<100, where f1n is a focal length of the negative lens, v1n is an Abbe number of the negative lens with respect to d-line, f1 is a focal length of the first lens unit, and vpave is an average of Abbe numbers of positive lenses included in the first lens unit with respect to d-line.