Compact Zoom Lens System Aberration Correction
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Solution Overview
Problem
Conventional zoom lens systems for electronic imaging apparatuses are bulky due to a large number of lens elements and inadequate refractive power balance, leading to unsatisfactory correction of aberrations such as field curvature, astigmatism, distortion, spherical aberration, and coma, which deteriorate optical performance.
Innovation Solution
A compact zoom lens system comprising a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group, where the second and third lens groups move along the optical axis to adjust distances, and the fourth lens group includes specific lens elements and refractive index conditions to optimize focal length ratios and Abbe numbers, ensuring effective aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of lens elements are used in the zoom lens system, then aberration correction is improved, but the system becomes bulky and heavy
Solution Approach 1:
The patent applies parameter changes by carefully selecting and optimizing the refractive indices and Abbe numbers of lens materials. Specifically, it uses a positive lens with refractive index 1.505-1.600 and Abbe number 80-96, and a negative lens with refractive index 1.600-1.700 and Abbe number 20-40, to achieve effective aberration correction with fewer lens elements, thereby reducing weight while maintaining optical performance
Solution Approach 2:
The patent employs composite material principles by combining lens elements with different optical properties (different refractive indices and Abbe numbers) into a cemented lens structure. This allows the system to achieve superior aberration correction through material composition rather than simply increasing the number of elements, thus avoiding weight increase
2Reliability
If more lens elements are added to the fourth lens group, then optical performance is improved, but the device complexity increases
Solution Approach 1:
The patent reduces device complexity by changing material parameters instead of increasing element count. The fourth lens group uses a positive lens with refractive index 1.505-1.600 and Abbe number 80-96 combined with a negative lens with refractive index 1.600-1.700 and Abbe number 20-40, achieving excellent aberration correction with only two lens elements rather than multiple elements
Solution Approach 2:
The patent applies composite material principles by creating a cemented lens structure that combines a positive lens and negative lens with specifically selected optical properties. This composite structure achieves superior aberration correction functionality that would otherwise require multiple separate elements, thereby simplifying the overall lens group design
3Ease of operation
If the refractive power balance between lens groups is not optimized, then zooming performance is improved, but aberration correction deteriorates
Solution Approach 1:
The patent optimizes refractive power balance by precisely controlling the refractive indices and Abbe numbers of lens materials in each group. The fourth lens group uses a positive lens with refractive index 1.505-1.600 and Abbe number 80-96 combined with a negative lens with refractive index 1.600-1.700 and Abbe number 20-40, achieving both smooth zooming and excellent aberration correction through parameter optimization rather than structural complexity
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 results in a lightweight zoom lens system with improved optical performance by reducing aberrations and maintaining consistent length during zooming and focusing, achieving higher image quality with fewer lens elements.
Implementation Method 1
a positive lens element having a convex surface on the object side
Implementation Method 2
a cemented lens formed from a positive lens element having a convex surface on the object side and a negative lens element having a concave surface on the image side
Implementation Method 3
a biconvex positive lens element
Implementation Method 4
a negative meniscus lens element having a convex surface on the image side
Data Source
AI summary
A zoom lens system includes a positive first lens group, a negative second lens group, and positive third and fourth lens groups, in that order from the object side. Upon zooming from the short to long focal length extremities, the first lens group does not move along the optical axis direction, and the second lens group and the third lens group are movable in the optical axis direction. The first lens group includes at least one negative lens element, and the following conditions are satisfied:νd1n<22.85and−8.0<f3/f2<−3.0,whereinνd1n designates the Abbe number, with respect to the d-line, of the negative lens element, which is provided closest to the object side within the first lens group, and f2 and f3 designate the focal lengths of the second and third lens groups, respectively.