Zoom Lens High Refractive Index Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional zoom lenses face challenges in achieving a high zoom ratio while maintaining excellent optical performance and compactness.
Innovation Solution
A zoom lens configuration comprising a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a fourth lens group with positive refractive power, where the distances between these groups change upon zooming, with specific refractive index conditions and aspherical surfaces to optimize optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional zoom lens configurations are used, then the total lens length can be kept short, but the zoom ratio cannot be increased while maintaining excellent optical performance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive indices of lens elements through the conditional expressions. By specifying that Nd11 (refractive index of the negative lens in the first lens group) must satisfy 1.90 < Nd11 < 2.30, and similarly constraining Nda and Ndb for other lens groups, the invention optimizes optical performance while achieving high zoom ratio. This parameter optimization allows the lens to maintain excellent aberration correction across the zoom range without increasing total length.
Solution Approach 2:
The zoom lens is divided into four distinct lens groups with specific configurations: first lens group (positive power with negative lens + positive meniscus lens), second lens group (negative power with two negative lenses + positive meniscus lens), third lens group (positive power), and fourth lens group (positive power). This segmentation allows each group to perform specific optical functions, enabling high zoom ratio while maintaining compact overall length and excellent optical performance through coordinated movement of the grouped elements.
2Adaptability or versatility
If the zoom ratio is increased, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The fourth lens group, consisting of a single positive lens element, serves multiple functions: it contributes to the overall positive power of the system, helps correct aberrations, and acts as the focusing element. This multi-functional design reduces complexity compared to having separate dedicated elements for each function, allowing high zoom ratio to be achieved without proportionally increasing device complexity.
Solution Approach 2:
The patent employs dynamic movement of lens groups during zooming operations. The distances between the first and second lens groups, second and third lens groups, and third and fourth lens groups all change upon zooming from wide-angle to telephoto end. This dynamic reconfiguration of inter-group distances enables high zoom ratio while maintaining a relatively compact structure, as the same physical elements serve different optical roles at different zoom positions.
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 compact zoom lens with high optical performance and a relatively high zoom ratio, effectively correcting various aberrations across different focal lengths.
Implementation Method 1
a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power
Data Source
AI summary
The present invention provides a zoom lens ZL comprising a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having positive refractive power, the first lens group G1 including a negative meniscus lens L11 and a positive meniscus lens L12, the second lens group G2 including a negative meniscus lens L21, a biconcave negative lens L22 and a positive meniscus lens L23, and the fourth lens group G4 including one positive lens L41, and the refractive indexes of at least three lenses in the zoom lens ZL being greater than 1.9.