Zoom Lens Aberration Control via Segmented Groups
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional zoom lens systems face challenges in achieving high optical performance due to increased variations in aberrations and the generation of flare or ghost images, especially when the zoom ratio is high, which affects image quality and correction of image blur.
Innovation Solution
A zoom lens system comprising specific lens groups with varying distances and refractive powers, along with an aperture stop placement, that satisfies certain conditional expressions to control aberrations and flare, including a configuration of a first lens group with positive refractive power, a second lens group with negative refractive power, and additional groups with varying refractive powers, and an aperture stop disposed to the image side of the second lens group, optimizing focal lengths and aperture diameters across zoom states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the zoom ratio is increased to achieve higher magnification, then the telephoto capability is improved, but variations in aberrations increase and optical performance deteriorates
Solution Approach 1:
The zoom lens system is divided into five lens groups (G1 to G5) with alternating positive and negative refractive powers. Each lens group is independently movable, allowing precise control of aberrations at different zoom positions. The segmentation enables the system to maintain high optical performance across the entire zoom range by adjusting individual lens groups to compensate for aberration variations.
Solution Approach 2:
Different lens groups are assigned specific functions to correct particular types of aberrations. For example, the second negative lens group (G2) and fourth negative lens group (G4) are specifically designed and positioned to correct chromatic aberrations and spherical aberrations that occur at different zoom positions. This localized optimization ensures that each part of the system contributes to maintaining overall optical quality.
2Adaptability or versatility
If the zoom ratio is increased to achieve higher magnification, then the telephoto capability is improved, but variations in aberrations upon correcting image blur increase
Solution Approach 1:
The lens groups are designed to move dynamically during zooming operations. Specifically, the first positive lens group (G1) moves in the opposite direction to the second negative lens group (G2), and the third positive lens group (G3) moves in coordination with the fourth negative lens group (G4). This dynamic movement allows the system to maintain proper optical compensation and aberration correction across all focal lengths, including during image blur correction operations.
Solution Approach 2:
The system changes multiple optical parameters simultaneously during zooming and focus adjustment. The focal lengths of individual lens groups are adjusted by changing their relative positions, and the aperture stop diameter is varied to control the cone angle of incident light. These parameter changes enable the system to maintain optimal aberration correction precision across the entire operating range.
3Device complexity
If conventional zoom lens system design is used, then the structure is simpler, but optical surfaces generate reflection light causing flare or ghost images
Solution Approach 1:
The patent converts the harmful effect of reflection at optical surfaces into a beneficial outcome by strategically designing the alternating positive-negative lens group configuration. This configuration causes reflection light to undergo multiple refractions and direction changes that ultimately direct the flare and ghost image-forming rays away from the image sensor. The system transforms potential harmful reflections into controlled light paths that do not degrade image quality.
Solution Approach 2:
Different lens groups are designed with specific refractive powers and curvatures optimized to control reflection behavior. The negative lens groups (G2 and G4) are particularly designed to diverge reflection light, while the positive lens groups (G1 and G3) are designed to control the overall light path. This localized optimization of each lens group's optical properties effectively suppresses flare and ghost images without requiring complex additional components.
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 effectively suppresses variations in aberrations and reduces flare and ghost images, ensuring excellent optical performance across the zoom range from wide-angle to telephoto end states, maintaining high image quality and correcting distortion effectively.
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; a fourth lens group having negative refractive power; and a fifth lens group having positive refractive power
Data Source
AI summary
In a zoom lens system, an optical apparatus, and a manufacturing method, there are provided, in order from an object side: a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, a fourth lens group having negative power, a fifth group having positive power, and an aperture stop disposed to an image side of the second lens group. Upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens and second lens groups increases, a distance between the second and third lens groups decreases, a distance between the third and fourth lens groups varies, and a distance between the fourth and fifth lens groups varies. With given conditions being satisfied, high optical performance with suppressing variation in aberrations are achieved.