Zoom Lens Six-Group Configuration for Compact Balance
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Solution Overview
Problem
Conventional zoom lenses face challenges in achieving a balance between focusing speed, compactness, and optical system stability due to the weight and size issues associated with zooming and focusing, leading to difficulties in maintaining a stable balance and efficient zooming performance, especially in high zoom ratio and wide-angle applications.
Innovation Solution
A zoom lens configuration with six lens groups, including a first positive lens group, a second negative lens group, a third negative lens group, a fourth positive lens group, a fifth positive lens group, and a last positive lens group, where the second and third lens groups move during zooming, and the fourth, fifth, and last groups move for focusing, with specific movements and fixed positions to optimize weight distribution and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the first lens group is fixed and the fourth lens group moves for focusing, then the focusing speed is increased and the lens becomes more compact, but the overall optical system becomes larger and the balance is not stabilized
Solution Approach 1:
The lens is divided into six separate lens groups (G1-G6) with different refractive powers, where each group can move independently or remain fixed. This segmentation allows the front portion (G1) to be fixed for stability while rear groups (G4-G6) move for focusing, resolving the contradiction between focusing speed and balance stability.
Solution Approach 2:
Multiple lens groups with positive and negative refractive powers are combined in a specific sequence (G1:+, G2:-, G3:-, G4:+, G5:+, G6:+) to achieve both compactness and stable balance. The combination of positive and negative power groups allows for corrected aberrations and balanced weight distribution.
2Adaptability or versatility
If zooming and focusing are carried out always, then the lens functionality is complete, but the weight increases and the focusing speed is governed by the lens weight
Solution Approach 1:
The lens is segmented into six groups where only specific groups (G2, G3 for zooming; G4, G5, G6 for focusing) move while others (G1) remain fixed. This reduces the overall moving weight compared to a design where the entire lens moves for both zooming and focusing, while maintaining complete functionality.
Solution Approach 2:
Different lens groups are assigned different movement characteristics: G2 and G3 move for zooming, while G4, G5, and G6 move for focusing. This dynamic assignment allows the lens to achieve both zooming and focusing functions with optimized weight distribution and movement efficiency.
3Manufacturing precision
If a fifth lens group is added to the image side of the fourth lens group, then the aberration correction is improved, but the device complexity increases
Solution Approach 1:
The lens is divided into six groups where G5 is specifically positioned between G4 and G6. This segmentation allows G5 to serve as a dedicated aberration correction group without significantly increasing overall complexity, as each group has a defined function and movement pattern.
Solution Approach 2:
The fifth lens group (G5) with positive refractive power serves multiple functions: it corrects aberrations introduced by previous groups, contributes to the overall zooming function when moved, and assists in focusing when combined with G4 and G6. This multi-functionality justifies the added 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
This configuration enhances zooming efficiency, stabilizes the optical system, and corrects various aberrations effectively, allowing for a high zoom ratio and wide-angle performance while maintaining a compact and balanced design.
Implementation Method 1
a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and a last lens group having a positive refractive power
Data Source
AI summary
A zoom lens includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and a last lens group having a positive refractive power. At the time of zooming from a wide angle end to a telephoto end, the second lens group and the third lens group move, and one of the fourth lens group, the fifth lens group, and the last lens group moves.