Zoom Lens System Compact Design Optical Performance
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Solution Overview
Problem
Existing zoom lens systems for interchangeable lens camera systems face challenges in achieving compact, lightweight designs with high resolution and excellent optical performance across a wide range of focal lengths while minimizing lens unit movement and fluctuations in the angle of view during wobbling, especially for moving image capture.
Innovation Solution
A zoom lens system comprising a first negative lens unit, a second positive lens unit, a third negative lens unit, and a fourth positive lens unit, where the first, second, and third lens units move along the optical axis during zooming, and the third lens unit moves for focusing, satisfying specific conditions for lateral magnification and back focal length to optimize optical performance and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multiple-unit configuration with negative lens unit closest to object side is used, then optical performance from wide-angle to telephoto limit is improved, but device complexity and size increase
Solution Approach 1:
The zoom lens system is divided into four distinct lens units (G1, G2, G3, G4) with alternating negative and positive optical powers. Each lens unit is independently configured and positioned to perform specific optical functions, allowing the system to achieve high optical performance across the zoom range while managing complexity through functional segmentation.
Solution Approach 2:
The patent specifies precise parameter ranges for the lens units, including focal length ratios (0.30 < |f1/fW| < 1.00, 0.70 < |f3/fW| < 2.00) and magnification constraints (2.5 ≤ |(1-β3T²)×β4T²| ≤ 7.0). These parameter optimizations enable compact design while maintaining excellent optical performance from wide-angle to telephoto limits.
2Reliability
If first, second, and third lens units move during zooming, then zooming performance is improved, but device complexity and weight increase
Solution Approach 1:
The zoom mechanism is segmented into three independently movable lens units (G1, G2, G3), each with specific movement characteristics. The fourth lens unit (G4) remains fixed, reducing the overall moving mass. This segmentation allows optimized zooming performance while minimizing weight by limiting movement to only the necessary lens units.
Solution Approach 2:
The patent defines specific movement parameters and constraints for each lens unit during zooming, with the zooming ratio set between 2.0 and 10.0. The coordinated movement of G1, G2, and G3 along the optical axis achieves high-quality zooming while controlling weight through optimized movement paths and ranges.
3Reliability
If third lens unit moves for focusing, then focusing ability is improved, but lens unit movement amount increases
Solution Approach 1:
The third lens unit (G3) with negative optical power is specifically positioned and configured to perform the focusing function. By concentrating the focusing action in this single lens unit rather than distributing it across multiple units, the patent achieves excellent focusing ability while controlling the overall movement amount to 0.30 < |M3/fW| < 1.30.
Solution Approach 2:
The patent optimizes the movement parameter M3 of the third lens unit with the constraint 0.30 < |M3/fW| < 1.30, where M3 is the movement amount for focusing and fW is the focal length at wide-angle limit. This parameter optimization enables effective focusing while minimizing lens unit movement, contributing to compact design suitable for moving image capture.
4Weight of moving object
If compact and lightweight design is achieved, then portability is improved, but optical performance and resolution may deteriorate
Solution Approach 1:
The patent employs precise parameter optimization across all lens units, including focal length ratios (0.30 < |f1/fW| < 1.00, 0.70 < |f3/fW| < 2.00), magnification constraints (2.5 ≤ |(1-β3T²)×β4T²| ≤ 7.0), and back focal length ratios (0.50 ≤ BfW/fW ≤ 4.00). These optimized parameters enable compact and lightweight design while maintaining high resolution and excellent optical performance throughout the zoom range.
Solution Approach 2:
The four-unit configuration with alternating negative and positive powers allows compact arrangement of optical elements. By segmenting the system into functional units with specific roles, the patent achieves space-efficient design that reduces overall size and weight while preserving high optical performance and resolution from wide-angle to telephoto limits.
5Reliability
If lens units are optimized for high resolution, then image quality is improved, but lens unit movement and angle of view fluctuations increase
Solution Approach 1:
The patent defines specific parameter ranges that simultaneously optimize image quality and stability: zooming ratio 2.0-10.0, focal length ratios 0.30 < |f1/fW| < 1.00 and 0.70 < |f3/fW| < 2.00, magnification constraint 2.5 ≤ |(1-β3T²)×β4T²| ≤ 7.0, and back focal length ratio 0.50 ≤ BfW/fW ≤ 4.00. These coordinated parameter optimizations ensure high resolution and image quality while suppressing angle of view fluctuations during wobbling, making the system suitable for moving image capture.
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 provides a compact and lightweight zoom lens system with high resolution and reduced lens unit movement, effectively addressing the challenges of maintaining optical performance and stability during zooming and focusing, making it suitable for moving image capture.
Implementation Method 1
the first lens unit, the second lens unit, and the third lens unit move along an optical axis in zooming from a wide-angle limit to a telephoto limit
Implementation Method 2
the third lens unit moves along the optical axis in focusing from an infinity in-focus condition to a close-object in-focus condition
Data Source
AI summary
A zoom lens system, in order from an object side to an image side, comprising: a negative first lens unit; a positive second lens unit; a negative third lens unit; and a positive fourth lens unit, wherein the first, second and third lens units move along an optical axis in zooming, the third lens unit moves along the optical axis in focusing, and the conditions: 2.5≦|(1−(β3T)2)×(β4T)2|≦7.0 and 0.5≦BfW/fW≦4.0 (β3T: a lateral magnification of the third lens unit at an infinite object point distance at the telephoto limit, β4T: a lateral magnification of the fourth lens unit at an infinite object point distance at the telephoto limit, BfW: a back focal length of the zoom lens system at the wide-angle limit, fW: a focal length of the zoom lens system at the wide-angle limit) are satisfied.