Five-Unit Zoom Lens Configuration for Compact Wide-Angle Distortion Control
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving compact size while maintaining high optical performance over the entire zoom range, particularly in correcting barrel-shaped distortion aberration at the wide-angle end.
Innovation Solution
A zoom lens configuration with specific refractive power arrangements and curvature radius relationships among lens units, including a first positive, second negative, and third positive lens units, with image-side negative lens units, and satisfying certain inequalities to optimize focal lengths and radii for compactness and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional zoom lens configuration is used, then optical performance can be maintained, but the overall lens length becomes excessive and the device becomes less compact
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive powers and focal lengths of individual lens units. Specifically, it sets the refractive power of the fourth lens unit within -0.03 to -0.06 times the inverse of the wide-angle focal length, and the fifth lens unit within 0.06 to 0.12 times the inverse of the wide-angle focal length. These parameter optimizations enable compact lens length while maintaining optical performance across the zoom range.
Solution Approach 2:
The zoom lens is divided into five distinct lens units with specific refractive power assignments (positive, negative, positive, negative, positive). This segmentation allows each unit to be optimized independently for its function, enabling the overall lens to achieve compact dimensions while correcting various aberrations and maintaining high optical performance throughout the zoom range.
2Reliability
If the number of lens units is increased to correct aberrations, then optical performance improves, but device complexity and mechanism sophistication increase
Solution Approach 1:
Rather than adding more lens units, the patent achieves superior aberration correction by optimizing the parameters of five lens units. The refractive powers are precisely controlled within specific ranges relative to the wide-angle focal length, and the curvature radii of lens surfaces are optimized. This parameter-based approach corrects barrel distortion, spherical aberration, and other optical imperfections without increasing mechanical complexity.
Solution Approach 2:
The patent combines multiple optical functions into a compact five-unit configuration. The alternating positive-negative refractive power arrangement allows single lens units to perform multiple functions (focusing, aberration correction, field curvature control), reducing the need for additional specialized lens units and simplifying the overall mechanism.
3Length of moving object
If lens units are arranged to achieve compact size, then overall length reduces, but optical performance and aberration correction deteriorate
Solution Approach 1:
The patent resolves this contradiction through precise parameter optimization. The fourth lens unit's refractive power is set between -0.03 and -0.06 times the inverse of the wide-angle focal length, and the fifth lens unit's refractive power is set between 0.06 and 0.12 times the inverse of the wide-angle focal length. These specific parameter ranges enable compact lens length while maintaining excellent optical performance and aberration correction across the entire zoom range.
Solution Approach 2:
Different regions of the optical system are assigned different refractive power characteristics tailored to their specific functions. The image-side lens units (fourth and fifth) have optimized refractive powers that specifically address aberrations in the compact configuration, while maintaining overall lens compactness. This localized optimization of optical properties enables simultaneous achievement of compact size and high performance.
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 zoom lens with a large zoom ratio, reduced overall length, and high optical performance across the zoom range, minimizing aberrations and shading, while allowing for size reduction and simplified lens mechanisms.
Implementation Method 1
a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a positive refractive power, which are arranged in order from the object side to the image side
Data Source
AI summary
A zoom lens ZL includes: a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens unit L3 having a positive refractive power, an N−1th lens unit, and an Nth lens unit, the lens units being arranged in order from an object side to an image side. The N−1th lens unit and the Nth lens unit are located on the image side with respect to an aperture stop SP.