Zoom Lens Compactness via Aperture Segmentation
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Solution Overview
Problem
Existing zoom lens systems for interchangeable lens cameras face challenges in achieving a compact, lightweight design with excellent optical performance and sufficient aberration compensation across varying focal lengths.
Innovation Solution
A zoom lens system comprising a four-unit construction with a first lens unit having negative optical power, a second lens unit with positive optical power, a third lens unit having negative optical power, and a fourth lens unit with positive optical power, where the second lens unit is composed of an object-side and an image-side unit, and an aperture diaphragm is located between them, satisfying specific focal length and distance conditions to reduce overall length and outer diameter while maintaining high optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional zoom lens system is used, then the overall length and outer diameter are reduced, but optical performance and aberration compensation deteriorate
Solution Approach 1:
The lens system is divided into four distinct lens units with specific optical powers arranged in a particular sequence. The second lens unit is further segmented into object-side and image-side units with the aperture diaphragm positioned between them. This segmentation allows each unit to be optimized for specific functions while achieving compact overall dimensions.
Solution Approach 2:
Each lens unit is designed with specific optical power characteristics tailored to its position and function within the system. The negative optical power of the first and third units is optimized for specific aberration correction, while the positive optical power of the second and fourth units is optimized for specific focal length ranges. This local optimization enables compact design without sacrificing optical performance.
2Length of moving object
If a compact zoom lens system is used, then the overall length is reduced, but aberration compensation is insufficient
Solution Approach 1:
The patent specifies precise parameter relationships including the ratio of composite focal lengths of the second lens unit (f2O/f2I), the distance from the object-side second lens unit to the aperture diaphragm (d2O), and the focal length of the entire system at wide-angle limit (fW). By controlling these parameters within specific ranges, the system achieves compact dimensions while maintaining effective aberration compensation.
3Reliability
If the second lens unit is divided into object-side and image-side units with aperture diaphragm between them, then optical performance is improved, but device complexity increases
Solution Approach 1:
The second lens unit, despite being divided into object-side and image-side units with the aperture diaphragm between them, functions as an integrated optical element that performs multiple functions: correcting aberrations, controlling light paths, and contributing to the overall focal length. This multi-functionality justifies the increased construction complexity by delivering superior optical 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 results in a compact, lightweight zoom lens system with excellent optical performance and effective aberration compensation, enabling a reduced overall length and outer diameter while maintaining high imaging quality across the zoom range.
Implementation Method 1
a zoom lens system, in order from an object side to an image side, comprising a first lens unit having negative optical power, a second lens unit having positive optical power, a third lens unit having negative optical power, and a fourth lens unit having positive optical power
Implementation Method 2
an aperture diaphragm is located between the object-side second lens unit and the image-side second lens unit
Data Source
AI summary
A zoom lens system comprising a negative first lens unit, a positive second lens unit, a negative third lens unit, and a positive fourth lens unit, wherein the second lens unit is composed of an object-side second lens unit and an image-side second lens unit, the object-side second lens unit has positive optical power, an aperture diaphragm is located between the object-side second lens unit and the image-side second lens unit, and the conditions: −0.5<f2O/f2I<1.0 and 0.12<d2O/fW<0.35 (f2O: a composite focal length of the object-side second lens unit, f2I: a composite focal length of the image-side second lens unit, d2O: an optical axial distance from a most object side lens surface of the object-side second lens unit to the aperture diaphragm, fW: a focal length of the entire system at a wide-angle limit) are satisfied.