Zoom Lens Aberration Correction via Multi-Unit Movement
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Solution Overview
Problem
Imaging optical systems for imaging apparatuses face challenges in achieving high optical performance, high zoom ratio, and small size, with existing designs experiencing magnification chromatic aberrations and field curvature issues at the wide angle end, and lengthening of the total lens length due to excessive refractive power in lens units.
Innovation Solution
A zoom lens configuration comprising a first positive refractive power unit, a second negative refractive power unit, a third positive refractive power unit, and a subsequent group of three or more lens units, where the first, third, and subsequent units move towards the object side during zooming, and the second unit moves convex towards the image side, satisfying specific focal length ratios to correct aberrations and maintain a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the second lens unit has a high refractive power to achieve high zoom ratio, then the zoom ratio is improved, but magnification chromatic aberrations increase at wide angle end
Solution Approach 1:
The zoom lens is divided into multiple lens units (first through sixth lens units) with different refractive powers arranged in sequence. The second lens unit with negative refractive power is specifically designed to counteract the chromatic aberrations generated by the first lens unit with positive refractive power, while still achieving high zoom ratio through coordinated movement of all lens units.
2Productivity
If the second lens unit has a high refractive power to achieve high zoom ratio, then the zoom ratio is improved, but changes in field curvature become significant
Solution Approach 1:
Each lens unit is assigned a specific refractive power characteristic (positive or negative) to address particular optical issues at its location in the optical path. The second lens unit with negative refractive power specifically addresses field curvature changes, while other lens units handle different aspects of optical performance, allowing high zoom ratio without significant field curvature degradation.
3Manufacturing precision
If lens units are arranged to correct aberrations to achieve high optical performance, then optical performance is improved, but total lens length increases
Solution Approach 1:
The zoom lens employs dynamic movement of multiple lens units during zooming operations. The first, third, fourth, fifth, and sixth lens units move toward the object side, while the second lens unit moves in a trajectory convex toward the image side. This coordinated dynamic adjustment allows the lens to maintain high optical performance across the zoom range while keeping the total lens length relatively compact.
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 achieves high optical performance, a high zoom ratio, and a small size by effectively correcting various aberrations and maintaining a short total lens length, preventing excessive movement and curvature issues while ensuring a high zoom ratio.
Implementation Method 1
a first lens unit B1 having a positive refractive power, a second lens unit B2 having a negative refractive power, a third lens unit B3 having a positive refractive power
Data Source
AI summary
A zoom lens comprises a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a subsequent group including three or more lens units, arranged in this order from an object side toward an image side, wherein in zooming from a wide angle end toward a telephoto end, the first lens unit, the third lens unit and all the lens units of the subsequent group move toward the object side, and the second lens unit moves in a trajectory that is convex toward the image side, and wherein predetermined inequalities are satisfied.