Zoom Lens Aberration Control via Segmented Units
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a wide field angle, high zoom ratio, and compact size while maintaining high optical performance over the entire zoom range, due to increased aberration variation and complex lens barrel structures required for refractive power enhancement and aperture correction.
Innovation Solution
A zoom lens design comprising a first lens unit with negative refractive power, a second lens unit with positive refractive power, and a third lens unit with positive refractive power, where all units move during zooming, and a secondary aperture with a constant diameter is placed on the image side of the second lens unit, satisfying specific conditional expressions to optimize lens positioning and movement ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the refractive power of each lens unit is enhanced to downsize the entire system and achieve high zoom ratio, then the system size is reduced and zoom ratio is increased, but aberration variation due to zooming increases making it difficult to obtain high optical performance
Solution Approach 1:
The zoom lens is divided into three lens units with specific refractive power distributions. The first lens unit has negative refractive power, the second has positive refractive power, and the third has positive refractive power. This segmentation allows each unit to contribute differently to the overall optical performance, enabling compact size while controlling aberration variation through coordinated movement of the segmented units during zooming.
Solution Approach 2:
The invention changes the refractive power parameters of individual lens units rather than uniformly enhancing all units. By setting the first lens unit with negative refractive power and the second and third units with positive refractive power, and by controlling their movement amounts during zooming, the system achieves high zoom ratio with controlled aberration variation.
2Reliability
If the number of lenses is increased to correct aberration sufficiently, then optical performance is improved, but the total lens length in the retracted state increases making it difficult to downsize the camera
Solution Approach 1:
Instead of increasing the number of lenses within each unit, the invention segments the zoom lens into three functional units with different refractive power characteristics. This allows aberration correction to be distributed across the units through their coordinated movement, achieving sufficient optical performance without increasing the total lens length in retracted state.
Solution Approach 2:
The invention employs dynamic movement of the three lens units during zooming and focusing operations. By controlling the movement amounts and directions of each unit, the system achieves aberration correction through spatial reconfiguration rather than through increased lens count, maintaining compact dimensions.
3Adaptability or versatility
If a wide field angle and high zoom ratio are attained without appropriate setting of the lens structure, then the field angle and zoom ratio are increased, but the front lens effective diameter increases causing the size of the entire zoom lens to increase
Solution Approach 1:
The invention applies local quality by assigning different refractive power characteristics to different lens units. The first lens unit has negative refractive power to control the field angle, while the second and third units have positive refractive power to achieve high zoom ratio. This localized optimization of optical properties allows wide field angle and high zoom ratio without increasing the front lens effective diameter.
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 design achieves a compact, high-performance zoom lens with a wide field angle and high zoom ratio, effectively suppressing aberrations and maintaining optical performance across the zoom range without increasing the lens system's size or complexity.
Implementation Method 1
a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power
Data Source
AI summary
Provided is a zoom lens including, in order from an object side to an image side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a positive refractive power, all the lens units moving during zooming; and a secondary aperture having a constant aperture diameter disposed on the image side of the second lens unit, in which the second lens unit includes lens components having a positive refractive powers disposed at a position closest to the object side and a position closest to the image side, and a distance (dd) on an optical axis between a lens surface closest to the image side in the second lens unit and the secondary aperture, and a focal length (fw) of the entire zoom lens at a wide angle end are appropriately set.