Zoom Lens Aberration Correction via Aspheric Extraction
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a compact size, reduced weight, high optical performance, and cost-effectiveness while maintaining aberration correction, especially with the placement of aspheric lenses and the need for high-speed zoom operation.
Innovation Solution
A zoom lens configuration comprising multiple units with specific refractive powers, where the first and fourth lens units are fixed relative to the image plane during zooming, and the second and third lens units move, utilizing spherical lenses in the second unit to correct aberrations and incorporating aspheric surfaces for distortion correction, while adhering to specific focal length and movement ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aspheric lens is placed in the second lens unit, then aberration correction is improved, but manufacturing difficulty increases and cost increases
Solution Approach 1:
The aspheric lens is extracted from the second lens unit and relocated to the third lens unit. This extraction resolves the contradiction by removing the source of manufacturing difficulty while preserving aberration correction functionality through the aspheric surface in a different position where it does not increase manufacturing complexity.
Solution Approach 2:
The third lens unit serves as an intermediary position for placing the aspheric lens. By positioning the aspheric surface in the third lens unit rather than the second, the patent finds a mediating solution that maintains aberration correction benefits while avoiding the manufacturing difficulties associated with high on-axis ray height positions.
2Productivity
If the first lens unit is fixed during zooming, then zoom operation speed is improved, but aberration correction deteriorates
Solution Approach 1:
The patent implements a dynamic zooming mechanism where the first lens unit remains fixed during zooming operations, while the second and third lens units move. This dynamic arrangement maintains high-speed zoom operation by minimizing moving mass, while the specific movement patterns of the second and third lens units preserve aberration correction throughout the zoom range.
Solution Approach 2:
The patent changes the operational parameters of the lens units during zooming: the first lens unit is kept stationary (parameter: position = fixed), while the second and third lens units are moved to specific positions that maintain optimal aberration correction. This parameter change strategy resolves the contradiction by decoupling the zoom speed requirement from the aberration correction requirement.
3Weight of moving object
If the zoom lens is made compact and lightweight, then portability is improved, but optical performance deteriorates
Solution Approach 1:
The zoom lens is segmented into four distinct lens units with specific refractive powers arranged in sequence. This segmentation allows for optimized distribution of optical functions across compact dimensions, achieving both weight reduction through minimized individual unit sizes and maintained optical performance through careful arrangement of the segmented units with specific focal length ratios.
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 enables a compact, lightweight zoom lens with high image quality, easy manufacturing, and high-speed zoom operation, effectively correcting aberrations and maintaining optical performance across the zoom range.
Implementation Method 1
a first lens unit L1 having negative refractive power, a second lens unit L2 having positive refractive power, a third lens unit L3 having negative refractive power, and a fourth lens unit L4 having positive refractive power
Data Source
AI summary
A zoom lens includes a plurality of lens units that consist of, in order from an object side to an image side, a first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having negative refractive power, and a fourth lens unit having positive refractive power. A distance between adjacent lens units changes during zooming from a wide-angle end to a telephoto end. During zooming from a wide-angle end to a telephoto end, the first lens unit and the fourth lens unit are fixed relative to an image plane, and the third lens unit moves to the object side. During focusing from infinity to a shortest distance, the first lens unit is fixed relative to the image plane. The second lens unit consists of four or more spherical lenses. A predetermined inequality is satisfied.