Zoom Lens Aberration Control via Segmented Optical Power
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Solution Overview
Problem
Existing zoom lens systems face challenges in achieving a high zooming ratio with reduced aberration fluctuation, especially in close-object in-focus conditions, while maintaining compactness and lightweight design.
Innovation Solution
A zoom lens system with a specific configuration where the lens unit closest to the object side has positive optical power and a focusing lens unit with negative optical power moves along the optical axis, satisfying conditions that optimize focal length and axial thickness relationships to minimize aberrations and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a zoom lens system is designed to achieve high zooming ratio, then the zooming capability is improved, but aberration fluctuation increases especially in close-object in-focus conditions
Solution Approach 1:
The lens system is divided into multiple lens units with specific positive and negative optical powers arranged in sequence. The first lens unit has positive optical power, the second lens unit has negative optical power, and the third lens unit has positive optical power. This segmentation allows independent optimization of each unit's contribution to aberration control while maintaining high zooming ratio.
Solution Approach 2:
Different regions of the lens system are assigned different optical powers and functions. The first lens unit (positive power) handles wide-angle coverage, the second lens unit (negative power) controls aberrations during zooming, and the third lens unit (positive power) optimizes close-object focusing. This local differentiation of optical properties reduces aberration fluctuation across the entire focusing range.
2Weight of moving object
If the lens system is made compact and lightweight, then the device size is reduced, but aberration compensation capability may be compromised
Solution Approach 1:
The optical powers of the lens units are carefully parameterized: the first lens unit has positive optical power, the second has negative optical power, and the third has positive optical power. This parameter configuration allows compact design while maintaining aberration compensation capability through the specific interaction of these powered elements.
Solution Approach 2:
Multiple functions are merged into a compact arrangement of three lens units. The system combines wide-angle coverage, zooming control, and close-object focusing within a single compact structure, eliminating the need for separate aberration correction components and reducing overall system weight.
3Ease of operation
If focusing is performed by moving lens units along the optical axis, then focusing capability is achieved, but aberration fluctuation occurs during focusing operation
Solution Approach 1:
The lens units are designed to move dynamically along the optical axis during focusing operations. The first, second, and third lens units can be independently positioned to optimize focus at different object distances. This dynamic adjustment maintains aberration stability while providing versatile focusing capability.
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 reduced aberration fluctuation and excellent optical performance across all focusing conditions, particularly in close-object in-focus scenarios, while maintaining a high zooming ratio.
Implementation Method 1
a lens unit having negative optical power is a focusing lens unit which moves along an optical axis in at least one zooming position from a wide-angle limit to a telephoto limit
Implementation Method 2
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, a lens unit located closest to an object side is fixed with respect to an image surface
Data Source
AI summary
A zoom lens system wherein a positive lens unit located closest to an object side is fixed with respect to an image surface in zooming, a negative lens unit, among lens units located on an image side relative to an aperture diaphragm, is a focusing lens unit which moves along an optical axis in focusing, and the conditions: −1.8<fn/fW<−0.3 and 0.1<T1/fW<1.5 (fn: a composite focal length of the negative lens unit, T1: an axial thickness of the positive lens unit located closest to the object side, fW: a focal length of the entire system at a wide-angle limit) are satisfied.