Zoom Lens with Integral Third and Fifth Group Movement
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Solution Overview
Problem
There is a demand for reducing the size of imaging apparatuses, particularly mirrorless cameras, while maintaining favorable optical performance and correcting aberrations accurately, especially in telephoto lens systems where the total lens length is typically long and large.
Innovation Solution
A zoom lens configuration comprising multiple lens groups with specific refractive powers and movements along the optical axis, where the third and fifth lens groups move integrally, and the fourth lens group moves during focusing, satisfying specific conditional expressions for focal lengths and Abbe numbers to achieve compactness and improved optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a telephoto type lens system is used to achieve long focal length, then the imaging performance is improved, but the total lens length becomes long and large
Solution Approach 1:
The lens system is divided into six distinct lens groups with different refractive powers (positive, negative, positive, positive, negative, positive). Each group can move independently along the optical axis during zooming and focusing operations, allowing compact arrangement while maintaining telephoto functionality. The segmentation enables complex optical paths within a compact structure.
Solution Approach 2:
The patent employs dynamic movement of lens groups along the optical axis to achieve zooming and focusing. The third and fifth lens groups move integrally during zooming, while the fourth lens group moves during focusing. This dynamic configuration allows the lens system to adapt its focal length and focus distance without increasing the physical length of the lens barrel.
2Measurement precision
If the number of pixels of the imaging element is increased to improve resolution, then the imaging quality is enhanced, but the demand for higher aberration correction accuracy increases
Solution Approach 1:
Different lens groups are designed with specific refractive powers and aberration correction characteristics tailored to their positions in the optical system. The sixth lens group (positive refractive power) is specifically positioned to correct aberrations at the image plane, while earlier groups handle different portions of the optical path. This localized optimization ensures high aberration correction accuracy for high-resolution imaging.
Solution Approach 2:
The lens system uses a composite structure combining multiple lens groups with different refractive indices and dispersion characteristics. The alternating positive and negative lens groups create a composite optical system that balances aberration correction across the entire zoom range, enabling accurate correction for high pixel count sensors.
3Length of moving object
If the lens system is made compact to reduce imaging apparatus size, then the portability is improved, but the complexity of the moving mechanism increases
Solution Approach 1:
The third and fifth lens groups are designed to move integrally as a unit during zooming operations, reducing the number of independent movement mechanisms. This merging of movement functions simplifies the overall drive system while maintaining the compact configuration. The integral movement of these groups allows coordinated adjustment of optical paths without requiring separate control mechanisms for each group.
4Length of moving object
If the total lens length is reduced to achieve compactness, then the imaging apparatus size is decreased, but the optical performance may deteriorate
Solution Approach 1:
The lens system uses dynamic reconfiguration of lens groups during zooming and focusing to maintain optimal optical performance across different focal lengths. The ability of lens groups to move along the optical axis allows the system to compensate for the reduced physical length by adjusting the relative positions and powers of individual groups, thereby preserving telephoto performance in a compact form factor.
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 enables a compact zoom lens system with improved optical performance, reducing the total lens length and weight, while effectively correcting aberrations and simplifying the moving mechanism, thus addressing the size and performance demands of modern imaging apparatuses.
Implementation Method 1
a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power
Data Source
AI summary
A zoom lens consists of, in order from an object side to an image side: a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power; a fourth lens group having a positive refractive power; a fifth lens group having a negative refractive power; and a sixth lens group having a positive refractive power. During zooming from the wide angle end to the telephoto end, the distance between the adjacent lens groups in the optical axis direction changes, and the third lens group and the fifth lens group move integrally along the optical axis.