Five-Group Zoom Lens with Variable Power Ratio and Compact Design
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Solution Overview
Problem
Prior art zoom lenses fail to achieve a balance between high variable power ratio, aberration compensation, and downsizing along the optical axis, with many designs either insufficient in magnification range or excessive in length.
Innovation Solution
A zoom lens comprising at least five lens groups with specific refractive powers and displacement mechanisms, meeting certain formulaic requirements to optimize focal lengths and lateral magnifications, allowing for enhanced variable power ratio and reduced dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lens groups is increased to enhance aberration compensation freedom, then image quality is improved, but the longitudinal extension along the optical axis increases
Solution Approach 1:
The optical system is divided into five distinct lens groups (G1-G5) with alternating positive and negative refractive powers. Each lens group is independently designed and can be displaced separately, allowing for optimized aberration compensation while maintaining a compact overall structure. The segmentation enables complex optical functions to be distributed across multiple modular units.
Solution Approach 2:
The patent implements dynamic displacement mechanisms for each lens group during zooming and focusing operations. The lens groups move along the optical axis according to predetermined trajectories, enabling the system to adapt its optical characteristics dynamically. This dynamic adjustment allows for effective aberration compensation across the entire zoom range without requiring a fixed, lengthy structure.
2Adaptability or versatility
If lens groups are displaced to vary magnification from wide angle to telephoto, then variable power ratio is enhanced, but distances between lens groups must be precisely controlled increasing complexity
Solution Approach 1:
Each lens group serves multiple functions simultaneously: G1 and G3 contribute to both zooming and focusing, G2 and G4 primarily handle zooming while G5 enables close-up focusing. This multi-functionality reduces the need for dedicated mechanisms for each operation, simplifying the overall control system while achieving a variable power ratio exceeding ×10.
Solution Approach 2:
The lens groups are designed to move along predetermined trajectories during zooming operations, with their displacement patterns automatically coordinating to maintain proper optical relationships. The system self-regulates the distances between lens groups through their coupled motion, reducing the need for complex active control mechanisms while achieving precise magnification variation.
3Length of moving object
If compact design is achieved by reducing lens group distances, then downsizing is improved, but aberration compensation capability is reduced
Solution Approach 1:
Each lens group is designed with specific local optical characteristics: G1 and G3 have positive refractive power with specific focal lengths, while G2 and G4 have negative refractive power. The aperture stop is positioned within G3 to optimize light control. These localized quality variations enable effective aberration compensation within a compact overall structure, as each region contributes specific corrective functions.
Solution Approach 2:
The patent utilizes parameter changes in the displacement distances of lens groups during zooming and focusing operations. By dynamically adjusting the distances between lens groups according to predetermined relationships, the system maintains optimal aberration compensation across the entire focal length range. The parameter changes enable the compact design to achieve the same optical performance as larger systems.
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 zoom lens with an improved variable power ratio, increased aberration compensation, and significant downsizing, achieving a more compact and lightweight design while maintaining high image quality.
Implementation Method 1
a first lens group G1 of positive refractivity, a second lens group G2 of negative refractivity, a third lens group G3 of positive refractivity, a fourth lens group G4 of negative refractivity, and a fifth lens group G5 of positive refractivity
Data Source
AI summary
Provided are: a zoom lens which exhibits a large variable-power ratio, an increased degree of freedom with respect to aberration correction, and which has been achieved having a sufficient reduction in size in the optical axis direction; and an imaging device equipped therewith. The zoom lens includes at least, from the object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group, and a fifth lens group, in that order. In the zoom lens, prescribed conditions are satisfied.