Variable Magnification Lens Group Segmentation for Bright F-Value
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Solution Overview
Problem
There is a growing demand for a variable magnification optical system with satisfactory optical performance and a brighter F-value, which existing systems have not adequately addressed, particularly in achieving a balance between wide angle of view and effective image stabilization.
Innovation Solution
The proposed variable magnification optical system includes a first lens group with negative refractive power, a second lens group with positive refractive power, an intermediate group with negative refractive power, and a vibration-reduction lens group that is movable orthogonal to the optical axis, allowing for varying magnification by adjusting the distances between these groups, and satisfies specific conditional expressions to ensure optimal imaging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a variable magnification optical system is designed with a wide angle of view, then the coverage area is improved, but the F-value becomes darker and optical performance deteriorates
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with negative refractive power, second lens group with positive refractive power, intermediate group, and vibration-reduction lens group) that can be independently positioned and adjusted. This segmentation allows each group to contribute to specific optical functions, enabling both wide angle of view and bright F-value simultaneously.
Solution Approach 2:
The system employs movable lens groups that can be positioned at different distances from the image sensor. The vibration-reduction lens group can move in directions orthogonal to the optical axis, while other groups adjust their positions along the optical axis to achieve variable magnification. This dynamic positioning enables optimization of both angle of view and F-value across different shooting conditions.
2Illumination intensity
If the F-value is increased to achieve brighter imaging, then illumination intensity is improved, but the angle of view becomes narrower
Solution Approach 1:
By dividing the optical system into multiple functional lens groups with specific refractive powers, the design achieves a bright F-value (F2.8 to F3.5) while maintaining wide angle of view. Each lens group is optimized for its specific contribution to achieving both brightness and field coverage.
Solution Approach 2:
The system achieves variable magnification by changing the distances between lens groups and the image sensor. By adjusting these parameters dynamically, the system can optimize the balance between F-value and angle of view for different shooting scenarios, providing both bright imaging and wide coverage when needed.
3Manufacturing precision
If lens groups are added to improve optical performance, then aberration correction is improved, but device complexity increases
Solution Approach 1:
The optical system is segmented into four distinct lens groups, each with specific functions: the first lens group (negative refractive power) for field curvature control, the second lens group (positive refractive power) for main focusing, the intermediate group for optical path adjustment, and the vibration-reduction lens group for image stabilization. This segmentation achieves excellent aberration correction while keeping the structure organized and manageable.
Solution Approach 2:
Each lens group serves multiple functions simultaneously. For example, the vibration-reduction lens group not only provides image stabilization but also contributes to aberration correction. The intermediate group adjusts optical paths while maintaining proper focus. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity.
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 achieves a bright F-value of approximately F2.8 to F3.5, effectively corrects aberrations such as spherical aberration, and provides a wide angle of view while maintaining satisfactory imaging performance across different focal lengths.
Implementation Method 1
a first lens group having a negative refractive power; a second lens group having a positive refractive power
Implementation Method 2
a vibration-reduction lens group disposed closer to the image side than the intermediate group and configured to be movable so as to have a component in a direction orthogonal to an optical axis
Data Source
AI summary
A variable magnification optical system includes: a first lens group (G1) having a negative refractive power; a second lens group (G2) having a positive refractive power; an intermediate group (Gn) disposed closer to an image side than the second lens group (G2); and a vibration-reduction lens group (VR) disposed closer to the image side than the intermediate group (Gn) and configured to be movable so as to have a component in a direction orthogonal to an optical axis. The system performs varying magnification by changing at least the distance between the first lens group (G1) and the second lens group (G2) and the distance between the second lens group (G2) and the intermediate group (Gn), and the system satisfies Conditional Expression (1).1.500<β(Gn)t<100.000 (1)whereβ(Gn)t: an imaging magnification of the intermediate group (Gn) in a telephoto end state.