Compact Zoom Lens Design with Stationary First Unit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current zoom lenses struggle to achieve a compact and lightweight design while maintaining high optical performance throughout the entire zoom range, especially at the telephoto end, due to the need for a long focal length and effective aberration correction.
Innovation Solution
The zoom lens design incorporates a first lens unit with positive refractive power, a second lens unit with negative refractive power, a third lens unit with negative refractive power, and a rear lens group with positive refractive power at the wide-angle end, where the first lens unit is stationary during zooming, and the intervals between adjacent lens units change, satisfying specific focal length and lens length inequalities to optimize optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the refractive power of the first lens unit is weakened to reduce its size, then the principal point shifts to the image side and the overall lens length increases
Solution Approach 1:
The lens system is divided into multiple functional groups: a first lens unit with positive refractive power, a second lens unit with negative refractive power, a third lens unit with negative refractive power, and a rear lens group with positive refractive power. This segmentation allows each unit to be optimized independently for its specific function while achieving compact overall dimensions.
Solution Approach 2:
The lens units are arranged in a nested configuration where the second and third lens units are positioned between the first lens unit and the rear lens group. This nested arrangement allows the negative refractive power units to be integrated within the structure defined by the positive refractive power units, reducing the overall lens length while maintaining the principal point on the object side.
2Reliability
If a long focal length is achieved at the telephoto end, then the optical performance is improved, but the lens becomes less compact
Solution Approach 1:
The lens design utilizes specific parameter relationships between the focal lengths of different lens units. By controlling the focal length of the first lens unit (f1), second lens unit (f2), and third lens unit (f3) to satisfy specific inequalities, the system achieves a long focal length at the telephoto end while maintaining compact dimensions. The rear lens group is also designed with specific refractive power characteristics to optimize the telephoto performance.
3Reliability
If aberration correction is enhanced, then the optical performance is improved, but the lens structure becomes more complex
Solution Approach 1:
Each lens unit is designed with specific refractive power characteristics tailored to its position and function in the system. The first lens unit has positive refractive power for compactness, while the second and third units have negative refractive power for aberration correction. The rear lens group has positive refractive power optimized for telephoto performance. This localized optimization of refractive properties achieves comprehensive aberration correction without excessive structural 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 results in a compact, lightweight zoom lens with high optical performance and long focal length, effectively correcting various aberrations and reducing size and weight, while maintaining a short overall lens length.
Implementation Method 1
a first lens unit having a positive refractive power, a second lens unit, a third lens unit having a negative refractive power
Data Source
AI summary
A zoom lens includes a first lens unit, a second lens unit, a third lens unit, and a rear lens group. The first lens unit has a positive refractive power. The third lens unit has a negative refractive power. The rear lens group includes one or more lens units. The first lens unit, the second lens unit, the third lens unit, and the rear lens group are disposed in order from an object side to an image side. An interval between lens units disposed adjacent to each other changes during zooming. The rear lens group includes all of lens units disposed closer to an image than the third lens unit. The first lens unit includes a first positive lens disposed closest to an object and having a positive refractive power. The rear lens group has a positive refractive power at a wide-angle end. Predetermined inequalities are satisfied.