Zoom Lens Miniaturization via Segmented Groups and Curvature Control
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Solution Overview
Problem
Consumer digital still camera zoom lenses face challenges in miniaturization while maintaining good optical performance, as existing designs struggle to achieve both size reduction and high optical quality.
Innovation Solution
A zoom lens design comprising multiple lens groups with specific refractive powers and aspheric surfaces, where the first lens group has negative power, the second group has positive power, and the third group also has positive power, with carefully controlled radii of curvature and focal lengths to ensure miniaturization and optimal optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the zoom lens is miniaturized to meet consumer electronics trends, then the size is reduced, but the optical performance deteriorates
Solution Approach 1:
The zoom lens is divided into multiple lens groups (first lens group with negative refractive power, second lens group with positive refractive power, third lens group with positive refractive power) that can move independently relative to each other. This segmentation allows each group to be optimized for specific functions while maintaining compact overall size, resolving the contradiction between miniaturization and optical performance.
Solution Approach 2:
The third lens in the first lens group is designed with an asymmetric curvature ratio where |R31/R32|≦0.39 (R31 being the object-side radius of curvature and R32 being the image-side radius of curvature). This asymmetric spherical design enables better correction of optical aberrations in a compact configuration, maintaining optical performance while reducing lens size.
2Reliability
If multiple lens groups are added to improve optical performance, then the optical quality is enhanced, but the device complexity increases
Solution Approach 1:
Each lens group serves multiple functions: the first lens group (negative power) provides both divergence and aberration correction, the second lens group (positive power) provides convergence and focal length adjustment, and the third lens group (positive power) provides additional focusing capability. This multi-functionality reduces the need for separate specialized components, maintaining optical performance while controlling complexity.
Solution Approach 2:
The invention optimizes specific parameters such as the curvature ratio |R31/R32|≦0.39 for the third lens and the focal length ratios between lens groups (1.24≦|fG1/fG2|≦1.27) to achieve high optical performance. By carefully controlling these parameters, the system achieves excellent optical quality with a manageable number of lens groups, avoiding excessive 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
The design achieves miniaturization while maintaining good optical performance by adjusting the intervals between lens groups and using aspheric surfaces, effectively correcting longitudinal aberration, field curvature, distortion, and lateral color, thereby providing a high-quality zoom lens with a zoom ratio of about 2.84.
Implementation Method 1
The first lens group has negative refractive power and includes a first lens, a second lens and a third lens... The second lens group has positive refractive power... The third lens group has positive refractive power
Implementation Method 2
The third lens includes two surfaces, at least one of which is an aspheric surface or both of which are aspheric surfaces... effectively correcting longitudinal aberration, field curvature, distortion, and lateral color
Data Source
AI summary
A zoom lens includes a first lens group, a second lens group and a third lens group, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens group is with negative refractive power and includes a first lens, a second lens and a third lens, wherein the first lens is with negative refractive power, the second lens is with positive refractive power and the third lens is with negative refractive power. The second lens group is with positive refractive power. The third lens group is with positive refractive power. The third lens satisfies |R31/R32|≦0.39, wherein R31 is a radius of curvature of an object side surface of the third lens and R32 is a radius of curvature of an image side surface of the third lens.