Imaging Lens Compact Design Aberration Correction
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Solution Overview
Problem
There is a demand for an imaging lens that is compact in size with a small F-number and wide angle while maintaining favorable optical performance, and existing technologies have not adequately addressed this need.
Innovation Solution
The imaging lens is configured with a front group, an aperture stop, and a rear group, where the rear group includes one or two focus lens groups that move along the optical axis during focusing, and specific conditional expressions are satisfied to ensure optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the imaging lens is designed with a small F-number and wide angle to reduce size, then the compactness is improved, but the optical performance deteriorates
Solution Approach 1:
The lens is divided into a front group and a rear group with distinct functions. The front group (including first through fourth lenses) handles wide-angle light gathering and initial aberration correction, while the rear group (including fifth through eighth lenses) focuses on focal length control and aberration correction. This segmentation allows each group to be optimized for its specific role, enabling compact design without sacrificing optical performance.
Solution Approach 2:
Different lens elements have different refractive powers and surface curvatures tailored to their specific positions and functions. For example, the first lens has negative refractive power with specific curvature relationships (0.3 < -R1/R2 < 2.0) to control wide-angle distortion, while the fourth lens has positive refractive power with controlled curvature (0.5 < R3/R4 < 2.0) to correct spherical aberration. This local optimization of optical properties enables the compact lens to achieve favorable overall optical performance.
2Ease of manufacture
If the lens structure is simplified to reduce size, then the manufacturing ease is improved, but the ability to correct aberrations deteriorates
Solution Approach 1:
The lens employs an aperture stop positioned between the front and rear groups that can be moved along the optical axis. This dynamic element allows the lens to maintain favorable optical performance across different focusing distances and aperture settings, enabling effective aberration correction without requiring a complex multi-element design throughout the entire lens structure.
Solution Approach 2:
The lens design incorporates specific parameter ranges for curvature radii and refractive powers that balance manufacturing feasibility with optical performance. For example, the curvature ratio constraints (0.3 < -R1/R2 < 2.0, 0.5 < R3/R4 < 2.0) and refractive power relationships ensure that each lens element can be manufactured with standard tolerances while collectively achieving superior aberration correction in the compact wide-angle design.
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 proposed imaging lens achieves a compact size with a small F-number and wide angle while maintaining favorable optical performance, including effective correction of various aberrations and suppression of fluctuation in the angle of view during focusing.
Implementation Method 1
an imaging lens consisting of, in order from an object side to an image side, a front group, an aperture stop, and a rear group
Data Source
AI summary
An imaging lens consists of, in order from an object side to an image side, a front group, an aperture stop, and a rear group. The rear group includes one or two focus lens groups that move along an optical axis during focusing. A distance on the optical axis from a lens surface of the front group closest to the object side to an image plane is invariant during the focusing. The imaging lens satisfies a predetermined conditional expression.