Five-Element Imaging Lens Aberration Correction
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Solution Overview
Problem
Conventional imaging lenses face difficulties in achieving high resolution and correcting aberrations, especially when a low F-number is required, leading to suboptimal optical performance.
Innovation Solution
The imaging lens configuration includes a specific arrangement of lenses with varying refractive powers and surface curvatures, along with conditional expressions that define optimal ranges for lens parameters, to achieve a balance between low profile and low F-number while effectively correcting spherical aberration, astigmatism, and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional imaging lens configuration is used, then the lens structure is relatively simple, but it is very difficult to correct aberrations at a peripheral area when a low F-number is required
Solution Approach 1:
The imaging lens is divided into five separate lens elements (L1-L5) with specific refractive power distributions. Each lens element is designed to correct specific types of aberrations, with the third lens (L3) specifically configured to correct peripheral area aberrations when F-number is 2.8 or lower. This segmentation allows complex aberration correction to be achieved through coordinated action of multiple simpler components.
Solution Approach 2:
The third lens (L3) is designed with specific local optical properties including a positive meniscus shape with the convex surface facing the image side, and its refractive power is specifically optimized for correcting spherical aberration and distortion at peripheral areas. The fourth lens (L4) is designed with negative refractive power and specific curvature ratios to locally correct coma and astigmatism. These localized quality adjustments enable effective peripheral aberration correction without requiring complete redesign of the entire lens system.
2Illumination intensity
If the F-number is reduced to achieve low F-number performance, then more light can be captured, but aberration correction at peripheral area becomes extremely difficult
Solution Approach 1:
The patent specifies precise parameter ranges for each lens element to maintain aberration correction when F-number is reduced. The third lens (L3) is designed with refractive power parameters satisfying 0.25 < f3/f < 0.65, and the fourth lens (L4) with -0.45 < r7/r8 < -0.15. These parameter constraints ensure that even at low F-numbers (F≤2.8), the lens system maintains excellent spherical aberration, coma, and distortion correction while capturing sufficient light.
3Manufacturing precision
If more lens elements are added to correct aberrations, then optical performance improves, but the total track length increases and compactness is reduced
Solution Approach 1:
The patent employs dynamic optimization of lens element positions and spacings to achieve compact design. The distance relationships between lens elements are carefully controlled, with the third lens (L3) positioned to effectively correct spherical aberration and the fourth lens (L4) positioned to correct coma and astigmatism. This dynamic arrangement of five lens elements achieves superior aberration correction while maintaining a compact total track length suitable for mobile devices.
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 an imaging lens that achieves high resolution and excellent aberration correction, enabling a low profile and low F-number performance, suitable for compact imaging devices.
Implementation Method 1
a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive or negative refractive power, a fourth lens L4 with negative refractive power, and a fifth lens L5 with positive refractive power
Data Source
AI summary
There is provided an imaging lens with excellent optical characteristics which satisfies demand of low profile and low F-number. An imaging lens comprising in order from an object side to an image side, a first lens with positive refractive power having an object-side surface being convex in a paraxial region, a second lens with negative refractive power having an object-side surface being convex in a paraxial region, a third lens with positive or negative refractive power in a paraxial region, a fourth lens with negative refractive power in a paraxial region, and a fifth lens with positive refractive power having an image-side surface being convex in a paraxial region, and predetermined conditional expressions are satisfied.