Five-Lens Imaging System for Chromatic Aberration Correction
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Solution Overview
Problem
Existing imaging lenses struggle to achieve high image formation performance across the entire angle of view, particularly in correcting longitudinal chromatic aberration and chromatic aberration in peripheral areas, while maintaining a reduced total length and high resolution, especially in compact devices like digital still cameras and smartphones.
Innovation Solution
A five-lens imaging lens structure is optimized with specific refractive powers and aspherical surfaces, where the focal lengths and refractive indices of individual lenses are carefully balanced to correct chromatic aberrations and reduce the lens system's length, using a configuration of a first convex positive lens, a second concave negative lens, a third meniscus-shaped positive lens, a fourth negative lens, and a fifth convex positive lens, with conditional formulas to ensure optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a five-lens structure is adopted to reduce total length and increase resolution, then the total length is reduced and resolution is increased, but longitudinal chromatic aberration and peripheral chromatic aberration correction are insufficient
Solution Approach 1:
The patent applies local quality by assigning different refractive powers and aberration correction characteristics to specific lens elements positioned at different locations in the optical system. The first lens (positive) and second lens (negative) are designed with specific refractive powers to correct chromatic aberration at different positions, while the third lens (positive) and fourth lens (negative) provide additional correction for peripheral areas. This localized optimization of optical properties allows simultaneous improvement of resolution and chromatic aberration correction across the entire image area.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the refractive indices and focal lengths of each lens element. The conditional formulas specify relationships between the refractive powers (f1, f2, f3, f4) and refractive indices (Nd1, Nd2, Nd3, Nd4) of the lenses. By optimizing these parameters within the given ranges, the system achieves both high resolution and effective correction of longitudinal and peripheral chromatic aberration while maintaining a compact total length.
2Length of moving object
If the total length of the imaging lens is reduced for compact devices, then the device size is reduced, but image formation performance and aberration correction deteriorate
Solution Approach 1:
The patent applies segmentation by dividing the optical system into five distinct lens elements, each with specific functions. The first lens (positive) and second lens (negative) handle central area correction, while the third lens (positive) and fourth lens (negative) address peripheral areas. This segmentation allows each element to be optimized for its specific function, achieving high image formation performance and aberration correction within a compact total length configuration.
Solution Approach 2:
The patent uses composite optical design by combining lenses with different refractive indices and aberration correction characteristics. The system includes positive and negative lens elements with specific refractive power ratios, creating a composite optical structure that achieves both compact size and high performance. The conditional formulas ensure the combined optical properties provide effective chromatic aberration correction while maintaining reduced total length.
3Measurement precision
If high resolution performance is achieved through optimized lens structure, then image quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by providing specific ranges for refractive indices (Nd1, Nd2, Nd3, Nd4) and focal lengths (f1, f2, f3, f4) that optimize image resolution while considering manufacturability. The conditional formulas establish practical relationships between these parameters, allowing manufacturers to select from standardized optical materials and design configurations. This parameter optimization balances high image quality with manufacturing feasibility and cost-effectiveness.
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 optimized lens structure achieves high image formation performance from the center to the periphery of the angle of view, effectively correcting longitudinal chromatic aberration and maintaining high resolution with a reduced total lens length, while also reducing production costs by allowing lenses to be made of resin.
Implementation Method 1
a first lens having a convex surface facing an object side in the vicinity of an optical axis and positive refractive power in the vicinity of the optical axis
Implementation Method 2
at least one of the surfaces of which is aspherical
Data Source
AI summary
An imaging lens substantially consists of five lenses of an aspheric first lens having a convex surface facing an object side and positive refractive power, an aspheric second lens having a concave surface facing the object side and negative refractive power, an aspheric third lens having a meniscus shape in which its object-side surface is convex toward the object side, and positive refractive power, an aspheric fourth lens having negative refractive power and a fifth lens having a convex surface facing the object side and positive refractive power, which are in this order from the object side. Further, the imaging lens satisfies predetermined conditional formulas.