Three-Element Plastic Lens System for Aberration Correction
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Solution Overview
Problem
Conventional compact optical systems for electronic devices, such as smartphones and tablets, fail to meet the requirements for high resolution and image quality due to unevenly distributed refractive power, which leads to increased sensitivity and difficulty in correcting aberrations and reducing the back focal length.
Innovation Solution
An optical imaging system comprising three lens elements with specific refractive powers and surface shapes, including a first lens element with positive refractive power, a second lens element with positive refractive power, and a third lens element with negative refractive power, optimized by conditions such as focal lengths, central thicknesses, and axial distances, to balance refractive power and reduce sensitivity and aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional two-element lens structure is used, then device complexity is reduced, but image quality and resolution are insufficient
Solution Approach 1:
The optical system is divided into three distinct lens elements with specific refractive powers (first: positive, second: positive, third: negative). Each element is optimized independently with specific surface curvature characteristics, allowing complex optical functions to be distributed across multiple simpler components rather than requiring a single complex element.
Solution Approach 2:
Each lens element has locally optimized surface characteristics - the first element has convex object-side and convex image-side surfaces, the second has concave object-side and convex image-side surfaces, and the third has specific curvature in off-axis regions. This local optimization of surface quality at different positions enables high image quality while maintaining manageable device complexity.
2Manufacturing precision
If three-element lens structure with unevenly distributed refractive power is used, then resolution is enhanced, but back focal length increases and sensitivity increases
Solution Approach 1:
The patent specifies precise parameter relationships: the third element's focal length satisfies |f3| < f2 < f1, and the ratio |f3|/f2 falls within 0.3-0.7. These parameter changes optimize the distribution of refractive power across elements, reducing sensitivity while maintaining high resolution capability.
Solution Approach 2:
The lens elements exhibit asymmetric surface characteristics - the first element has different convex curvatures on object-side and image-side, the second element has concave-convex asymmetry, and the third element has specific off-axis convex regions. This asymmetric design enables balanced refractive power distribution that reduces sensitivity while achieving high resolution.
3Manufacturing precision
If three-element lens structure with unevenly distributed refractive power is used, then resolution is enhanced, but aberration correction becomes difficult
Solution Approach 1:
Aberration correction is segmented across the three lens elements, with each element contributing specific corrective functions based on its surface characteristics and refractive power. This distributes the complex task of aberration correction across multiple simpler components rather than requiring a single complex element.
Solution Approach 2:
Specific surface regions of each lens element are optimized for local quality - particularly the third element's off-axis convex regions - to address specific aberration types locally rather than requiring global complexity throughout the entire optical system.
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 system achieves improved image quality, reduced sensitivity, and a compact design by balancing refractive powers and correcting aberrations, while allowing for efficient light incidence and proper curvature distribution, suitable for high-resolution imaging in electronic devices.
Implementation Method 1
The first lens element with positive refractive power, the second lens element with positive refractive power, and the third lens element with negative refractive power
Data Source
AI summary
An optical imaging system includes, in order from an object side to an image side, a first lens element, a second lens element and a third lens element. The first lens element with positive refractive power has an object-side surface being convex and an image-side surface being convex in a paraxial region. The second lens element with positive refractive power has an object-side surface being concave and an image-side surface being convex in a paraxial region. The third lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the third lens element has at least one convex shape in an off-axis region thereof. The optical imaging system further comprises a stop between the image-side surface of the first lens element and the object-side surface of the second lens element. The lens elements are made of plastic material.