Four-Lens Imaging System Aberration Correction Miniaturization
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Solution Overview
Problem
Conventional imaging lenses for small cameras face challenges in achieving both miniaturization and satisfactory aberration correction as the resolution of imaging elements increases, making it difficult to maintain optical performance and correct aberrations while keeping the lens size small.
Innovation Solution
The imaging lens configuration includes a first positive lens, a second negative lens, a third negative lens, and a fourth negative lens, with specific curvature radius relationships and focal length ratios that satisfy conditional expressions to ensure miniaturization and effective aberration correction, including axial and off-axis chromatic aberration control, while using aspheric surfaces and shared materials to simplify production and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a two- or three-lens configuration is used, then the lens size can be kept small, but satisfactory aberration correction becomes difficult to achieve as resolution increases
Solution Approach 1:
The imaging lens is divided into four distinct lens units with specific refractive power configurations (positive, negative, negative, negative). This segmentation allows each lens unit to contribute differently to the overall optical performance, enabling effective aberration correction while maintaining a compact form factor suitable for mobile devices.
2Manufacturing precision
If the number of lenses is increased to four or more, then aberration correction improves, but the total length of the lens increases
Solution Approach 1:
The patent employs aspheric surfaces on specific lens surfaces to change the geometric parameters of the lens system. This allows for more flexible control of light paths and aberration correction without proportionally increasing the total lens length, enabling better optical performance in a compact configuration.
Solution Approach 2:
The use of aspheric surfaces introduces a dimensional change from traditional spherical surfaces, allowing for more complex light control in the same physical space. This enables effective aberration correction in a four-lens configuration without significantly increasing the overall lens length.
3Ease of manufacture
If aspheric surfaces and shared materials are used, then manufacturing cost and complexity are reduced, but optical performance must be maintained
Solution Approach 1:
The patent specifies that the second and third lenses are made of the same material, reducing the number of material types from four to three. This merging of materials simplifies the supply chain and manufacturing process while the aspheric surface design compensates to maintain the required optical performance and aberration correction.
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 allows for a compact imaging lens that effectively corrects aberrations, maintains optical performance, and reduces manufacturing costs by using fewer materials and aspheric surfaces, thereby enhancing image-forming performance in small cameras.
Implementation Method 1
a first lens having positive refractive power; a second lens having negative refractive power; a third lens having negative refractive power; and a fourth lens having negative refractive power, arranged in this order from an object side to an image plane side
Data Source
AI summary
An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having negative refractive power; and a fourth lens having negative refractive power, arranged from an object side to an image plane side. In the first lens, a curvature radius on an object-side surface is positive and a curvature radius of an image-side surface is negative. In the third lens, curvature radii of an object-side surface and an image-side surface are both negative. In the fourth lens, curvature radii of an object-side surface and an image-side surface thereof are both positive. When the whole lens system has a focal length f and a distance from the object-side surface of the first lens to an image-side surface of the fourth lens is L14, the imaging lens satisfies the following expression:0.5<L14/f<0.8