Aspheric Imaging Lens Design for Micro-Camera Miniaturization
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Solution Overview
Problem
Current micro-camera lenses face challenges in achieving smaller sizes while maintaining high imaging quality and cost-effectiveness, as the wafer level lens manufacturing method is limited by the size of each micro-lens, and there is a need for further advancements in lens design to increase production numbers and image performance.
Innovation Solution
The design of an imaging lens comprising a first and second lens group with four aspheric surfaces, where the first lens group includes a first and second aspheric surface with a transparent plate between them, and the second lens group includes a third and fourth aspheric surface with another transparent plate, satisfying the condition −8<f2/f<−4, which enhances image quality and allows for miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of each micro-lens is reduced to increase production numbers per wafer, then productivity increases, but imaging quality deteriorates
Solution Approach 1:
The patent employs aspheric surfaces instead of traditional spherical surfaces for the lens elements. The aspheric surfaces are defined by specific mathematical equations with multiple coefficients (k, C4, C6, C8, C10, C12) that allow precise control of the surface curvature. This enables the lens to maintain high imaging quality even when miniaturized, resolving the contradiction between reduced lens size and maintained image performance.
Solution Approach 2:
The patent systematically optimizes multiple parameters including the focal length ratio (f1/f2 between 0.5-1.5), the aspheric coefficients, and the relative positions of lens groups. By carefully adjusting these parameters, the design achieves compact dimensions while maintaining diffraction-limited image quality, thus increasing the number of lenses per wafer without sacrificing imaging performance.
2Adaptability or versatility
If the lens size is miniaturized for portable devices, then adaptability improves, but imaging quality deteriorates
Solution Approach 1:
The lens system is divided into multiple lens groups (first lens group with positive power and second lens group with negative power) rather than using a single lens element. This segmentation allows each group to be optimized independently for its specific function while maintaining compact overall dimensions. The divided structure enables better control of aberrations in the miniaturized system, preserving image quality for portable device integration.
Solution Approach 2:
Each lens element within the segmented groups utilizes aspheric surfaces with precisely controlled curvature profiles. The aspheric design allows the compact lens groups to achieve the necessary optical power and aberration correction in a miniaturized form factor, enabling adaptation to portable devices without compromising image performance.
3Manufacturing precision
If aspheric surfaces are used to improve imaging quality, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent uses aspheric surfaces defined by a standardized mathematical formulation with a specific set of coefficients. This standardized approach, while more complex than spherical surfaces, provides the necessary degrees of freedom to correct multiple types of aberrations simultaneously. The systematic use of aspheric surfaces across multiple elements achieves high imaging quality while the mathematical standardization facilitates manufacturing.
Solution Approach 2:
The aspheric surface design serves multiple functions simultaneously: it provides the necessary optical power, corrects spherical aberration, controls coma, and manages field curvature. This multi-functionality reduces the need for additional separate optical elements, thereby managing overall device complexity while achieving superior imaging quality through the aspheric surfaces.
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 provides good imaging quality while enabling the production of more micro-lenses per wafer, reducing costs, and simplifying assembly through miniaturization, making it suitable for integration into portable electronic devices.
Implementation Method 1
The imaging lens comprises a first lens group and a second lens group with aspheric surfaces that refract light to form images with high quality while correcting optical aberrations
Data Source
AI summary
An imaging lens including a first lens group and a second lens group is provided. The first lens group is disposed between an object side and an image side. A surface closest to the object side in the first lens group is a first aspheric surface. A surface closest to the image side in the first lens group is a second aspheric surface. The second lens group is disposed between the first lens group and the image side. A surface closest to the first lens group in the second lens group is a third aspheric surface. A surface closest to the image side in the second lens group is a fourth aspheric surface. The imaging lens satisfies: −8<f2/f<−4, where f is an effective focal length (EFL) of the imaging lens, and f2 is an EFL of the second lens group.