Four-Element Imaging Lens Assembly with Aspheric Inflection Points
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Solution Overview
Problem
Existing high-resolution photographic lens assemblies face challenges with complex assembly processes, low yield rates, and high manufacturing costs due to shorter axial distances between lens elements and thicker central thickness, leading to longer optical total lengths, which hinder the development of compact imaging systems.
Innovation Solution
The proposed imaging lens assembly consists of a specific configuration of lens elements with positive and negative refractive powers, including a first lens element with a convex object-side surface, a second lens element with concave surfaces, a third lens element with aspheric surfaces, and a fourth lens element with aspheric surfaces and inflection points, optimized by conditions such as axial distances, Abbe numbers, and focal lengths to reduce optical length and improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the axial distance between the first lens element and the second lens element is shortened to achieve high resolution, then the manufacturing complexity and assembly difficulty increase, but the assembly process becomes more complex and yield rate decreases
Solution Approach 1:
The lens assembly is divided into four distinct lens groups with specific positive and negative refractive powers. This segmentation allows each group to be optimized independently for its function while maintaining overall compactness, resolving the contradiction between high resolution and assembly complexity by distributing optical functions across modular components
Solution Approach 2:
The patent specifies precise parameter ranges for axial distances (T12, T23, T34), central thicknesses (CT1, CT2, CT3, CT4), and refractive powers (f1, f2, f3, f4) of each lens element. By controlling these parameters within defined ranges, the patent achieves high resolution imaging while maintaining manufacturable assembly complexity, directly addressing the contradiction between precision and complexity
2Measurement precision
If the central thickness of the second lens element is increased to improve optical performance, then the image quality improves, but the optical total length increases
Solution Approach 1:
The patent employs aspheric surfaces with inflection points on the third and fourth lens elements. These dynamic surface profiles allow for optimized light path control that achieves high image quality without requiring increased central thickness, thereby maintaining compact optical total length while improving image quality
Solution Approach 2:
The lens assembly uses a composite configuration of elements with different refractive powers and material properties (indicated by different Abbe numbers V1, V2, V3, V4). This composite approach allows the system to achieve superior image quality through synergistic optical design rather than relying on increased thickness of individual elements, thus controlling the overall optical length
3Volume of moving object
If the axial distance between lens elements is reduced to make the device more compact, then the portability improves, but the manufacturing cost increases due to lower yield rate
Solution Approach 1:
The patent establishes predetermined axial distance relationships (T12/CT2, T23/CT3, T34/CT4) and thickness-to-distance ratios as design constraints. By pre-defining these geometric relationships, the patent simplifies the manufacturing and assembly processes, improving yield rates and reducing costs while maintaining compact dimensions
Solution Approach 2:
The patent specifies precise parameter ranges for the ratios of axial distances to central thicknesses (T12/CT2, T23/CT3, T34/CT4) and for focal length relationships (f3/f1, f4/f2). These parameter constraints standardize the manufacturing process, making it more reproducible and cost-effective while achieving compact form factor
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 effectively addresses the complexity and cost issues by optimizing lens spacing and refractive power distribution, resulting in a more compact and cost-effective imaging lens assembly with improved image quality and reduced sensitivity, while maintaining high resolution and wide-angle capabilities.
Implementation Method 1
a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power, and a fourth lens element with negative refractive power
Data Source
AI summary
An imaging lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive power having a concave object-side surface and a concave image-side surface, a third lens element with positive refractive power having a concave object-side surface and a convex image-side surface, and a fourth lens element with negative refractive power having a concave object-side surface and a concave image-side surface. The third lens element and the fourth lens element are aspheric. The fourth lens element has at least one inflection point. By adjusting the distance between the second lens element and the first lens element as well as the thickness of the second lens element, the imaging lens assembly can be easy to be manufactured and assembled without decreasing its imaging quality.