Five-element imaging lens system for compact design and coma correction
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Solution Overview
Problem
Conventional imaging lens systems with a five-element design face challenges in achieving high resolution and compactness while effectively correcting aberrations, particularly coma aberration, due to limitations in f-number and total length.
Innovation Solution
The design incorporates a five-element imaging lens system with specific optical power configurations, including a first positively powered lens, a second negatively powered lens, a third positively powered lens, a fourth positively powered meniscus lens, and a fifth negatively powered biconcave lens, with conditional formulae defining the relationships between focal lengths, axial distances, and radii of curvature to achieve a fast f-number and corrected aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the interval between the second and third lens elements is shortened to make the lens system more compact, then the total length of the lens system is reduced, but the coma aberration cannot be sufficiently corrected because the beam does not diverge enough before entering the third lens element
Solution Approach 1:
The patent applies parameter changes by modifying the object-side curvature radius of the third lens element to a specific range (0.05f < R3-1/f < 0.3) and adjusting the interval between the second and third lens elements (0.1f < d4/f < 0.5). These parameter optimizations enable sufficient coma aberration correction while maintaining a compact total length, resolving the contradiction between compactness and aberration correction quality.
2Length of stationary object
If the object-side curvature of the third lens element is reduced to make the lens system more compact, then the total length is shortened, but the coma aberration in off-axial beams cannot be sufficiently corrected
Solution Approach 1:
The patent optimizes the object-side curvature radius of the third lens element within a specific range (0.05f < R3-1/f < 0.3) to achieve the right balance. This parameter change ensures that the lens element has sufficient curvature to correct coma aberration in off-axial beams while keeping the overall lens system compact, thereby resolving the contradiction between compactness and off-axial aberration correction.
3Length of stationary object
If a five-element design is used to achieve high performance and compactness, then the lens system can be made more compact compared to three- or four-element designs, but the aberration correction becomes more difficult due to the complex power arrangement
Solution Approach 1:
The patent applies parameter changes by defining specific focal length ratios for the five lens elements (0.3 < f1/f < 0.6, 0.2 < f4/f < 0.5, -0.3 < f5/f < -0.1). These parameter specifications simplify the power arrangement design process and enable effective aberration correction while maintaining compactness, thus resolving the contradiction between compactness and design complexity.
Solution Approach 2:
The patent assigns specific optical powers and curvature characteristics to each of the five lens elements, with the third lens element having a specifically optimized object-side curvature. This local optimization of each element's properties enables the complex five-element system to achieve effective aberration correction and compactness, resolving the contradiction between complexity and performance.
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 results in a compact, high-performance imaging lens system with satisfactorily corrected aberrations, enabling high-quality image capture in digital devices such as smartphones and portable terminals.
Implementation Method 1
a first lens element having a positive optical power and convex to the object side, a second lens element having a negative optical power, a third lens element having a positive optical power and convex to the object side, a fourth lens element having a positive optical power and having a meniscus shape convex to the image side, and a fifth lens element having a negative optical power and having a biconcave shape
Data Source
AI summary
An imaging lens system includes, from the object side, an aperture stop, a positive first lens convex to the object side, a negative second lens, a positive third lens convex to the object side, a positive meniscus fourth lens convex to the image side, and a negative biconcave fifth lens, and fulfills the conditional formulae 0.8<f/f1<1.30, 0.5<f4/f1<0.90, 0.6<d4/d3<2.0, and 0.80<R3_1/f<2.20, where f is the focal length of the entire imaging lens system, f1 and f4 are the focal lengths of the first and fourth lenses, d3 is the axial thickness of the second lens, d4 is the axial aerial distance between the second and third lenses, and R3_1 is the radius of curvature of the object-side surface of the third lens on the optical axis.