Imaging Lens Aberration Correction via Aperture Placement
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Solution Overview
Problem
Existing imaging lenses for miniaturized digital cameras face challenges in achieving high image formation performance while maintaining a compact configuration and cost-effectiveness, as they often require complex aspheric surfaces that increase manufacturing costs and can lead to upsizing.
Innovation Solution
A three-lens configuration with specific optical design parameters, including a convex first lens, a meniscus-shaped second lens, and a convex third lens, along with an aperture diaphragm placement between the first lens's object-side and image-side surfaces, to optimize focal lengths and curvature radii, ensuring high image quality and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an aspheric surface is used to improve image formation performance, then performance is improved, but manufacturability deteriorates and cost increases
Solution Approach 1:
The patent changes the optical parameters by using a three-lens configuration with specific focal length relationships (f1/f2 between 0.6-1.5, f3/f2 between 0.6-1.5) and controlled curvature radii to achieve high image formation performance without requiring aspheric surfaces. This resolves the contradiction by achieving performance through parameter optimization rather than complex surface geometry.
2Manufacturing precision
If a four-lens configuration is used to improve performance, then performance is improved, but device size increases and cost increases
Solution Approach 1:
The patent segments the optical system into three lenses with specific functional assignments: the first lens (positive power) handles spherical aberration, the second lens (negative power, meniscus shape) handles field curvature and coma, and the third lens (positive power, meniscus shape) handles residual aberrations. This segmented approach achieves high performance with fewer elements than traditional four-lens configurations.
Solution Approach 2:
The patent uses composite optical design combining lenses of different powers and shapes (positive meniscus, negative meniscus, positive convex) to achieve aberration correction that would traditionally require more elements or aspheric surfaces. The combination of lens types creates a composite optical system that is both compact and high-performance.
3Volume of moving object
If a three-lens configuration is used to reduce size and cost, then compactibility is improved, but image formation performance is insufficient
Solution Approach 1:
The patent optimizes the parameters of the three-lens configuration by controlling focal lengths (f1/f2=0.6-1.5, f3/f2=0.6-1.5) and curvature radii to achieve superior image formation performance. The aperture diaphragm position parameter (0.05<f1/d1<0.30) is also optimized to balance performance and compactness, resolving the contradiction between size and performance.
4Ease of operation
If the aperture diaphragm is placed at the image-side surface of the first lens, then telecentricity is ensured, but the lens length increases
Solution Approach 1:
The patent optimizes the aperture diaphragm position parameter (0.05<f1/d1<0.30) to balance telecentricity and compact lens length. This parameter optimization allows the diaphragm to be positioned optimally within the first lens without extending the overall lens length, resolving the contradiction between telecentricity and compactness.
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 solution provides high image formation performance with a compact configuration, effectively correcting spherical aberrations, field curvature, and coma aberrations, while ensuring telecentricity and minimizing the lens's overall length, making it suitable for digital cameras with a large number of pixels.
Implementation Method 1
a first lens having a convex surface directed to an object side on an optical axis and having a positive power
Implementation Method 2
a second lens on an image side of the first lens, the second lens having a meniscus shape with a concave surface directed to the object side on the optical axis
Implementation Method 3
a third lens on the image side of the second lens, the third lens having a meniscus shape with a convex surface directed to the object side on the optical axis
Data Source
AI summary
An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens having a convex surface directed to the object side on an optical axis and having a positive power; an aperture diaphragm placed between a top position of an object-side surface of the first lens and a position of an image-side surface of the first lens on the optical axis; a second lens having a meniscus shape with a concave surface directed to the object side on the optical axis; and a third lens having a meniscus shape with a convex surface directed to the object side on the optical axis. Further, the imaging lens satisfies specific conditional expressions.