Multi-element Plastic Lens Module for Chromatic Aberration Correction
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Solution Overview
Problem
Mobile camera terminals face challenges in achieving high-resolution performance and a bright optical system due to limitations in plastic lens technology, which struggles with chromatic aberration and brightness compared to glass lenses, while also requiring miniaturization and cost-effectiveness.
Innovation Solution
A lens module design comprising multiple plastic lenses with specific refractive powers and shapes, including a first lens with positive refractive power, a second lens with negative refractive power, a third lens with a meniscus shape, a fourth lens with negative refractive power, and a fifth lens with negative refractive power, satisfying conditional expressions to optimize focal distances and Abbe numbers, and incorporating a filter member and image sensor to enhance resolution and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic lenses are used to reduce weight and cost, then manufacturing cost and weight are reduced, but chromatic aberration correction becomes more difficult and brightness decreases
Solution Approach 1:
The lens module divides the optical system into multiple plastic lens elements (first through fifth lenses) with different refractive powers and Abbe numbers. By segmenting the correction function across multiple elements rather than relying on a single glass lens, the system achieves chromatic aberration correction using plastic materials while maintaining manufacturing cost advantages.
Solution Approach 2:
The invention uses composite optical design combining multiple plastic lens materials with different Abbe numbers (ν1, ν2, ν3, ν4, ν5) and refractive indices. This composite approach allows the plastic lens system to achieve chromatic aberration correction comparable to glass lenses by leveraging the complementary optical properties of different plastic materials.
2Measurement precision
If multiple plastic lenses are used to achieve high resolution, then resolution performance improves, but chromatic aberration correction becomes more difficult
Solution Approach 1:
Each lens element is designed with specific local optical properties: the first and fourth lenses have positive Abbe numbers while the second, third, and fifth lenses have negative Abbe numbers. This local differentiation of optical characteristics across the lens system enables chromatic aberration correction while maintaining high resolution performance through the cumulative effect of each element's specialized design.
Solution Approach 2:
The invention systematically varies key optical parameters across the lens elements including Abbe numbers (ν1-ν5), focal lengths (f1-f5), and curvature radii (r1-r12). By carefully controlling and varying these parameters, the system achieves both high resolution and effective chromatic aberration correction in a plastic lens configuration.
3Volume of moving object
If the lens module is miniaturized for mobile terminals, then device size is reduced, but achieving high resolution and bright optical system becomes more difficult
Solution Approach 1:
The lens module employs aspherical surfaces with dynamically optimized curvature profiles rather than simple spherical surfaces. This allows for more efficient light path control within a compact form factor, enabling high resolution performance in a miniaturized device by reducing the number of lens elements needed and optimizing the optical path length.
Solution Approach 2:
The invention utilizes aspherical surface geometry to add dimensional complexity to the lens surfaces, allowing for more effective light control in a reduced axial length. This dimensional approach enables compact design while maintaining high resolution by controlling spherical aberration and other optical errors that would otherwise require additional lens elements.
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 lens module achieves high-resolution performance and a bright optical system while being miniaturized and cost-effective, effectively correcting chromatic aberration and improving brightness, thus addressing the limitations of plastic lenses in mobile camera terminals.
Implementation Method 1
a first lens L1 having positive refractive power, a second lens L2 having negative refractive power, a third lens L3 having positive refractive power, a fourth lens L4 having negative refractive power, and a fifth lens L5 having negative refractive power
Implementation Method 2
an difference between an Abbe number of the first lens and an Abbe number of the fourth lens, and a ratio between a focal distance of the first lens and a focal distance of the fourth lens
Data Source
AI summary
There is provided a lens module, including: a first lens having positive refractive power, an object-sided surface thereof being convex; a second lens having negative refractive power, an image-sided surface thereof being concave; a third lens having positive refractive power; a fourth lens having negative refractive power, an image-sided surface thereof being convex; and a fifth lens having negative refractive power, an image-sided surface thereof being concave, wherein the fourth lens satisfies Conditional Expression 1,f4f<-3.0[ConditionalExpression1]where f is an overall focal distance of an optical system and f4 is a focal distance of the fourth lens.