Five-Lens Optical Imaging Assembly for Compact Camera Systems
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Solution Overview
Problem
Conventional optical imaging lens assemblies for compact electronic products face challenges in achieving a short total length while maintaining high image quality and aberration correction, particularly due to the difficulty in reducing the total length and rear focal length with existing designs that often involve cemented glass lenses and complex refractive power combinations.
Innovation Solution
The design incorporates five non-cemented lenses with specific refractive powers and surface curvatures, including a first lens with positive refractive power, a second lens with negative refractive power, a third lens with a concave object-side surface, a fourth lens made of plastic with aspheric surfaces, and a fifth lens with negative refractive power and inflection points, optimized by specific curvature radius and Abbe number relationships to achieve a telecentric effect and improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If five lens elements with complex refractive power combinations are used to achieve high image quality and aberration correction, then image quality and aberration correction are improved, but the total length of the optical system increases
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices and curvatures of the lens surfaces. Specifically, it uses a first lens with positive refractive power and a second lens with negative refractive power, where the negative lens has a curvature radius ratio (R1/R2) within a specific range. This careful parameter selection allows the system to achieve high image quality and aberration correction while keeping the total length compact, resolving the contradiction between optical performance and system size.
Solution Approach 2:
The patent employs composite material principles by combining lens elements with different refractive properties. The first lens has positive refractive power while the second lens has negative refractive power, creating a composite optical system that leverages the complementary characteristics of each material to achieve both compact size and high image quality through balanced refractive power distribution.
2Manufacturing precision
If glass lenses are used to achieve high refractive power and aberration correction, then optical performance is improved, but manufacturing cost increases and total length cannot be shortened
Solution Approach 1:
The patent applies the principle of using cost-effective plastic materials instead of expensive glass for the lens elements. By selecting appropriate plastic materials with suitable refractive indices and designing the lens shapes accordingly, the system achieves acceptable aberration correction at a lower manufacturing cost, making the optical system more suitable for mass production in compact electronic products.
3Manufacturing precision
If the first lens element with negative refractive power is adopted to correct aberrations, then aberration correction is improved, but the difficulty to reduce total length increases significantly
Solution Approach 1:
The patent inverts the conventional approach by making the first lens have positive refractive power and the second lens have negative refractive power, rather than the reverse. This inversion allows the positive lens to serve as the primary refractive element while the negative lens corrects aberrations, achieving a more balanced optical design that is easier to compact while maintaining aberration correction performance.
4Manufacturing precision
If fourth and fifth lens elements with negative refractive power are installed to correct aberrations, then aberration correction is improved, but the rear focal length and total length increase
Solution Approach 1:
The patent changes the refractive power parameters of the later lens elements by making the fourth lens have positive refractive power and the fifth lens have negative refractive power. This parameter adjustment creates a more favorable optical path that reduces the rear focal length while maintaining aberration correction, as the positive fourth lens helps converge light before it reaches the negative fifth lens.
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 reduces the total length of the optical imaging lens assembly, enhances aberration correction, and improves the modulation transfer function, enabling a shorter optical system with better image quality and reduced manufacturing costs by using plastic lenses.
Implementation Method 1
an optical imaging lens assembly, comprising five non-cemented lenses with refractive power, sequentially arranged from an object side to an image side along an optical axis
Data Source
AI summary
An optical imaging lens assembly comprising five non-cemented lens elements with refractive power, sequentially arranged from an object side to an image side, comprising: the first lens element with positive refractive power, the second lens element with negative refractive power, the third lens element with refractive power having a concave object-side surface and at least one aspheric surface, the fourth lens element with positive refractive power having two aspheric surfaces, and the fifth lens element with negative refractive power having a concave object-side surface and a convex image-side surface with both being aspheric. Wherein an image sensor disposed on an image plane and a stop are also provided. By such arrangements, the image pickup optical system satisfies conditions related to shorten the total length and to reduce the sensitivity for use in compact cameras and mobile phones with camera functionalities.