Six-Lens Mobile Camera Module for Low Illumination Resolution
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Solution Overview
Problem
The challenge is to develop a lens module for mobile communications terminals that can achieve high resolution images with a low F-number, even with the decreasing pixel size of imaging devices, which requires an optical system capable of capturing clear images under low illumination conditions.
Innovation Solution
The lens module incorporates six or more lenses with specific refractive powers and aspherical shapes, including a first lens with positive refractive power, a second lens with convex surfaces, a third lens with negative refractive power, a fourth lens with positive refractive power, a fifth lens with negative refractive power, and a sixth lens featuring inflection points on its surfaces, optimized through conditional expressions for focal lengths, Abbe numbers, and radii of curvature to minimize size and correct optical aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pixel size of the imaging device is decreased to reduce module size, then the overall device size is reduced, but the resolution and image quality deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices, Abbe numbers, and focal lengths of multiple lenses in the optical system. Specifically, it defines conditional expressions for the relationship between focal lengths (e.g., 0.3 < f2/f1 < 1.5, 0.5 < |f3/f1| < 2.0) and optical properties of lenses to achieve high resolution with small pixel sizes. The sixth lens introduces inflection points on its image-side surface to correct optical aberrations, enabling high-quality imaging despite miniaturization.
2Illumination intensity
If the F-number is reduced to improve light gathering capability, then low illumination performance is improved, but optical aberrations and manufacturing complexity increase
Solution Approach 1:
The patent segments the optical system into six distinct lenses, each with specific refractive power and surface characteristics. This segmentation allows distribution of optical functions: the first four lenses provide positive refractive power for light gathering, while the fifth and sixth lenses with negative refractive power correct optical aberrations. The sixth lens specifically features inflection points on its image-side surface to control spherical aberration and coma, enabling low F-number operation with maintained image quality.
Solution Approach 2:
The patent employs parameter changes by defining specific conditional expressions for lens parameters to balance light gathering and aberration control. It specifies relationships such as 0.05 < (r6-CT6)/(r7+CT6) < 0.50 for the sixth lens, where r6 is the radius of curvature of the image-side surface and CT6 is the thickness at the center. These parameter optimizations enable the system to achieve low F-number (high light gathering) while controlling the increase in manufacturing complexity through standardized design constraints.
3Measurement precision
If aspherical surfaces with inflection points are added to correct optical aberrations, then image quality is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by introducing inflection points specifically on the image-side surface of the sixth lens rather than making all lens surfaces complex. The inflection points are strategically positioned to correct spherical aberration and coma in the specific region where they most impact image quality. This localized application of aspherical design with controlled inflection points (typically one or two per surface) reduces manufacturing complexity compared to making all six lenses fully aspherical, while still achieving high image quality through targeted aberration correction.
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 enables the lens module to achieve high resolution images with a low F-number, effectively capturing subjects even under low illumination, while being compact and minimizing manufacturing defects, thus addressing the need for miniaturization and improved image quality.
Implementation Method 1
a first lens having positive refractive power; a second lens having positive refractive power; a third lens having refractive power; a fourth lens having positive refractive power; a fifth lens having negative refractive power; and a sixth lens having negative refractive power
Data Source
AI summary
A lens module may include a first lens having positive refractive power, a second lens having positive refractive power, a third lens having refractive power, a fourth lens having positive refractive power, a fifth lens having negative refractive power, and a sixth lens having negative refractive power and having one or more inflection points formed on an image-side surface thereof. An overall focal length of the lens module f and a focal length of the first lens f1 may satisfy the following Conditional Expression:1.0<f1/f<2.0 [Conditional Expression].