Subminiature Optical System with Aspherical Lenses for Compact Imaging
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Solution Overview
Problem
The challenge is to develop a subminiature imaging optical system for camera phones that is miniaturized, lightweight, low-cost, and capable of high resolution with a wide viewing angle, while minimizing the number of lenses to maintain optical capabilities.
Innovation Solution
A subminiature optical system comprising a biconvex first lens, a meniscus-shaped second lens, a meniscus-shaped third lens, and a negative refractive power fourth lens, with specific refractive power and curvature conditions, using plastic and glass materials, and an aperture stop placement to reduce aberrations and weight, and enhance manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of lenses is reduced to achieve miniaturization and low cost, then the device size and manufacturing cost decrease, but the optical capabilities and degree of freedom in design are undermined
Solution Approach 1:
The patent applies parameter changes by using aspherical lens surfaces instead of traditional spherical surfaces. This allows a single lens to correct multiple types of aberrations (spherical aberration, coma, astigmatism, field curvature) that would otherwise require multiple lenses. The aspherical parameters are optimized to achieve high-resolution imaging with only 4 lenses, resolving the contradiction between reduced lens count and maintained optical capabilities
Solution Approach 2:
The patent uses composite material design by combining plastic and glass materials in the lens assembly. Plastic lenses (first, third, and fourth lenses) provide cost-effectiveness and ease of mass production, while the glass lens (second lens) provides superior optical properties for aberration correction. This composite approach enables achieving high optical performance with a minimal number of lenses while maintaining low cost and ease of manufacture
2Volume of moving object
If miniaturization is pursued to fit portable devices, then the device size decreases, but the viewing angle and resolution are compromised
Solution Approach 1:
The patent employs aspherical surfaces (non-spherical curvature) in the lens design, particularly in the first, second, and fourth lenses. These aspherical surfaces enable effective correction of spherical aberration and other monochromatic aberrations within a compact form factor. The specific aspherical parameters are optimized to maintain high resolution (capable of resolving fine details) while keeping the total optical system length minimal, thus achieving both miniaturization and high measurement precision
Solution Approach 2:
The patent changes the optical parameters by using aspherical lens surfaces with specifically optimized curvature profiles. This allows the compact optical system to achieve a wide viewing angle (62 degrees) and high resolution simultaneously. The aspherical parameters enable the lenses to focus light more effectively across a wider field of view without increasing system size, resolving the contradiction between miniaturization and imaging precision
3Weight of moving object
If plastic lenses are used to reduce weight and manufacturing cost, then the device weight and production cost decrease, but the optical precision may be reduced
Solution Approach 1:
The patent uses a composite material strategy where plastic lenses (first, third, and fourth lenses) are combined with a glass lens (second lens). The plastic lenses contribute to weight reduction and cost effectiveness, while the glass lens provides superior optical precision for critical aberration correction. This composite approach maintains high optical precision while achieving significant weight reduction compared to all-glass designs
Solution Approach 2:
The patent optimizes the parameters of plastic lenses by using aspherical surfaces with specifically designed curvature profiles. This allows plastic material to achieve optical precision comparable to glass in critical applications. The aspherical parameters are optimized to compensate for the lower inherent precision of plastic molding, enabling mass production of high-precision optical components with reduced weight and cost
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 system achieves high-resolution, wide viewing angles, reduced weight, and low manufacturing costs, with improved optical characteristics and aberration correction, facilitating mass production and compact design.
Implementation Method 1
a first lens (L1) that is a biconvex lens with a positive refractive power
Implementation Method 2
a second lens (L2) with a negative refractive power, the second lens formed in a meniscus shape convex toward an object side
Implementation Method 3
a third lens (L3) with a positive refractive power, the third lens formed in a meniscus shape convex toward an image side
Implementation Method 4
a fourth lens (L4) with a negative refractive power
Data Source
AI summary
A subminiature optical system including: a first lens that is a biconvex lens with a positive refractive power; a second lens with a negative refractive power, the second lens formed in a meniscus shape convex toward an object side; a third lens with a positive refractive power, the third lens formed in a meniscus shape convex toward an image side; and a fourth lens with a negative refractive power, wherein a size in a direction of an optical axis satisfies Condition 1, and the refractive power of the first lens satisfies Condition 2, 1.2<TL/f<1.3 . . . Condition 1, 0.6<f1/f1<0.8 . . . Condition 2 where TL indicates a length from an aperture stop to an image-side surface, f indicates an effective focal length of the overall optical system, and f1 indicates a focal length of the first lens.