Eight-Lens Optical Imaging Design for Slim, Bright Mobile Cameras
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Solution Overview
Problem
High-performance cameras in mobile devices face challenges in achieving a balance between lens size and image sensor size due to thickness constraints, leading to design issues such as camera bumps, and existing designs struggle to optimize for both slimness and brightness.
Innovation Solution
An optical imaging system comprising eight lenses, including specific refractive power and Abbe number conditions, arranged to satisfy certain ratios and relationships, such as TTL/(2*IMG HT) * Fno < 1.000, with lenses made of plastic material and aspherical surfaces, to achieve a slim and bright design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lens size is increased to match the image sensor size, then the image quality is improved, but the mobile device thickness increases
Solution Approach 1:
The optical imaging system is divided into eight separate lens elements (first lens through eighth lens) with different refractive powers and surface curvatures. Each lens element contributes differently to the overall optical performance, allowing the system to achieve high image quality while maintaining a compact total length that fits within mobile device thickness constraints.
Solution Approach 2:
Different lens elements have locally optimized properties: some lenses have positive refractive power while others have negative refractive power, and surfaces are either convex or concave. The fourth lens specifically has a concave object-side surface and convex image-side surface. This local variation in optical properties allows the system to correct aberrations and maintain image quality without increasing overall size.
2Length of moving object
If the lens size is minimized to meet thickness constraints, then the device slimness is improved, but the brightness and image quality deteriorate
Solution Approach 1:
The system optimizes multiple parameters simultaneously: the ratio TTL/(2×IMG HT) is controlled to be 0.200 or less, and the product {TTL/(2×IMG HT)}×Fno is controlled to be 0.850 or less. These parameter changes enable the compact lens system to maintain adequate brightness and image quality despite the minimized size required for mobile device integration.
Solution Approach 2:
The optical system uses composite lens design with eight different lens elements made of materials with varying refractive indices and Abbe numbers. This composite approach allows the compact system to achieve the necessary light-gathering capability and optical performance that would otherwise require a larger single-element lens.
3Manufacturing precision
If more lens elements are added to improve image quality, then the optical performance is improved, but the device complexity increases
Solution Approach 1:
The optical system is segmented into eight lens elements with specific assignments of refractive power and surface curvature. This segmentation allows each element to be optimized for specific optical functions (correcting spherical aberration, coma, astigmatism, etc.) while maintaining an overall compact design suitable for mobile devices.
Solution Approach 2:
The eight-lens configuration serves multiple functions simultaneously: it achieves high image quality, maintains compact size, controls brightness through the optimized TTL/(2×IMG HT) ratio, and corrects various optical aberrations. This multi-functionality reduces the need for additional separate components, thereby managing system complexity.
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 effectively balances slimness with brightness, optimizing lens design to fit within mobile device thickness constraints while maintaining high image quality.
Implementation Method 1
a first lens, a second lens, a third lens, a fourth lens having a concave object-side surface and a convex image-side surface, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in order from an object-side to an image plane
Data Source
AI summary
An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens having a concave object-side surface and a convex image-side surface, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in order from an object-side to an image plane, wherein {TTL/(2*IMG HT)}*Fno<1.000 is satisfied, where TTL is a distance on an optical axis from an object-side surface of the first lens to the image plane, IMG HT is a distance half of a diagonal length of the image plane, and Fno is an F value of the optical imaging system.