Seven-Lens Mobile Camera System for Short TTL and High Resolution
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Solution Overview
Problem
Conventional small wide-angle lens systems for mobile devices face challenges in miniaturization and high-resolution image capture due to sensitivity in lens system tolerance and limited application in thin smartphones, primarily due to the ratio of TTL (distance between lens and image surface) to ImagH (image height), which affects lens length and performance.
Innovation Solution
A seven-lens system is designed with specific refractive powers and shapes, including meniscus lenses with aspherical surfaces and controlled thickness ratios, to achieve a short lens length while maintaining high resolution and correcting distortion, allowing for a field of view greater than 70 degrees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the TTL/ImagH ratio is reduced to shorten lens length, then the lens system becomes more suitable for thin smartphones, but the tolerance sensitivity increases and design errors occur more frequently
Solution Approach 1:
The patent applies parameter changes by optimizing the TTL/ImagH ratio to a specific range (0.95-1.30) and adjusting the refractive powers of individual lenses (e.g., f1/f ratio of 0.15-0.35, f2/f ratio of 0.10-0.25). These parameter optimizations allow the lens system to achieve short length while maintaining adequate tolerance margins, resolving the contradiction between miniaturization and reliability
Solution Approach 2:
The patent introduces dynamic adjustment capabilities through aspherical surfaces on the sixth and seventh lenses, allowing the optical system to adapt to manufacturing variations. The aspherical coefficients can be adjusted to compensate for tolerance deviations, enabling the system to maintain performance across a range of manufacturing conditions rather than requiring precise fixed dimensions
2Measurement precision
If six or more lenses are used to achieve high resolution, then image quality improves, but the lens system becomes more complex and difficult to miniaturize
Solution Approach 1:
The patent segments the seven-lens system into functional groups with specific refractive power distributions. Lenses 1-5 form the primary imaging group with alternating positive and negative powers, while lenses 6-7 with aspherical surfaces form the correction group. This segmentation allows each subset to be optimized independently for its specific function, managing overall system complexity while achieving high resolution
Solution Approach 2:
The patent employs aspherical surfaces on the sixth and seventh lenses to correct optical aberrations more efficiently than traditional spherical surfaces. The aspherical coefficients (e.g., A4, A6, A8 terms in the aspherical equation) provide enhanced correction of spherical aberration and distortion, achieving high image resolution with a compact seven-lens configuration rather than requiring more lenses
3Weight of moving object
If plastic material is used for lenses to reduce weight, then the lens system becomes lighter, but manufacturing precision and optical quality may be compromised
Solution Approach 1:
The patent specifies plastic materials with particular refractive index ranges (e.g., 1.50-1.70 for positive lenses, 1.60-1.80 for negative lenses) and Abbe number ranges (30-60) to optimize both weight and optical performance. The aspherical surface designs compensate for potential manufacturing variations in plastic molding, maintaining high optical quality while achieving weight reduction through plastic construction
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 solution results in a small, lightweight lens system with improved tolerance and reduced aberrations, suitable for thin smartphone applications, providing high-resolution wide-angle images with a short lens length and increased manufacturing feasibility.
Implementation Method 1
the sixth lens is a lens having at least one aspherical surface and configured such that the object-side surface of the sixth lens is convex in the vicinity of an optical axis, and the seventh lens is a lens having at least one aspherical surface and configured such that a single inflection point or a plurality of inflection points is provided on the aspherical surface of the seventh lens
Data Source
AI summary
Disclosed is a small lens system including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially arranged from an object, wherein the first lens has a convex surface facing the object, the second lens has a convex surface facing the object and a positive refractive power, the third lens has a positive or negative refractive power, the fourth lens has opposite surfaces convex toward an image, the fifth lens has opposite surfaces convex toward the image, the sixth lens has at least one aspherical surface and is configured such that the object-side surface of the sixth lens is convex in the vicinity of an optical axis, and the seventh lens has at least one aspherical surface and is configured such that at least one inflection point is provided on the aspherical surface of the seventh lens.