Five-Element Compact Lens Assembly with Inflection Points
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Solution Overview
Problem
Conventional compact photographing lens assemblies for portable electronic devices fail to meet the increasing demands for higher image quality and shorter total track length, especially with the trend towards high-performance and compact size in modern electronics.
Innovation Solution
A photographing optical lens assembly comprising a specific configuration of lens elements with positive and negative refractive powers, including a first lens element with a convex object-side surface, a second lens element with a concave object-side surface, a fourth lens element with a concave object-side and convex image-side surface, and a fifth lens element made of plastic with a concave image-side surface and at least one inflection point, optimized to reduce total track length and correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional four-element lens structure is used, then the device complexity is low, but the image quality and megapixel performance cannot satisfy high specification mobile products
Solution Approach 1:
The patent divides the lens system into five distinct lens elements with specific refractive power distributions. The first lens element has positive refractive power, the second has negative refractive power, and the third, fourth, and fifth elements have additional refractive power characteristics. This segmentation allows each element to contribute specifically to correcting different types of optical aberrations, thereby improving overall image quality and enabling high megapixel performance while maintaining a manageable structural complexity.
2Length of moving object
If the total track length is reduced for compact size, then the device becomes more compact, but the field of view and image quality deteriorate
Solution Approach 1:
The patent employs specific parameter relationships to achieve compact design without sacrificing field of view. The focal length f satisfies 2.5mm < f < 4.0mm, and the ratio f/f1 (where f1 is the focal length of the first lens element) is controlled within 0.45 < f/f1 < 0.65. Additionally, the distance SL from the aperture stop to the image plane and the total track length TTL satisfy 0.65 < SL/TTL < 0.85. These parameter optimizations enable a compact total track length while maintaining sufficient field of view and image quality.
Solution Approach 2:
The patent introduces an aperture stop positioned at a specific location within the lens assembly, where the distance from the aperture stop to the image plane (SL) is optimized relative to the total track length (TTL). This dynamic positioning of the aperture stop allows for flexible control of light paths and aberrations, enabling the system to achieve both compact size and adequate field of view by dynamically adjusting the effective optical path.
3Manufacturing precision
If the aperture stop position is optimized, then the sensitivity is reduced and image quality improves, but the total track length increases
Solution Approach 1:
The patent optimizes the parameter relationship between the aperture stop position and the total track length. By controlling the ratio SL/TTL (where SL is the distance from the aperture stop to the image plane and TTL is the total track length) within the range 0.65 < SL/TTL < 0.85, the system achieves reduced sensitivity to manufacturing tolerances and improved image quality without excessive increase in total track length. This parameter optimization balances the trade-off between image quality and compactness.
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 provides improved image quality and a compact size by balancing refractive power distribution, correcting aberrations, and maintaining a desirable total track length, while ensuring sufficient field of view and reduced sensitivity.
Implementation Method 1
a first lens element (110), a second lens element (120), a third lens element (130), a fourth lens element (140) and a fifth lens element (150. The first lens element (110) with positive refractive power has a convex object-side surface (111)
Implementation Method 2
The second lens element (120) with negative refractive power
Implementation Method 3
The fifth lens element (150) with negative refractive power has a concave image-side surface (152), wherein the fifth lens element (150) has at least one inflection point on the object-side surface (151) and the image-side surface (152)
Data Source
AI summary
A photographing optical lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive, a third lens element, a fourth lens element, and a fifth lens element having a concave image-side surface and having at least one inflecting point.