Six-Lens Optical Imaging Group for Compact High-Aperture Design
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Solution Overview
Problem
The challenge is to design an optical imaging lens group that achieves miniaturization while maintaining high image quality and large aperture, which is difficult due to the reduction in design freedom caused by minimizing the number of lenses in portable electronic devices, and the increasing demands on imaging performance with advancements in CCD and CMOS image sensors.
Innovation Solution
The optical imaging lens group consists of six lenses with specific refractive powers and surface shapes, including a combination of positive and negative refractive powers, convex and concave surfaces, and carefully configured focal lengths and thicknesses, to achieve a compact size and high image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the number of lenses is reduced to achieve miniaturization, then the size of the imaging lens group is reduced, but the design freedom is reduced making it difficult to meet high imaging performance demands
Solution Approach 1:
The imaging lens group is divided into six distinct lens elements (first lens L1 through sixth lens L6), each with specific refractive power and surface characteristics. This segmentation allows independent optimization of each lens element's parameters (radii of curvature, thickness, refractive index) to achieve both compact size and high imaging performance. The patent specifies that at least one surface of each lens should be an aspheric surface, further enabling precise control over light paths while maintaining a reduced overall lens count.
Solution Approach 2:
The patent employs systematic parameter optimization across all lens elements, including refractive powers, radii of curvature (R1 through R24), thicknesses (CT1 through CT6), and spacing distances (T12 through T56). By carefully controlling these parameters and their relationships (e.g., f/EPD ≤ 1.8, TTL/ImgH ≤ 1.2), the design achieves miniaturization while maintaining sufficient design freedom to correct optical aberrations and meet high imaging performance requirements.
2Volume of moving object
If the number of lenses is reduced for miniaturization, then the imaging lens group becomes more compact, but imaging performance deteriorates due to limited design freedom
Solution Approach 1:
The patent specifies that at least one surface of each of the six lens elements should be an aspheric surface, characterized by a conic coefficient k and higher-order terms (A4 through A20). This curvature variation allows precise control over light ray paths, enabling correction of spherical aberration, coma, and other optical imperfections. The aspheric surfaces provide additional degrees of freedom for optimizing imaging performance while maintaining a compact six-lens configuration, directly addressing the trade-off between size reduction and performance maintenance.
3Volume of moving object
If lenses are configured with specific refractive powers and surface shapes for compact size, then miniaturization is achieved, but the complexity of configuring focal lengths and thicknesses increases
Solution Approach 1:
The patent establishes specific parameter ranges and relationships to guide the configuration process: refractive power signs (+, -, +, +, +, - for lenses L1-L6), focal length ratios (f1/f, f6/f), combined focal length ratios (f45/f123), and dimensional ratios (DT41/DT52, ET1/ET5, SAG41/SAG51, SAG52/SAG62). These standardized parameter specifications simplify the design process by providing clear design criteria, reducing the complexity of configuring a compact six-lens system with high performance.
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 allows for a compact, high-quality imaging lens group with a large aperture, meeting the demands for miniaturization and image quality in portable electronic devices, as evidenced by the specific relationships between focal lengths, surface ratios, and aberration control.
Implementation Method 1
a first lens having positive refractive power, and an object-side surface thereof is a convex surface
Implementation Method 2
a sixth lens having negative refractive power, an object-side surface thereof is a concave surface, and an image-side surface thereof is a convex surface
Data Source
AI summary
The present disclosure discloses an optical imaging lens group including, sequentially from an object side to an image side along an optical axis, a first lens having positive refractive power with a convex object-side surface; a second lens having refractive power; a third lens having refractive power; a fourth lens having refractive power; a fifth lens having refractive power; and a sixth lens having negative refractive power with a concave object-side surface and a convex image-side surface. A total effective focal length f of the optical imaging lens group, an entrance pupil diameter EPD of the optical imaging lens group and half of a maximal field-of-view Semi-FOV of the optical imaging lens group satisfy: f/EPD<2, and f*tan(Semi-FOV)>4.5 mm.