Five-Lens Camera Optical Lens Miniaturization via Refractive Index Optimization
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Solution Overview
Problem
Conventional five-piece lens structures for camera optical lenses in portable devices face challenges in miniaturization and lightweight design due to large optical effective half caliber, which hinders further reduction in size and weight while maintaining high imaging quality.
Innovation Solution
A camera optical lens design comprising five lenses with specific refractive powers and configurations, including an aperture and optical filter, where the fourth lens is made of high refractive power material to reduce the effective half caliber and overall volume, combined with aspheric surfaces to minimize aberrations and system length, allowing for miniaturization and lightweight construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a five-piece lens structure is adopted to improve imaging quality, then imaging quality is improved, but the optical effective half caliber increases making miniaturization difficult
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices and Abbe numbers of lens materials. Specifically, the fourth lens uses material with refractive index 1.7≤nd<2.0 and Abbe number 20≤vd<40, while the fifth lens uses material with refractive index 1.5≤nd<1.7 and Abbe number 30≤vd<60. This material parameter selection enables better light control with reduced optical effective half caliber.
Solution Approach 2:
The patent segments the optical system into five distinct lens elements with specific power distributions. The first lens has positive power, the second and third have negative power, the fourth has positive power, and the fifth has negative power. This segmentation allows each element to contribute specifically to aberration correction while maintaining compact overall dimensions.
2Measurement precision
If more lens elements are added to improve imaging quality, then imaging quality is improved, but the system length and weight increase
Solution Approach 1:
The patent employs aspheric surfaces on multiple lens elements to dynamically control light paths. The aspheric coefficients are specifically optimized to reduce the optical path length while maintaining imaging quality. This allows the five-piece lens to achieve compact system length despite having multiple elements.
Solution Approach 2:
The patent changes the geometric parameters of the lens elements, including surface curvatures, thicknesses, and spacing. The conditional expressions for focal lengths (0.5<f1/f<1.0, -1.0<f2/f>-0.3, -1.0<f3/f>-0.3, 0.3<f4/f<0.8, -1.0<f5/f>-0.3) optimize the power distribution to minimize system length while maintaining five elements for quality imaging.
3Volume of moving object
If high refractive power material is used to reduce effective half caliber, then miniaturization is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by using aspheric surfaces only on specific lens elements where needed for miniaturization. The fourth and fifth lenses have aspheric surfaces with optimized coefficients to control the high refractive power material's light bending, reducing manufacturing complexity while achieving compact size.
Solution Approach 2:
The patent selects refractive index ranges (1.7≤nd<2.0 for fourth lens, 1.5≤nd<1.7 for fifth lens) that balance miniaturization benefits with manufacturing feasibility. These parameter ranges provide sufficient light control power while remaining within practical material selection and fabrication capabilities.
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 design achieves a compact and lightweight camera optical lens with improved imaging quality by controlling focal lengths, refractive powers, and Abbe numbers of the lenses, reducing system color and lateral color, and enabling high-performance miniaturization and sensitivity.
Implementation Method 1
the fourth lens is made of high refractive power material to reduce the effective half caliber and overall volume
Implementation Method 2
combined with aspheric surfaces to minimize aberrations and system length
Data Source
AI summary
A camera optical lens, includes a first lens power, a second lens, a third lens, a fourth lens, and a fifth lens. A focal length of the camera optical lens is f, a focal length of the first lens is f1, a focal length of the third lens is f3, a focal length of the fourth lens is f4, a refractive power of the fourth lens is n4, an axial distance from an image side of the fourth lens to an object side of the fifth lens is d8, an effective half caliber of an image side of the fourth lens is SD8, the maximum image height of the camera optical lens is ImgH, an optical total length of the camera optical lens is TTL. The camera optical lens satisfies conditions: 0.5<f1/f<1; 1.55<n4<1.7; −3<f3/f4<−0.5; 0.2<SD8/ImgH<0.5; and 0.07<d8/TTL<0.3.