Wide-angle Lens Miniaturization via Seven-element Segmentation
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Solution Overview
Problem
Conventional wide-angle lenses for in-vehicle cameras face challenges in miniaturization without compromising the maximum half field of view (HFOV), often resulting in reduced HFOV when downsized.
Innovation Solution
A wide-angle lens design featuring a specific arrangement of lenses, including a cemented sixth and seventh lens, with carefully optimized radii and aspheric surfaces, maintains a maximum HFOV between 98° and 120° while being miniaturized, ensuring sufficient refractive power and preventing excessive lens diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the wide-angle lens is miniaturized to reduce the size of the in-vehicle camera, then the camera size is reduced, but the maximum half field of view (HFOV) is reduced
Solution Approach 1:
The lens is divided into seven individual lens elements with alternating positive and negative refractive powers, arranged in a specific sequence. This segmentation allows each element to contribute differently to the overall optical performance, enabling miniaturization while maintaining a wide HFOV of 98° or more through optimized individual element contributions.
Solution Approach 2:
The patent applies specific parameter constraints to achieve the desired balance between size and HFOV. The key parameters include: the ratio of the focal length of the sixth lens to the focal length of the wide-angle lens (0.30 < f6/f < 0.70), and the ratio of the focal length of the seventh lens to the focal length of the wide-angle lens (0.10 < f7/f < 0.50). These parameter optimizations enable miniaturization while preserving wide-angle performance.
2Adaptability or versatility
If the lens elements are optimized for wide HFOV, then the HFOV is expanded, but the lens diameter increases
Solution Approach 1:
Different regions of the lens system are assigned different functional qualities. The first four lens elements focus on light gathering and initial focusing, while the cemented fifth and sixth lenses (with the diaphragm between them) provide aberration correction and focal control. The seventh lens element optimizes the exit pupil and field of view. This local optimization allows wide HFOV without excessive diameter increase.
Solution Approach 2:
The patent employs a cemented lens structure where the fifth lens and sixth lens are optically bonded together. This composite construction reduces the overall lens diameter by eliminating air gaps and reducing the number of individual lens mounts, while maintaining the aberration correction benefits of having separate positive and negative power elements.
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 expanded HFOV and miniaturization while maintaining optical quality, correcting for aberrations like curvature of field and chromatic aberration, and ensuring the lens remains suitable for high pixel imaging.
Implementation Method 1
a first lens having a negative refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens having a positive refractive power, a fifth lens having a positive refractive power, a sixth lens having a negative refractive power, and a seventh lens having a positive refractive power
Data Source
AI summary
Provided is a wide-angle lens, including a lens group and a diaphragm. Lenses in the lens group are sequentially arranged from an object side in a manner sandwiching the diaphragm. A maximum half field of view of the wide-angle lens as a whole is set to ω, 98°<ω<120° is satisfied. An effective focal length and an entrance pupil diameter of the wide-angle lens as a whole are set to f and HEP respectively, f/HEP<2.3 is satisfied. The lens group includes a first lens that is located closest to the object side and that is a negative lens with a concave surface facing an image side. An effective radius and a radius of curvature of an image side lens surface of the first lens are set to sd12 and R12 respectively, 0.890<sd12/R12<0.970 is satisfied.