Compact Imaging Lens with Aberration Correction
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Solution Overview
Problem
Conventional imaging lenses for small cameras face challenges in achieving a wide angle of view while maintaining a small size and satisfactory aberration correction, as they often result in increased lens system length and difficulty in downsizing.
Innovation Solution
The imaging lens configuration includes a specific arrangement of lenses with negative and positive refractive powers, along with aspheric surfaces, and strategically placed aperture stops to balance refractive power and correct aberrations, adhering to conditional expressions that optimize focal lengths, distances, and diameters to achieve a compact design with a wide angle of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lenses is increased to correct aberrations and achieve a wide angle of view, then the imaging performance is improved, but the total length of the lens system increases
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices and Abbe numbers of lens materials, as well as the curvature radii and thicknesses of individual lenses. Specifically, the first lens uses material with refractive index 1.5015-1.5920 and Abbe number 52.06-64.15, while the second lens uses material with refractive index 1.6387-1.7000 and Abbe number 23.18-30.18. These parameter optimizations enable satisfactory aberration correction with a reduced total of only 6 lenses, achieving both high image quality and compact lens system length
Solution Approach 2:
The patent employs aspheric surfaces on multiple lenses to correct aberrations more efficiently. The first lens has an aspheric object-side surface, the third lens has an aspheric image-plane-side surface, and the sixth lens has an aspheric image-plane-side surface. These aspheric curvatures enable better aberration correction with fewer lenses, reducing the overall lens system length while maintaining high manufacturing precision
2Adaptability or versatility
If the angle of view is widened, then the imaging coverage is improved, but the lens size and complexity increase
Solution Approach 1:
The patent achieves a wide angle of view (67.2°-72.6°) by optimizing specific parameters including the focal length ratio f1/f2 between -0.2746 and -0.1936, the distance ratio D12/D23 between 1.4386 and 2.0642, and the curvature radii of individual lens surfaces. These parameter optimizations enable the lens to achieve a wide angle of view without increasing device complexity, as the 6-lens configuration maintains manageable complexity while delivering enhanced imaging coverage
Solution Approach 2:
The patent divides the lens system into 6 distinct lens groups with specific functions: the first lens (negative power) for wide-angle correction, the second lens (positive power) for focal length control, the third lens (positive power) for aberration correction, the fourth lens (negative power) for distortion correction, the fifth lens (positive power) for field curvature correction, and the sixth lens (negative power) for final aberration refinement. This segmentation enables each lens to contribute specifically to achieving a wide angle of view without requiring the entire system to become more complex
3Length of moving object
If the lens system is downsized, then the compactness is improved, but the refractive power of each lens increases making aberration correction difficult
Solution Approach 1:
The patent successfully downsizes the lens system while maintaining aberration correction by changing material parameters and geometric parameters. The use of high-refractive-index materials (first lens: 1.5015-1.5920, second lens: 1.6387-1.7000) enables stronger refractive power in smaller lenses. Combined with optimized curvature radii and thicknesses, this allows the compact 6-lens system to achieve satisfactory aberration correction despite the reduced size and increased refractive power requirements
Solution Approach 2:
The patent employs composite material selection by combining lenses with different refractive indices and Abbe numbers to achieve chromatic aberration correction. The first lens uses material with refractive index 1.5015-1.5920 and Abbe number 52.06-64.15, while the second lens uses material with refractive index 1.6387-1.7000 and Abbe number 23.18-30.18. This composite material approach enables the downsized lens system to correct chromatic and spherical aberrations effectively despite the increased refractive power of individual lenses
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 imaging lens with improved aberration correction, enabling a wider angle of view and reduced size, suitable for small cameras like smartphones and onboard cameras, while maintaining high image resolution and performance.
Implementation Method 1
The first lens has negative refractive power, the second lens has positive refractive power, the third lens has positive refractive power, the fourth lens has negative refractive power, the sixth lens has negative refractive power
Data Source
AI summary
An imaging lens includes a first lens having negative refractive power; an aperture stop; a second lens; a third lens; a fourth lens; a fifth lens; and a sixth lens, arranged in this order from an object side to an image plane side. The fourth lens is formed in a meniscus shape at a paraxial region thereof. The fifth lens is formed in a shape so that a surface thereof on the object side is convex at a paraxial region thereof. The sixth lens is formed in a meniscus shape at a paraxial region thereof. The first lens and the sixth lens have specific Abbe's numbers.