Compact Wide Angle Lens Design for Low Distortion
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Solution Overview
Problem
Wide-angle lenses face challenges in producing high-resolution images with low distortion and color aberration, especially in compact forms, which are difficult to manufacture consistently and cost-effectively, particularly for fields of view greater than 80° and super wide-angle lenses.
Innovation Solution
The design comprises three lens groups, including a first group with negative power, a second group with a cemented doublet and aperture stop, and a third group featuring complex aspheric elements, satisfying specific focal length and aperture diameter ratios to minimize distortion and color aberration, while incorporating aspheric surfaces to correct optical distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact lens design is used to reduce size, then the lens becomes smaller and lighter for portable devices, but optical distortion and color aberration increase
Solution Approach 1:
The lens is divided into three distinct groups: a first group with negative power elements, a second group with positive power elements including a cemented doublet, and a third group with aspheric elements. This segmentation allows each group to address specific optical aberrations while maintaining compact overall size.
Solution Approach 2:
The third lens group incorporates aspheric elements with non-spherical surfaces that have complex curvature profiles. These aspheric surfaces are specifically designed to correct optical distortion and color aberration while maintaining a compact lens structure, directly addressing the harmful optical effects in a space-efficient manner.
2Area of stationary object
If wide-angle field of view is achieved to capture more scene, then the lens covers greater area, but distortion and aberration become more significant
Solution Approach 1:
Different regions of the lens system are assigned different optical characteristics. The first group handles peripheral rays with negative power elements to control distortion, the second group manages chromatic aberration with the cemented doublet, and the third group corrects remaining aberrations with aspheric elements. This local optimization across the field of view enables wide-angle coverage with minimal distortion.
Solution Approach 2:
The lens design employs specific parameter relationships including the ratio of aperture diameter to focal length and the curvature parameters of the aspheric surfaces. By optimizing these parameters, the lens achieves wide field of view while maintaining low distortion and color aberration characteristics throughout the entire image area.
3Object-affected harmful factors
If complex lens elements are used to reduce aberration, then optical performance improves, but manufacturing difficulty and cost increase
Solution Approach 1:
The cemented doublet in the second lens group combines two lens elements with different powers and characteristics into a single integrated unit. This merging approach corrects chromatic aberration effectively while simplifying the overall manufacturing process compared to using separate complex elements, as the cemented structure provides mechanical stability and optical performance in a unified component.
Solution Approach 2:
The lens system utilizes composite optical designs combining different glass materials with specific refractive indices and dispersion characteristics. The cemented doublet employs materials with complementary properties to correct chromatic aberration, while the aspheric elements use materials optimized for their specific optical function. This material composition achieves high optical performance with manufacturable complexity.
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 achieves low optical distortion and color aberration across a wide field of view, enabling the production of compact wide-angle lenses that meet high performance standards, are easy to manufacture, and can be automatically assembled, suitable for various applications including consumer devices.
Implementation Method 1
The lens is comprised of three lens groups... the third lens group comprises at least two elements, wherein at least one of the two elements is an aspheric element
Data Source
AI summary
Compact wide angle lens designs are described. The lens has three lens groups and includes complex aspherical lens elements. The lens designs have a field of view of 80° or greater and satisfies at least one of the conditional equations a) BFL/EFL<=0.6 where BFL is the distance from the image surface vertex of the complex aspheric lens element to the image plane, EFL is the effective focal length of the optical lens, and,b) BFL/CA<=0.3 where CA is the clear aperture of the complex aspheric lens element, EFL is the effective focal length of the optical lens, and,c) 3=<TTL/EFL<=6.6 where TTL is the distance from the vertex of the first element of group 1 to the image plane of the lens assembly when focused at infinity, EFL is the effective focal length of the optical lens.