Compact Camera Lens Design for Wide-Angle Aberration Control
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Solution Overview
Problem
Conventional image taking optical systems for compact electronic devices face challenges in achieving good aberration correction and a short total length while maintaining high image quality and a wide field angle, often resulting in increased distortion and astigmatic field curving due to the large refractive angle of the first lens element and insufficient refractive power of subsequent lens elements.
Innovation Solution
The optical system comprises a front lens group with a meniscus lens element and a rear lens group featuring a positive glass lens element with inflection points, a negative lens element, and a plastic rear lens element, along with a stop between the groups, optimizing refractive powers and curvature radii to achieve balanced aberration correction and a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional optical system uses a first lens element with negative refractive power to increase field angle, then the field angle is improved, but the refractive angle becomes too large causing light divergence and difficult aberration correction
Solution Approach 1:
The patent changes the refractive power parameter of the first lens element from negative to positive, and adjusts the refractive power distribution of subsequent lens elements to achieve both wide field angle and good aberration correction. Specifically, the first lens element has positive refractive power with |f1/f| between 0.2-0.8, and the second lens element has negative refractive power with |f2/f| between 0.15-0.5, creating a balanced refractive power distribution that controls light rays effectively.
Solution Approach 2:
The patent applies different refractive power characteristics to different lens elements within the optical system. Each lens element is designed with specific refractive power signs and magnitudes tailored to its position and function: positive for the first element, negative for the second, and alternating patterns for subsequent elements, creating localized optical corrections that collectively achieve overall aberration control.
2Manufacturing precision
If multiple lens elements (4-6 lenses) are used to achieve good aberration correction and MTF performance, then the aberration correction is improved, but the total length of the optical system increases
Solution Approach 1:
The patent optimizes the refractive power distribution parameter across lens elements to achieve better aberration correction with fewer elements. By setting specific ranges for |f1/f| (0.2-0.8) and |f2/f| (0.15-0.5), and alternating refractive power signs in subsequent elements, the system achieves effective aberration control with reduced total length compared to conventional 4-6 element designs.
Solution Approach 2:
The patent combines multiple functions into fewer lens elements through optimized refractive power distribution. The alternating positive and negative refractive power pattern allows each element to contribute to both aberration correction and focal length control, merging the functions of aberration correction and compact design that were previously requiring separate element groups.
3Device complexity
If the refractive power of lens elements behind the first lens element is insufficient, then the design is simpler, but the astigmatic field curving and distortion increase
Solution Approach 1:
The patent establishes specific parameter ranges for refractive power distribution: |f1/f| between 0.2-0.8 for the first element and |f2/f| between 0.15-0.5 for the second element, with alternating signs for subsequent elements. This parameter optimization ensures sufficient refractive power in each element to control astigmatic field curving and distortion while maintaining design simplicity.
Solution Approach 2:
Instead of using a conventional pattern where the first element has negative refractive power, the patent inverts this approach by giving the first element positive refractive power and the second element negative refractive power. This inversion creates more effective light ray control with reduced astigmatic field curving and distortion while keeping the overall design straightforward.
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 effectively corrects aberrations, reduces distortion, and enhances the modulation transfer function, resulting in improved image quality and a more compact optical system suitable for compact electronic devices.
Implementation Method 1
a front-group first lens element which is a meniscus lens element nearest to the object side and has a convex object-side surface
Implementation Method 2
at least one of the object-side surface and image-side surface thereof has at least one inflection point
Data Source
AI summary
An image taking optical system, sequentially arranged from an object side to an image side along an optical axis comprising: a front lens group, a stop and a rear lens group. The front lens group comprises at least a meniscus front-group first lens element with a convex object-side surface. The rear lens group comprises at least three lens elements. Through the means of field adjustments that result in desirable distorted images, the image taking optical system may shorten the total length while enhancing the ability to create a larger field of view for panorama usages in compact cameras and mobile phones.