Three-Plastic Lens System Aberration Control
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Solution Overview
Problem
Existing miniaturized optical lens systems for digital cameras and mobile phones face challenges in achieving both miniaturization and high resolution, with issues such as increased total optical length, poor incident angle characteristics, and limited field of view due to the inclusion of glass covers and IR Cut filters, and previous solutions have either high magnification, restricted design, low brightness, or insufficient field of view.
Innovation Solution
A three-piece optical lens system comprising a positive meniscus first lens element, a negative meniscus second lens element, and a positive meniscus third lens element, all made of plastic with aspheric surfaces, arranged to satisfy specific focal length and radius of curvature ratios to control magnification and aberration correction, ensuring a smaller magnification and wider field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of an optical lens system is miniaturized and glass cover and IR Cut filter are inserted, then the optical system can be made smaller, but the total optical length becomes too long and back focal length cannot be ensured
Solution Approach 1:
The patent employs aspheric surfaces on all lens elements to optimize light path control and reduce optical length. The aspheric design allows for better aberration correction in a compact configuration, enabling miniaturization without sacrificing optical performance or increasing total optical length
Solution Approach 2:
The patent changes material parameters by using plastic lens elements with specific refractive indices (1.50-1.70) and Abbe numbers (30-55), along with optimizing curvature radii and thickness parameters to achieve compact design while maintaining appropriate back focal length
2Length of stationary object
If the total optical length of an optical lens system is shortened, then miniaturization is achieved, but the characteristic of incident angle becomes worse
Solution Approach 1:
The patent applies different aspheric coefficients to different zones of each lens element, optimizing local light path control. This allows for proper incident angle characteristics at the image plane even in a shortened optical system, as each zone of the lens is optimized for its specific function
3Length of stationary object
If previous solutions use smaller lens elements with aperture stop at object side, then back focal length is ensured, but magnification becomes too high (1.19-1.48) restricting miniaturization design
Solution Approach 1:
The patent merges the functions of multiple lens elements into a compact three-element configuration where each element contributes to both focusing and aberration correction. This combined approach achieves appropriate magnification (0.50-0.70) while maintaining back focal length, unlike previous solutions that required separate aperture stop positioning
4Ease of manufacture
If plastic material with aspheric shape and inflection point is used, then manufacturing is simplified, but field of view becomes limited in previous designs
Solution Approach 1:
The patent uses aspheric surfaces with inflection points on all three lens elements, which can be manufactured using injection molding techniques. The aspheric design with proper curvature distribution expands the field of view to 60-80 degrees while maintaining manufacturing simplicity through plastic material formation
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 effectively miniaturizes the optical lens system while maintaining good incident angle characteristics and correcting aberrations, achieving a smaller magnification and wider field of view compared to existing technologies, with improved optical performance and cost-effectiveness.
Implementation Method 1
A first lens element is a positive meniscus lens element with its convex surface facing the object side; A second lens element is a negative meniscus lens element with its convex surface facing the image side; and A third lens element is a positive meniscus lens element with its convex surface facing the object side. The three lens elements have an aspheric surface respectively
Data Source
AI summary
An optical lens system for taking image, from object side along the optical axis comprises an aperture stop, a first lens element, a second lens element, and a third lens element. The first lens element is a positive meniscus lens element with its convex surface facing the object side. The second lens element is a negative meniscus lens element with its convex surface facing the image side. The third lens element is a positive meniscus lens element with its convex surface facing the object side. The three lens elements are made of plastic, and both surfaces of each lens element are aspheric. The focal length of the optical lens system is f, the focal lens of the first lens element is f1, the focal length of the second lens system is f2, and they satisfy the relations: 0.7<f1/f<0.9 and −0.35<f2/f<−1.2.