Five-Element Aspheric Lens System for Compact Wide-Angle Imaging
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Solution Overview
Problem
Conventional compact imaging systems face challenges in achieving a large field of view and short total track length while maintaining high image quality, often resulting in limited angle of views and aperture sizes, or experiencing issues with stray light and image quality due to longer lengths and larger sizes.
Innovation Solution
A photographing optical lens system comprising five lens elements with specific refractive powers and surface curvatures, including positive and negative refractive powers, aspheric surfaces, and strategically placed IR-cut filters, to balance aberrations and reduce stray light, allowing for a wide field of view and compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional compact imaging systems are used, then the device size is reduced, but the field of view and aperture size are limited
Solution Approach 1:
The imaging system is divided into five distinct lens elements with alternating positive and negative refractive powers. This segmentation allows each element to contribute differently to the overall optical performance, enabling a compact total track length while maintaining a wide field of view through coordinated aberration correction across all elements
Solution Approach 2:
The patent employs aspheric surfaces on all five lens elements, fundamentally changing the geometric parameters from traditional spherical surfaces. This parameter change enables more flexible control of light rays, allowing the system to achieve both compact size and wide field of view by optimizing the aspheric coefficients to correct aberrations that would otherwise require larger optical paths
2Area of moving object
If conventional lens configurations are used, then the field of view is increased, but the total track length becomes longer
Solution Approach 1:
Instead of using the conventional sequence of positive-positive-negative-negative or similar configurations, this patent inverts the pattern by using alternating positive-negative-positive-negative-positive refractive powers. This inverted configuration allows for more efficient folding of the optical path, achieving wide field of view with a shorter total track length by strategically placing negative elements to diverge and redirect light rays
Solution Approach 2:
The patent utilizes aspheric surfaces that introduce additional degrees of freedom in the optical design space. By changing from spherical to aspheric geometry, the system can control off-axis rays more effectively, achieving wide field of view without proportionally increasing the axial track length through sophisticated surface curvature variations
3Illumination intensity
If conventional lens designs are used, then the aperture size is increased, but the image quality deteriorates due to stray light
Solution Approach 1:
The patent converts the potential harm of large aperture-induced stray light into a benefit by using aspheric surfaces on all five elements to precisely control light ray paths. The aspheric coefficients are optimized to redirect off-axis rays and minimize veiling glare, transforming what would be a stray light problem into an opportunity for enhanced image quality through sophisticated aberration correction
Solution Approach 2:
The five lens elements act as intermediaries between the large aperture and the image plane. Each element, particularly the negative elements, serves as a mediator to control and condition the light rays, filtering out stray light paths while maintaining the benefits of large aperture for light gathering, thereby protecting image quality
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 reduces the total track length, enhances image quality, and prevents stray light, enabling a compact imaging system with a wide field of view and high image quality suitable for portable electronic devices.
Implementation Method 1
a first lens element with positive refractive power, a second lens element with positive refractive power, a third lens element with negative refractive power, a fourth lens element with positive refractive power, and a fifth lens element with negative refractive power
Implementation Method 2
both of an object-side surface and the image-side surface thereof being aspheric
Data Source
AI summary
The present disclosure provides a photographing optical lens system comprising five lens elements, the five lens elements being, in order from an object side to an image side: a first lens element with positive refractive power having an object-side surface being convex in a paraxial region thereof, a second lens element having positive refractive power, a third lens element having negative refractive power, a fourth lens element having positive refractive power, and a fifth lens element with negative refractive power having an image-side surface being concave in a paraxial region thereof with at least one convex critical point in an off-axial region thereof, both of an object-side surface and the image-side surface thereof being aspheric.