Four-Element Optical Imaging Lens Compact Design
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Solution Overview
Problem
The challenge is to design an optical imaging lens that is lighter, thinner, and shorter with a smaller F-number while maintaining good imaging quality for portable electronic devices, which existing designs have not adequately addressed.
Innovation Solution
A four-lens element optical imaging lens configuration with specific refracting power distributions and air gaps, along with an aperture stop placement, is proposed to achieve a reduced system length and improved optical performance, including convex and concave surface regions on the lens elements to correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the lens system is made lighter, thinner, and shorter with a smaller F-number, then the luminous flux is increased, but the imaging quality deteriorates
Solution Approach 1:
The optical system is divided into four separate lens elements (first lens element, second lens element, third lens element, and fourth lens element) with specific refracting power distributions. This segmentation allows each lens to be optimized for particular optical functions while collectively achieving both high luminous flux and good imaging quality, resolving the contradiction between increased light gathering capability and maintained image quality.
Solution Approach 2:
Different regions of the lens elements are designed with different properties - specifically, the first lens element has a convex periphery region on its image-side surface, the third lens element has a concave periphery region on its image-side surface, and the fourth lens element has a convex periphery region on its image-side surface. These localized surface quality variations enable precise control over optical aberrations while maintaining the overall compact design with small F-number.
2Length of moving object
If the system length is reduced, then the lens is shorter, but the imaging quality may deteriorate
Solution Approach 1:
The four lens elements are arranged in a nested configuration along the optical axis with specific air gaps between them. The lens elements are positioned such that they occupy overlapping or adjacent spatial regions, allowing the entire optical system to achieve a reduced system length while maintaining sufficient optical path length for high-quality imaging. This nested arrangement is evident in the parameter relationships provided in the patent.
3Illumination intensity
If the F-number is made smaller, then the luminous flux is increased, but the aberrations increase
Solution Approach 1:
The patent deliberately introduces specific surface curvature characteristics (convex and concave periphery regions) that create optical aberrations as a means to correct other aberrations. The convex periphery region of the first lens element, concave periphery region of the third lens element, and convex periphery region of the fourth lens element work together to balance and cancel out harmful aberrations, converting what would normally be detrimental features into beneficial correction mechanisms that enable small F-number operation.
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 results in a smaller F-number and enhanced imaging quality, effectively reducing system length while maintaining good optical performance and correcting spherical, curvature, and distortion aberrations.
Implementation Method 1
Each first lens element, second lens element, third lens element and fourth lens element respectively has an object-side surface which faces toward the object side and allows imaging rays to pass through as well as an image-side surface which faces toward the image side and allows the imaging rays to pass through
Data Source
AI summary
An optical imaging lens includes a first lens element to a fourth lens element. A periphery region of the image-side surface of the first lens element is convex, the second lens element has positive refracting power, an optical axis region of the object-side surface of the second lens element is convex, a periphery region of the image-side surface of the second lens element is convex, the third lens element has positive refracting power, a periphery region of the image-side surface of the third lens element is concave and a periphery region of the image-side surface of the fourth lens element is convex. EFL is an effective focal length, AAG is a sum of three air gaps along the optical axis, T3 is a thickness of the third lens element and G12 is an air gap between the first lens element and the second lens element to satisfy (EFL+AAG)/(G12+T3)≤3.800.