Seven-Element Optical Lens Layout for Compact Low-Light Imaging
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Solution Overview
Problem
The challenge lies in designing an optical imaging lens set for portable electronic devices that is both compact in size and maintains high imaging quality, particularly under dim light conditions, while addressing the longer distance from the object-side surface of the first lens element to the image plane in conventional designs.
Innovation Solution
An optical imaging lens set with seven lens elements, each with specific refractive power and surface configurations, including concave and convex portions near the optical axis, adhering to specific ratios and distances to achieve a shorter total length and enhanced image definition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional optical lens design is used, then imaging quality can be maintained, but the total length from object-side surface to image plane becomes longer
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive indices, Abbe numbers, and curvature radii of all seven lens elements. Specific conditional expressions are established (e.g., 0.5 < f6/f < 1.5, 30 < ν6 < 70) to optimize the optical parameters, enabling the lens set to achieve compact length while maintaining superior imaging quality and dim light performance
Solution Approach 2:
The optical system is segmented into seven distinct lens elements with specific functions assigned to each. The first lens element has positive refractive power with convex object-side surface, while the sixth and seventh elements have negative refractive power. This segmentation allows each element to contribute optimally to reducing total length while maintaining imaging quality
2Length of moving object
If lens size is reduced for thinner devices, then device thickness decreases, but imaging quality under dim light conditions deteriorates
Solution Approach 1:
The patent employs composite material principles by selecting lens elements with specific refractive index and Abbe number combinations. The sixth lens element uses material with 30 < ν6 < 70 and 1.5 < n6 < 1.7, while the seventh element uses material with 20 < ν7 < 60 and 1.4 < n7 < 1.7. These material selections enable compact lens size while maintaining light-gathering capability for dim light imaging
Solution Approach 2:
The patent optimizes the dynamic balance between lens element thickness, air gaps, and focal lengths. The conditional expressions (e.g., 0.3 < T6/f < 0.7, 0.4 < T7/f < 0.8) ensure that each lens element maintains optimal dimensions relative to the focal length, enabling the compact design to perform well under varying light conditions
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 proposed lens set achieves a shorter total length, improved imaging quality, and enhanced image definition, while maintaining good optical performance under dim light conditions.
Implementation Method 1
An optical imaging lens set of seven lens elements from an object side toward an image side in order along an optical axis has a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element
Data Source
AI summary
An optical-lens-set includes a first lens element of a concave image-side surface near its optical-axis, a sixth lens element of negative refractive power and of a concave image-side surface near its optical-axis to go with a fifth lens element of a concave object-side surface near its optical-axis or with a seventh lens element of negative refractive power. The Abbe number υ1 of the first lens element, the Abbe number υ3 of the third lens element, the Abbe number υ4 of the fourth lens element, the Abbe number υ5 of the fifth lens element, the Abbe number υ6 of the sixth lens element and the Abbe number υ7 of the seventh lens element together satisfy 5≤5υ1−(υ3+υ4+υ5+υ6+υ7).