Four-Element Aspheric Lens System for Compact Imaging
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Solution Overview
Problem
Conventional compact imaging lens systems for portable electronic devices face challenges in achieving high image quality and manufacturing yield due to sensitivity to manufacturing process variations, and they are not optimized for both visible and infrared wavelength ranges.
Innovation Solution
An image capturing lens system comprising four lens elements with specific refractive power distributions and surface profiles, including a first lens with a convex object-side and concave image-side surface, a second lens with positive refractive power and convex image-side surface, a third lens with concave object-side and convex image-side surface, and a fourth lens with convex object-side and concave image-side surfaces at paraxial and peripheral regions, respectively, optimized to reduce aberrations and manufacturing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional three-lens configuration is used, then the device complexity is reduced, but the image quality deteriorates and manufacturing sensitivity increases
Solution Approach 1:
The patent divides the imaging function into four separate lens elements instead of three, with each element having specific refractive power assignments (first: positive, second: negative, third: positive, fourth: positive). This segmentation allows better distribution of optical functions and reduces sensitivity to individual manufacturing variations.
Solution Approach 2:
The patent applies aspheric surfaces specifically to certain lens elements (first and fourth lenses) rather than all elements, optimizing local optical quality where needed. The fourth lens element has a specific surface configuration with convex object-side and concave image-side surfaces at paraxial and peripheral regions respectively, providing localized correction for manufacturing tolerances.
2Manufacturing precision
If a four-lens configuration with negative refractive power is used, then the image quality is improved, but the total track length increases
Solution Approach 1:
The patent carefully controls the refractive power parameters of each lens element, specifically setting the second lens with negative power and the others with positive power in specific ratios. The focal length relationships (|f2| < f1 < f3 < f4 and f1+f2+f3+f4=f) are optimized to maintain compact total track length while achieving high image quality.
Solution Approach 2:
The patent employs aspheric surfaces on the first and fourth lens elements to correct aberrations more effectively than spherical surfaces. The fourth lens specifically has convex object-side and concave image-side surfaces with controlled curvature profiles, enabling compact design with improved imaging performance.
3Length of stationary object
If lens elements with higher refractive power concentration are used, then the focal length is reduced, but the manufacturing sensitivity increases
Solution Approach 1:
The total refractive power is segmented across four lens elements rather than concentrated in one or two elements. The first lens has positive power, the second has negative power, and the third and fourth have positive power, creating a distributed power structure that reduces sensitivity to manufacturing variations in any single element.
Solution Approach 2:
The patent uses lens elements with different refractive indices and dispersion properties (first lens: n1, second lens: n2, third lens: n3, fourth lens: n4) to achieve chromatic aberration correction while maintaining compact focal length. This composite approach allows each element to contribute differently to the overall optical performance.
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 lens system achieves improved image quality, reduced manufacturing sensitivity, and enhanced yield rate, while supporting both visible and infrared applications by balancing refractive powers and correcting aberrations, thus meeting the requirements for compactness and performance in portable 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 positive refractive power; and a fourth lens element with positive refractive power
Data Source
AI summary
This disclosure provides an image capturing lens system, in order from an object side to an image side comprising: a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface; a second lens element with positive refractive power; a third lens element with positive refractive power; and a fourth lens element with positive refractive power having a convex object-side surface, a concave at a paraxial region and convex at a peripheral region image-side surface, and both of the object-side and image-side surfaces thereof being aspheric; wherein the lens elements of the image capturing lens system with refractive power are the first lens element, the second lens element, the third lens element and the fourth lens element.