Five-element Imaging Lens System Aberration Correction
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Solution Overview
Problem
Conventional compact imaging lens systems for mobile phone cameras are insufficient for high-resolution imaging due to increased pixel size reduction and demand for better image quality, requiring a more efficient optical design to correct aberrations and maintain a compact form.
Innovation Solution
The proposed imaging lens system consists of five elements, including a first lens with positive refractive power, a second with negative power, a third with positive power, a fourth with an aspheric image-side surface and at least one inflection point, and a fifth with a concave object-side surface, along with an aperture stop between the object and the second lens element, optimizing refractive power distribution and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional four-lens element assembly is used, then the device complexity is reduced, but the image quality becomes insufficient for high-resolution sensors with reduced pixel size
Solution Approach 1:
The imaging lens system is divided into five distinct lens elements with specific refractive power configurations (positive, negative, positive, positive/negative, positive/negative). Each element is optimized for specific aberration correction, allowing the system to achieve high-resolution imaging capability that exceeds conventional four-element designs while maintaining manageable complexity through functional segmentation
Solution Approach 2:
Different lens elements are assigned specific optical properties: the first element has positive refractive power for basic convergence, the second has negative power for aberration correction, the third has positive power with aspheric surfaces for distortion correction, the fourth has aspheric image-side surface with inflection points for off-axis aberration control, and the fifth has concave object-side surface with aspheric features. This localized optimization of each element's properties enables superior overall image quality
2Length of moving object
If the aperture stop is disposed near the object side, then the total track length is reduced, but the field of view is limited
Solution Approach 1:
The aperture stop is positioned between the imaged object and the second lens element, and the focal length of the first lens element is specifically controlled within the range 1.86mm < f1 < 2.86mm. This parameter optimization allows the system to achieve a compact total track length while maintaining a wide field of view through coordinated design of the stop position and lens parameters
Solution Approach 2:
The system provides design flexibility by allowing the aperture stop to be positioned at different locations (between object and first lens element for telecentricity, or between object and second lens element for wide field of view). This dynamic positioning capability enables the same lens structure to be optimized for different application requirements, achieving both compactness and versatility
3Manufacturing precision
If the image-side surface of the fourth lens element is made aspheric with inflection points, then off-axis aberrations are corrected, but the manufacturing precision requirements increase
Solution Approach 1:
The image-side surface of the fourth lens element is designed as an aspheric surface with at least one inflection point. This curved surface profile enables effective correction of off-axis aberrations including astigmatism and field curvature, significantly improving image quality at the edges of the field of view compared to conventional spherical surfaces
Solution Approach 2:
The aspheric surface is characterized by specific parameter ranges: the curvature radius R4 satisfies -2.00mm < R4 < 2.00mm, and the aspheric coefficients A4, B4, C4 satisfy specific inequalities. These controlled parameter ranges balance the need for effective aberration correction with manufacturability, ensuring the complex aspheric shape can be produced with reasonable precision
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 effectively reduces the total track length, improves image quality by correcting aberrations, and enhances photosensitivity and field of view, making it suitable for high-resolution mobile phone cameras while maintaining compactness.
Implementation Method 1
a first lens element with positive refractive power having a convex object-side surface
Implementation Method 2
a second lens element with negative refractive power
Implementation Method 3
at least one of the object-side and image-side surfaces thereof being aspheric
Data Source
AI summary
The present invention provides an imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element with positive refractive power, at least one of the object-side and image-side surfaces thereof being aspheric; a fourth lens element, the image-side surface thereof being aspheric and provided with at least one inflection point; a fifth lens element having a concave object-side surface, at least one of the object-side and image-side surfaces thereof being aspheric; and an aperture stop disposed between an imaged object and the second lens element. Such an arrangement of optical elements can effectively reduce the total track length and sensitivity of the optical system, and image quality can also be improved.