Imaging Lens Aspheric Fifth Surface Aberration Correction
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Solution Overview
Problem
Conventional imaging lenses face difficulties in achieving a wide field of view, low-profileness, and low F-number while effectively correcting aberrations, particularly in the peripheral areas.
Innovation Solution
The imaging lens configuration includes a first lens with positive refractive power and a convex surface, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens, and a fifth lens with negative refractive power and an aspheric surface, optimized by specific conditional expressions to correct spherical aberration, chromatic aberration, astigmatism, and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional lens configurations are used to achieve wide field of view, low-profileness and low F-number, then compactness and high performance are improved, but aberration correction in peripheral areas deteriorates
Solution Approach 1:
The fifth lens employs an aspheric surface on its image-side surface with specific curvature characteristics (conditional expression: 0.5 < r5/r6 < 1.5). This aspheric design enables effective correction of peripheral aberrations including distortion and field curvature, while maintaining wide field of view and compact form factor. The aspheric surface replaces traditional spherical surfaces to achieve superior optical performance in the peripheral areas.
Solution Approach 2:
The patent applies multiple conditional expressions to optimize lens parameters: refractive powers (0.3 < f1/f < 0.6, -0.6 < f2/f < -0.2), focal length ratios, and curvature radii (0.5 < r5/r6 < 1.5). These parameter optimizations enable the lens system to achieve wide field of view, low F-number, and excellent aberration correction simultaneously by precisely controlling the optical path and ray angles.
2Manufacturing precision
If the fifth lens has a concave surface facing the image side near the optical axis, then field curvature and distortion are corrected, but the complexity of lens surface formation increases
Solution Approach 1:
The image-side surface of the fifth lens is designed as an aspheric surface with a concave shape facing the image side near the optical axis. This specific curvature configuration (conditional expression: 0.5 < r5/r6 < 1.5) effectively corrects field curvature and distortion aberrations. The aspheric design, while more complex than spherical surfaces, is achieved through modern manufacturing techniques and provides superior correction of peripheral aberrations.
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 achieves high-resolution imaging with a balanced wide field of view, low-profileness, and low F-number, while effectively correcting aberrations, thereby enhancing the optical performance of compact imaging devices.
Implementation Method 1
The image-side surface of the fifth lens is formed as an aspheric surface having at least one off-axial pole point. When the image-side surface of the fifth lens is formed as the aspheric surface having at least one off-axial pole point, the field curvature and the distortion can be properly corrected and the light ray incident angle to an image sensor can be properly controlled.
Data Source
AI summary
There is provided an imaging lens with high-resolution which satisfies demand of the wide field of view, the low-profileness and the low F-number, and excellently corrects aberrations. An imaging lens comprises in order from an object side to an image side, a first lens having positive refractive power and a convex surface facing the object side near the optical axis, a second lens having negative refractive power near the optical axis, a third lens having the positive refractive power near the optical axis, a fourth lens, and a fifth lens having the negative refractive power and a concave surface facing the image side near the optical axis, wherein the image-side surface of said fifth lens is formed as an aspheric surface having at least one off-axial pole point, and predetermined conditional expressions are satisfied.