Five-Lens Imaging Lens for Compact Wide-Angle Aberration Correction
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Solution Overview
Problem
Existing imaging lenses for compact devices struggle to achieve a low-profile design with a wide field of view and high brightness while effectively correcting aberrations, particularly in the peripheral areas.
Innovation Solution
The proposed imaging lens configuration consists of five lenses with specific refractive powers and surface shapes, including a first lens with positive refractive power, a second lens with negative refractive power, a third lens with weak negative refractive power, a fourth meniscus double-sided aspheric lens, and a fifth double-sided aspheric lens, satisfying conditional expressions to ensure low-profileness, wide field of view, and proper aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the imaging lens is designed to be compact and low-profile with a wide field of view, then the total track length is reduced and field of view is increased, but aberrations in the peripheral area become difficult to correct
Solution Approach 1:
The imaging lens is divided into five distinct lens groups with different refractive powers and surface shapes. Each lens group is optimized for specific functions: the first lens group provides positive refractive power with a convex surface, the second and third lens groups provide negative refractive power, the fourth lens group uses a meniscus double-sided aspheric lens, and the fifth lens group uses a double-sided aspheric lens. This segmentation allows each component to address specific aberration issues while maintaining overall compactness.
Solution Approach 2:
The patent employs aspheric surfaces on multiple lens groups (fourth and fifth lens groups) to correct peripheral aberrations. The aspheric surface geometry allows for precise control of light rays at oblique angles, enabling effective aberration correction in a compact lens configuration. The specific curvature parameters of these aspheric surfaces are optimized to balance field of view and image quality.
2Illumination intensity
If the F-value is reduced to increase brightness, then the imaging brightness is improved, but aberration correction becomes more difficult
Solution Approach 1:
Different regions of the lens system are assigned different optical properties. The first lens group has strong positive refractive power to control chief ray angles, while the second and third lens groups have negative refractive power to correct chromatic and spherical aberrations. The fourth and fifth lens groups use aspheric surfaces specifically optimized for peripheral ray control. This local optimization of optical properties allows the system to achieve F-value of 2.5 or less while maintaining proper aberration correction.
3Area of stationary object
If the field of view is increased to provide wider coverage, then the imaging coverage is improved, but aberrations in peripheral areas worsen
Solution Approach 1:
The fourth and fifth lens groups utilize aspheric surfaces with specifically designed curvature parameters to control peripheral rays. The aspheric constant and higher-order terms are optimized to minimize coma, astigmatism, and field curvature at large field angles. This allows the lens to achieve a field of view of 70 degrees or more while maintaining sharp peripheral images.
Solution Approach 2:
The patent employs a composite lens structure combining multiple lens materials with different refractive indices and dispersion characteristics. The first lens uses a material with high refractive power, while subsequent lenses use materials optimized for aberration correction. This composite approach allows the system to achieve both wide field of view and proper aberration correction by leveraging the complementary properties of different optical materials.
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 compact imaging lens that offers a wide field of view of 70 degrees or more and high brightness with an F-value of 2.5 or less, effectively correcting various aberrations and maintaining a low total track length, suitable for integration in compact devices like smartphones and mobile phones.
Implementation Method 1
an imaging lens which forms an image of an object on a solid-state image sensor... includes, in order from an object side to an image side, a first lens with positive refractive power, a second lens with negative refractive power, a third lens with negative refractive power, a fourth lens with negative refractive power as a meniscus double-sided aspheric lens, and a fifth lens as a double-sided aspheric lens
Data Source
AI summary
An imaging lens which forms an image of an object on a solid-state image sensor includes a first through fifth lens in order from an object side to an image side of the imaging lens. The imaging lens includes: a first lens that is a meniscus lens having a convex surface facing the object side; a second lens; and a third lens that is a meniscus lens and has a convex surface facing the image side near an optical axis of the imaging lens. The imaging lens further includes: a fourth lens having a concave surface facing the object side and a convex surface facing the image side near the optical axis; and a fifth lens. An F-value of the imaging lens is 2.5 or less.