Imaging Lens with Inflection Points for Wide Angle and Aberration Control
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Solution Overview
Problem
There is a demand for an imaging lens that offers a wider angle of view while maintaining high performance and miniaturization, particularly for applications in video distribution and communication via the Web.
Innovation Solution
The proposed imaging lens consists of a first positive meniscus lens, a second lens with an inflection point and low thickness deviation ratio, a third positive lens with a convex surface and inflection point, and a fourth negative lens with a concave surface and inflection point. These lenses are arranged in a specific configuration with an aperture stop on the object side, satisfying conditions related to focal lengths and refractive indices to achieve optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels of the solid-state imaging element is increased to achieve higher optical performance, then the imaging quality is improved, but the imaging lens requires more complex optical design and larger size
Solution Approach 1:
The imaging lens is divided into four specific lens elements (first positive meniscus lens, second lens with inflection point, third positive lens with inflection point, fourth negative lens with inflection point), each with specific optical functions. This segmentation allows complex aberration correction to be distributed across multiple specialized elements rather than requiring a single complex element, thereby improving imaging quality while managing design complexity.
Solution Approach 2:
Each lens element is designed with specific local characteristics: the first lens has a convex object-side surface, the second lens has low thickness deviation ratio, the third and fourth lenses have inflection points on peripheral portions. These localized quality variations enable precise control of optical properties in different regions of the lens system, achieving high imaging quality without uniform complexity throughout the entire system.
2Volume of moving object
If the imaging lens is miniaturized to improve portability, then the device size is reduced, but the angle of view and optical performance are compromised
Solution Approach 1:
The first lens is designed as a positive meniscus lens with a convex object-side surface, and the third and fourth lenses incorporate inflection points on their peripheral portions. These curved surface designs enable compact lens element configurations that achieve wide angle of view (75 degrees or more) while maintaining miniaturization, as the curvature allows for more efficient light path folding and reduced overall lens length.
Solution Approach 2:
Specific parameter ranges are defined for the lens system: the focal length ratio f/f1 is controlled within 0.50 to 0.80, the fourth lens focal length ratio f4/f1 within -0.50 to -0.25, and the inflection point positions are precisely controlled on peripheral portions of lenses 2, 3, and 4. These parameter optimizations enable the lens to achieve wide angle of view and bright performance (F-number 2.0 or less) in a miniaturized form factor.
3Illumination intensity
If the F-number is reduced to make the lens brighter, then light gathering ability is improved, but aberration correction becomes more difficult and lens complexity increases
Solution Approach 1:
The aperture stop is extracted and positioned on the object side of the first lens, separate from the main lens body. This extraction allows for optimized light control and aberration correction independent of the lens element design, enabling bright performance (F-number 2.0 or less) while managing the complexity of aberration correction through dedicated stop positioning rather than complex lens element interactions.
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 solution provides a bright, high-performance, and compact imaging lens with a wide angle of view, suitable for various applications including video recording and communication, while maintaining good aberration correction and miniaturization.
Implementation Method 1
the first lens is a positive meniscus lens having a convex surface facing the object side
Implementation Method 2
the second lens is a lens having an inflection point on at least one surface with a low thickness deviation ratio
Implementation Method 3
the third lens is a positive lens having a convex surface facing an image plane side and an inflection point on a lens peripheral portion
Implementation Method 4
the fourth lens is a negative lens having a concave surface on an image plane side and an inflection point on a peripheral portion
Data Source
AI summary
An imaging lens includes: a first lens to a fourth lens disposed in order from an object side; and an aperture stop on a foremost object side. The first lens is a positive meniscus lens having a convex surface facing the object side. The second lens is a lens having an inflection point on at least one surface with a low thickness deviation ratio. The third lens is a positive lens having a convex surface facing an image plane side and an inflection point on a lens peripheral portion. The fourth lens is a negative lens having a concave surface on an image plane side and an inflection point on a peripheral portion.