Imaging Lens with Inflection Points for Wide Angle and Miniaturization
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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 configuration includes a first positive 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, satisfying specific focal length ratios and refractive index conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the imaging lens is designed with a wider angle of view, then the field of view is improved, but the optical performance and miniaturization are compromised
Solution Approach 1:
The imaging lens is divided into multiple lens units (first lens unit with positive lens, second lens unit with negative lens, third lens unit with positive lens) arranged in sequence. Each lens unit is designed with specific curvature characteristics and inflection points to independently control optical aberrations, enabling the system to achieve wide angle of view while maintaining high optical performance through coordinated optimization of each segment.
Solution Approach 2:
The patent employs specific parameter conditions including the inflection point ratio (0.05 ≤ i ≤ 0.30), thickness deviation ratio (0.03 ≤ t ≤ 0.15), and focal length relationships (0.45 ≤ f/f1 ≤ 0.70, 0.30 ≤ |f4/f1| ≤ 0.50). These parameter optimizations allow the lens system to balance the angle of view with optical performance and miniaturization requirements.
2Volume of moving object
If the imaging lens is miniaturized, then the device size is reduced, but the optical performance and brightness are compromised
Solution Approach 1:
The patent utilizes curved surfaces with inflection points on multiple lens elements. The first lens has a convex surface with an inflection point on the peripheral portion, the second lens has an inflection point on at least one surface, and the fourth lens has a concave surface with an inflection point on the peripheral portion. These curvature designs enable effective aberration correction within a compact structure, achieving miniaturization without sacrificing optical performance.
Solution Approach 2:
The imaging lens employs a composite structure combining positive and negative lens materials with different refractive indices and dispersion characteristics. The first lens uses material with refractive index 1.50 ≤ N1 < 1.60, the second lens uses material with 1.60 ≤ N2 < 1.70, and the fourth lens uses material with 1.60 ≤ N4 < 1.70. This composite material approach enables optimized optical performance within a miniaturized structure.
3Illumination intensity
If the imaging lens is made brighter (lower F-number), then the light gathering capability is improved, but the optical performance and size are compromised
Solution Approach 1:
The patent employs aspherical surface designs with inflection points that effectively correct optical aberrations including spherical aberration, coma, and astigmatism. The aspherical coefficients are optimized to minimize aberrations while maintaining a low F-number, enabling the lens to gather light efficiently without sacrificing image quality.
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 a bright, high-performance, and small imaging lens with a wide angle of view, effectively balancing optical performance and miniaturization, and is suitable for various imaging environments, including dark conditions and high-speed video recording.
Implementation Method 1
an imaging lens including a first lens to a fourth lens disposed in order from an object side... the first lens is a positive lens having a convex surface facing the object side, the second lens is a positive or negative lens having an inflection point on at least one surface
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 disposed between the first lens and the second lens. The first lens is a positive lens having a convex surface facing the object side. The second lens is a positive or negative 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.