Four-Element Imaging Lens Assembly Refractive Power Balance
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Solution Overview
Problem
Conventional three-element and four-element lens structures in compact optical systems for portable electronic devices fail to achieve high image quality and resolution due to refractive power imbalances and sensitivity issues, leading to low manufacturing yield rates.
Innovation Solution
A four-element imaging lens assembly with specific refractive power distributions and surface shapes for each lens element, including aspheric surfaces, is designed to balance refractive power and reduce sensitivity, with relationships between axial distances and curvature radii optimized for improved image quality and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional three-element lens structure is used, then the device complexity is reduced, but the image quality and resolution cannot satisfy high-end requirements
Solution Approach 1:
The patent divides the optical system into four distinct lens elements with specific refractive power assignments (first: positive, second: negative, third: positive, fourth: negative). Each element is optimized independently with specific surface curvature relationships, allowing complex optical functions to be distributed across multiple simpler components, thereby achieving high image quality while maintaining manageable structural complexity.
2Manufacturing precision
If a conventional four-element lens structure is used, then the refractive power distribution is unbalanced, but increasing the number of elements increases device complexity
Solution Approach 1:
The patent establishes specific parameter relationships between lens elements to balance refractive power: the curvature radius of the object-side surface of the second element (R3) and image-side surface (R4) satisfy 0.05 < R4/|R3| < 0.50; the focal lengths satisfy 4.0 < f/f3 + |f/f4| < 6.0, where f is the total focal length. These parameter constraints ensure balanced refractive power distribution across the four elements, achieving optimal image quality without excessive complexity.
3Reliability
If the surface shape of the third lens element is not optimized, then the sensitivity of the optical system increases, but manufacturing precision decreases
Solution Approach 1:
The patent applies different surface shape characteristics to different lens elements based on their specific optical functions. The third lens element (with positive refractive power) is designed with a convex object-side surface and convex image-side surface at the paraxial region, creating a specific local surface quality that reduces system sensitivity. This localized optimization of surface geometry allows the system to achieve low sensitivity without compromising manufacturing 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
The solution achieves high image quality, corrects aberrations, and increases manufacturing yield rates by effectively balancing refractive power and reducing sensitivity in the imaging lens assembly, making it suitable for compact optical systems in electronic devices.
Implementation Method 1
The first lens element with positive refractive power has a convex object-side surface at a paraxial region thereof. The second lens element with negative refractive power has a concave image-side surface at a paraxial region thereof... both of an object-side surface and the image-side surface of the second lens element are aspheric.
Data Source
AI summary
An imaging lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element. The positive first lens element has a convex object-side surface at a paraxial region. The negative second lens element has a concave image-side surface at a paraxial region, wherein the image-side surface thereof has a convex shape at a peripheral region, and the surfaces thereof are aspheric. The positive third lens element has a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region. The negative fourth lens element has a concave image-side surface at a paraxial region, wherein the image-side surface thereof has a convex shape at a peripheral region, and the surfaces thereof are aspheric. The imaging lens assembly has a total of four lens elements with refractive power.