Plastic Imaging Lens with Aspheric Surfaces for Compact Wide-Angle Design
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Solution Overview
Problem
Existing imaging lenses for compact mobile devices struggle to achieve a balance between compactness, wide angle of view, and low F-value while effectively correcting aberrations, and are often costly and inefficient in terms of material usage.
Innovation Solution
A fixed-focus imaging lens configuration with specific refractive power distribution and aspheric surface shapes, including a biconvex first lens, biconcave second lens, meniscus third lens, and meniscus fourth lens, all made of plastic, optimized by conditional expressions to minimize total track length and correct various aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the F-value is reduced to increase brightness, then the brightness is improved, but the total track length increases making the lens less compact
Solution Approach 1:
The patent employs aspheric surfaces on multiple lens elements (first, second, third, and fourth lenses) to control light paths more efficiently. The aspheric shapes enable better aberration correction and allow the lens to achieve a compact total track length while maintaining a low F-value of 2.6 or less, thus resolving the contradiction between compactness and brightness.
Solution Approach 2:
The patent optimizes specific parameter ranges including the ratio of focal length to the curvature radius of the fourth lens (0.06 < f/r8 < 0.15) and the refractive powers of individual lenses. By carefully controlling these parameters, the lens achieves both compact dimensions and high brightness performance simultaneously.
2Adaptability or versatility
If the angle of view is widened to capture more scene, then the angle of view is improved, but aberration correction becomes more difficult
Solution Approach 1:
The patent divides the optical system into four distinct lens elements with specific refractive power distributions (positive, negative, positive, negative). Each lens element is optimized for specific aberration correction tasks, allowing the system to achieve a wide angle of view (70-80 degrees) while maintaining excellent aberration correction performance.
Solution Approach 2:
Multiple aspheric surfaces are implemented across the lens elements to correct off-axial aberrations that become more pronounced with wider angles of view. The aspheric shapes enable precise control of light rays at large angles while maintaining compact dimensions.
3Reliability
If glass materials are used to achieve high optical performance, then the optical performance is improved, but the manufacturing cost and weight increase
Solution Approach 1:
The patent replaces traditional glass lens materials with plastic materials for all four lens elements. This substitution significantly reduces manufacturing cost and enables mass production while maintaining the required optical performance through optimized aspheric surface designs and controlled refractive power distribution.
Solution Approach 2:
The patent carefully selects and optimizes the refractive indices and Abbe numbers of the plastic materials used, along with the curvature radii and thicknesses of each lens element. By controlling these parameters, the plastic lens achieves optical performance comparable to glass while benefiting from lower cost and reduced weight.
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 compact lens system with a wide angle of view (70-80 degrees) and low F-value (2.6 or less), effectively correcting aberrations and allowing for mass production at a lower cost using plastic materials.
Implementation Method 1
an imaging lens which forms an image of an object on a solid-state image sensor
Implementation Method 2
a biconcave second lens, both surfaces of which are aspheric
Data Source
AI summary
An imaging lens comprising, in order from the object side: an aperture stop; a positive first lens having convex object-side and image-side surfaces; a double-sided aspheric negative second lens having a concave object-side surface; a meniscus double-sided aspheric positive third lens having a convex image-side surface; and a meniscus double-sided aspheric negative fourth lens having a concave image-side surface. All of the lenses are made of a plastic material.