Five-Lens Optical Imaging Assembly with Aspheric Surfaces for Compact Length
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Solution Overview
Problem
Conventional optical imaging lens assemblies for compact electronic devices face challenges in achieving a short total length while maintaining good aberration correction and high image quality, particularly with five-lens designs where the fourth and fifth lens elements with different refractive powers and inflection points struggle to meet compactness and image quality requirements.
Innovation Solution
The optical imaging lens assembly is designed with a specific arrangement of five lens elements, including a first lens with positive refractive power, a second with negative refractive power, a third with positive refractive power, a fourth with aspheric surfaces, and a fifth with both aspheric object-side and image-side surfaces, along with a stop and image sensor, satisfying specific relations to optimize refractive power distribution and reduce the total length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a five-lens design is used to improve image quality and aberration correction, then the resolution and image quality are improved, but the total length of the optical imaging lens assembly increases
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive powers of individual lens elements (first lens: +0.5 to +1.5, second lens: -1.0 to -2.0, third lens: +1.0 to +2.5, fourth lens: -0.5 to +0.5, fifth lens: +0.5 to +1.5) and controlling specific geometric parameters (axial distances T12, T23, T34, T45; curvature radii R1-R10; thicknesses CT1-CT5) to achieve compact total length while maintaining five-lens image quality
Solution Approach 2:
The patent employs aspheric surfaces for the fourth and fifth lens elements, where at least one surface of each lens has an inflection point. This curvature design enables better aberration correction and allows the lens assembly to achieve high resolution with reduced total length compared to conventional spherical lens designs
2Measurement precision
If the fourth lens element or fifth lens element has an inflection point to correct aberration, then the aberration correction is improved, but the axial distance between the third lens element and the fourth lens element increases
Solution Approach 1:
The patent controls the axial distance T34 between the third and fourth lens elements within a specific range (0.2f to 0.5f, where f is the focal length of the lens assembly). This parameter optimization allows the fourth lens element with inflection point to correct aberration effectively while maintaining a compact overall length
Solution Approach 2:
The patent applies inflection points specifically to the fourth and fifth lens elements rather than all lens elements. This localized application of complex surface geometry provides the necessary aberration correction at the locations where it is most effective, while keeping other parts of the system simpler and more compact
3Length of stationary object
If a combination of positive and negative refractive powers is used to achieve compact design, then the total length is reduced, but the aberration correction ability deteriorates
Solution Approach 1:
The patent uses a balanced combination of positive and negative refractive powers across five lens elements, with specifically controlled power distribution (first lens: +0.5 to +1.5, second lens: -1.0 to -2.0, third lens: +1.0 to +2.5, fourth lens: -0.5 to +0.5, fifth lens: +0.5 to +1.5). This optimized parameter distribution achieves both compact total length and effective aberration correction
Solution Approach 2:
The patent employs a composite lens system combining five different lens elements with varying refractive powers and aspheric characteristics. This composite design integrates the advantages of both positive and negative power elements to achieve compact form factor while maintaining superior aberration correction capability
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 provides effective aberration correction, improved modulation transfer function, and a shorter total length, enabling high-resolution imaging with reduced manufacturing sensitivity and lower production costs, suitable for compact electronic devices.
Implementation Method 1
the first lens element with positive refractive power has a convex object-side surface
Implementation Method 2
the second lens element with negative refractive power has a convex object-side surface and a concave image-side surface
Implementation Method 3
the fourth lens element with refractive power has both object-side and image-side surfaces being aspheric; the fifth lens element with refractive power has a concave image-side surface, both object-side surface and image-side surface being aspheric
Data Source
AI summary
This disclosure discloses an optical imaging lens assembly, sequentially arranged from an object side to an image side along an optical axis, comprising: the first lens element with positive refractive power, the second lens element with negative refractive power having a convex object-side surface and a concave image-side surface, the third lens element with positive refractive power, the fourth lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the fifth lens element with refractive power having a concave image-side surface, and both object-side surface and image-side surface being aspheric, wherein a stop and an image sensor disposed on an image plane are also provided. By such arrangements, the image pickup optical system satisfies conditions related to shorten the total length and to reduce the sensitivity for use in compact cameras and mobile phones with camera functionalities.