Five-Lens Optical Assembly with Inflection Point for Compact Design
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Solution Overview
Problem
Conventional five-lens image pickup optical systems face challenges in achieving a compact design with good aberration correction and high resolution, as the total length of the optical lens assembly often exceeds the requirements for small electronic devices, and the placement of lens elements with inflection points complicates aberration correction and modulation transfer function optimization.
Innovation Solution
The design incorporates a specific arrangement of five lens elements with varying refractive powers and aspheric surfaces, including a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive or negative refractive power, a fourth lens with positive refractive power made of plastic, and a fifth lens with negative refractive power, featuring a concave image-side surface with an inflection point, optimized by specific curvature radius and refractive index relationships to achieve aberration correction and reduced total length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional five-lens designs are used to achieve good aberration correction and high resolution, then image quality is improved, but the total length of the optical lens assembly becomes too long for compact electronic devices
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices, curvature radii, and axial distances of the five lens elements. Specifically, the fourth lens element has a positive refractive power with a curvature radius ratio between 0.5-2.0, and the fifth lens element has a negative refractive power with an inflection point on its image-side surface. These parameter optimizations enable the system to achieve high image quality while reducing the total length to satisfy compact device requirements.
Solution Approach 2:
The patent employs composite material principles by combining lens elements with different refractive powers and material properties. The system integrates positive and negative refractive power elements, including plastic lens elements, to achieve aberration correction and compact design. This composite approach allows the optical system to maintain high resolution while minimizing the total length through synergistic interaction of different optical elements.
2Measurement precision
If the fifth lens element with an inflection point is used to correct aberration, then aberration correction is improved, but the distance between the third and fourth lens elements must be greater, which increases the total length
Solution Approach 1:
The patent resolves this contradiction by optimizing the axial distance T34 between the third and fourth lens elements through parameter changes. By carefully selecting the curvature radii and refractive powers of adjacent lens elements, the system achieves effective aberration correction using the inflection point on the fifth lens element while maintaining T34 within a compact range that satisfies overall length requirements.
3Length of stationary object
If the total length is shortened to meet compact device requirements, then the optical lens assembly becomes more compact, but the aberration correction becomes difficult
Solution Approach 1:
The patent employs composite material principles by combining lens elements with different refractive powers and material properties. The system integrates positive and negative refractive power elements, including plastic lens elements, to achieve aberration correction and compact design. This composite approach allows the optical system to maintain high resolution while minimizing the total length through synergistic interaction of different optical elements.
Solution Approach 2:
The patent applies parameter changes by optimizing the refractive indices, curvature radii, and axial distances of the five lens elements. Specifically, the fourth lens element has a positive refractive power with a curvature radius ratio between 0.5-2.0, and the fifth lens element has a negative refractive power with an inflection point on its image-side surface. These parameter optimizations enable the system to achieve high image quality while reducing the total length to satisfy compact device requirements.
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 effectively shortens the optical lens assembly while maintaining high image quality, improving aberration correction and modulation transfer function, and allowing for a greater effective photosensitive area within the same total length, suitable for compact electronic devices.
Implementation Method 1
the first lens element with positive refractive power has a convex object-side surface; the second lens element with negative refractive power has a concave object-side surface and a convex image-side surface
Data Source
AI summary
An image pickup optical lens assembly, sequentially arranged from an object side to an image side along an optical axis, comprises the first lens element with positive refractive power having a convex object-side surface, the second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the third lens element with refractive power, the fourth lens element with positive refractive power having a concave object-side surface and a convex image-side surface, the fifth lens element with negative refractive power having a concave image-side surface with at least one inflection point, and a stop. Each of the five lens elements may be made of plastic with bi-aspherical surfaces. Additionally, the image pickup optical lens assembly satisfies conditions of shortening the total length and reducing the sensitivity for usage in compact cameras and mobile phones with camera functionalities.