Optical Imaging System with Mixed Abbe Number Lens Groups
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Solution Overview
Problem
Mobile device cameras with fixed magnification suffer from image quality deterioration due to the non-axisymmetric shape of lenses, which affects the resolving power of plastic lenses and is exacerbated by the use of only a portion of a circular lens, leading to compromised image quality, especially in digital zoom applications.
Innovation Solution
An optical imaging system comprising three lens groups with specific configurations, including glass and plastic lenses with varying Abbe numbers, refractive powers, and aspherical surfaces, where the second and third lens groups move relative to the first, optimizing focal lengths, field of view, and F-number to maintain image quality across zoom levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a non-axisymmetric lens shape (e.g., D-cut) is used to reduce camera module thickness, then the thickness is reduced, but the resolving power and image quality of plastic lenses deteriorate
Solution Approach 1:
The patent applies asymmetry by intentionally designing non-axisymmetric lens shapes (e.g., D-cut shape) in the optical imaging system. This allows the camera module to achieve reduced thickness while maintaining acceptable image quality through optimized asymmetric lens configurations that compensate for the loss of circular symmetry.
Solution Approach 2:
The patent combines glass and plastic lenses with different Abbe numbers in a composite optical system. Specifically, it uses at least one glass lens and at least one plastic lens where the absolute difference between their Abbe numbers is greater than 25, creating a composite material approach that leverages the strengths of both materials to maintain resolving power despite non-axisymmetric shapes.
2Length of stationary object
If only a portion of a circular lens is used to reduce thickness, then the thickness is reduced, but the image quality and resolving power deteriorate
Solution Approach 1:
The patent applies local quality by optimizing specific regions of the lens system. It uses aspherical surfaces on plastic lenses to locally correct optical aberrations in the non-axisymmetric regions, ensuring that each part of the lens system contributes optimally to image quality despite the overall reduced thickness and non-circular shape.
Solution Approach 2:
The patent changes optical parameters by selecting lens materials with specific Abbe numbers where |vg2_g - vg2_p| > 25, and by designing aspherical surfaces with specific curvature profiles. These parameter changes enable the system to maintain reliable image quality while using portioned or non-axisymmetric lens shapes that reduce thickness.
3Speed
If digital zoom is used to enlarge distant objects, then the magnification is increased, but the image quality deteriorates
Solution Approach 1:
The patent applies dynamics by designing an optical imaging system with movable lens groups that can physically adjust their positions along the optical axis. This dynamic configuration enables optical zoom functionality where the second and third lens groups move relative to the first lens group, providing real magnification adjustment without the image quality deterioration associated with digital zoom.
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 system maintains high image quality and robustness against environmental changes while reducing manufacturing costs by combining glass and plastic lenses, ensuring effective performance at both wide-angle and telephoto ends with improved resolving power and resistance to temperature and humidity variations.
Implementation Method 1
an optical imaging system includes a first lens group including at least one lens; a second lens group including at least one lens; and a third lens group including at least one lens, wherein the first lens group, the second lens group, and the third lens group are sequentially disposed in ascending numerical order along an optical axis
Implementation Method 2
Each plastic lens of the at least one plastic lens of the second lens group may be an aspherical lens, and each glass lens of the at least one glass lens of the second lens group may be a spherical lens
Data Source
AI summary
An optical imaging system includes a first lens group including at least one lens; a second lens group including at least one lens; and a third lens group including at least one lens, wherein the first lens group, the second lens group, and the third lens group are sequentially disposed in ascending numerical order along an optical axis from an object side toward an image side, each of the second lens group and the third lens group is configured to move along the optical axis relative to the first lens group, the at least one lens of the second lens group includes at least one glass lens and at least one plastic lens, an Abbe number of a glass lens of the second lens group is vg2_g, an Abbe number of a plastic lens of the second lens group is vg2_p, and |vg2_g−vg2_p| is greater than 25.