Three-Lens Capturing System Aberration Correction
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Solution Overview
Problem
Conventional compact imaging lens systems face challenges in achieving high image quality while maintaining a compact form and correcting aberrations, particularly chromatic and astigmatism, due to limitations in the number of lens elements and their refractive powers.
Innovation Solution
A capturing lens system comprising three lens elements with specific refractive powers and surface profiles, including a plastic second lens element with the greatest central thickness, which has negative refractive power and aspheric surfaces, and a third lens element with positive refractive power and inflection points, optimized to correct aberrations and reduce the total track length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If two-lens structure is used to reduce manufacturing costs, then manufacturing cost is reduced, but aberration correction ability is limited
Solution Approach 1:
The patent divides the optical system into three distinct lens elements with specific refractive powers and surface curvatures. This segmentation allows each lens element to contribute differently to aberration correction, with the first lens element having positive refractive power, the second having negative refractive power, and the third having positive refractive power, thereby achieving superior aberration correction compared to a two-lens structure
Solution Approach 2:
The patent applies local quality by giving each lens element specific local characteristics: the first lens element has a convex object-side surface and concave image-side surface, the second lens element has a concave object-side surface and convex image-side surface, and the third lens element has a convex object-side surface and concave image-side surface. These localized surface configurations enable targeted aberration correction at different positions within the optical path
2Manufacturing precision
If three or more lens elements are used to improve image quality, then aberration correction is improved, but total track length increases
Solution Approach 1:
The patent employs parameter changes by precisely controlling the refractive powers, surface curvatures, and thicknesses of the three lens elements. Specifically, the first lens element has positive refractive power, the second has negative refractive power, and the third has positive refractive power. The patent also specifies that the second lens element has the greatest central thickness among the three elements, and defines specific relationships between axial distances and central thicknesses to optimize the compact form factor while maintaining aberration correction
Solution Approach 2:
The patent utilizes aspheric surfaces on all three lens elements, representing a dimensional change from traditional spherical surfaces. This allows for more complex light path control within a compact volume, enabling superior aberration correction without proportionally increasing the total track length
3Length of stationary object
If all three lens elements have positive refractive power, then compact form is achieved, but chromatic aberration cannot be corrected
Solution Approach 1:
The patent applies the counterweight principle by introducing a second lens element with negative refractive power between two positive lens elements. This negative power element acts as an optical counterweight that balances and corrects chromatic aberrations introduced by the positive power elements, enabling chromatic aberration correction while maintaining a compact three-element structure
4Length of stationary object
If the second lens element has smaller central thickness, then total track length is reduced, but manufacturing complexity and yield rate are affected
Solution Approach 1:
The patent optimizes the central thickness of the second lens element by specifying that it has the greatest central thickness among the three lens elements, and by defining specific relationships between the central thicknesses and axial distances. This parameter optimization ensures that the second lens element is thick enough for simple manufacturing and high yield rate, while the overall design maintains a compact form factor through careful control of other dimensions
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 enhances image quality, corrects aberrations, and maintains a compact form, suitable for portable electronic products by efficiently distributing refractive power and reducing the system's sensitivity to off-axis light.
Implementation Method 1
a first lens element with positive refractive power
Implementation Method 2
a plastic second lens element with negative refractive power
Implementation Method 3
a plastic third lens element with positive refractive power
Data Source
AI summary
This invention provides a capturing lens system in order from an object side to an image side comprising: a first lens element with positive refractive power; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, both the object-side and image-side surfaces thereof being aspheric; and a plastic third lens element with positive refractive power having a convex object-side surface and a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof. Additionally, the central thickness of the second lens element is controlled favorably for the efficient spatial arrangement of the lens assembly and the simpler individual lens production while assuring suitable thickness of the second lens element, thereby assuring high image quality and improving yield rate of the product.