Four-Element Lens System with Aspheric Surfaces for Peripheral Image Quality
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Solution Overview
Problem
Conventional compact optical systems for portable electronic devices face challenges in balancing image quality between the center and peripheral images due to difficulties in controlling the refractive powers of lens elements, leading to suboptimal performance in miniaturized designs.
Innovation Solution
A photographing lens system comprising four independent non-cemented lens elements with specific refractive powers and aspheric surfaces, including a first lens with positive power, a second with negative power, a third with positive and concave image-side surface, and a fourth with negative and concave surfaces, along with an aperture stop, to optimize image quality and reduce aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional four-element lens structure is adopted, then the device can be miniaturized, but the image quality of peripheral image deteriorates due to difficulty in controlling refractive powers
Solution Approach 1:
The patent applies aspheric surfaces to the third and fourth lens elements. The aspheric surfaces allow for better control of light rays passing through the lens system, particularly improving peripheral image quality by reducing aberrations. This enables the maintenance of compact dimensions while achieving improved image quality across the entire field of view.
Solution Approach 2:
The patent modifies the refractive power distribution among the four lens elements, specifically making the third lens element have positive refractive power with an aspheric image-side surface and the fourth lens element have negative refractive power with aspheric surfaces. This parameter optimization allows for better control of the optical path and reduction of aberrations in a compact configuration.
2Manufacturing precision
If refractive powers of lens elements are adjusted to improve peripheral image quality, then image quality improves, but the complexity of controlling aberrations increases
Solution Approach 1:
The patent divides the optical system into four distinct lens elements with specific functional assignments. The third lens element (positive power, aspheric image-side surface) and fourth lens element (negative power, aspheric surfaces) are designed to specifically address different aspects of aberration control. This segmentation allows for targeted optimization of each element's contribution to overall image quality.
Solution Approach 2:
The patent employs a composite lens structure where cemented lens elements are combined with air gaps between specific elements. The cemented elements provide structural integrity and controlled optical paths, while the air gaps between the third and fourth elements allow for independent adjustment of their optical properties, simplifying aberration control.
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 enhances image quality by correcting aberrations, improving peripheral image resolution, and maintaining a compact design, while the use of aspheric surfaces and air gaps between lens elements allows for better manufacturing and assembly, resulting in improved image capturing performance.
Implementation Method 1
The third lens element has positive refractive power and an image-side surface being concave, wherein an object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element has an object-side surface being concave, wherein the object-side surface and an image-side surface of the fourth lens element are both aspheric.
Data Source
AI summary
A photographing lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, and a fourth lens element. The first lens element has positive refractive power. The second lens element has negative refractive power. The third lens element having positive refractive power has an image-side surface being concave, and an object-side surface and the image-side surface thereof being aspheric. The fourth lens element has an object-side surface being concave, and the object-side surface and an image-side surface thereof being aspheric. The photographing lens system further includes an aperture stop, and no lens elements are disposed between the aperture stop and the first lens element. The photographing lens system has a total of four lens elements.