Four-Element Aspheric Lens Assembly for Wide Field of View
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Solution Overview
Problem
Conventional compact optical systems for electronic devices fail to meet the requirements of high resolution and image quality, particularly in terms of field of view and image quality, due to limitations in lens design and refractive power distribution.
Innovation Solution
A compact optical photographing lens assembly with four non-cemented lens elements, including a first lens with negative refractive power, a second with positive refractive power, a third with positive refractive power and an aspheric image-side surface, and a fourth with negative refractive power, optimized by specific axial distances and curvature radii to enhance field of view and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional three-element lens structure is used, then the optical system is compact, but the field of view and image quality are insufficient
Solution Approach 1:
The optical system is divided into four separate lens elements instead of three, with each element having specific refractive powers and surface curvatures. The first lens element has negative refractive power with a concave image-side surface, the second has positive refractive power with a convex image-side surface, the third has positive refractive power with both surfaces aspheric, and the fourth has negative refractive power with both surfaces aspheric. This segmentation allows independent optimization of each element to achieve both compact size and high image quality.
2Manufacturing precision
If a four-element lens structure with first lens having positive refractive power is used, then image quality may improve, but the field of view cannot be enlarged
Solution Approach 1:
Instead of giving the first lens element positive refractive power as in conventional designs, this patent assigns it negative refractive power with a concave image-side surface. This inversion allows the optical system to achieve a wider field of view while maintaining image quality through the coordinated design of subsequent lens elements with positive refractive powers.
3Area of moving object
If both second and third lens elements have negative refractive powers, then field of view may increase, but the back focal length increases and the system becomes less compact
Solution Approach 1:
The patent optimizes the refractive power parameters by assigning positive refractive power to the second lens element and positive refractive power to the third lens element, while giving negative refractive power only to the first and fourth elements. This parameter configuration, combined with specific surface curvatures and axial distances, achieves a wide field of view while keeping the back focal length short and the overall system compact.
4Ease of manufacture
If conventional lens surface designs are used, then manufacturing is simpler, but image quality and aberration correction are insufficient
Solution Approach 1:
The patent employs aspheric surfaces on the third lens element (both object-side and image-side surfaces) and the fourth lens element (both object-side and image-side surfaces). These aspheric curvatures enable superior aberration correction and image quality enhancement compared to conventional spherical surfaces, while the specific curvature profiles are designed to be manufacturable using modern molding techniques.
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 provides improved image quality and a wider field of view while maintaining a compact size, reducing aberrations and astigmatism, and is suitable for applications in electronic devices such as digital cameras and smart TVs.
Implementation Method 1
a first lens element, a second lens element, a third lens element and a fourth lens element... The first lens element with negative refractive power... The second lens element with positive refractive power... The third lens element with positive refractive power... The fourth lens element has negative refractive power
Data Source
AI summary
An optical photographing lens assembly 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 with negative refractive power has an image-side surface being concave in a paraxial region thereof. The second lens element with positive refractive power has an image-side surface being convex in a paraxial region thereof. The third lens element with positive refractive power has an image-side surface being convex in a paraxial region thereof, wherein both of an object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element has negative refractive power, wherein both of an object-side surface and an image-side surface of the fourth lens element are aspheric. The optical photographing lens assembly has a total of four non-cemented lens elements with refractive power.