Four-Lens Imaging System for Wide-Angle Downsizing
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Solution Overview
Problem
Conventional imaging lenses for small cameras, such as smartphones and portable devices, face challenges in achieving a wider angle and smaller size while maintaining image-forming performance, as existing lens configurations have limitations in correcting aberrations and downsizing.
Innovation Solution
The proposed imaging lens configuration includes a first lens with negative refractive power, a stop, a second lens with positive refractive power, a third lens with negative refractive power, and a fourth lens with positive refractive power, optimized by specific curvature radius ratios and focal length relationships to achieve a wider angle and downsizing, while effectively correcting chromatic aberration, field curvature, and astigmatism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional four-lens configuration is used, then the imaging lens can achieve a relatively wide angle of view, but the size reduction is limited and cannot satisfy the demands for smaller cameras
Solution Approach 1:
The patent applies parameter changes by optimizing the curvature radii of lens surfaces and the refractive powers of individual lenses. Specifically, it sets the curvature radius of the object-side surface of the first lens (R1) and the image plane-side surface of the fourth lens (R8) to specific ranges, and defines relationships between focal lengths (f1/f2, f3/f4) and curvature radii ratios (R2/R3, R6/R7) to achieve both size reduction and maintained image quality
Solution Approach 2:
The imaging lens is segmented into four distinct lens units with alternating positive and negative refractive powers. Each lens unit (L1, L2, L3, L4) has specific curvature radius relationships (e.g., |R1| < |R2|, |R6| < |R7|) that are optimized independently to contribute to the overall size reduction while maintaining collective image-forming performance
2Volume of moving object
If the first lens is formed as a meniscus lens directing a concave surface to the object side to achieve wider angle, then the angle of view increases, but the distance from image plane to exit pupil becomes long, making downsizing difficult
Solution Approach 1:
The patent changes the parameter of the first lens from a conventional meniscus shape to a biconvex shape with specific curvature radius relationships (|R1| < |R2|). This parameter change shortens the distance from the image plane to the exit pupil while maintaining the wide angle of view capability, thereby enabling imaging lens downsizing
3Measurement precision
If high resolution lens configuration is used for high pixel count imaging elements, then image quality improves, but the lens size increases and angle of view decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the focal length ratios (f1/f2, f3/f4) and curvature radius relationships (R2/R3, R6/R7) of the four-lens configuration. These parameter optimizations enable the lens to achieve high resolution suitable for high pixel count imaging elements while maintaining a compact size and wide angle of view
Solution Approach 2:
The imaging lens is segmented into four lens units with alternating positive and negative refractive powers. Each unit is designed with specific curvature radius relationships to correct aberrations and maintain image quality, allowing the system to achieve high resolution while keeping the overall lens size small
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 allows for a wider angle and reduced size while maintaining satisfactory image-forming performance by optimizing the refractive powers and curvature radii of the lenses, thereby addressing the limitations of conventional imaging lenses.
Implementation Method 1
a first lens (L1) having negative refractive power
Implementation Method 2
a second lens (L2) having positive refractive power
Implementation Method 3
a third lens (L3) having negative refractive power... keep an angle between an incident light beam and an emitting light beam (angle of deviation) small and to restrain generation of aberrations
Implementation Method 4
a fourth lens (L4) having positive refractive power
Data Source
AI summary
An imaging lens includes a first lens having negative refractive power; a stop; a second lens having positive refractive power; a third lens having negative refractive power; and a fourth lens having positive refractive power, arranged in the order from an object side to an image plane side. The first lens has an object-side surface and an image plane-side surface, curvature radii of which are both negative. The second lens has an object-side surface and an image plane-side surface, curvature radii of which are both positive. The third lens has an object-side surface and an image plane-side surface, curvature radii of which are both negative. The fourth lens has an object-side surface, a curvature of which is positive.