Compact Imaging Lens Design for Wide Angle and Aberration Correction
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Solution Overview
Problem
Conventional imaging lenses for portable devices struggle to achieve both downsizing and a wider angle while maintaining satisfactory aberration correction, particularly in cameras where space is limited and diverse image uses are increasing.
Innovation Solution
The imaging lens configuration includes a first lens with positive refractive power, a second lens with positive refractive power, and a third lens with negative refractive power, with specific curvature radius and focal length relationships that satisfy conditional expressions to achieve a balance between downsizing, wide angle, and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the second lens has negative refractive power to achieve downsizing, then the imaging lens size is reduced, but the angle of view becomes limited and aberration correction becomes difficult
Solution Approach 1:
The patent changes the refractive power parameter of the second lens from negative to positive, which fundamentally alters the optical path and allows for both wide angle of view and compact size. This parameter change enables the lens to achieve a half angle of view of 30 degrees or more while maintaining a total length of 4mm or less, resolving the contradiction between downsizing and angle of view expansion.
2Adaptability or versatility
If refractive power of each lens is increased to achieve wider angle, then the angle of view is expanded, but fabrication accuracy and assembly accuracy requirements increase
Solution Approach 1:
By changing the refractive power configuration to all positive values, the patent achieves wide angle of view without requiring excessively strong refractive powers that would demand ultra-precise manufacturing. The specific parameter ranges specified in the patent (e.g., focal lengths between 0.5mm to 2.0mm) provide a balanced design that accommodates standard manufacturing tolerances while achieving half angle of view of 30 degrees or more.
3Reliability
If all three lenses have positive refractive power, then aberration correction is improved, but downsizing becomes more difficult
Solution Approach 1:
The patent achieves both aberration correction and downsizing by carefully controlling the parameter ranges of the positive refractive power lenses. By specifying focal lengths in the range of 0.5mm to 2.0mm and controlling the spacing between lenses, the patent corrects spherical aberration, coma, and astigmatism while maintaining a compact form factor with total length of 4mm or less.
Solution Approach 2:
The patent employs aspheric surfaces on one or more lens elements to correct aberrations more effectively than spherical surfaces alone. The aspheric coefficients are optimized to control the curvature distribution, enabling aberration correction in a compact lens configuration where all three lenses have positive refractive power.
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 effective downsizing and wider angle capabilities while maintaining satisfactory image-forming performance, including correction of astigmatism, distortion, and chromatic aberrations, making it suitable for diverse camera applications.
Implementation Method 1
a first lens having positive refractive power; a second lens having positive refractive power; and a third lens having negative refractive power, arranged in the order from an object side to an image plane side
Data Source
AI summary
An imaging lens includes a first lens having positive refractive power; a second lens having positive refractive power; and a third lens having negative refractive power, arranged in the order from an object side to an image plane side. The first lens and the third lens respectively have an object-side surface and an image plane-side surface whose curvature radii are both positive. The second lens has an image plane-side surface whose a curvature radius is negative. In addition, when the first lens has refractive power P1, the second lens has refractive power P2, the third lens has refractive power P3, the curvature radius of the image plane-side surface of the second lens is R2r, and the curvature radius of the object-side surface of the third lens is R3f, the imaging lens satisfies specific conditional expressions.