Five-Lens Imaging System with Aspheric Surfaces for Compact Optical Length
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Solution Overview
Problem
The challenge is to design an imaging lens with a shorter optical length and finer aperture using a limited number of lenses, while meeting the requirements of slim and high-performance camera modules, particularly for high-pixel camera modules where the increasing number of lenses leads to longer optical lengths.
Innovation Solution
The proposed imaging lens configuration consists of five lenses arranged sequentially, each with at least one aspheric surface, including a first lens with positive refractive power, a second lens with negative power and a convex surface facing the object side, a third lens with positive power and a concave surface facing the object side, a fourth lens with negative power and a concave surface facing the image side, and a fifth lens with positive power and a convex surface facing the object side. This configuration includes an aperture between the first and second lenses and a transparent element, optimizing optical parameters such as back focal length, total optical length, and focal lengths to achieve a shorter optical length and larger aperture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of lenses is increased to satisfy high-pixel camera modules, then the image resolution is improved, but the optical length becomes longer
Solution Approach 1:
The patent employs aspheric surfaces on multiple lens elements (first lens has aspheric object-side surface, second lens has aspheric image-side surface, third lens has aspheric object-side surface, fourth lens has aspheric image-side surface). These curved non-spherical surfaces enable better light control and reduced aberrations, allowing high-resolution imaging with fewer lens elements, thereby shortening the optical length while maintaining image quality.
2Length of stationary object
If the number of lenses is reduced to shorten optical length, then the optical length is reduced, but the image resolution deteriorates
Solution Approach 1:
The patent optimizes specific parameter ranges: the first lens has positive refractive power with focal length ratio 0.35<f1/f<0.65, the second lens has negative refractive power with focal length ratio -0.50<f2/f<-0.20, the third lens has positive refractive power with focal length ratio 0.25<f3/f<0.50, the fourth lens has negative refractive power with focal length ratio -0.40<f4/f<-0.15. These parameter optimizations enable effective light control and aberration correction with only five lens elements, achieving high resolution while maintaining short optical length.
3Reliability
If the aperture is made finer to improve optical performance, then the optical performance is improved, but the optical length increases
Solution Approach 1:
The patent divides the optical system into five distinct lens groups with alternating positive and negative refractive powers. This segmentation allows each lens element to be optimized for specific functions: the first lens (positive) for light gathering, the second lens (negative) for aberration correction, the third lens (positive) for focusing, the fourth lens (negative) for distortion control, and the fifth lens (positive) for final image formation. This functional segmentation achieves fine aperture control and high optical performance while maintaining compact overall length.
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 effectively reduces the optical length of the imaging lens, allowing it to be applied in high-pixel and slim camera modules, achieving outstanding optical performance, a larger aperture, and improved image quality with reduced shutter time.
Implementation Method 1
The first lens has at least one aspheric surface. The second lens has negative optical power and has at least one aspheric surface. The third lens has positive optical power and has at least one aspheric surface. The fourth lens has negative optical power and has at least one aspheric surface. The fifth lens has positive optical power and has at least one aspheric surface.
Data Source
AI summary
An imaging lens including the first˜fifth lens arranged in sequence from an object side to an image side is provided. The first lens has at least one aspheric surface. The second lens with negative optical power has at least one aspheric surface and a convex surface facing towards the object side. The third lens with positive optical power has at least one aspheric surface and a concave surface facing towards the object side. The fourth lens with negative optical power has at least one aspheric surface and a concave surface facing towards the image side. The fifth lens with positive optical power has at least one aspheric surface and a convex surface facing towards the object side. By the above arrangement, the imaging lens has a shorter optical total length and a larger aperture for enhancing the image quality.