Curved Image Surface Imaging Lens Aberration Correction
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Solution Overview
Problem
Conventional imaging lenses for small image capturing devices in mobile terminals face challenges in achieving high resolving power while maintaining a short length, as increasing the number of lenses leads to a longer lens length and larger space requirements.
Innovation Solution
The imaging lens configuration includes a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with positive or negative refractive power, and a fifth lens with an aspherical surface and negative refractive power, with specific focal length conditions to minimize lens length and correct aberrations, including a curved image surface to reduce curvature of field and coma aberration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of lenses is increased to achieve high resolving power, then the imaging quality is improved, but the length of the imaging lens becomes longer
Solution Approach 1:
The patent applies parameter changes by optimizing the focal length ratios between lenses (specifically f/|f4| ≥ 0.005) and using aspherical surfaces with specific curvature parameters. This allows the lens system to achieve high resolving power through precise parameter optimization rather than simply increasing the number of lenses, thereby maintaining a compact length while improving imaging quality.
Solution Approach 2:
The patent utilizes aspherical lens surfaces instead of traditional spherical surfaces. The aspherical design allows for better correction of optical aberrations and enables high resolving power with fewer lens elements. Specifically, the fifth lens has an aspherical surface that helps achieve the desired imaging performance while keeping the overall lens length short.
2Reliability
If the number of lenses is increased to correct aberrations, then the imaging performance is improved, but the device complexity increases
Solution Approach 1:
The patent optimizes specific parameter relationships, particularly the focal length ratio f/|f4| ≥ 0.005, to achieve effective aberration correction. This parameter-based approach allows for correcting optical aberrations with a manageable number of lens elements, avoiding the need for complex multi-lens systems while maintaining high imaging performance.
Solution Approach 2:
The aspherical surface design on the fifth lens provides effective aberration correction capability. The aspherical geometry allows a single lens element to perform what would traditionally require multiple spherical lenses, thereby reducing device complexity while maintaining or improving imaging performance.
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 achieves favorable imaging performance with a shorter lens length and effective aberration correction, ensuring high resolving power and telecentric property without the need for a large number of lenses.
Implementation Method 1
a first lens L1 having positive refractive power; a second lens L2 having negative refractive power; a third lens L3 having positive refractive power; a fourth lens L4 having positive or negative refractive power; and a fifth lens L5 having at least one lens surface formed as an aspherical surface and having negative refractive power
Data Source
AI summary
An imaging lens (PL) has an image surface (I) curved to have a concave surface facing an object and comprises, in order from the object along the optical axis (Ax): a first lens (L1) having positive refractive power; a second lens (L2) having negative refractive power; a third lens (L3) having positive refractive power; a fourth lens (L4) having positive or negative refractive power; and a fifth lens (L5) having at least one lens surface formed as an aspherical surface and having negative refractive power. The following conditional expression is satisfied:0.005<f/|f4|<0.5where, f denotes a focal length of the imaging lens (PL), andf4 denotes a focal length of the fourth lens (L4).