Five-Lens Imaging Lens Aberration Correction

The patent applies parameter changes by optimizing the refractive powers, curvatures, and spacing of each lens element. Specifically, it uses conditional formulas relating focal lengths (e.g., 0.2 < f/f1 < 0.5, -0.5 < f/f2 < -0.1) and surface curvatures to achieve the desired balance between imaging performance and compact size. The fifth lens is designed with specific curvature constraints (0.01 < 1/R51 < 0.1 and 0.01 < 1/R52 < 0.1) to control aberrations while maintaining a short total length.

The patent employs composite lens designs where different lens elements with varying refractive indices and dispersion properties are combined. The system uses lenses with different Abbe numbers (e.g., 20 < νd2 < 60, 20 < νd3 < 60) to correct chromatic aberrations. This composite approach allows the five-lens system to achieve high resolution and color accuracy while keeping the total length manageable through careful material selection and arrangement.

The patent applies local quality by assigning specific functional characteristics to different regions of the lens system. The first lens has a convex surface toward the object side to control incoming light, the second and third lenses have negative refractive powers for aberration correction, the fourth lens has a convex surface toward the image side for focusing, and the fifth lens has an inflection point on its image-side surface for fine-tuning aberrations. Each lens element is optimized for its specific role in the overall light gathering and aberration correction process.

The patent converts the potential harm of a small F-number (which typically exacerbates aberrations) into a benefit by using the small F-number configuration to gather more light, then compensating for the resulting aberrations through the carefully designed five-lens arrangement. The negative refractive power lenses (second and third) and the inflection-point lens (fifth) are specifically configured to correct the aberrations introduced by the small F-number, turning what would normally be a disadvantage into an advantage for low-light performance.

The patent applies the nesting principle by arranging the five lens elements in a compact sequence where each lens is positioned close to the others, minimizing the overall length. The lenses are nested along the optical axis with small air gaps between them, allowing the system to achieve a short total length while maintaining sufficient space for each lens to perform its optical function. This compact nesting enables the entire imaging system to fit within the constrained dimensions of portable devices.

The patent addresses the length-performance tradeoff by optimizing parameters in other dimensions, specifically the curvatures and refractive powers of the lens surfaces. Instead of increasing the axial length, the design uses highly curved surfaces (with curvature constraints like 0.01 < 1/R51 < 0.1) and varies the refractive indices of different lens elements to achieve the necessary optical power and aberration correction in a compact form. This dimensional shift from length to surface curvature allows miniaturization without performance loss.