Six-Element Imaging Lens Aberration Correction

The patent applies local quality by assigning specific refractive power signs and focal length ratios to individual lens elements. The first lens has negative refractive power with specific curvature relationships (Expression 3), the second lens has positive refractive power with controlled focal length ratio (Expression 2), and subsequent lenses have optimized parameters. This localized optimization of each element's optical properties enables effective aberration correction while maintaining wide angle and compact form factor.

The patent utilizes parameter changes by establishing specific mathematical relationships between lens parameters. Key expressions include: f2/f1 = 1.68 (Expression 2), (R1f+R1r)/(R1f-R1r) = 1.0 (Expression 3), f4/f2 ≤ 2.45 (Expression 5), and νd6 ≥ 23.0 (Expression 6). These parameter constraints optimize the balance between wide angle, compact size, and optical performance by systematically adjusting focal lengths, curvatures, and material properties.

The patent applies segmentation by dividing the optical system into six distinct lens elements with specific refractive power arrangements: negative, positive, negative, positive, positive, and negative from object side. This segmentation allows each element to address specific aberration types while maintaining a compact overall structure. The alternating positive-negative power distribution enables effective correction of spherical aberration, coma, and chromatic aberration within a reduced form factor.

The patent employs composite materials principle by specifying Abbe number constraints for lens materials, particularly νd6 ≥ 23.0 for the sixth lens and νd3 ≥ 20.0 for the third lens. These material selections, combined with the six-element configuration, create a composite optical system that achieves superior aberration correction. The specific material properties work synergistically with the lens geometry to correct chromatic and spherical aberrations in a compact design.