Four-Surface Narrow Field-Of-View Compound Lens Design

The patent merges multiple lens functions into a four-surface compound lens structure where the first and second lenses work together with the first biplanar substrate, and the third and fourth lenses work together with the second biplanar substrate. This integration achieves narrow field of view correction while reducing the total number of discrete optical elements compared to conventional telescope-like designs, thereby lowering manufacturing cost.

The patent employs lenses made from different materials with distinct Abbe numbers (first lens: first material, second lens: second material, third lens: third material, fourth lens: fourth material) to correct chromatic aberrations. This composite material approach enables effective aberration correction in a compact four-surface design, avoiding the need for more complex multi-element telescopic lenses.

The compound lens is segmented into two functional groups: the first group comprising the first lens, first biplanar substrate, and second lens; and the second group comprising the third lens, second biplanar substrate, and fourth lens. This segmentation allows each group to address specific aberration corrections, achieving high image quality with only four optical surfaces instead of more complex designs.

Each lens surface is designed with specific local optical properties - the first and third lenses have positive power with specific curvature radii, while the second and fourth lenses have negative power. The biplanar substrates provide additional local refraction control. This localized optimization of each surface's optical function achieves superior image quality correction within the constrained four-surface structure.