Four-Element Optical Imaging Lens with Convex Periphery

The patent applies local quality by giving different surface shapes (convex, plane, concave) to different regions of the lens elements. Specifically, the first lens element has a convex periphery region on its object-side surface, the second lens element has plane optical axis regions, and the third lens element has concave optical axis regions. This localized variation in surface geometry allows each region to contribute differently to aberration correction, enabling good imaging quality in a miniaturized lens design.

The patent employs parameter changes by carefully controlling the refracting powers and thickness ratios of the four lens elements. The conditional expression HFOV/(Tmax+Tmax2)≥39.000 degrees/mm establishes a quantitative relationship between field of view and lens thickness parameters. By optimizing these parameters - including making the first lens element have negative refracting power with convex periphery, and configuring the third or fourth lens element with specific refracting powers - the patent achieves both miniaturization and maintained imaging quality.

The patent resolves this contradiction through parameter optimization, specifically establishing the conditional expression HFOV/(Tmax+Tmax2)≥39.000 degrees/mm. This mathematical relationship ensures that even as the lens thickness parameters (Tmax and Tmax2) are reduced for miniaturization, the half field of view (HFOV) is maintained at adequate levels. The specific configuration of lens elements with varying refracting powers and surface curvatures enables this parameter balance.

The patent divides the optical system into four distinct lens elements, each with specific functions. The first lens element with negative refracting power and convex periphery handles initial light convergence, the second lens element with plane regions provides transition, and the third or fourth lens element with specific refracting powers completes the optical path. This segmentation allows each element to contribute optimally to achieving both compact size and adequate field of view.

The patent applies local quality extensively to correct aberrations in the miniaturized lens. The first lens element has a convex periphery region on its object-side surface that helps control spherical aberration. The second lens element has plane optical axis regions that provide stable reference surfaces. The third lens element has concave optical axis regions that help correct field curvature and other off-axis aberrations. This localized surface geometry control compensates for the increased aberration tendencies inherent in small-scale optical systems.

The patent uses parameter changes to control aberration by optimizing the refracting powers and thickness ratios of all four lens elements. The conditional expression HFOV/(Tmax+Tmax2)≥39.000 degrees/mm serves as a constraint that guides parameter selection. By carefully adjusting parameters such as the negative refracting power of the first element, the plane surface configuration of the second element, and the refracting powers of the third and fourth elements, the patent achieves aberration correction while maintaining miniaturization.