Patent ID: 11421847

Abstract:
A lens for headlamps of vehicles provided with a diffraction grating on a surface, wherein a phase function of the diffraction grating is represented by where r represents distance from the central axis of the lens, and the relationship |β2|·(0.3R)2<|β4|·(0.3R)4  is satisfied where R represents effective radius of the lens, and wherein a second derivative of the phase function has at least one extreme value and at least one point of inflection where r is greater than 30% of R, a difference in spherical aberration between the maximum value and the minimum value at any value of r in 0≤r≤R  is equal to or less than the longitudinal chromatic aberration for visible light, the diffraction grating is at least partially on the surface where r is greater than 30%, and the relationship  is satisfied.