aspherical surface
Technical term in optics and lens design for a surface that is not part of a sphere.
This lens uses an aspherical surface.
noun which may take the genitive case particle 'no'
aspherical
Used attributively with の to describe lenses, mirrors, or optical elements that are not spherical.
Aspherical lenses can correct spherical aberration.
Compound of 非 (hi, 'non-') + 球面 (kyūmen, 'spherical surface').