Patent ID: 7898746

Claim:
A method for making an aspheric lens, comprising: a) selecting a radially varying focal length value f(ρ) for the lens, where ρis the lens radius; and determining a corresponding radially varying phase delay function φ(ρ); and relating f(ρ) and φ(ρ) via the expression φ ⁡ ( ρ ) = ∫ 0 ρ ⁢ - k ⁢ ⁢ ρ [ f 2 ⁡ ( ρ 1 ) + ρ 1 2 ] 1 / 2 ⁢ ⅆ ρ 1 , where ρ 1 is the variable of integration running from zero to ρ and k is a constant.