Patent ID: 8116189

Claim:
An optical pickup lens for focusing a light beam having a wavelength of 410 nm or shorter from a laser light source onto an optical information recording medium, the optical pickup lens being a single lens in which a numerical aperture NA is equal to or larger than 0.84 and an effective diameter D satisfies 1.8 mm≦D≦2.05mm, the optical pickup lens comprising: a first surface on which the light beam is made incident; and a second surface that is opposed to the optical information recording medium, the optical information recording medium being positioned at an opposite side against the first surface and including an optical disk substrate and a light transmitting layer, wherein the second surface has radii h 1 , h 2 and h 3 from an optical axis to a lens periphery side, wherein h 1 <h 2 <h 3 , and wherein sags at the radii h 1 , h 2 , and h 3 are sag 1 , sag 2 , and sag 3 , respectively, and differentials in the sag 1 , sag 2 , and sag 3 are Δsag 1 , Δsag 2 , and Δsag 3 , respectively, wherein 0 >Δsag 1 >Δsag 2 and Δsag 2 <Δsag 3 , and a refractive index n for a 405 nm wavelength light beam is 1.51≦n≦1.57, and an Abbe number vd satisfies 50≦vd≦72.1.