Patent ID: 8184521

Claim:
An optical disc apparatus that reads out information from an optical disc by focusing a light beam having 410 nm or shorter wavelength from a laser light source onto the optical disc, which includes an optical disk substrate and a light transmitting layer, to form a light spot thereon through a collimator lens and an optical pickup lens, the optical disc apparatus comprising: the optical pickup lens that is a single lens in which a numerical aperture NA to focus the light beam onto the optical disk is equal to or greater than 0.84, an effective diameter D satisfies 2.04 mm≦D≦2.45 mm, and a center thickness d is equal to or greater than 1.1 mm, wherein the optical pickup lens comprises: a first surface on which the light beam from the laser light source is made incident, the first surface having a continuous shape; and a second surface that is opposed to the optical disk that is positioned opposite to the first surface, the second surface having a continuous shape, the continuous shape of the second surface having radii h 1 , h 2 , and h 3 from an optical axis to a lens periphery side, where 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, where 0>Δsag 1 >Δsag 2 and Δsag 2 <Δsag 3 , the second surface comprising a projecting shape at a center thereof and comprising no recess at a peripheral portion thereof, and a curvature radius r 2 of the second surface being −1.766506 mm≦r 2 ≦−1.297362 mm.