Patent ID: 7512055
Filing Date: 2009-03-31
Classification: G11B

Abstract:
1. An objective optical element for use in an optical pickup apparatus having: a first light source for emitting a first light flux with a wavelength λ 1 (380 nm≦λ 1 ≦420 nm); a second light source for emitting a second light flux with a wavelength λ 2 (λ 1 <λ 2 ); a third light source for emitting a third light flux with a wavelength λ 3 (λ 1 <λ 2 <λ 3 ); and an objective optical element for converging the first light flux on an information recording surface of a first optical information recording medium, converging the second light flux on an information recording surface of a second information recording medium, and converging the third light flux on an information recording surface of a third optical information recording medium, the objective optical element comprising: an optical surface including a common area and an exclusive area; and a wavelength selective film formed on at least one of the common area and the exclusive area for transmitting at least one of the first light flux and a light flux with a wavelength excluding the wavelength λ wherein the common area transmits the first light flux which is formed into a converged spot on the information recording surface of the first optical information recording medium, and transmits the second light flux which is formed into a converged spot on the information recording surface of the second optical information recording medium, and the exclusive area transmits the first light flux which is formed into a converged spot on the information recording surface of the first optical information recording medium, and transmits the second light flux which is not formed into a converged spot on the information recording surface of the second optical information recording medium, wherein the wavelength λ wherein an optical surface including the wavelength selective film of the objective optical element is a curved surface, the wavelength selective film transmits the third light flux going toward the third optical information recording medium when the third light flux enters from outside of the objective optical element into the optical surface including the wavelength selective film at an angle less than a predetermined angle θ does not transmit the third light flux going toward the third optical information recording medium when the third light flux enters from outside of the objective optical element into the optical surface including the wavelength selective film at an angle equal to the predetermined angle θ the predetermined angle θ