Patent ID: 7872959

Claim:
An optical pickup apparatus, comprising: a first light source to emit a first light flux having a wavelength λ1 to conduct reproducing and/or recording information for a first optical information recording medium having a first protective substrate with a first thickness t1, a second light source to emit a second light flux having a wavelength λ2 to (λ1<λ2) conduct reproducing and/or recording information for a second optical information recording medium having a second protective substrate with a second thickness t2 (t1≦t2), a third light source to emit a third light flux having a wavelength λ3 (λ2<λ3) to conduct reproducing and/or recording information for a third optical information recording medium having a third protective substrate with a third thickness t3 (t2≦t3), and an objective lens for converging the first light flux onto an information recording plane of the first optical information recording medium, the second light flux onto an information recording plane of the second optical information recording medium, and the third light flux onto an information recording plane of the third optical information recording medium, wherein the objective lens is a single lens, wherein the second light source and the third light source are united as a unit, and wherein the following formulas are satisfied: m1=0, m2<0, m3<0, where m1 represents a magnification of the objective lens for the first light flux when the reproducing and/or recording of the information is conducted onto the first optical information recording medium, m2 represents a magnification of the objective lens for the second light flux when the reproducing and/or recording of the information is conducted onto the second optical information recording medium, and m3 represents a magnification of the objective lens for the third light flux when the reproducing and/or recording of the information is conducted onto the third optical information recording medium.