Optical disk recording/reproduction apparatus for recording/reproducing information to/from optical disk of different standards

An optical disk recording/reproduction apparatus for recording and/or reproducing information to/from an optical disk, the optical disk recording/reproduction apparatus comprising:

• an objective lens disposed in association with the optical disk;
• an optical system producing a laser beam to the objective lens;
• a tracking servo mechanism disposed to move said objective lens in a radial direction of said optical disk to make said laser beam trace a track of said optical disk;
• and
• an aperture control device disposed between the optical system and the objective lens, the aperture control device defining an aperture that passes the laser beam therethrough without intercepting the laser beam in case that the optical disk has a first standard, and intercepting a portion of the laser beam to set the laser beam to include a first diameter along the radial direction of the optical disk and a second diameter shorter than the first diameter along a tangential direction of the optical disk which is orthogonal to the radial direction in case that the optical disk has a second standard different from the first standard.