Patent ID: 7965609

Claim:
An optical pickup device comprising: a light emission device for emitting at least one or more light beam; a light focusing device for focusing a light beam that is emitted from the light emission device onto an optical recording medium; a light diffraction device that is located between the light emission device and light focusing device, and that forms the light that is emitted from the light emission device into a main light beam, and at least two or more sub light beams at positions on the optical recording medium on which the main light beam is irradiated that are symmetrical with respect to the main light beam in a direction orthogonal to the direction of a track on which information is recorded; a main light beam receiving device for receiving light of the main beam that is reflected from the optical recording medium; and a sub light beam receiving device for receiving light of the sub light beams that is reflected from the optical recording medium; wherein each of the sub light beam is made up of a pair of semi sub beams such that the distance between the centers of a pair of semi sub spots that are formed on the optical recording medium and that correspond to the pair of semi sub beams that are irradiated on the optical recording device is an odd multiple of the length of approximately half the track pitch length of a first optical recording medium, and the distance in the radial direction of the optical recording medium between the center of a main spot that is formed on the optical recording medium and that corresponds to the main beam and the center of a sub spot made up from the pair of semi sub spots is an odd multiple of the length of approximately half the track pitch length of a second optical recording medium.