Optical pickup device which can be adapted to a plurality of types of optical disks

Claim 2

An optical pickup device, comprising: a laser (20, 29) for directing a laser beam to an optical disk (11a, 11b); a first objective lens (Lb) designed to be adapted to one type of said optical disk (11a); a second objective lens (La) designed to be adapted to another type of said optical disk (11b); and a moving unit (14, 16, TRa1 to TRa4, TRb1 to TRb4) for selectively moving said first and second objective lenses so that their optical axes match an optical path of said laser beam according to the type of said optical disk.

Claim 3

The optical pickup device according to claim 2, further comprising a holder (13) for holding said first and second objective lenses in common, wherein said moving unit moves said holder to move said first and second objective lenses.

Claim 4

The optical pickup device according to claim 2, wherein a substrate of said one type of optical disk has a first thickness, a substrate of said another type of optical disk has a second thickness smaller than said first thickness, said first objective lens is designed to converge said laser beam on a recording surface of said one type of optical disk, and said second objective lens is designed to converge said laser beam on a recording surface of said another type of optical disk.

Claim 5

The optical pickup device according to claim 4, wherein said first thickness is 1.15 mm to 1.25 mm, and said second thickness is 0.55 mm to 0.65 mm.

Claim 6

The optical pickup device according to claim 4, wherein said first thickness is 1.15 mm to 1.25 mm, and said second thickness is 0.75 mm to 0.85 mm.

Claim 7

The optical pickup device according to claim 4, wherein said first thickness is 0.75 mm to 0.85 mm, and said second thickness is 0.55 mm to 0.65 mm.

Claim 8

The optical pickup device according to claim 2, wherein said one type of optical disk has a first recording density, said another type of optical disk has a second recording density higher than said first recording density, said optical pickup device further comprising a holder (13) for holding in common said first objective lens and said second objective lens positioned closer to the center of said optical disk than said first objective lens.

Claim 9

The optical pickup device according to claim 4, wherein said one type of optical disk has a first recording density, said another type of optical disk has a second recording density higher than said first recording density, said optical pickup device further comprising a holder (13) for holding in common said first objective lens and said second objective lens positioned closer to a periphery of said optical disk than said first objective lens.

Claim 10

The optical pickup device according to claim 2, wherein said one type of optical disk has a first track pitch, said another type of optical disk has a second track pitch narrower than said first track pitch, said first objective lens is designed to converge said laser beam on each track of said one type of optical disk, and said second objective lens is designed to converge said laser beam on each track of said another type of optical disk.

Claim 11

The optical pickup device according to claim 10, wherein said first track pitch is 1.5 µm to 1.7 µm, and said second track pitch is 0.695 µm to 0.755 µm.

Claim 12

The optical pickup device according to claim 10, wherein said first track pitch is 1.5 µm to 1.7 µm, and said second track pitch is 0.81 µm to 0.87 µm.

Claim 13

The optical pickup device according to claim 10, wherein said first track pitch is 0.81 µm to 0.87 µm, and said second track pitch is 0.695 µm to 0.755 µm.

Claim 14

The optical pickup device according to claim 2, wherein said laser beam has a wavelength of 620 nm to 665 nm.

Claim 15

The optical pickup device according to claim 2, wherein said laser includes a first laser element (20) for directing a first laser beam having a first wavelength, a second laser element (29) for directing a second laser beam having a second wavelength longer than said first wavelength, and an activating unit (31) for selectively activating said first and second laser elements according to the type of said optical disk.

Claim 16

The optical pickup device according to claim 15, wherein said first wavelength is 620 nm to 665 nm, and said second wavelength is 765 nm to 795 nm.

Claim 17

The optical pickup device according to claim 2, further comprising a tracking controller (2, 4, 5, 14, 16, 19, TRa1 to TRa4, TRb1 to TRb4) for controlling said moved objective lens so that said laser beam traces a track of said optical disk.

Claim 18

The optical pickup device according to claim 3, further comprising: a shaft (12) for rotatably supporting said holder; a first conductive line (TRa1) fixed to said holder in parallel with said shaft; a second conductive line (TRb1) fixed to said holder in parallel with said shaft; a magnetic field generator (14) for generating a magnetic field in a direction perpendicular to said first and second conductive lines and crossing said shaft; and a tracking controller (2, 4, 5, 19) for, when said first objective lens is moved so that its optical axis matches an optical path of said laser beam, supplying a current to said first conductive line in one direction upon displacement of said laser beam to one side of a track of said optical disk and supplying the current to said first conductive line in the other direction opposite to said one direction upon displacement of said laser beam to the other side opposite to said one side, and for, when said second objective lens is moved so that its optical axis matches an optical path of said laser beam, supplying the current to said second conductive line in one direction upon displacement of said laser beam to one side of the track of said optical disk and supplying the current to said second conductive line in the other direction opposite to said one direction upon displacement of said laser beam to the other side opposite to said one side.

Claim 19

An optical pickup device, comprising: a laser (20, 29) for directing a laser beam to an optical disk; a first objective lens (Lb) having a first numerical aperture: a second objective lens (La) having a second numerical aperture larger than said first numerical aperture; a holder (13) for holding said first and second objective lenses in common; and a shaft (12) for rotatably supporting said holder; said holder having a cylindrical surface with an axis common to said shaft, said optical pickup device further comprising: a magnetic field generator (14) for generating a magnetic field perpendicular to said cylindrical surface; a first coil pair (TRb1, TRb2) including a first coil (TRb1) affixed onto said cylindrical surface, and a second coil (TRb2) located apart from said first coil and affixed onto said cylindrical surface; and a second coil pair (TRa2, TRa1) including a third coil (TRa2) positioned between the center of said first coil and the center of said second coil and affixed onto said cylindrical surface, and a fourth coil (TRa1) located apart from said third coil and affixed onto said cylindrical surface, said first coil being positioned between the center of said third coil and the center of said fourth coil; said optical pickup device further comprising: a lens positioning unit (4, 5, 7, 8) for selectively supplying a positioning current to said first and second coil pairs according to the type of said optical disk; and a tracking controller (2, 4, 5, 19) for, when said positioning current is supplied to said first coil pair, supplying a tracking drive current to said second coil pair in one direction upon displacement of said laser beam to one side of a track of said optical disk and supplying the tracking drive current to said second coil pair in the other direction opposite to said one direction upon displacement of said laser beam to the other side opposite to said one side, and for, when said positioning current is supplied to said second coil pair, supplying the tracking drive current to said first coil pair in one direction upon displacement of said laser beam to one side of the track of said optical disk and supplying the tracking drive current to said first coil pair in the other direction opposite to said one direction upon displacement of said laser beam to the other side opposite to said one side.

Claim 20

An optical reproducing apparatus, comprising: a laser (20) for directing a laser beam to an optical disk; a first objective lens (Lb) having a first numerical aperture; a second objective lens (La) having a second numerical aperture larger than said first numerical aperture; a holder (13) for holding said first and second objective lenses in common; a moving unit (3 to 8, 14, 16, TRa1 to TRa4, TRb1 to TRb4) for moving said holder so that optical axes of said first and second objective lenses selectively match an optical path of said laser beam according to the type of said optical disk; a detector (26) for detecting light reflected from said optical disk; and a signal processing circuit (16) for generating a video and/or sound signal by applying predetermined processing to an output signal from said detector.