Matsushita Electric Industrial Co., Ltd.

Kouki Kojima

Syougo Horinouchi

Fuminobu Furukawa

Takashi Haruguchi

Shogo Horinouchi

Kazuyuki Nakashima

Satoshi Kiyomatsu

An optical pick-up composed of an objective lens and a liquid crystal element, for recording and reproduction of optical discs having different recording densities, the liquid crystal element having nine zones, including: zones 2, 4 located in center parts of half circles of a small diameter beam for a low density optical disc, zones 3, 5 laid along the outer peripheries of zones 2, 4 within the half circles so as to surround zones 2, 4, zones 6, 7 along the outer peripheries of zones 3, 5, between the outer periphery of the small diameter beam and a large diameter beam, extending along substantially half circumferential parts of the small diameter beam, zones 8, 9 extending along substantially half circumferential parts of the large diameter beam, a remainder first zone and including a diameter whose the direction is the same as a tilt direction to be corrected.

Optical pickup of tilt control type

An optical pickup capable of recording or reproducing information from optical disks having different recording densities includes a first optical unit having a light source which emits rays having a first wavelength for DVDs and a first light sensor which detects reflected rays, a second optical unit having a light source which emits rays having a second wavelength for CDs and a second light sensor which detects reflected rays, a beam splitter which directs the rays having the first wavelength and the rays having the second wavelength along substantially the same optical axis, and directs reflected rays from an optical disk to the first light sensor and the second light sensor, and an objective lens which has a numerical aperture (NA) of 0.6 or more, a focal length of 2.5 mm or less, an effective diameter of incidence of 3.0 mm or less and a working distance of 1.2 mm or less. The light pickup as a whole has a thickness of 7.5 mm or less as measured from a bottom surface of the optical disk. The light pickup is capable of reproducing information from optical disks having different recording densities, is composed of a small number of parts, and is compact and thin.

Light pickup

An optical pickup is disclosed which is capable of recording or reproducing information from optical disks having different recording densities and includes a first optical unit having a light source which emits rays having a first wavelength for DVDs and a first light sensor which detects reflected rays, a second optical unit having a light source which emits rays having a second wavelength for CDs and a second light sensor which detects reflected rays, a beam splitter which directs the rays having the first wavelength and the rays having the second wavelength along substantially the same optical axis, and directs reflected rays from an optical disk to the first light sensor and the second light sensor, and an objective lens which has a numerical aperture (NA) of 0.6 or more, a focal length of 2.5 mm or less, an effective diameter of incidence of 3.0 mm or less and a working distance of 1.2 mm or less. The light pickup as a whole has a thickness of 7.5 mm or less as measured from a bottom surface of the optical disk. The light pickup is capable of reproducing information from optical disks having different recording densities, is composed of a small number of parts, and is compact and thin.

Light pickup of thin type

An optical pickup for recording on and reproduction from recording media of different recording densities (e.g. a high density disk such as a DVD and a lower density disk such as an ordinary CD), and having a compact, thin and low power-consumption design. The optical pickup includes an objective lens, a first optical unit having a light-emitting element and a light-receiving element which are used for recording on and reproduction from the high-density optical disk, a second optical unit having a light-emitting element and a light-receiving element which are used for recording on and reproduction from the low-density optical disk, a beam splitter for guiding optical axes of the first and second optical units to the same optical axis, and a wavelength filter for changing a diameter of light beams incident on the objective lens between at the time of recording and reproduction for the high-density optical disk and at the time of recording and reproduction for the low-density optical disk.

Optical pickup

An optical pickup for use in optically recording or picking up information on and from a recording medium using a light-emitting device. The optical pickup comprises first and second light reflecting surfaces disposed in opposed relation to each other, the first reflecting surface reflects a light beam from the light-emitting device and the second reflecting surface reflects the light beam reflected from the first reflecting surface. Around the first reflecting surface there is provide a grating lens which condenses the light beam reflected from the second reflecting surface to be focused on the recording medium. The light beam from the recording medium is reflected by the second reflecting surface to be directed to the first reflecting surface. The first reflecting surface diffracts the reflected light beam from the second reflecting surface toward a light receiving device to read the information concurrently detecting focusing and tracking error signals. This arrangement can achieve the size-reduction of the optical pickup.

Optical pickup having a transparent lens member with two reflecting

Optical pickup for information recording/reproducing apparatus having

Optical pickup for information recording/reproducing apparatus

An optical pickup to be used in an optical disc apparatus for optically recording and reproducing information on and from an optical disc. The optical pickup is arranged such that a laser light from a semiconductor laser is reflected plural times within an optical system and then focused on the optical disc and the light from the optical disc is diffracted by a hologram and then received by a light-receiving device for reproducing the information recorded on the optical disc. This arrangement can achieve the size-reduction of the optical pickup concurrently with obtaining a necessary optical path length.

Growing community of inventors

Fukuoka, Japan

Kouki Kojima