Abstract: An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.

Abstract: An optical pickup according to the present invention includes an integrated circuit element (LDD) 5 for driving first, second, and third semiconductor lasers 3, 4, and 5. The LDD 50 is shaped so as to have a rectangular principal face surrounded by one side, with a plurality of input/output pins being arranged along each side. The plurality of input/output pins include a first pin group connected to a blue-violet laser 5 whose oscillation wavelength is the shortest, a second pin group connected to a red laser 4, and a third pin group connected to an infrared laser 3. The wiring structure of the optical pickup includes a first transmission line 41 for connecting the first pin group to the blue-violet laser 5, a second transmission line 33 for connecting the second pin group to the red laser 4, and a third transmission line 31 for connecting the third pin group to the infrared laser 3, where the first transmission line 41 is shorter than both the second and third transmission lines 31 and 33.

Abstract: An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.

Abstract: An inspection apparatus for inspecting a phase modulated wobble track of an optical disk is provided. A radial push-pull signal (a wobble signal) of an optical disk is supplied to a low pass filter where a phase boundary portion of the wobble signal is smoothed, and then binarized by a binarizer and supplied to a time interval analyzer. The time interval analyzer analyzes a period of the binary wobble signal to extract two peak values T1 and T2 thereof. An operation device computes a difference value of the two periods T1 and T2 and a standard deviation of each peak, and compares each computed value to a threshold value for simultaneously evaluating CNR and a phase shift. The low pass filter and the binarizer may be incorporated into an optical disk apparatus for smoothing the phase boundary portion of the reproduced wobble signal.

Abstract: The present invention provides an optical recording medium that includes a recording layer composed mainly of an organic compound and can utilize blue-violet semiconductor laser light (390 to 420 nm in wavelength) as recording/reproducing laser light. The present invention also provides an optical recording/reproducing method using the optical recording medium. The optical recording medium 1 comprises at least a supporting substrate 2; a recording layer 3 on the supporting substrate 2, the recording layer 3 containing an organic compound as a major component; and a light-transmitting layer 5 on the recording layer 3, the light-transmitting layer 5 being capable of transmitting laser light with a wavelength of 390 to 420 nm for recording and reproducing information.

Abstract: A probe (100) is provided with: a substrate (110) having a surface facing a medium (20); and a point electrode (120), formed in the substrate, for performing at least one of detection operation of a state of a domain of the medium and change operation of the state of the domain of the medium, a tip portion, which is an edge portion on a side facing the medium, out of the point electrode being disposed in one point in a plane which is formed in a vicinity of an area portion in which the point electrode is formed by the surface.

Abstract: A hybrid disk useable with a recording and or reproducible apparatus having an optical pickup. The hybrid disk includes a first recording layer having a first format on which data is recordable or readable by a first format beam and a second recording layer having a second format on which the data is recordable or readable by a second format beam. The transmivities and reflectivities of the first and second recording layers are interrelated to control relative intensities of the first and second format beams incident on the optical pickup.

Abstract: The present invention provides a magnetooptic device, a magnetooptic head, and a magnetic disk drive each capable of performing optically assisted magnetic recording and each having a small size, improved recording density, and a higher transfer rate. In a magnetooptic device, a magnetic circuit including a magnetic gap and a thin film magnetic transducer having a coil portion are stacked on the surface of a semiconductor laser. By the arrangement, optically assisted magnetic recording can be performed, small size and light weight are achieved, and higher transfer rate can be implemented.

Abstract: A driver IC 1 has a bias terminal 20a via which a bias voltage fed from a microcomputer 2 to drive and control a loading motor 4 is fed in and a bias terminal 20b via which a bias voltage fed from a DSP 3 to drive and control a focus coil 5, a tracking coil 6, a sled motor 7, and a spindle motor 8 is fed in.

Abstract: An optical pickup (1) includes a light source (6) capable of emitting laser beams of various wavelengths and an objective optical system (2). The objective optical system (2) includes at least two wavefront conversion surfaces (13a) and (16a) and an objective lens (10). The at least two wavefront conversion surfaces (13a) and (16a) convert a wavefront of any laser beam entered therein into a different wavefront in response to the kind of an optical information recording medium (3) corresponding to the laser light. The objective lens (10) focuses the laser beam came out of the wavefront conversion surface (16a) on an optical information recording surface (3R). The optical pickup (1) satisfies the following condition for every wavelength of the corresponding laser beams: |SCMAX|<0.036??(1) wherein SCMAX is the maximum value of an offence against the sine condition of the objective optical system (2).

Abstract: A disc with a temporary defect management information area and a defect management area includes a defect management area that is present in at least one of a lead-in area, a lead-out area, and an outer area, a temporary defect information area which is formed in the data area and in which temporary defect information is recorded, and a temporary defect management information area which is present in at least one of the lead-in area, and the lead-out area. Accordingly, it is possible to record user data in a recordable disc, especially, a write-once disc, while performing defect management thereon, thereby enabling efficient use of a defect management area having a limited recording capacity.

Abstract: An optical head device may include a frame type of laser beam emitting element provided with a heat radiating fin on which a laser chip is mounted, a device frame on which the laser beam emitting element, a light receiving element and an optical system are mounted, and a heat radiation member formed of material having a superior heat conduction property. The upper face of the laser beam emitting element is fixed to the device frame, and an under face of the heat radiating fin which corresponds to a portion where the laser chip is mounted is exposed on an outer side to form an exposed part, and the heat radiation member is disposed to extend over the exposed part and the device frame.

Abstract: An objective lens actuator is provided which includes two objective lenses mounted on a movable body, and which is capable of preventing the movable body from coming into contact or collision with a disk and whose thickness becomes thinner. When a light beam is concentrated and focused on a high-density optical disk, D1 represents the distance between the disk surface and the part of the movable body in the closest position to the disk; when a light beam is concentrated and focused on a CD, D2 represents the distance between the disk surface and the part of the movable body in the closest position to the disk; when a light beam is concentrated and focused on a DVD, D3 represents the distance between the disk surface and the part of the movable body in the closest position to the disk; and the following relational expression (1) is satisfied, D1<D2<D3??(1).

Abstract: An information recording medium is provided that includes a data area for recording user data and a defect management area for recording a defect list for managing N number of defect areas existing in the data area, where N is an integer satisfying N?0. The defect list includes two or more blocks, and further includes a header located at a fixed position in the defect list and N number of defect entries, located subsequent to the header, including position information on the respective positions of the N number of defect areas. An anchor is located subsequent to the defect entries, and the header includes first update times information representing the number of times that the defect list has been updated. The anchor includes second update times information representing the number of times that the defect list has been updated.

Abstract: To provide an excellent optical information recording method, optical information recording medium and optical information recording apparatus both of which use the method. The method generates no excessively-exposed region, can sufficiently fix recorded information, and never reduce the sensitivity of non-recorded regions. This is achieved because the method applies a fixing beam onto at least a portion of an exposed region of a recording layer of the optical information recording medium, the recording layer recording information by holography, at an exposure level T (mJ/cm2) that satisfies the condition H<(S+T)<2H (where S is an integrated exposure level (mJ/cm2), which is the total of the exposure level in each predetermined region that constitutes the exposed region where an interference image has been recorded by irradiating the recording layer with an information beam and a reference beam, and H is a minimum fixing exposure level (mJ/cm2) required to fix the interference image).

Abstract: A recording medium, such as a high-density and/or read-only recording medium, such as BD-ROM, which includes copy protection information for preventing illegal copying of the contents recorded on the recording medium, and to methods and apparatuses for forming, recording, and reproducing data on the recording medium.

Abstract: An optical recording medium 10 is recorded and reproduced with irradiation of light L and recorded pits are recorded with irradiation of light L through an objective lens 4 of which numerical aperture is greater than 1, at least a silicon layer 3 and a silicon oxide layer 2 being formed from the light irradiation side, in that order. An optical recording medium and an optical recording and reproducing method thereof are suitable for use with a near-field optical recording and reproducing system using an objective lens of which numerical aperture is greater than 1.

Abstract: A near-field optical probe has a planar substrate formed with a through-hole and a phase shifter layer translucent to light having a wavelength of illumination light used to illuminate the substrate for producing near-field light. The phase shifter layer is effective to cause a shift of phase in the illumination light by 180 degrees and is provided on the substrate so as to cover one opening of the through-hole to form a microscopic aperture for producing near-field light.

Abstract: The present invention relates to an optical disc for use as a recording medium in an optical disc drive, which has a transparent protection film (120) formed on a recording layer on one plane of the disc substrate (110) and a printing label film 130 being of approximately the same film quality and film structure as the transparent protection film (120) formed on the other plane thereof. The printing label film (130) is a synthetic resin film made mainly of polycarbonate and formed on the disc substrate by screen printing, etc. Thus, the optical disc has the same film quality and film structure on the respective one and the other planes, which prevents occurrence of skew caused by the deformation due to the asymmetry of the structure along the thickness direction of the optical disc. The optical disc has a function to present contents of information recorded therein with the printing label film provided on the other plane of the disc substrate.

Abstract: An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.