Abstract: An optical pickup device which includes a semiconductor laser selectively generating a laser beam with a wavelength of 635 nm, a laser beam with a wavelength of 780 nm, and an optical device having a central region in which a hologram is formed and a peripheral region in which a diffraction grating is formed. In particular, the optical device is arranged immediately below an objective lens, and the central region allows transmission of the laser beam with the wavelength of 635 nm without any diffraction but increases the diameter of the teaser beam to the wavelength of 780 nm by diffraction. On the other hand, peripheral region allows transmission of the laser beam with the wavelength of 635 nm without any diffraction, but substantially shields the laser beam with the wavelength of 780 nm by diffraction. Thus, each laser beam with the wavelength 635 nm is transmitted through objective lens and focused on a signal recording surface of a DVD.

Abstract: A phase corrector unit has first to fifth regions on its plane on which a laser beam is incident. The second and fourth regions are formed of protrusions each having height d of approximately 730 nm, and the thickness of a quartz glass where the protrusions are formed is 0.5 mm. The second region is larger in the width than the fourth region. The width of the third region is larger than the width (diameter) of the fifth region, and the width in the direction of the side of the first region is larger than the width of the third region. An optical pickup device includes the phase corrector unit placed between a semiconductor laser and an objective lens. Thus, the optical pickup device emits a small-diameter laser beam without seriously deteriorating the efficiency of use of the laser beam.

Abstract: A magneto-optical disk apparatus includes a magnetic head in a position opposed to an objective lens included in an optical head with a magneto-optical record medium therebetween. The magneto-optical disk apparatus includes a magnet for cancelling a first magnetic field emitted toward the magnetic head from a magnet for focus servo-control or tracking servo-control of the objective lens. The magnet emits a second magnetic field in a direction toward the magnetic head. The second magnetic field is opposite in direction to the first magnetic field, and has the same intensity as the first magnetic field. Consequently, the signal can be accurately reproduced from the magneto-optical record medium while removing a magnetic influence from the magnet included in the optical head.

Abstract: An optical disk recording/reproduction apparatus includes a semiconductor laser, an objective lens provided opposite an optical disk, an optical system for supplying a laser beam from the semiconductor laser to the objective lens, an aperture for not intercepting the laser beam in reproducing from a digital video disk and intercepting an outermost portion of the laser beam in reproducing from a compact disk, and a tracking servo mechanism for moving the objective lens in a tracking direction orthogonal to the running direction of a track of the optical disk. The aperture has an oblong opening that is longer in the tracking direction than in the track running direction.

Abstract: An optical disk recording/reproduction apparatus includes a semiconductor laser, an objective lens provided opposite an optical disk, an optical system for supplying a laser beam from the semiconductor laser to the objective lens, an aperture for not intercepting the laser beam in reproducing from a digital video disk and intercepting an outermost portion of the laser beam in reproducing from a compact disk, and a tracking servo mechanism for moving the objective lens in a tracking direction orthogonal to the running direction of a track of the optical disk. The aperture has an oblong opening that is longer in the tracking direction than in the track running direction.

Abstract: In a double density CD for an optical pickup device including a laser with a wavelength of &lgr;&mgr;m and an objective lens (4) with a numerical aperture of NA, the expression 0.7<TP/(&lgr;/NA)<0.8, where TP is a track pitch in &mgr;m and/or the expression 0.40<L/(&lgr;/NA)<0.45, where L is a minimum pit length in &mgr;m are/is satisfied. Thus, jitter is suppressed and the reproduction characteristic is improved.

Abstract: An apparatus for discriminating optical disks has an optical pickup provided with an objective lens having an effective numerical aperture of 0.55 to 0.65, which can compatibly reproduce information from a CD and an SD. The apparatus discriminates presence/absence of waveforms of two focus error signals detected when the effective numerical aperture of the objective lens is set at 0.55 to 0.65 and 0.20 to 0.45 respectively in a process of performing focus servo control, thereby discriminating various types of optical disks from each other. Thus, optical disks having different substrate thicknesses, different track pitches, different minimum pit lengths and different reflectivity can be quickly and simply discriminated from each other.

Abstract: The optical pickup device includes a two wavelength semiconductor laser (23) selectively generating a laser beam having the wavelength of 635 nm and laser beam having the wavelength of 780 nm, a collimator lens (24), a hologram (25) formed on a surface of collimator lens (24), a polarizing glass (22) having an annular polarizing region (40) and an objective lens (21). Hologram (25) does not diffract the laser beam having the wavelength of 635 nm, and diffracts outward the laser beam having the wavelength of 780 nm. Therefore, virtual light source of the laser beam having the wavelength of 780 nm comes closer to the collimator lens (24) than the light source of the laser beam having the wavelength of 635 nm. Therefore, objective lens (21) focuses the laser beam having the wavelength of 635 nm on a recording surface of a transparent substrate (31) of a DVD, and focuses the laser beam having the wavelength of 780 nm on a recording surface of a transparent substrate (32) of a CD-R.

Abstract: An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.

Abstract: An optical pick-up device includes an optical active element (11) which transmits an introduced laser beam (18) with its polarization direction (17) rotated by 90.degree. in playback of a DVD and also transmits an introduced laser beam (18) without rotating its polarization direction (17) in playback of a CD, and a polarizer (14) which transmits the entirety of a laser beam with its polarization direction rotated in playback of a DVD and also blocks the perimeter of a laser beam with its polarization direction not rotated in playback of a CD to reduce the effective numerical aperture of an objective lens (15). A rubbing direction (28) of an rubbing film (24) of the optical active element (11) that is positioned at the incident side of the laser beam, is adapted to be parallel to the polarization direction (17) of the introduced laser beam (18). Thus, the optical pick-up device can play back DVD as well as CD while reducing laser beam loss.

Abstract: An injection blow molding system includes an injection molding station 22, a first delivery section 24, a cooling station 26, a heating station 30, a second delivery section 32 and a plurality of blow molding stations 34. The injection molding station 22 is designed to simultaneously injection mold M rows of N preforms 36 arranged in a second direction B perpendicular to a first direction A in which the preforms 36 are carried. The first delivery section 24 is designed to remove the M rows of preforms 36 injection molded by the injection molding station 22 through a removing mechanism 102 in their upright state while decreasing the pitch in the rows. The preforms 36 are inverted with the column pitch being changed by an inverting mechanism 104 before they are delivered to the cooling station in their inverted state. The cooling and heating stations 26, 30 are designed to cool and heat one row of N preforms 36 while parallel carrying them along a first carrying chain 200.

Abstract: An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.

Abstract: An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.

Abstract: A method of molding a heat-resistant container comprising a primary blow molding step, a primary heat treatment step, a secondary heat treatment step, and a secondary blow molding step. In the primary blow molding step a synthetic resin preform is blow-molded into a primary blow-molded article. In the primary heat treatment step, the primary blow-molded article is held in a heat treatment mold and subjected to heat treatment. The primary blow-molded article, removed from the mold, shrinks, and forms an intermediate molded article. In the secondary heat treatment step, the intermediate molded article is subjected to heat treatment outside the mold. At this time, almost no shrinkage occurs. In the secondary blow molding step, the intermediate molded article is blow molded within a final blow mold to form a final molded product.

Abstract: An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.

Abstract: An optical pickup apparatus including a polarization plane rotary unit arranged between a semiconductor laser and an objective lens, and a polarizing film arranged between the polarization plane rotary unit and the objective lens. The polarization plane rotary unit includes liquid crystal, two glass plates sandwiching the liquid crystal, and transparent electrodes patterned to a predetermined configuration on an inner face of these glass planes. The polarization plane rotary unit permits passage of the laser beam without rotating the plane of polarization of the entire laser beam at the time of recording, and permits passage of the laser beam with the plane of polarization of the center portion of the laser beam rotated and the plane of polarization of the remaining outer portion of the laser beam not rotated at the time of reproduction. Only the outer portion of the laser beam is focused on a magneto-optical disk in a reproduction mode, so that a main beam of a small spot is formed by mutual interference.

Abstract: An optical disc player for reproducing an optical disc having a pit width of 0.2-0.35 .mu.m, a pit depth of 100-120 nm, and a track pitch of 0.7-0.85 .mu.m. The optical disc player includes a semiconductor laser having a wavelength of 590-670 .mu.m and a laser beam projector which projects the laser beam from the laser onto the optical disc with a spot of a predetermined diameter.

Abstract: An apparatus for discriminating optical disks has an optical pickup provided with an objective lens having an effective numerical aperture of 0.55 to 0.65, which can compatibly reproduce information from a CD and an SD. The apparatus discriminates presence/absence of waveforms of two focus error signals detected when the effective numerical aperture of the objective lens is set at 0.55 to 0.65 and 0.20 to 0.45 respectively in a process of performing focus servo control, thereby discriminating various types of optical disks from each other. Thus, optical disks having different substrate thicknesses, different track pitches, different minimum pit lengths and different reflectivity can be quickly and simply discriminated from each other.

Abstract: A high density optical disc having a track pitch of 0.85 .mu.m, a shortest pit length of 0.49 .mu.m, a pit depth of 100 nm, and a pit width of 0.35 .mu.m is rotated at a linear velocity of 2.4-2.8 m/s such that the same is optically reproduced by a laser beam having a wavelength of 635 nm which is converged to a spot size of 0.9 .mu.m by an objective lens having a numerical aperture of 0.6. Accordingly, data is read from the optical disc at a transfer rate of 5.6 Mbps.

Abstract: An optical pickup device includes two objective lenses having numerical apertures different from each other, a lens holder for holding these objective lenses in common, a cylinder fixed to the lens holder, and four tracking coil pairs affixed onto a cylindrical surface of the cylinder. Two tracking coil pairs are displaced from the remaining two tracking coil pairs by a predetermined angle. When one objective lens is used, two tracking coil pairs corresponding to the objective lens are used for tracking control of the objective lens. The remaining two tracking coil pairs are used for positioning control of the objective lens.