Abstract: An optical pickup apparatus includes a light source and a light detector provided on a stem for detecting source emitted light reflected by an optical recording medium; and a light separating device, having first and second areas, for separating light incident thereon into a plurality of light components respectively directed in prescribed directions. The light detector includes a light receiver, divided into first and second light receiving regions for receiving the light components detected by those first and second areas. The first and second light receiving regions are located in a predetermined orientation determined in part by a light emitting point of the light source and a focal point on the light detector. The stem material and the wavelength emitted by the light source are selected to limit movement of that focal point in that orientation in response to temperature change of the apparatus.

Abstract: A housing for opto-electronic array devices. The housing includes a base and walls that form a region that receives an opto-electronic semiconductor array. Conductive traces are disposed on a wall such that a front part of the traces are exposed for external electrical connections, while the back part is exposed for internal electrical connections. A transparent substrate having a plurality of micro-lenses cover the base, walls and opto-electronic semiconductor array device. Each micro lens is beneficially made from optical epoxy that is deposited by an ink-jet nozzle. The base and walls are beneficially comprised of a ceramic.

Abstract: An optical head in which focussing error is detected by a spot size method used for recording and/or reproducing information signals on or from an optical disc. The optical head includes a unit for correcting the spot shape between the objective lens and a photodetector device. The spot shape correcting unit corrects part or all of light spots formed on the photodetector by a light beam reflected back by the optical disc so that the spot diameter in a direction traversing a track on the optical disc will be larger than the spot diameter along the track.

Abstract: A pocket 10 is formed in a bottom surface 2a of a groove portion 2 in such a manner as to oppose a rear surface 3a of a half mirror 3, and an adhesive-injecting recessed passage 11 extending from the pocket 10 to an open end of the groove portion 2 is formed in the bottom surface 2a of the groove portion 2. Further, the bottom of the pocket 10 is closed by a positioning base 12 which is formed on the bottom surface 2a of the groove portion 2 to abut against the rear surface 3a of the half mirror 3, and a pair of protrusions 14 are formed which extend from the open end of the groove portion 2 to the positioning base 12 along both side edges of the adhesive-injecting recessed passage 11.

Abstract: A light branching element which branches a light beam emitted from a light source and reflected on a magneto-optical recording medium is provided with four light branching portions, and three phase compensating means which give a fixed phase &dgr;M to a light beam branched by an M-th (M=2 to 4) light branching portion is disposed on paths of light beams branched by the three light branching portions except the first light branching portion of the four light branching portions. In this optical pickup, servo signals of four kinds of optical recording mediums are respectively detected using light beams detected by three or less groups of light receiving portions selected from among four groups of light receiving portions.

Abstract: In an optical pickup device for emitting at least two laser beams suitable for respective optical recording mediums selectively operated on an optical disk driver so that a signal is read out from and/or recorded onto the selected one of the optical recording mediums, an anamorphic system is arranged to change a cross-sectional shape of one of the laser beams from an oval toward a circle between a divergence point and a confluence point along the one of the laser beam between an upstream common optical paths of the laser beams from the light beam source and a downstream common optical paths of the laser beams toward the objective lens, at which divergence point the laser beams from the upstream common optical path diverge from each other, and at which confluence point the laser beams converge into the downstream common optical path.

Abstract: In an optical pickup device for conducting reproducing and/or recording of information in at least two kinds of optical information recording media, an optical element divides a light flux into k(k≧4) pieces of ring-shaped light flux. When reproducing or recording is conduced for a first optical information recording medium, the first light flux and the k-th light flux are converged on the first information recording surface and at least two pieces of light flux of the second light flux to the (k-1)th light flux form an apparent best image plane at a position different from the position of the best image plane formed by the first light flux and the k-th light flux. A wave front aberration of each light flux passing in a required numerical aperture for the first optical information recording medium is made approximately mi&lgr;1.

Abstract: An optical head is provided so as to include one prism having a wavelength separation function for reducing the number of steps for adjustment. The optical head includes a first light source, a second light source, a third light source and a beam splitter. The beam splitter includes a first prism, a second prism, a third prism, a fourth prism, a first optical film, a second optical film, a third optical film and a fourth optical film. The first to the fourth optical films have desired optical characteristics for allowing the light beam from the first light source that enters into the first prism and has a first wavelength, the light beam from the second light source that enters into the second prism and has a second wavelength and the light beam from the third light source that enters into the third prism and has a third wavelength to pass through or for reflecting these light beams.

Abstract: An object of the present invention is to attain stable tracking servo performance by suppressing an offset caused by a shift of an object lens or a tilt of a disk, despite the one-beam method which does not cause reduction in light quantity of the main beam. A diffraction grating is provided between a hologram and a light receiving section, and a diffraction efficiency of the diffraction grating is varied in a grating longitudinal direction. For example, if an incident light beam on the diffraction grating is shifted in the grating longitudinal direction, the quantity of received light in each light receiving section varies to cause offset. By performing tracking servo so as to cancel the change, it is possible to correct the offset, thereby attaining stable tracking servo performance.

Abstract: The invention provides an optical apparatus. and the optical pickup of that optical apparatus, for which the number of parts of the optical pickup can be reduced and thus a data-recording apparatus that contains this optical pickup can be made more compact. An optical pickup P1 that projects a red-LASER beam RL for a DVD and a blue-LASER beam for a high-recording-density optical disc, whose optical axes coincide with each other, onto the respective optical discs, and comprising: a first expander lens 4 and second expander lens 6 that correct distortion that occurs in the blue-LASER beam BL and red-LASER beam RL; and a dichroic prism 5 that is located between the first expander lens 4 and second expander lens 6 in the optical path of the blue-LASER beam BL and its reflected beam; and where the second expander lens 6, working together with the first expander lens 4, corrects spherical distortion that occurs in the blue-LASER beam BL, as well as converts the red-LASER beam RL to a parallel beam.

Abstract: The present invention relates to an optical pickup and a disc drive for preventing aberrations of laser light due to variations in temperature and humidity to ensure satisfactory characteristics of the laser light. A compound lens (14) is disposed in the optical path of the laser light, which is emitted by a light-emitting device (11) to be incident on a beam splitter (15), and in the optical path of the laser light, which exits from the beam splitter to be incident on a photodetector (13). The compound lens includes a diffractive section (23) for diffracting the laser light and a lens section (24) having a predetermined function for the laser light. The compound lens is formed by integrating individual sections including the diffractive section and the lens section. The compound lens is provided with a passage hole (14c) that lets in the laser light emitted by the light-emitting device to be incident on the beam splitter.

Abstract: An object of the invention is to simplify the configuration of an optical system for recording or reproduction without causing a reduction in the amount of information. For recording, a spatial light modulator (27) generates information light by spatially modulating light according to information to be recorded. The information light is collected by an objective lens (21) and applied to an optical information recording medium (1) while converging to become minimum in diameter on the interface between a transparent substrate (2) and a protective layer (5). Recording-specific reference light is collected by an objective lens (31) and applied to the optical information recording medium (1) while converging to become minimum in diameter on the interface between the transparent substrate (2) and the protective layer (5). In an information recording layer (3), the information light and the recording-specific reference light interfere with each other to form an interference pattern.

Abstract: First, second semiconductor lasers and a photodetector are integrated in a laser package of an integrated laser unit. A composite PBS is so structured that generally 100% of s-polarized light derived from the first semiconductor laser is reflected while generally 100% of s-polarized light derived from the second semiconductor laser is transmitted. Then, return beams of s-polarized light of the first, second semiconductor lasers separated by the composite PBS 18 are converged on the same photodetector by the first, second polarization hologram devices. By doing so, the first, second polarization hologram devices are adjusted independently of each other, so that the offset adjustment of servo error signals for the first, second semiconductor lasers can be easily achieved in assembly process. Thus, the optical pickup becomes easy to assemble and adjust.

Abstract: A laser beam emitted from a laser source provided at a silicon substrate passes through a hologram element formed of a translucent flat plate and a grating, thereby being subjected to NA conversion executed by an NA converting lens, passing through a polarizing film of a polarization beam splitter, and converging onto a magneto-optical disk via a collimator lens and an objective. A part of back-reflection from the magneto-optical disk, which is reflected by a polarizing film of the polarization beam splitter, is reflected by a reflection surface of the splitter, then branched into two polarized light beams by a Wollaston prism, and guided to one light receiving element group. On the other hand, another part of the back-reflection, which passes through the polarization beam splitter, is branched into two beams by the hologram element and guided to the other light receiving element groups.

Abstract: An optical pickup apparatus is provided with two light sources; an objective lens for focusing light originating from each light source on an optical recording medium; a light separation optical element for transmitting or reflecting the light originating from each light source; a collimator lens for converting the light originating from each light source into a generally parallel beam; an upward-directing mirror for changing the optical path of the light originating from each light source by reflecting it; reflectors disposed between the light separation optical element and the respective light sources, for reflecting parts of light beams emitted from the light sources, respectively; photodetectors for detecting light beams reflected from the reflectors, respectively; and an APC circuit for controlling the power of the light beam emitted from each light source in accordance with a detection output of each photodetector.

Abstract: An optical disc drive compatible with optical discs of different types, for example, is provided. For focusing, through an optical system used in common with the different types of optical discs, a laser beam emitted from a selected one of a plurality of light sources disposed apart from each other radially of the optical disc, the optical system is moved radially of the optical disc corresponding to the selection of the light source for emitting the laser light. Namely, it is possible to prevent the optical property from being deteriorated when a single optical pickup is used in common with such optical discs of different types.

Abstract: An optical disk apparatus which records/reproduces data on/from a plurality of types of optical disks. The optical disk apparatus has a plurality of laser diodes. Two laser light rays emanating from two laser diodes are coupled together by means of a coupling prism. The thus-coupled laser light is radiated onto an optical disk. A photodetector is disposed in close proximity to the coupling prism. The coupling prism guides, to the photodetector, a laser light component of at least one laser light ray of the two laser light to be coupled together, the component having not been radiated onto the optical disk on an optical path. Laser light which is not radiated onto the optical disk on the optical path includes diffracted light other than a main beam emanating from the laser diode or laser beam which has not been subjected to coupling at the coupling surface of the coupling prism.

Abstract: A device for reading from and/or writing to optical recording media 10, on which information is present in the form of pits, with a linearly polarized light beam 2.

Abstract: A pickup includes a light source for emitting a light beam that travels to an information recording medium along a first optical path, a first light receiving element group for detecting an error signal, a second light receiving element group for detecting a magneto-optical signal, a diffraction grating for diffracting light returned along the first optical path, a polarization beam splitter for separating a part of the return light such that a beam of the return light travels to the second light receiving element group along a second optical path, a mirror for bending the second optical path so that a light beam reflected thereby is directed toward the second light receiving element group, and an anisotropic crystal member that has an optic axis inclined between 30° and 60° and that includes a substantially parallel flat plate portion between the mirror and the first light receiving element group.

Abstract: An optical pickup device has a first combination reception and emission device (1) which emits laser beams (10) to an optical disk, and a second combination reception and emission device (2) which emits laser beams (11) having a wavelength different from that of the laser beams (10) to an optical disk. A DBS (3) is disposed on a path of the laser beams for making axes (12, 13) of the laser beams coincident with each other at an output side. A monitoring light detection element (9) is disposed near and above the DBS such that a light-receiving surface of the monitoring light detection element is substantially parallel with the optical axes (12, 13) of the laser beams (10, 11). The monitoring light detection element (9) receives laser beams outside of an effective region emitted by the first and second combination reception and emission devices (1, 2).

Abstract: An optical pickup device includes an illuminating optical system for focusing light beams, split in a main beam and at least one side beam, onto a track on an information storage surface of an optical storage medium to form optical spots thereon. The device also includes a light detecting optical system for introducing return light reflected back from the information storage surface and a polarizing optical element. The polarizing optical element has regions split at the center of an optical path by a parting line extending at least either in a direction of extension of the track or in a direction perpendicular to the direction of extension. The polarizing optical element also splits the main beam return light at least in two for each of the regions on a plane perpendicular to the optical path of the return light of the reflected main beam in the light detecting optical system. The polarizing optical element is disposed where the return light of the main and side beams is spatially separated.

Abstract: An adhesive is coated on at least one surface of a thin film of organic material having birefringent properties and a phase-difference producing function, and a fixing substrate having transmitting or reflecting properties is bonded to the thin film of organic material by the adhesive, wherein materials satisfying relations of E1<E2 and E3<E2 where E1 is the linear expansion coefficient of the thin film of organic material, E2 is the linear expansion coefficient of the adhesive and E3 is the linear expansion coefficient of the fixing substrate, and the glass transition temperature of the thin film of organic material being 150° or more, are selected.

Abstract: In an optical pickup device for recording information onto and/or reading out information from an optical recording medium, comprising a light beam source for generating a light beam to be projected toward the optical recording medium, and a light beam detector for receiving the light beam reflected by the optical recording medium so that the information is read out from the light beam after reflected by the optical recording medium, a container houses therein the light beam source and includes an aperture through which the light beam proceeds toward the optical recording medium, and a light beam guide member is mounted on an outer surface of the container and covers the aperture to guide the light beam after reflected by the optical recording medium toward the light beam detector.

Abstract: An optical element is composed of a first substrate and a second substrate that are joined to each other. The first substrate is composed of a plurality of transparent base materials joined to each other through a first joint surface on which an optical film is formed. The second substrate is composed of a plurality of transparent base materials joined to each other through at least two second joint surfaces parallel to each other. On each of the second joint surfaces, an optical film is formed. One part of light incident on the first substrate is reflected from the first joint surface to be incident on the second substrate, and at least one part thereof is reflected from at least one of the second joint surfaces. A virtual plane including an incident light axis and a reflected light axis on the first joint surface and a virtual plane including incident light axes and reflected light axes on the respective second joint surfaces form an angle of substantially 45 degrees.

Abstract: An optical pickup capable of reducing cross-talk due to signal interference of adjacent tracks of an optical medium during playback of a radio frequency (RF) signal from a main track of the optical recording medium. In the optical pickup, optical spots can be converged on the main track and the adjacent tracks of the recording medium without a time lag, wherein different polarized component beams are focused as a primary optical spot and secondary optical spots on the main and adjacent tracks, respectively, of the optical recording medium. Thus, the primary optical spot and the secondary optical spots, which have different polarized components, can be separately received by different light receiving portions. Also, the optical spots are photoelectrically converted in the light receiving portions and are differentially amplified through multiplication using a predetermined operation constant, thereby reducing cross-talk from a detected RF signal.

Abstract: A laser beam emitted from a laser diode and having a wavelength of 780 nm is S-polarized. A polarization plane rotating means (&lgr;/4 phase plate) is disposed between a super-resolution cut-off filter comprising a polarizing filter film and an objective lens. When reading on DVD, the objective lens, the polarization plane rotating means and the super-resolution cut-off filter in combination are set to the optical path. The S-polarized laser beam is focused to a micro spot diameter by super-resolution effects by the super-resolution cut-off filter together with the objective lens. Also, the S-polarized laser beam reflected at a disk and traveling backward along the incoming optical path is converted into a P-polarized laser beam while passing backward through the polarization plane rotating means. The P-polarized laser beam passes through the super-resolution cut-off filter without loss is received by a photo-detector.

Abstract: An optical pickup apparatus for reading and recording information on recording media includes a semiconductor laser, a collimating lens, a half mirror, a reflecting mirror, and an objective lens. Further included therein are a super-resolution cutoff filter and an aperture control filter, one of which is appropriately selected and set right before the objective lens by a filter switching-over device. When reading the DVD, the super-resolution cutoff filter is set at the optical path, whereas when reading the CD, the aperture control filter is set thereat. The filter switching device is arranged separately from an actuator driving system having the objective lens integrally structured therewith.

Abstract: An optical pickup apparatus includes: one laser beam source for emitting two laser beams having respective optical paths parallel to each other and wavelengths different from each other; an optical-axis aligning means adapted to make the laser beams coaxial with each other; a collimating lens; a reflecting mirror; and an objective lens. A laser beam reflected at a high or low density disk takes the incoming path backward, passes through the optical-axis aligning means, is incident on a photo-detector, and converted thereby into an electrical signal. The optical-axis aligning means is structured such that one kind of dielectric multilayer film is formed on a transparent substrate, a transparent plate is attached on the one kind of dielectric multilayer film, and that another kind of dielectric multilayer film is formed on the transparent plate, and has its reflectance varied according to the wavelength of the laser beam.

Abstract: A pocket 10 is formed in a bottom surface 2a of a groove portion 2 in such a manner as to oppose a rear surface 3a of a half mirror 3, and an adhesive-injecting recessed passage 11 extending from the pocket 10 to an open end of the groove portion 2 is formed in the bottom surface 2a of the groove portion 2. Further, the bottom of the pocket 10 is closed by a positioning base 12 which is formed on the bottom surface 2a of the groove portion 2 to abut against the rear surface 3a of the half mirror 3, and a pair of protrusions 14 are formed which extend from the open end of the groove portion 2 to the positioning base 12 along both side edges of the adhesive-injecting recessed passage 11.

Abstract: A read head optical system capable of reading either CD or DVD disks is provided. A monolithic molded hollow plastic block includes three lenses integrally molded into its exterior surfaces. A 780 nm laser diode is aligned with the first lens for reading CD disks, a 655 nm laser is aligned with the second lens for reading DVD disks and a detector for providing signal, focus and tracking data is aligned with the third molded lens. The hollow plastic block has an interior cavity adapted to support optical elements to receive and transmit the output of the laser diodes to the disks and to the detector. The three lenses are formed in the hollow plastic block in various embodiments.

Abstract: An optical head device and an optical recording and reproducing apparatus using this optical head device, which can record information and reproduce the recorded information at any of optical recording media, such as a next generation optical recording medium, in which the wavelength of the light source is made to be shorter, the numerical aperture of the objective lens is made to be higher, and the thickness of the recording medium is made to be thinner, and conventional recording media of DVD and CD standards, are provided. A light having wavelength of 405 nm, emitted from one of optics, is inputted to an objective lens as a collimated light, and is focused on a disk having thickness of 0.1 mm. A light having wavelength of 650 nm, emitted from the other of optics, is inputted to the objective lens as a diverged light, and is focused on a disk having thickness of 0.6 mm.

Abstract: A 3-beam-generating grating 2, a collimating lens 3, a polarizing beam splitter 4, a rising mirror 5 and an objective lens 6 are arranged sequentially in the optical path between a semiconductor laser device 1 and an information recording medium 7. The reflecting face of the polarizing beam splitter 4 has a reflection characteristic such that the reflectance is minimum for return light L2 at an angle of 45 degrees whereas the reflectance increases as the incident angle of the return light L2 deviates from 45 degrees. This realizes an optical head device that is not likely to cause the decrease in tracking error signals even if the objective lens shifts in radial directions of the recording medium.

Abstract: A reflection type compound prism and an optical pickup apparatus employing the same. As a light beam is passed through the compound prism, a size of the light beam in a direction perpendicular to a reference plane is reduced by a first reflection surface, propagated toward an objective lens by second and third reflection surfaces and the size restored by reflecting the light beam from a fourth reflection surface forming an angle less than 45° with respect to the reference plane so that a height of an optical system is reducible to obtain a small thin optical pickup with a desired NA. The second and third reflection surfaces are spaced apart in a direction perpendicular to the reference plane by an amount close to a diameter of the light beam at a point of incidence of the light beam with the compound prism.

Abstract: An optical head includes a light source for generating a luminous flux, a polarization beam splitter, an object lens opposed to an appropriate recording medium, and a power monitoring device for monitoring the power of the luminous flux output from the light source. The power monitoring device is adapted to utilize a peripheral portion of the luminous flux. This peripheral portion of the luminous flux is distinct from the portion of the luminous flux that is used for reproducing predetermined information from the recording medium and recording the predetermined information onto the recording medium.

Abstract: In an optical pickup device for emitting at least two laser beams suitable for respective optical recording mediums selectively operated on an optical disk driver so that a signal is read out from and/or recorded onto the selected one of the optical recording mediums, an anamorphic system is arranged to change a cross-sectional shape of one of the laser beams from an oval toward a circle between a divergence point and a confluence point along the one of the laser beam between an upstream common optical paths of the laser beams from the light beam source and a downstream common optical paths of the laser beams toward the objective lens, at which divergence point the laser beams from the upstream common optical path diverge from each other, and at which confluence point the laser beams converge into the downstream common optical path.

Abstract: An optical head of a type useable in a optical disk reader/writer is provided. One of the optical elements is provided in a fashion that one or more optical parameters or characteristics of the system are invariant, regardless of whether the one optical element is used, or not. In one embodiment the optical element is a beamshaper. In order to provide the desired invariant property, the surfaces of the optical element are preferably formed with high accuracy. One manner of economically achieving high accuracy is to measure errors or imperfections in a first formed, preferably etched, surface and adjust the shape or position of a second aligned etched surface so as to at least partially compensate for the errors or imperfections.

Abstract: Laser beams h1, h2 with different wavelengths emitted from semiconductor lasers 2a, 3 are incident to an optical path joint prism 13 and each of optical intensities of the laser beams h1, h2 is detected by a photoelectric conversion element 15 provided in an optical path integrated by the optical path joint prism 13 on which a semi-transmission film HM is provided and APC control of each of light emission intensities of the semiconductor lasers 2a, 3 is performed on a basis of each of detection results. As a result of this, the beam intensity of the laser beam h1 passing through the optical path joint prism 13 to be applied to an information recording medium and the laser beam h2 reflecting the optical path joint prism 13 to be applied to the information recording medium are controlled properly.

Abstract: A reflective mirror 14 is inclined and placed with respect to an objective lens 16 and a photoelectric conversion element 15 for monitor is placed in the back side of the reflective mirror 14. The reflective mirror 14 is formed into a structure in which a semi-transmission film HM having predetermined reflectance and transmittance is formed on one surface of a substrate of a transparent medium. When a laser beam for information record or information reproduction is launched from semiconductor lasers 2a, 3 to the reflective mirror 14, the semi-transmission film HM splits the laser beam into a reflected beam and a transmitted beam and the reflected beam is emitted to the side of the objective lens 16 and the transmitted beam is emitted to the side of the photoelectric conversion element 15.

Abstract: There can be obtained a miniaturized, 3-beam optical pickup device using a polarization separating prism of an inexpensive material and capable of reliably detecting light of a signal. The present pickup device includes an optical element having the first, second and third members, and having a first boundary surface receiving light from a semiconductor laser and reflecting and directing it toward a collimator lens, and also transmitting light reflected by an MO disc and directing it toward a photodetector, and a second boundary surface separating polarized light of light transmitted through the first boundary surface.

Abstract: An optical pickup includes an aberration correction element to correct chromatic aberration caused by variation of power from a light source when changing between operating modes in a recording medium. The aberration correction includes a first retardation member, which includes a stepped convex pattern with a plurality of steps at one side, and a second retardation member combined with the first retardation member. The second retardation member includes a stepped concave pattern with a plurality of steps at one side facing the first retardation member, the stepped concave pattern corresponding to the stepped convex pattern. The first and the second retardation members include different refractive indices for a light beam, which allows the first and the second retardation members to selectively create a phase difference of an incident light beam according to a polarization of the incident light beam.

Abstract: There is disclosed a compact optical information storage apparatus in which noise attributed to wobbling or the like is reduced and high-density recording is possible. An optical device 410 comprises a reflective surface 64 including a main portion for reflecting a signal light reflected by a separation surface 61 in a predetermined direction, and a mask portion 411 having an optical property different from the optical property of the main portion.

Abstract: The optical pickup apparatus 100 uses a semiconductor laser element 50 integrated a first light emission source 36 for emitting a first laser beam with a second light emission source 40 for emitting a second laser beam, of which wavelength is different from that of the first laser beam. The optical pickup apparatus 100 is constructed so that a first half mirror functional surface 52b and a second half mirror functional surface 52c are provided in a beam splitter 52 to match an optical path in which the first laser beam passes through the first half mirror functional surface 52b of the beam splitter 52 and then is reflected at the second half mirror functional surface 52c and again is emitted from the first half mirror functional surface 52b to be directed toward a bifocal lens 54 with an optical path in which the second laser beam is reflected at the first half mirror functional surface 52b to be directed toward the bifocal lens 54.

Abstract: An information recording and reproduction apparatus for a magneto-optical medium includes a synchronizing signal generation circuit for generating a synchronizing signal to provide a pulsed laser beam at the time of reproduction according to an internal clock obtained from a reproduction signal. The laser beam is driven on/off according to the synchronizing signal at the time of reproduction to have the laser spot on the signal plane prevented from being enlarged, so that the reproducible domain is smaller than the domain of when a laser beam is continuously emitted. In reproduction, an optical superresolution method is applied simultaneous to provision of a pulsed laser beam to allow reproduction of higher density. An external synchronizing signal generation circuit for generating an external synchronizing signal according to a wobble on a surface of a recording medium can be used instead of a synchronizing signal generation circuit according to an internal clock.

Abstract: A light source is provided for emitting a first beam having a far-field pattern of an elliptic shape. The first beam is a linearly polarized light having a first polarizing direction in a major axis of the elliptic shape. A half-wave plate is provided for rotating the polarizing direction of the first beam 90 degrees, thereby changing the first beam to a second beam. A beam splitter is provided for changing the elliptic shape of the second beam into a circular shape. The beam splitter is arranged to transmit the second beam and to reflect a third beam having a polarizing direction different from that of the second beam by 90 degrees. A quarter-wave plate is provided for transmitting the second beam from the beam splitter to apply it to an optical disc, and for changing the second beam reflected from the optical disc into the third beam. The third beam reflected from the beam splitter is applied to a photodetector.

Abstract: An optical pickup apparatus includes a light source and a light detector provided on a stem for detecting source emitted light reflected by an optical recording medium; and a light separating device, having first and second areas, for separating light incident thereon into a plurality of light components respectively directed in prescribed directions. The light detector includes a light receiver, divided into first and second light receiving regions for receiving the light components detected by those first and second areas. The first and second light receiving regions are located in a predetermined orientation determined in part by a light emitting point of the light source and a focal point on the light detector. The stem material and the wavelength emitted by the light source are selected to limit movement of that focal point in that orientation in response to temperature change of the apparatus.

Abstract: An information recording and reproduction apparatus for a magneto-optical medium includes a synchronizing signal generation circuit for generating a synchronizing signal to provide a pulsed laser beam at the time of reproduction according to an internal clock obtained from a reproduction signal. The laser beam is driven on/off according to the synchronizing signal at the time of reproduction to have the laser spot on the signal plane prevented from being enlarged, so that the reproducible domain is smaller than the domain of when a laser beam is continuously emitted. In reproduction, an optical superresolution method is applied simultaneous to provision of a pulsed laser beam to allow reproduction of higher density. An external synchronizing signal generation circuit for generating an external synchronizing signal according to a wobble on a surface of a recording medium can be used instead of a synchronizing signal generation circuit according to an internal clock.

Abstract: An optical pickup head which utilizes two or three laser beams of different wavelengths for reading or writing data on different kinds of optical recording media through a same optical output path is disclosed. According to the present invention, a beam shaper located in optical paths of multiple laser beams is used. The beam shaper is composed of two prisms in which several laser beam interfaces are formed. Each laser beam interface is furnished with a specific coating for reflecting laser beam of a specific wavelength and transmitting and refracting laser beams of other wavelengths. Therefore, laser beams in different wavelengths can be shaped into a same optical output path for reading and writing data from optical recording media. The laser beams passing through the beam shaper can be eliminated of their chromatic aberrations, and improved their cross-sectional shapes to get higher usage efficiencies of the laser beams. And, the optical pickup head is constructed as a compact unit with small size.

Abstract: A small-sized, inexpensive optical pickup apparatus can be assembled with high accuracy. The optical pickup apparatus has a various-purpose semiconductor laser, an integrated optical assembly for guiding outgoing light to an optical disk and for separating reflected light, a light receiver for receiving light and converting the received light into an electrical signal, and a coupling member for retaining a positional relationship among the various-purpose semiconductor laser, the integrated optical assembly, and the light receiver. By using a various-purpose semiconductor laser, the optical pickup apparatus can be made in a small size at low cost, and can be accurately assembled. The apparatus is also capable of accurately and efficiently detecting the optical power of the various-purpose semiconductor laser.

Abstract: An optical pickup apparatus is provided with: a light source (20) for emitting a light beam; an optical system (21, 22, 24, 25, 26, 27), which comprises an optical element (24) having an incident surface (24a), to which an AR (Anti-Reflection) coat is not applied and to which the light beam emitted from the light source is inputted obliquely by a predetermined incident angle, for guiding one portion of the emitted light beam transmitted through the incident surface onto an information record medium (32) and guiding a reflection light of one portion of the emitted light beam reflected from the information record medium, and also reflecting another portion of the emitted light beam by the incident surface; a main light detector (30) for receiving the reflection light from the information record medium guided by the optical system and outputting a main detection signal corresponding to record information recorded on the information record medium; a monitor detector (23) for receiving another portion of the emitt

Abstract: An information recording and reproduction apparatus for a magneto-optical medium includes a synchronizing signal generation circuit for generating a synchronizing signal to provide a pulsed laser beam at the time of reproduction according to an internal clock obtained from a reproduction signal. The laser beam is driven on/off according to the synchronizing signal at the time of reproduction to have the laser spot on the signal plane prevented from being enlarged, so that the reproducible domain is smaller than the domain of when a laser beam is continuously emitted. In reproduction, an optical superresolution method is applied simultaneous to provision of a pulsed laser beam to allow reproduction of higher density. An external synchronizing signal generation circuit for generating an external synchronizing signal according to a wobble on a surface of a recording medium can be used instead of a synchronizing signal generation circuit according to an internal clock.