Abstract: An optical lens whose focal length is different on first and second planes perpendicular to each other is provided. The optical lens is configured such that a convex element, which is formed integrally with a substrate having a flat face, has a convex curved face that functions as an optical lens and is shaped such that the curvature on a first cross section and the curvature on a second cross section perpendicular to and intersecting with the first cross section are different from each other, whereby the focal lengths on the first and second cross sections are different from each other. A groove of a substantially elliptical shape or a substantially rectangular shape is formed along the boundary between the substrate and the convex element. The optical lens is used to produce a focus error signal or is incorporated into an optical pickup apparatus.

Abstract: The present invention is directed to an object lens drive device adapted for moving an object lens (21) in a focus direction of optical axis direction and in a tracking direction perpendicular to the optical axis direction, and comprises a fixed portion (10) provided in such a manner that a supporting shaft (14) is projected, a movable portion (11) comprised of an object lens (21), and a bobbin (16) adapted so that the object lens (21) is attached and a hole (18) through the supporting shaft is inserted is formed, the bobbin (18) being supported movably along the supporting shaft and rotatably with the supporting shaft being as center, a drive portion including a magnet portion provided at either one of the fixed portion and the movable portion, and a coil portion (22) provided at the other portion to move the movable portion along the supporting shaft to thereby move the object lens in the focus direction, and to rotate the bobbin with the supporting shaft being as center to thereby move the object lens in t

Abstract: An object of the present invention is to provide an optical pickup apparatus which changes characteristics of a light-emitting device or hologram to reduce problems of track servo deviation due to scratches on a surface of an optical disc. By aligning a photoreceptive domain for focusing error signal (PDf) and a photoreceptive domain for tracking error signal (PDt), even in a case where scattering light made by a scratch in the tangent direction of a track of an optical disc reaches the photoreceptive domains, light diffracted in a HA+B domain of a hologram pattern does not enter into photoreceptive portion F or G of the PDt. Therefore, scattering of light which enters the PDf does not influence a tracking error signal (TES), so that the TES does not become abnormally large, and track servo deviation can be prevented.

Abstract: The optical information recording and reproducing apparatus includes a light source for emitting a light beam, an objective lens for converging the light beam emitted from the light source to an information recording medium, and a light detector for detecting the light beam reflected from the information recording medium. The information bits are recorded into a recording member of the information recording medium in a three-dimensional arrangement by using a change in optical constant of the recording member. Furthermore, a thickness of the recording member is larger than a wavelength of the light beam and the information bits are sequentially recorded into the recording member in a three-dimensional arrangement in such an order that a converging light beam from the objective lens does not pass through information bits that have already been recorded.

Abstract: An optical pickup unit includes a light source emitting a light beam, an objective lens focusing the light beam onto an information recording medium, a light detection part receiving the light beam reflected from the information recording medium, and a light blocking part selectively blocking a part of the light beam with respect to a radial direction. The light blocking part is provided in an optical path of the light beam centered on an optical axis.

Abstract: An auto-focus system for a DVD reader or other optical access unit which reads and/or writes information from/to at least two information layers on an optical storage medium such as a DVD or DVR. The auto-focus system includes an astigmatic lens. A confocal aperture is placed at the first focal line image generated by the astigmatic lens from light rays reflected from the addressed information layer. The placement of the confocal aperture allows extraneous out-of-focus light rays reflected from non-addressed information layers to be blocked from reaching the photo detector array which then creates a focus error signal (FES). The FES drives a servo assembly connected to an access head of the optical access unit, bringing the access head into focus. In some embodiments, the confocal aperture is “bow-tie” shaped, allowing for simplified assembly and easing in-plane rotational alignment.

Abstract: An information recording/reproducing apparatus of the present invention includes: a light source for emitting a first light beam having a predetermined light power Ppre; a determination section for determining the number of recording layers included in the information recording medium; a light beam transmission adjustment section for adjusting the quantity of the first light beam transmitted therethrough; and a light condensing section for condensing the first light beam on the information recording medium. When the information recording medium has one recording layer, the adjustment section adjusts the predetermined light power Ppre so as to be a first light power P1. When the information recording medium has two recording layers, the adjustment section adjusts the predetermined light power Ppre so as to be a second light power P2. The predetermined light power Ppre, the first light power P1, and the second light power P2 satisfy the relationship of P1<P2?Ppre.

Abstract: An apparatus for reproducing information stored in an optical recording medium which comprises marks or pits which are arranged at a pitch less than ?/2NA, wherein ? is a wavelength of light used for reproduction and NA is an numerical aperture of an objective lens. The apparatus generally comprises a laser diode, a polarization beam splitter, an objective lens, beam splitters, a low-frequency light detecting system with a photodetector, a high-frequency light detecting system with a photodetector, and a signal processing circuit for combining detection signals from the photodetectors. In the high-frequency light detecting system, before a convergent lens, a shielding band is provided so as to shield the middle of a bundle of rays of reproduction light.

Abstract: There is disclosed an optical device in which a first light source for outputting a first wavelength light is apart from a second light source for outputting a second wavelength light by a predetermined distance. An information recording medium is irradiated with the first and second wavelength lights transmitted through a holographic optical element having first and second diffraction areas. The first and second diffraction areas are provided with grating arrangements in which grating axis directions are parallel to each other and grating pitches are different from each other. The first and second wavelength lights reflected by the information recording medium are transmitted through the holographic optical element and diffracted by the first and second diffraction areas.

Abstract: An optical storage device capable of at least reproducing information recorded on first and second optical storage media different in distance from a medium surface on which a light beam is incident to a recording surface and in operating wavelength. The optical storage device includes a first light emitting element for emitting a light beam having a first wavelength, a second light emitting element for emitting a light beam having a second wavelength, a first photodetector for detecting a reproduction signal from a light beam reflected on the first optical storage medium, a second photodetector for detecting a reproduction signal from a light beam reflected on the second optical storage medium, and a beam splitter for combining optical paths of the light beams emitted from the first and second light emitting elements.

Abstract: The present invention aims to perform high-accuracy focus control in an optical disk drive, even if a solid immersion lens (SIL) or a solid immersion mirror (SIM) is set between an objective lens and the optical disk in order to increase a numerical aperture, by accurately detecting a change of the distance between an SIL or SIM and an optical disk. The present invention comprises light detection means (8) for detecting the light incoming to an SIL (2) or an SIM from an objective lens (1) at an incidence angle at which a numerical aperture is larger than 1 and reflected from a plane of the SIL (2) or SIM facing an optical disk, light detection means 10 for detecting the light incoming to the objective lens (1), comparison means (11) for finding a ratio between light amounts of the light detected by light detection means (8) and (10), and control means (11) for controlling operations of a focus actuator in accordance with the ratio.

Abstract: An optical disc device of the present invention includes spherical aberration changing means for changing spherical aberration occurring on a converging position of a light beam converged by a lens, an actuator for moving the spherical aberration changing means in a relatively precise manner, and an actuator for moving the spherical aberration changing means in a relatively rough manner. The optical disc device drives a second actuator and a third actuator based on a signal of spherical aberration detecting means and performs control so that spherical aberration is almost 0. The third actuator moves the spherical aberration changing means based on a direct current component included in a signal of the spherical aberration detecting means, and the second actuator moves the spherical aberration changing means based on an alternating current component included in the signal of the spherical aberration detecting means.

Abstract: An optical device for making light converge produces a convergent light beam with a satisfactorily great numerical aperture and acceptably small aberrations. The optical device has a plurality of diffraction gratings that each make light converge. The light shone into the optical device is passed through one after another of those diffraction gratings in such a way that the light is made to converge to a higher degree every time it passes through one of the diffraction gratings. The diffraction gratings may be all transmissive, all reflective, or a combination of both. The diffraction gratings are formed on a surface of or at an interface inside the optical device, and two diffraction gratings may be formed on a single surface. The light is made to eventually converge on the exit surface of the optical device so that the optical device functions as a solid immersion device.

Abstract: An optical head which implements high recording density of a recording medium and which is miniaturized in size and improved in data transfer rate, a disk apparatus, and a method for manufacturing the optical head are provided. A laser beam is emitted from a semiconductor laser, the laser beam is collimated by the collimator lens to a collimated beam and reflected by a mirror, condensed by an condense lens, and incident to an incident surface of a transparent condensing medium. The condensed beam which was incident to the incident surface is refracted by the incident surface, the refracted beam is condensed on a condense surface, a beam spot is formed on the condense surface, and a near field wave leaks from a slit. The near field wave leaked from the slit propagates in a recording layer of a recording. The beam is served for recording/reproduction on the recording layer.

Abstract: An optical head apparatus is provided with a first laser element, a second laser element and a polarized beam splitter. The first laser element emits a laser beam having a first wavelength. The second laser element emits a laser beam having a second wavelength. The second wavelength may be equivalent to the first wavelength, alternatively, it may be different from the first wavelength. The polarized beam splitter enables the laser beams of the first and second laser elements to be simultaneously radiated to the recording layer of an optical disk. When information are recorded in the optical disk, the laser beams of the first and second laser elements are used at the same time. At least one of the laser elements emits a laser beam having such a wavelength as enables the recording layer of the optical disk to absorb the largest possible amount of energy.

Abstract: The present invention relates to an optical head, a magneto-optical head, and a disk apparatus, that have high light efficiency, can realize high-density recording medium and perform high-speed recording and reproduction, and can prevent erroneous record or erroneous reproduction, and a manufacturing method of the optical head. When a converged beam enters an incident surface of a transparent condensing medium, its refracted beam is condensed on a light-condensed surface and forms a light spot. Since leaking out to an aperture formed on an outer surface of the light-condensed surface of this light spot, near field light is scattered by a micro metal member. In addition, since, also in the micro metal member, plasmon resonance occurs by the irradiation of a laser beam, near field light leaks out therefrom. This near field light becomes propagation light and enters a recording medium of a disk, and recording into the recording medium is performed by this light.

Abstract: The present invention relates to a device for reading from or writing to optical recording media, which device has a scanning beam generation means, a focusing means and a photodetector comprising at least two detector zones and serving to receive zeroth- and first-order diffraction beams from the recording medium. The object of the invention is to obtain a reduction in interfering influences in a signal derived from signals of the photodetector, a signal such as, for example, a focus error signal or a track error signal. This object is achieved by virtue of the fact that a beam splitting means is provided, which splits a light spot falling onto the photodetector into two separate partial spots. The device is, for example, a CD or DVD player, but in particular a recording and reproduction device for so-called DVD-RAMs or similar optical recording media.

Abstract: It is an object of the present invention to provide an optical information storage device capable of performing stable information accessing at a high recording density, and an optical head, and the optical information storage device and the optical head of the present invention comprise: a light shielding body held in a position close to/in contact with a surface of a recording medium, and provided with a slit adapted to intersect a track of the recording medium by an angle &agr; of 45° or lower; condensing means for condensing a light emitted from a light source on the slit of the light shielding body; and moving means for moving the light S condensed on the slit by the condensing means along the slit.

Abstract: An optical pickup unit includes a light source emitting a light beam, an objective lens focusing the light beam onto an information recording medium, a light detection part receiving the light beam reflected from the information recording medium, and a light blocking part selectively blocking a part of the light beam with respect to a radial direction. The light blocking part is provided in an optical path of the light beam centered on an optical axis.

Abstract: In a recording apparatus for reproducing information recorded on a recording medium by utilizing near-field light, the recording apparatus realizes reliable information reproduction with a simple structure. Illumination light 20 is illuminated to the recording medium 10 to create near-field light on a surface of the recording medium 10. The created near-field light is scattered by a microscopic aperture 12 formed in the aperture element 11 so that scattering light (propagation light) thereof is detected to create a reproduced signal. Derived from the created reproduced light a distance control signal representative of a distance between the microscopic aperture 12 and the recording medium 10. Based on the distance control signal, the aperture element 11 is controlled in position. Due to this, the microscopic aperture 12 is brought into proximity to the recording medium 10.

Abstract: An optical head comprises a photodetector 8 having divided photosensitive areas to detect light 13 reflected from an optical disk 7, means 10, 11, 12 for obtaining tracking error signal by operating signals from the photosensitive areas. The photodetector 8 has a first division line 9a parallel to an information track on the optical disk and second and third division lines 9b, 9c perpendicular to the first division line 9f and symmetrical to the optical axis. Further, a light-shielding area 8i is provided for shielding a part of the reflected light between the division lines 9b and 9c. The signals are operated to reduce offset of the tracking error signal due to a shift of object lens and a tilt of the optical disk. Accordingly, the optical head of the present invention has a small offset of tracking error signal with a simple structure.

Abstract: A device for reading from or writing to optical recording media comprising a scanning beam generation means, a focusing means and a photodetector comprising at least two detector zones and serving to receive zeroth- and first-order diffraction beams from the recording medium. The object of the invention is to obtain a reduction in interfering influences in a signal derived from signals of the photodetector, a signal such as, for example, a focus error signal or a track error signal. This object is achieved by virtue of the fact that a beam splitting means is provided, which splits a light spot falling onto the photodetector into two separate partial spots. The device is, for example, a CD or DVD player, but in particular a recording and reproduction device for so-called DVD-RAMs or similar optical recording media.

Abstract: The present invention relates to a device for the reading and/or writing of optical recording media [(AT)] of various structures, which device operates with a single objective lens [(OL)]. The invention proposes to use a diaphragm varying in diameter, in particular a polarizing filter arranged in the optical path in order to adapt the aperture to each type of optical recording medium [(AT)] used. The wavefront can be corrected using a divergent lens [(SL)] which can also be positioned in the beam path. The Diaphragm formed by the polarizing filter PF is linked to the objective lens [(OL)]. The field of application of the invention relates to, in particular, devices for reading and/or writing optical recording media [(AT)] of various structure such as compact discs and digital video discs.

Abstract: Light emitted from a light source is converged by an objective lens, and an auxiliary lens increases an effective numerical aperture to project the light on a recording medium. The temperature of a recording mark recording on the recording medium is increased by the projection of the light, and saturation magnetization which is in accordance with the information is generated, thus generating magnetic flux. There is a reproducing magnetic layer, which is provided on the auxiliary lens. Magnetization generated on the reproducing magnetic layer has an effect on the polarization direction of the reflected light at the reproducing magnetic layer. Reflected light from the reproducing magnetic layer reaches a photodetector to generate a reproduced signal.

Abstract: The optical information recording and reproducing apparatus comprises a light source for emitting a light beam, an objective lens for converging the light beam emitted from the light source to an information recording medium, and a light detector for detecting the light beam reflected from the information recording medium. The information bits are recorded into a recording member of the information recording medium in a three-dimensional arrangement by using a change in optical constant of the recording member. Furthermore, a thickness of the recording member is larger than a wavelength of the light beam and the information bits are sequentially recorded into the recording member 11b in a three-dimensional arrangement in such an order that a converging light beam from the objective lens does not pass through information bits that have already been recorded.

Abstract: An optical storage unit which uses a light beam to record information on and/or reproduce information from a recording medium. The recording medium is provided with at least one land and at least one groove, and information is recorded in plural sectors in each of the land(s) and groove(s). The optical storage unit includes an optical phase adjuster for adjusting a phase of a polarization component of the light beam reflected from the recording medium based on a track type determination of a target address. An optical pickup is provided for reproducing information recorded on the recording medium using the phase-adjusted polarization component of the light beam.

Abstract: An optical pick-up device for use in an information recording/reproducing apparatus for recording and/or reproducing information on an optical record medium. The device comprises a semiconductor laser, an information record medium having plural record layers laminated thereon, an outward route system for irradiating laser light from the semiconductor laser onto the information record medium through a beam splitter and objective lens, and an inward route system having a light detector for receiving the light reflected from the information record medium and transmitted through the objective lens, the beam splitter and pin-hole. The pin-hole has a radius, which is decided in such a manner that an expression Vp=2&pgr;r/(&lgr;/NA) satisfies following condition 3≦Vp≧6, wherein r is radius of the pin-hole, NA is lens aperture of the detection system, &lgr; is wave length of the laser light, and Vp is radius of Airy disc.

Abstract: An optical pickup apparatus and method which can selectively perform optical pickup with respect to at least two types of optical disks, on which information recording surfaces are formed, having a different thickness. The optical pickup apparatus includes an optical path alteration unit for altering a path of a light beam so that the light beam emitted from each light source proceeds toward the disk, a numerical aperture adjustment unit, including an annular shielding region which is disposed concentrically about an optical path axis between the optical path alteration unit and the disk supporter, for providing different numerical apertures according to a characteristic of a light beam to be incident; and an objective lens for respectively focusing the light beams having passed through the numerical aperture adjustment unit on the information recording surfaces of the disks to form a beam spot. Accordingly, the apparatus provides a relatively simple structure thereby reducing fabricating cost.

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 disc can increase an information storage capacity by reducing the track width of the optical disc. An optical pickup for a narrow track optical disc includes an optical shielding portion having a desired light intensity distribution with respect to a target track and the tracks adjacent to the target track on the optical disc. The optical shielding portion is disposed on the optical path between the light source and the optical disc and shields part of the light beam proceeding toward the optical disc, to provide a light intensity distribution such that only the beam spot focused on the target track is used to detect information stored in the target track. Thus, the beam spot focused on the target track of the optical disc has track crosstalk having a magnitude by which information can be read from the target track. The optical pickup can provide an excellent performance even in the case that the optical pickup is adapted in a high-definition DVD to be commercialized in the future.

Abstract: The present invention provides an optical disc provided with a watermark inside, which is visible with naked eyes from a reproduction side of the optical disc, and the producing method and the production apparatus thereof. The optical disc comprises a transparent substrate having an information signal recorded surface, a reflective layer formed on the information signal recorded surface thereof, an adhesive layer formed on the reflective layer, a mask layer on the adhesive layer and a transparent dummy substrate on the mask layer stacked in this order. The adhesive layer is made of an adhesive of which curing speed is changed according to a controlled amount of radiation of ultraviolet rays. The watermark is recorded in the optical disc by irradiating the ultraviolet rays on the adhesive through the mask layer provided with light shielding members to cause the adhesive to be cured by controlling a curing speed of the adhesive corresponding to existence or nonexistence of the light shielding members.

Abstract: An optical head comprises a photodetector 8 having divided photosensitive areas to detect light 13 reflected from an optical disk 7, means 10, 11, 12 for obtaining track error signal by operating signals from the photosensitive areas. The photodetector 8 has a first division line 9a parallel to an information track on the optical disk and second and third division lines 9b, 9c perpendicular to the first division line 9f and symmetrical to the optical axis. Further, a light-shielding area 8i is provided for shielding a part of the reflected light between the division lines 9b and 9c. The signals are operated to reduce offset of the tracking error signal due to a shift of object lens and a tilt of the optical disk. Accordingly, the optical head of the present invention has a small offset of tracking error signal with a simple structure.

Abstract: A recording/reproducing apparatus includes an optical pickup device having an optical phase plate which is compatible with optical recording mediums having different thicknesses, and an optical signal processing device processes information read from the optical recording mediums and processes information to be recorded thereon using the optical pickup device.

Abstract: An information encoding method in which, if desired to reproduce an information recording medium recorded in accordance with an encoding method for a new standard by a reproducing device adapted for coping with the encoding method for an old standard, the user is apprised of the fact that part of the recorded signals cannot be reproduced by a reproducing device adapted for coping only with the encoding method for the old standard. For encoding the information in accordance with the encoding method for the new standard, the message information in addresses 200000 to 239999 is encoded simultaneously. The message information has been encoded in accordance with the encoding method for the old standard and which can be reproduced by the reproducing device adapted for coping with the encoding method for the old standard.

Abstract: An optical tracking system is presented which aligns a recording head with a magnetic tape. The system relies on an optically detectable servo track on the back of the tape. The servo track is formed by repeatedly engraving, at spaced intervals, three colinear marks perpendicular to the length of the tape. Laser light reflects off the marks, and passes through a ball lens that directs the reflected light on to separate light detectors, one for each mark. By recording characteristics of the reflected light, the detectors transmit information to the system that permits the recording head to be properly aligned with the tape.

Abstract: Optical storage systems based on air-bearing-suspended optical heads in a near-field configuration. Such a system comprises an optical head for reading and writing data and a head positioning system, an optics module including beam relay optics and signal detectors, and a medium holding and loading module to hold an optical medium. An electronic control system is also provided to control the system operation. The optical head includes a near-field lens with a high index of refraction and in a near-field configuration in which the near-field lens has a numerical aperture greater than unity when the spacing between an exit facet of the optical head and a recording layer in the optical medium is a fraction of one wavelength of optical beam.

Abstract: An optical pickup using a light-emitting diode (LED), which is capable of forming a light spot of an appropriate size for high-density recording/reproduction. The optical pickup includes a light-emitting diode (LED) to generate and emit light; a condensing unit to condense the light emitted from the LED; an optical filter to selectively transmit a predetermined wavelength of the light emitted from the LED; a spatial filter having a pin-hole, to limit a transmission range of the light condensed by the condensing unit; and a collimating lens to condense the divergent light passed through the spatial filter to form a parallel light. The parallel light is directed by a beam splitter toward an objective lens which focuses the parallel light on an optical disk. The light reflected from the optical disk is received by a photodetector.

Abstract: The present invention preferably includes a shading band which is suitably electro-optically created in a grid pattern formed through a photolithographic process, so consequently, the electro optic shading band is easily eliminated or re-configured dynamically to substantially eliminate its shading effect for lower density optical disks which do not experience substantial adjacent track crosstalk (ATC). Eliminating or reconfiguring the shading effect also helps in accommodating different media types and generations and those of different manufacturers. Moreover, the electro-optic shading band suitably adjusts the amplitude, phase, frequency, polarization and/or the like of the light beam to compensate for possible material property variations, defects, misalignments or other imperfections in the reading process. The present electro-optic shading band substantially restricts or alters any portion of a light beam containing signal information read from an optical disk.

Abstract: An optical surface measurement device is disclosed. A beam of light is focused through an optical system into a spot on a sample and the optical system collects light reflected and scattered by the sample forming an image of the illuminated part of the sample on a focus detector. A control system responds to the focus detector moving the optical system to keep the spot in focus on the sample as the sample is tracked past the apparatus. The optical system may be moved as a whole or one of the lenses therein may be moved with respect to the others. Alternatively the movable lens may be set to oscillate and its position is recorded each time focus is achieved. The focus detector has two outputs one of which is larger than the other when the surface of the sample is above the plane focussed by the optical system and the other being larger when it is below. The control system uses both sum and difference signals calculated from those outputs to discriminate the point of focus.