Patent application number | Description | Published |
20100020670 | OPTICAL PICKUP DEVICE, OPTICAL DISC DEVICE, AND DIFFRACTION GRATING - An optical pickup device and an optical recording/reproduction device are provided that can suppress a tracking error signal offset generated in the boundary between an unrecorded area and a recorded area. A three-beam diffraction grating is divided into two areas. A division line that divides the diffraction grating into two areas has a step in the direction almost vertical to a groove period structure, and the part of the division line in the step has a staircase shape. The phase difference in the groove period structures between one area and the other area, separated by the division line, is about 180 degrees. | 01-28-2010 |
20100061202 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - In the optical pickup device, while reflection light reflected from the optical multi-layer disc is divided into a plurality of regions so as to produce a plurality of divided optical beams, the divided optical beams are focused onto different positions on a photodetector, and a focus error signal is detected by employing a plurality of the divided optical beams by utilizing the knife edge method, and further, a tracking error signal is detected by employing a plurality of the divided optical beams. Furthermore, the dividing regions of the optical beam and light receiving parts are arranged in such a manner that stray light derived from other layers of the optical disc is not entered to a servo signal-purpose light receiving part of the photodetector when the divided optical beam is focused onto a target layer of the optical disc. | 03-11-2010 |
20100226229 | OPTICAL PICKUP DEVICE - In a multilayer disc has an increased number of recording layers) spaced by spacing from each other, a generation interval between focus error (FE) signals detected from the respective recording layers becomes small. This causes mutual interference between the FE signals and a resulting undesired offset and the like in the signals, leading to a significantly deteriorated quality of the FE signals. To avoid this, in an optical pickup device according to the present invention, detection surfaces are newly added at positions adjacent to the FE signal detection surfaces, a predetermined detection signal obtained from the newly-added detection surfaces is multiplied by a predetermined coefficient value depending on the spacing between the recording layers, and the multiplied signal is subtracted from the original FE signal. As a result, mutual interference between the FE signals can be remarkably reduced. | 09-09-2010 |
20110013502 | OPTICAL PICK-UP AND OPTICAL INFORMATION RECORDING AND REPRODUCING APPARATUS - An optical pick-up which permits the relative position of a diffracting optical element and a photodetector to be adjusted by feedback control with signals which are generated when more than one kind of diffracted light differing in order is received, the diffracted light occurring as the reflected light from the optical disc is divided and diffracted by the diffracting optical element having multiple regions. The photodetector which detects the light beam passing through the central region of the diffracting optical element and generates RF signals is juxtaposed with sub-photodetectors, so that they receive reflected stray light from out-of-focus layers and perform computation to calculate the reflected stray light component which the RF signal detector receives, thereby detecting only the component of signals of the reflected light from a target layer. | 01-20-2011 |
20110063956 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - An optical pickup device includes a polarization diffraction grating to diverge an optical beam reflected from an optical disc and an optical detector to receive the optical beam diverged by the polarization diffraction grating, a polarization of 0 order diffracted light diffracted through the polarization diffraction grating is substantially perpendicular to that of a +1 order diffracted light diffracted therethrough, and a polarization filter having a plurality of domains is mounted between the polarization diffraction grating and the optical detector. | 03-17-2011 |
20110063967 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS USING THE SAME - A diffractive optical element having a diffraction region for diffracting a part of a luminous flux is mounted and an unwanted luminous flux generated in a multi-layer optical disc is suppressed from entering a photodetector surface. Using the above-described structure, fluctuation of a tracking error signal can be suppressed from being caused by the unwanted luminous flux and preferable recording or reproduction quality can be obtained also in the multi-layer optical disc. | 03-17-2011 |
20110211437 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - An optical pickup device including: a laser diode for emitting laser light; an objective lens which irradiates an optical beam emitted from the laser diode; an actuator which displaces the objective lens in a radius direction of the optical disc; a grating for branches an optical beam reflected by an information recording layer into plural regions; and one photodetector having plural light receiving parts for receiving the branched optical beams, wherein the photodetector has a first light receiving part which detects zero-th order grating diffracted light and plural second light receiving parts which detecting grating diffracted light having an order not less than that of ±first order grating diffracted light; a detected signal of the zero-th order grating diffracted light is defined as a reproduction signal; and a detected signal of the grating diffracted light is defined as a signal for servo controlling. | 09-01-2011 |
20110299375 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - In a small-sized optical pickup device for enabling to obtain a stable servo-signal, as well as, a focus error signal and a tracking error signal, without receiving ill influences of stray lights from other layers, when recording/reproducing a multi-layer optical disc, a reflection light from the multi-layer optical disc is divided into plural numbers of regions by a diffraction grating. And, it is divided into at least four (4) regions, by a division line in the tangential direction of the optical disc and a division line in the radial direction thereof. Light receiving parts, for detecting either one of grating diffraction lights, i.e., a +1 | 12-08-2011 |
20120002532 | Optical Pickup Device And Optical Disc Apparatus - An optical pickup device includes a semiconductor laser for emitting laser light, an objective lens for irradiating luminous flux emitted from the semiconductor laser to an optical disc, a branching element having a plurality of regions for branching luminous flux reflected from the optical disc to a plurality of fluxes, and a photodetector having a plurality of light receiving parts which receive luminous flux branched by said branching element. Luminous flux which enters at least two regions arrayed along a direction which is made substantially coincident with a tangential direction of the optical disc in regard to substantially a center of the branching element is arranged along a direction which is made substantially coincident with a radial direction of the optical disc on the photodetector. | 01-05-2012 |
20120057445 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - For obtaining stable servo-signals without receiving ill influences of stray lights from other layers, on both a focus error signal and a tracking error signal, when recording/reproducing a multi-layer optical disc having small gap between layers thereof, a light beam is divided with using a first and a second diffraction gratings. The first diffraction grating is a polarization diffraction grating, and is mounted on an actuator. The second diffraction grating is disposed on a fixed portion. The first diffraction grating has a first region having a center of a light beam and other(s), and among signal lights reflecting from the disc, the light beam entering into the first region is diffracted, and the light beam entering into the second region transmits therethrough. The second diffraction grating transmits the light beam diffracting on the first region of the polarization diffraction grating therethrough, while diffracting the light beam diffracting on the second region. | 03-08-2012 |
20120213046 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - In an optical pickup device for a simple optical system, a light beam emitted from a laser diode is split into first and second light beams by a polarized beam splitter, an optical disc is irradiated with the first light beam to obtain signal light, and the second beam is reflected by a reflection element to obtain reference light. Light beams of the signal light and the reference light are synthesized into one light beam, the synthesized light beam is separated into four light beams by a phase difference forming unit including a grating, a divided wave plate and a polarization grating, and different phase differences are afforded to the signal light and the reference light in each light beam. The four light beams are detected by one detector to generate the reproduction signal. | 08-23-2012 |
20120272254 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - Stable performance of additional recording and erasing and rewriting operations is allowed regardless of a change in inclination of a guide layer separable optical disc. An optical pickup device includes an angle variable reflection mirror (an optical axis angle variable element) which changes directions of optical axes of first and second light beams when the first light beam for recording or reproduction and the second light beam for servo signal detection are emitted from laser diodes and incident upon the optical disc through an objective lens. When additional recording is performed on the optical disc, the optical axis angle of the angle variable reflection mirror is adjusted such that a tracking error signal detected from a record layer with the first light beam is reduced to almost zero while tracking control is being performed on a guide layer with the second light beam. | 10-25-2012 |
20120314556 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - An optical pickup device includes a laser diode for emitting a laser beam, an objective lens for collecting the light beam emitted from the laser diode and irradiating an optical disc with the collected light beam, a diffraction element for making the light beam reflected from the optical disc diverge, and a detector having a plurality of detection parts for receiving the diverging light beams caused by the diffraction element. The diffraction element has first, second, and third divided areas, wherein a 0th-order diffracted light from the first divided area, the second divided area, and the third divided area is detected by at least four divided detection parts; and at least two detection parts for detecting the light beam diffracted at the first divided area into first or higher diffraction order are aligned in a direction generally perpendicular to the track of the optical disc. | 12-13-2012 |
20130003512 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS EQUIPPED WITH THE SAME - An optical pickup device includes a light source for emitting a light beam, an objective lens for collecting the light beam which is emitted and for irradiating an optical disc with the collected light beam, a diffraction element with a plurality of areas for dividing the light beam which is reflected from the optical disc, a detector with a plurality of detection parts for receiving the light beam which is made to diverge by the diffraction element, and a branching mirror for making the light beam branch into an optical path from the light source to the objective lens and an optical path from the objective lens to the detector. The diffraction element gives an aberration to the light beam diffracted at a specified area. | 01-03-2013 |
20130003517 | OPTICAL PICKUP DEVICE, OPTICAL DISC APPARATUS, AND INFORMATION RECORDING METHOD - An optical pickup device and an optical disc apparatus including the optical pickup device are provided which can obtain a stable servo signal in the recording/reproduction of an information recording medium inexpensively fabricated with multiple information recording surfaces. The optical pickup device includes: a laser diode that emits a light beam; a grating that splits the light beam into at least a main beam, a first sub beam, and a second sub beam; and an objective lens that condenses the light beams and forms at least three spots on an optical disc, wherein the spot of the first sub beam and the spot of the second sub beam are located inside or outside the spot of the main beam on the optical disc, and a tracking error signal is generated from signals obtained by detecting the first sub beam and the second sub beam. | 01-03-2013 |
20130229898 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS FOR RECORDING AND REPRODUCING INFORMATION ON AND FROM OPTICAL DISC PLURALITY OF RECORDING LAYERS - Provided is an optical pickup device that suppresses a fluctuation of a tracking error signal caused by stray light when recording/reproducing information on/from an optical disc including a plurality of recording layers and attains size reduction. It includes a laser diode emitting laser light of about 405 nm in wavelength, an objective lens irradiating the optical disc with an optical beam emitted from the laser diode and having a numerical aperture of about 0.85, and a detector including a detection part receiving the optical beam reflected from the optical disc. An optical magnification from the optical disc to the detector is set within a range from about 10× to 15×. | 09-05-2013 |
Patent application number | Description | Published |
20080219119 | Optical pickup and optical disc unit - Provided is an optical pickup which can eliminate a problem of causing a focus error signal and a tracking error signal to fluctuate due to interference of a signal light beam with a return light beam from another recording surface of a multi-layer optical disc during reproduction, | 09-11-2008 |
20090168618 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - An optical pickup device divides signal light so as to detect the divided signal light. A photodetector contains two regions constructed of a region “A” and another region “B.” Among diffracted light diffracted from a track on an optical disc, only zeroth-order diffraction light enters to the region “A” of the photodetector, whereas the zeroth-order diffraction light, + first-order diffraction light, and − first-order diffraction light enter to the region “B” thereof. A focusing error signal from the photodetector is produced based upon a signal detected by the photodetector, whereas a tracking error signal is produced based upon signals detected from the regions “A” and “B.” A stable focusing error signal and a stable tracking error signal can be detected with respect to a dual layer optical disc, or a multi layer optical disc. | 07-02-2009 |
20090185463 | DIFFRACTION GRATING, OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - A pickup device splits and detects a light beam reflected from a disc with the use of a grating. The grating has first to six areas, wherein the first area and the second area, the third area and the fifth area, and the fourth area and the sixth area are arranged in point symmetry with respect to the center of the grating, respectively. The first area is interposed between the fourth area and the fifth area and the second area is interposed between the third area and the sixth area. Further, the centers of the first area and the second area are arranged to be spaced by a distance d in a direction perpendicular to the displacement direction of the optical pickup device. Even though the center of an optical disc is not located on a straight line in the displacement direction of the optical pickup device, objective lens can obtain a stable servo signal. | 07-23-2009 |
20090185471 | Optical Pickup Device and Optical Disc Apparatus - In an optical pickup device, an optical reflection beam from a multi-layer optical disc is divided into a plurality of areas, divided optical fluxes focus upon different positions on a photodetector, a focusing error signal is detected by using a plurality of divided optical fluxes by a knife edge method, and a tracking error signal is detected by using a plurality of divided optical fluxes. The optical flux divided areas and light receiving parts are disposed in such a manner that in an in-focus state of a target layer, stray light from another layer does not enter servo signal light receiving parts of the photodetector. It is therefore possible to obtain stable servo signals including both the focusing error signal and tracking error signal during recording/reproducing a multi-layer optical disc, without being influenced by stray light from another layer. | 07-23-2009 |
20090268584 | Optical Pickup Apparatus And Optical Disc Apparatus Using Same - An optical pickup apparatus is provided with a dividing element having a plurality of regions. The dividing element is capable of dividing a light flux reflected by the optical disc into a plurality of light fluxes having different outgoing directions. Each region of the dividing element and light receiving parts of a light detector are structured such that when a target information recording layer of the optical disc is brought into focus, a light flux reflected from the target information recording layer is focused on the light receiving parts of the light detector, and a light flux reflected from other information recording layer than the target information recording layer is not irradiated onto the light receiving parts of the light detector. | 10-29-2009 |
20110214138 | Diffraction Grating, Optical Pickup Device And Optical Disc Apparatus - An optical pickup device includes a semiconductor laser which emits a light beam, first and second objective lenses which focus the light beam onto a first and second optical disc, respectively, a grating which branches a light beam reflected from the second optical disc, an optical detector having a plurality of light receiving parts, which receives light beams branched by the grating, and an actuator which displaces the first and second objective lenses in a radial direction of the first optical disc and the second optical disc. The grating has a first area on which a 0-order diffraction light beam and a +1-order diffraction light beam upon reflection at the second optical disc enter, and a second area on which a 0-order diffraction light beam and a −1-order diffraction light beam upon diffraction through the second optical disc enter. | 09-01-2011 |
20130016599 | OPTICAL PICKUP DEVICE AND OPTICAL DISC APPARATUS - Optical pickup device including: semiconductor laser diode emitting optical flux; objective lens converging flux emitted from the diode and radiating flux to an optical disc; diffraction grating branching an optical flux reflected from the disc; and a photodetector receiving flux branched by the grating and has a plurality of light receiving parts, wherein: the grating has areas A, B and C; among diffracted beams diffracted by a track of the optical disc, only a 0-th order diffracted beam becomes incident upon area A, and 0-th and ±1-st order diffracted beams become incident upon area B; the photodetector detects a reproduction signal from optical fluxes diffracted in areas A, B and C; the plurality of light receiving parts which detect the +1-st order diffracted beam or the −1-st diffracted beam diffracted in area A are aligned in a direction substantially perpendicular or parallel to a track direction of the disc. | 01-17-2013 |
Patent application number | Description | Published |
20130322224 | HOLOGRAPHIC OPTICAL PICKUP DEVICE, OPTICAL INFORMATION RECORDING AND REPRODUCING DEVICE, AND METHOD OF RECORDING AND REPRODUCING OPTICAL INFORMATION - A holographic optical pickup device includes an image sensor that detects a diffracted beam generated from the region to be reproduced when irradiating an optical information recording medium with a reference beam, and sets the detected diffraction beam as a reproduction signal, and a photodetector that is different from the image sensor, which detects the diffracted beam generated from a recorded region in the recording medium when irradiating the recording medium with the reference beam. A light receiver of the photodetector is divided into a plurality of light receiving planes so as to generate the position error signal indicating the positional shifting of the region to be recorded/reproduced of the recording medium with respect to the objective lens from a differential signal of a plurality of signals derived from the respective light receiving planes. | 12-05-2013 |
20130322225 | HOLOGRAPHIC OPTICAL PICKUP DEVICE, OPTICAL INFORMATION RECORDING AND REPRODUCING DEVICE, AND METHOD OF RECORDING AND REPRODUCING OPTICAL INFORMATION - An optical pickup device includes a galvanometer mirror that changes an incident angle of a reference beam to an optical information recording medium, an image sensor that detects a diffracted beam from a region to be reproduced upon irradiation of the recording medium with the reference beam, and sets the detected diffracted beam to a reproduction signal, and a photodetector that detects the diffracted beam generated from a plurality of recorded regions upon irradiation of the recording medium with the reference beam. The photodetector includes a plurality of light receivers, and generates an angular error signal indicating positional shifting of the incident angle of the reference beam from a differential signal of a plurality of signals derived from the respective light receivers so as to control the angle of the galvanometer mirror. | 12-05-2013 |
20130336099 | HOLOGRAPHIC OPTICAL PICKUP DEVICE, OPTICAL INFORMATION RECORDING AND REPRODUCING DEVICE, AND METHOD OF REPRODUCING OPTICAL INFORMATION - A holographic optical pickup device includes an optical axis split element for splitting a reference beam into two light beams in different propagation directions having polarized states substantially orthogonal to each other, angular variable elements for changing incident angle of the reference beam for irradiating an optical information recording medium, an image sensor for detecting a diffracted beam generated from a recorded region upon irradiation of the optical information recording medium with the reference beam to form a reproduction signal, and photodetectors for detecting the diffracted beam generated from the recorded region upon irradiation of the optical information recording medium with the reference beam. An angular error signal is generated for controlling the angular variable element using signals detected by the photodetectors. | 12-19-2013 |
20130343172 | OPTICAL PICKUP DEVICE, OPTICAL INFORMATION RECORDING DEVICE, OPTICAL INFORMATION RECORDING METHOD, AND OPTICAL INFORMATION RECORDING MEDIUM - There is disclosed an optical information recording device using a multilayer optical disc as a recording medium, in which the number of components of the device is reduced. The optical disc has, e.g., one recording layer with prepits and a plurality of recording layer without prepits. An optical pickup included in the information recording device includes a switchable lens element to focus laser beams to be applied to the multilayer optical disc onto two adjoining recording layers. A tracking error signal offset obtained for a recording layer with prepits is stored. Recording an information signal into a recording layer from which a tracking error signal cannot be detected is performed, while maintaining the accuracy of positioning on track with respect to the prepits based on the stored offset. When reading out an information signal, tracking control based on the prepits of recorded information signals is exerted. | 12-26-2013 |