Abstract: A recording device of the present disclosure includes a light source, an objective lens, a beam splitter, an optical element, a detector and an operation circuit. The optical element divides a light beam into a first main region, a second main region, a first main end region, a second main end region, a first sub-region, and a second sub-region. The operation circuit generates a main signal in which a first main end region signal is multiplied by a coefficient a and added to the first main region signal, and a second main signal in which a second main end region signal is multiplied by the coefficient ? and added to the second main region signal.

Abstract: An optical disc information device is an optical disc information device for reproducing and/or recording information with respect to an optical disc including a track in the form of a groove, and capable of recording information in a land portion and in a groove portion of the groove. The optical disc information device includes a laser light source, an objective lens, a transmittance limiting element, a dividing element, a light detector, a central amplifier, at least two end amplifiers, a gain controller, an adder, a reproduction signal processor, and a control signal processor. The transmittance limiting element includes a first central region, and at least two first end regions which interpose the first central region therebetween, and attenuates light passing through at least the first end regions out of a light flux emitted from the laser light source more strongly than light passing through the first central region.

Abstract: A recording device of the present disclosure includes a light source, an objective lens, a beam splitter, an optical element, a detector and an operation circuit. The optical element divides a light beam into a first main region, a second main region, a first main end region, a second main end region, a first sub-region, and a second sub-region. The operation circuit generates a main signal in which a first main end region signal is multiplied by a coefficient a and added to the first main region signal, and a second main signal in which a second main end region signal is multiplied by the coefficient ? and added to the second main region signal.

Abstract: An RF hologram is divided in a direction perpendicular to a tangent line of an information track of an information recording surface of an optical disc, and includes a central region including an optical axis of laser light as well as a first end portion region and a second end portion region which sandwich the central region, the central region is formed by a binary diffraction grating and generates ±1 order diffracted light, the first end portion region is formed by a blazed diffraction grating and generates first +1 order diffracted light, the second end portion region is formed by a blazed diffraction grating and generates second +1 order diffracted light, and an RF light receiving element receives both the ±1 order diffracted light, the first +1 order diffracted light, and the second +1 order diffracted light.

Abstract: An RF hologram is divided in a direction perpendicular to a tangent line of an information track of an information recording surface of an optical disc, and includes a central region including an optical axis of laser light as well as a first end portion region and a second end portion region which sandwich the central region, the central region is formed by a binary diffraction grating and generates ±1 order diffracted light, the first end portion region is formed by a blazed diffraction grating and generates first +1 order diffracted light, the second end portion region is formed by a blazed diffraction grating and generates second +1 order diffracted light, and an RF light receiving element receives both the ±1 order diffracted light, the first +1 order diffracted light, and the second +1 order diffracted light.

Abstract: An optical disc information device is an optical disc information device for reproducing and/or recording information with respect to an optical disc including a track in the form of a groove, and capable of recording information in a land portion and in a groove portion of the groove. The optical disc information device includes a laser light source, an objective lens, a transmittance limiting element, a dividing element, a light detector, a central amplifier, at least two end amplifiers, a gain controller, an adder, a reproduction signal processor, and a control signal processor. The transmittance limiting element includes a first central region, and at least two first end regions which interpose the first central region therebetween, and attenuates light passing through at least the first end regions out of a light flux emitted from the laser light source more strongly than light passing through the first central region.

Abstract: An optical disk information device includes a laser light source that emits a luminous flux with a wavelength ?, an objective lens having a numerical aperture NA, a splitting element, a photodetector, a central portion amplifier, at least two end portion amplifiers, an adder, a control signal processing section having a tracking switcher that inverts a polarity of a tracking control signal depending on whether a track scanned by a condensing spot corresponds to a land portion or a groove portion, and a gain controller that, when the polarity of the tracking control signal is inverted, switches gains of the central portion amplifier and the end portion amplifiers and sets the gain of the central portion amplifier substantially lower than the gain of at least one of the end portion amplifiers so as to reduce crosstalk from adjacent tracks in the optical disk.

Abstract: An optical pickup device includes a single objective lens that focuses a light beam to irradiate an optical disk, and an objective lens actuator that drives the objective lens. The objective lens actuator includes a lens holder that holds the objective lens. Two gaps (Ga, Gb) are formed between the lens holder and the objective lens. In an xy plane in which the center of the objective lens is defined as an origin, the tracking direction is defined as an y axis, and the tangential direction of tracks of the optical disk is defined as an x axis, the gap (Ga) is positioned at least in the first quadrant of the xy plane, and the gap (Gb) is positioned at least in the third quadrant of the xy plane.

Abstract: An optical disk information device includes a laser light source that emits a luminous flux with a wavelength ?, an objective lens having a numerical aperture NA, a splitting element, a photodetector, a central portion amplifier, at least two end portion amplifiers, an adder, a control signal processing section having as tracking switcher that inverts a polarity of a tracking control signal depending on whether a track scanned by a condensing spot corresponds to a land portion or a groove portion, and a gain controller that, when the polarity of the tracking control signal is inverted, switches gains of the central portion amplifier and the end portion amplifiers and sets the gain of the central portion amplifier substantially lower than the gain of at least one of the end portion amplifiers so as to reduce crosstalk from adjacent tracks in the optical disk. When a groove pitch in the optical disk is denoted by Gp, (Gp/2)<(1.2•?)/(2•NA) is satisfied.

Abstract: A ratio Xm of an information item recorded on an adjacent track relative to an information item recorded on a main track included in a first signal obtained from a first light flux having passed through a center region (6c) is different from ratios Xs1 and Xs2 of the information items recorded on the adjacent track relative to the information items recorded on the main track included in second and third signals obtained from second and third light fluxes having passed through first and second end regions (6r, 6l), and a ratio of respective gains of a first waveform equalizer (80c), a second waveform equalizer (80r), and a third waveform equalizer (80l) is determined so as to cancel the information item recorded on the adjacent track in each of frequency components of the first signal, the second signal, and the third signal.

Abstract: A ratio Xm of an information item recorded on an adjacent track relative to an information item recorded on a main track included in a first signal obtained from a first light flux having passed through a center region (6c) is different from ratios Xs1 and Xs2 of the information items recorded on the adjacent track relative to the information items recorded on the main track included in second and third signals obtained from second and third light fluxes having passed through first and second end regions (6r, 6l), and a ratio of respective gains of a first waveform equalizer (80c), a second waveform equalizer (80r), and a third waveform equalizer (80l) is determined so as to cancel the information item recorded on the adjacent track in each of frequency components of the first signal, the second signal, and the third signal.

Abstract: A photodetector outputs a first signal and a second signal corresponding to light amounts of the received first light flux and the received second light flux, first and second low band extraction circuits extract low band components of the first signal and the second signal, first and second high band extraction circuits extract high band components of the first signal and the second signal, a differential circuit calculates a difference signal between a high band component difference signal as a difference between the high band component of the first signal and the high band component of the second signal and a low band component difference signal as a difference between the low band component of the first signal and the low band component of the second signal, and a control signal processing section generates a tilt control signal based on the calculated difference signal.

Abstract: An optical pickup device includes a single objective lens (1) that focuses a light beam to irradiate an optical disk, and an objective lens actuator (29) that drives the objective lens (1). The objective lens actuator (29) includes a lens holder (2) that holds the objective lens (1). Two gaps (Ga, Gb) are formed between the lens holder (2) and the objective lens (1). In an xy plane in which the center of the objective lens (1) is defined as an origin, the tracking direction is defined as an y axis, and the tangential direction of tracks of the optical disk is defined as an x axis, the gap (Ga) is positioned at least in the first quadrant of the xy plane, and the gap (Gb) is positioned at least in the third quadrant of the xy plane.

Abstract: An objective lens unit according to the present invention includes a first objective lens 41; and a first lens holder 2 for supporting the first objective lens 41. The first lens holder 2 is formed of a material which transmits ultraviolet. Preferably, the first lens holder 2 includes a through-hole, having first and second openings 2a and 2b, through which light incident on the first objective lens 41 passes, and an opening limiting section 3 provided along a circumferential direction of the through-hole and projecting toward a central axis of the through-hole. The first objective lens 41 is supported so as to block the first opening 2b. The opening limiting section 3 guides light incident thereon from the second opening 2a in a direction away from an optical axis of the first objective lens.

Abstract: When performing a read or write operation on an optical disc with information storage layers, this compatible optical head with a two-focus lens can reduce interference caused by an unnecessary diffracted light reflected from a non-target layer and not contributing to reading or writing. The head reads and/or writes information from/on storage media, including first and second media with different protective substrate thicknesses, by irradiating a given one with a laser beam and includes: a diffraction element that diffracts the beam to produce diffracted light of multiple orders; an objective lens for converging nth and mth order ones of the light on the respective storage layers of the first and second media; a photodetector that receives the beam reflected from the medium and condensed; and a light shielding portion for preventing a portion of the beam reflected from the storage layer of the second medium and including its optical axis from reaching the photodetector.

Abstract: An optical disk driving apparatus includes an optical head device having a laser light source, a converging optical system converging a light beam emitted by the laser light source onto an optical disk, a photo detector receiving reflected light reflected by the optical disk, and an aberration correcting optical system controlling aberration of the converging optical system; a motor rotating the optical disk; and a control section receiving a signal from the photo detector, wherein the converging optical system has an objective lens formed using resin as a main material, the aberration correcting optical system has a spherical aberration correcting element correcting spherical aberration, and the control section evaluates quality of a reproduction signal for information in the optical disk by using the reflected light received by the photo detector, and utilizes a result of the evaluation to perform closed loop control on the spherical aberration correcting element.

Abstract: An information recording medium includes a first information recording layer and a second information recording layer. The first information recording layer is formed at a laser beam entrance surface, and is configured so that information can be recorded thereupon and/or reproduced therefrom using a first objective lens having a numerical aperture NA1 and laser beam of a wavelength ?1. The second information recording layer is formed so as to have a distance to the laser beam entrance surface of 0.05 mm to 1.2 mm and is configured so that information can be recorded thereupon and/or reproduced therefrom using a second objective lens having a numerical aperture NA2 and laser beam of a wavelength ?2. When a diffraction limit ?2, determined by numerical aperture NA2 and wavelength ?2, is taken as ?2=0.61×?2/NA2, a track pitch Tp1 of a track formed on the first information recording layer is Tp1<?2.

Abstract: An optical disc type is determined by detecting focus error signals and an amount of returned light, while (i) emitting light having a wavelength maximizing a focal length and (ii) moving an objective lens in a direction of an optical axis. If an S shape and AS immediately after a surface are greater than those at the surface, the optical disc is determined to have a largest capacity. It is also determined whether there is a reflective layer at a depth equal or less than 0.1 mm, if not, then it is determined whether there is a reflective layer at a depth of 0.6 mm. If there is a reflective layer at the depth of 0.6 mm, then the type of the reflective layer is determined based on TE/RF signals, using blue light. If the blue light is not adaptable, red light is emitted to replay at a depth of 0.6 mm.

Abstract: An optical disk driving apparatus includes an optical head device having a laser light source, a converging optical system converging a light beam emitted by the laser light source onto an optical disk, a photo detector receiving reflected light reflected by the optical disk, and an aberration correcting optical system controlling aberration of the converging optical system; a motor rotating the optical disk; and a control section receiving a signal from the photo detector, wherein the converging optical system has an objective lens formed using resin as a main material, the aberration correcting optical system has a spherical aberration correcting element correcting spherical aberration, and the control section evaluates quality of a reproduction signal for information in the optical disk by using the reflected light received by the photo detector, and utilizes a result of the evaluation to perform closed loop control on the spherical aberration correcting element.

Abstract: An objective lens unit according to the present invention includes a first objective lens 41; and a first lens holder 2 for supporting the first objective lens 41. The first lens holder 2 is formed of a material which transmits ultraviolet. Preferably, the first lens holder 2 includes a through-hole, having first and second openings 2a and 2b, through which light incident on the first objective lens 41 passes, and an opening limiting section 3 provided along a circumferential direction of the through-hole and projecting toward a central axis of the through-hole. The first objective lens 41 is supported so as to block the first opening 2b. The opening limiting section 3 guides light incident thereon from the second opening 2a in a direction away from an optical axis of the first objective lens.