Abstract: An objective lens actuator comprises, two objective lenses, each for focusing lights upon an optical disc, an objective lens holder member for holding the objective lenses thereon, and lens protectors for preventing the objective lenses from being contacted on the optical disc, wherein the lens protectors include first and second lens protectors, which are provided on both end portions of the objective lens holder member in a tracking direction, and a third lens protector, which is provided in a middle of the two objective lenses, wherein the first and second lens protectors, which are provided on both end portions of the objective lens holder member in the tracking direction, are provided the objective lenses and end portion of the objective lens holder member in the tracking direction, and the third lens protector, which is provided between the objective lenses, has a height closer to that of the optical disc than the protectors, which are provided on both end portions of the objective lens holder member in

Abstract: An optical pickup, mounting a lens actuator 101 thereon, the lens actuator comprises: a lens 1 having an optical axis in direction in parallel with an optical disc; a holder 2, which holds the lens thereon; a first guide shaft 3 holding the holder, so as to regulate the holder to change a position thereof, into an inner surface direction of a surface having the optical axis of the lens as a normal line vector thereof; a second guide shaft 4, which regulates the holder to change the position thereof, into a normal line vector of an optical disc; and a reed screw, which moves the holder into direction of the optical axis of the lens, wherein a distance between the optical axis of the lens and the optical disc, a distance between a central axis of the first guide shaft and the optical disc, and a distance between a central axis of the second guide shaft and the optical disc are lager than a distance between a central axis of the reed screw and the optical disc.

Abstract: An optical-pickup apparatus comprising: a laser-light source including first-and-second-light-emitting points for laser lights with first-and-second wavelengths which points are disposed at positions deviating in a direction optically corresponding to an optical-disc-tracking direction; a diffraction grating including a plurality of periodic structures which are joined to be different in phase from each other in the direction and each of which includes a recess and projection repeated in a direction optically corresponding to an optical-disc-tangential direction, the diffraction grating being configured to generate main-and-sub-luminous fluxes from the laser light; a holder to hold the diffraction grating to be movable in the direction corresponding to the tracking direction; a collimating lens; an objective lens to focus the main-and-sub-luminous fluxes from the collimating lens on the same track of an optical disc; and a photodetector to be applied with reflected lights of the main-and-sub-luminous fluxes f

Abstract: An objective optical system is formed of a diffractive optical element with a diffractive surface formed on a virtual plane and an objective lens for focusing three collimated light beams of three different wavelengths at three different numerical apertures onto desired positions of three different recording media with substrates that include different thicknesses, such as an AOD, a DVD, and a CD, that introduce different amounts of spherical aberration in the focused beams. The objective optical system provides compensating spherical aberration to the three light beams by varying the distance between the diffractive optical element and the objective lens with the recording medium being used. The objective optical system focuses second-order diffracted light of one wavelength and first-order diffracted light of the other two wavelengths. An optical pickup device includes the objective optical system, the recording media, and a light source that provides the three light beams.

Abstract: Semiconductor lasers emit lights having wavelengths of about 400 nm, 650 nm, and 780 nm, respectively. A transmittance adjustment element is provided in an optical path of the light reflected from a disk. The transmittance adjustment element includes a first optical thin film that changes transmittance of a 650-nm-wavelength light relatively to transmittance of 400-nm- and 780-nm-wavelength lights, and a second optical thin film that changes transmittance of a 780-nm-wavelength light relatively to transmittance of 400-nm- and 650-nm-wavelength lights. The transmittance adjustment element has the function of maintaining constant the intensity of light incident onto a photodetector irrespective of the type of medium.

Abstract: The invention relates to a method and a device for producing a hologram in an optical medium, particularly for storing data in the optical medium. In the method, the hologram is produced in the optical medium using laser beams, wherein the laser beams are formed from a laser beam emitted by a free-running semiconductor laser, are directed onto the optical medium, optionally contradirectionally, and at least partially spatially overlap in the optical medium. For producing holograms using inexpensive components with a high contrast, the invention provides for arranging the reflection unit (15) such that the optical path length (?x) between the focus of the laser beam in the storage medium (10) and the reflecting surface of the reflection unit (15) satisfies the condition ?x=0.5*?s*a in the region of the optical axis, wherein a is a natural number greater than or equal to 1 and ?s is a distance between neighboring coherence centers of the laser beam produced by the semiconductor laser (16).

Abstract: In a particular type of high-density optical recording systems, a solid immersion lens (SIL) is used in the objective system to focus a radiation beam onto an information layer of an optical record carrier. The distance between the exit surface of the SIL and the entrance surface of the record carrier is typically 25 nm to allow evanescent coupling of the radiation from the SIL to the optical record carrier for a system using a blue laser as radiation source. Such a system is also called a near-field system, deriving its name from the near field formed by the evanescent wave at the exit face of the SIL. A suitable gap signal, representing the width of the gap, is used to control the width of the gap during operation of the system. Tolerances in the optical elements and opto-mechanical components of the optical system of the optical recording system can lead to an offset in the position of the focus point of the objective system.

Abstract: An optical pickup including a light source unit having a first radiating unit for radiating a light beam of a first wavelength, a second radiating unit for radiating a light beam of a second wavelength and a third radiating unit for radiating a light beam of a third wavelenght, a collimator lens having different focal lengths dependent on the first to third wavelengths, and an objective lens for condensing light beams, radiated from the first to third radiating units, on an information recording surface of an optical disc, and a recording and/or reproducing apparatus employing the optical pickup, are disclosed. The optical pickup and the recording and/or reproducing apparatus are used for recording and/or reproducing the information for plural sorts of the information recording medium of different formats. Certain components of the optical pickup are used in common for the different light beams to reduce the size of the device as well as to correct the spherical aberration.

Abstract: An image processing method which contains: delivering laser light to a thermoreversible recording medium to heat the medium and record an image thereon, the medium reversibly changing a transparency or tone thereof depending on a temperature thereof; and heating the medium to erase the image recorded thereon, wherein the delivering is carried out using an image processing device containing: a laser light emitting unit; a light scanning unit disposed on a plane onto which laser light emitted from the laser light emitting unit is delivered; a light intensity distribution adjusting unit to change a light intensity distribution of the laser light; and a f? lens to condense the laser light, and wherein energy of the laser light passing through a peripheric portion of the f? lens and traveling onto the medium is lower than energy of the laser light passing through a center portion of the f? lens and traveling onto the medium.

Abstract: An optical module having a laser element which emits a laser beam, include an optical path setting material which reflects a part of the laser beam in a predetermined direction; and a shield element which blocks the laser beam that is reflected by the optical path setting material.

Abstract: An optical scanning device for scanning optical record carriers, the optical record carriers including a first optical record carrier, a second optical record carrier and a third optical record carrier, the scanning device including a radiation source system (7) for producing first, second and third radiation beams for scanning said first, second and third record carriers, respectively, in first, second and third scanning modes, said first, second and third radiation beams having different predetermined wavelengths, the scanning device comprising an objective lens and an optical compensator, the optical compensator having a non-periodic phase structure through which each of said first, second and third radiation beams are arranged to pass, said non-periodic phase structure including a plurality of stepped annular zones separated by steps, the zones forming a non-periodic radial pattern, the stepped annular zones introducing first, second and third different wavefront modifications into at least part of the fi

Abstract: A fabrication method of a multilayer optical recording medium having a plurality of recording layers, comprises a step of preparing an optical recording medium having at least one record area; a write-position mark generating step of recording write-position marks in the record area beforehand; a step of preparing an optical system including a common objective lens to focus a data recording beam and a position mark recording beam on different positions in a thickness direction of the record area; a first data writing step of writing data between the write-position marks with following the write-position marks by the data recording beam; a position mark recording step of, in parallel with the first data writing step, recording new write-position marks in the record area by the position mark recording beam; and a second data writing step of writing data between the new write-position marks with following the new write-position marks by the data recording beam.

Abstract: An optical pickup apparatus for reproducing information from an optical information recording medium or for recording information onto an optical information recording medium, is provided with a first light source for emitting first light flux having a first wavelength; a second light source for emitting second light flux having a second wavelength, the first wavelength being different from the second wavelength; a converging optical system having an optical axis and a diffractive portion, and a photo detector; wherein in case that the first light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the first light flux is greater than that of any other ordered diffracted ray of the first light flux, and in case that the second light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the second light flux is greater than that of any other ordered diffracted

Abstract: An optical pickup apparatus comprising: an objective lens configured to apply a laser beam for recording or reproducing information to a plurality of layers of information recording surfaces selectively, the plurality of layers of information recording surfaces being included in an optical disc mounted on a turn table; and a spherical aberration correction lens configured to be movable on a light path on the side where the laser beam is incident on the objective lens, so as to correct spherical aberration when the laser beam is applied from the objective lens to any one of the plurality of information recording surfaces in the optical disc, a distance between the spherical aberration correction lens and the objective lens on each light path when the laser beam is focused on each of the plurality of layers of information recording surfaces in the optical disc with movement of the spherical aberration correction lens, including a distance at which optical magnification of an optical system including the spheric

Abstract: An objective lens for use in an optical pickup apparatus for recording and/or reproducing information on a first optical information recording medium having a protective substrate with a thickness t1 using a light flux with a wavelength ?1, on a second optical information recording medium having a protective substrate with a thickness t2 using a light flux with a wave length ?2 and a third optical information recording medium having a protective substrate with a thickness t3 using a light flux with a wavelength ?2, the objective lens includes: an optical surface including a central area and a peripheral area, wherein when the objective optical lens forms the portion of the light flux with the wavelength ?2 passed the central area into a converged spot through a substrate with a thickness t4, the objective optical lens makes a spherical aberration of the converged spot a minimum value.

Abstract: The adverse influence of reflected light from adjacent layers as stray light on a control signal or data signal is reduced when tracking a multilayered optical disc using differential push-pull method. The reflected light from the optical disc including stray light from an adjacent layer is once condensed with a condenser lens having little aberration and is then reflected by a reflecting mirror having a partial reflecting region. The resultant reflected light, which has the influence of stray light reduced, passes through a polarization beam splitter and becomes incident on a four-quadrant detector (for main beam) and a split detector (for sub beam) via a condenser lens having astigmatic aberration.

Abstract: A Fresnel member for an optical system is configured to receive at least reflected light having a first wavelength at a first envelope and reflected light having a second wavelength different from the first wavelength at a second envelope. The Fresnel member includes a plurality of ring zone portions having predetermined surface heights for achieving a maximum diffraction efficiency.

Abstract: An optical pickup apparatus includes an astigmatic element, an angle adjusting element for contradicting propagation directions of luminous fluxes within four different luminous flux regions out of a reflected light, a polarization adjusting element. Two of the luminous flux regions are placed in a direction in which aligned are a set of opposite angles made by the two mutually crossing straight lines respectively parallel to a first convergence direction and a second convergence direction vertical to the first convergence direction by the astigmatic element, and the remaining two luminous flux regions are placed in a direction in which an alternate set of opposite angles are aligned. The polarization adjusting element differentiates polarization directions of luminous fluxes which are selected out of the luminous fluxes within the four luminous flux regions and which are adjacent in a peripheral direction in which the optical axis of reflected light serves as an axis.

Abstract: An optical disc apparatus includes a light separator configured to separate a light beam emitted from a light source into a main beam and a sub-beam, an objective lens configured to, when the light beam is condensed and irradiated to an optical disc having a uniform recording layer in which a track is formed by record marks, irradiate at least part of the sub-beam to an area where the main beam is not irradiated in a radial direction which is defined as a direction of radius of the optical disc, and a signal generating unit configured to generate a mark layer distance signal, representing a distance between a focus of the light beam and a mark layer to which the track belongs, based on a return light beam resulting from at least one of the main beam and the sub-beam, which has been irradiated to the track.

Abstract: An optical pickup apparatus is provided with an angle adjusting element. The angle adjusting element changes a propagation direction of luminous fluxes of four luminous flux regions set about an optical axis of the laser light, out of laser light reflected by a disc, and mutually disperses the luminous fluxes. A signal light region in which signal light only is present appears on a detecting surface of a photodetector. A sensor pattern for signal light is placed at a position irradiated with the signal light within this region. A sensor pattern for a spherical aberration detection is placed on an inner side of this region.

Abstract: An optical pickup apparatus is provided with an angle adjusting element. The angle adjusting element changes a propagation direction of luminous fluxes of four luminous flux regions set about an optical axis of the laser light, out of laser light reflected by a disc, and mutually disperses the luminous fluxes. A signal light region in which signal light only is present appears on a detecting surface of a photodetector. A sensor pattern for signal light is placed at a position irradiated with the signal light within this region. A sensor pattern for a coma aberration detection is placed on an inner side of this region.

Abstract: An objective lens unit for an optical pickup device which is composed of a first optical element including a first element body positioned on an optical information recording medium side and a first annular portion formed on the outer periphery of the first element body, and further composed of a second optical element including a second element body and a second annular light source side of the first element body and a second annular portion formed on the outer periphery of the second element body and coupled to the first annular portion, and at least one of the first and second annular portion has a portion in which the size of outer shape is smaller than the vicinity on at least a part of the light source side.

Abstract: There is provided an optical reading/writing apparatus. The optical reading/writing apparatus includes an object lens barrel for mounting an object lens, an SIL (solid immersion lens) barrel for mounting an SIL, the SIL barrel being separated from the object lens barrel, and a movement control unit for selectively aligning the SIL with the object lens according to a type of an optical storage medium.

Abstract: An objective lens used for an optical information recording/reproducing apparatus for an optical disc based on a predetermined standard is made of resin and has a numerical aperture larger than or equal to 0.75. When f (unit: mm) represents a focal length at a wavelength ? (unit: nm), d (unit: mm) represents a thickness, and n represents a refractive index of the objective lens at the wavelength ?, the objective lens satisfies following conditions: 1.00<f<1.50 ??(1) 1.55<d·n/f<1.82 ??(2). At least a light source side surface of the objective lens is an aspherical surface. The objective lens satisfies a following condition: 2.80<(SAG1)?MAX·n<4.10 ??(3), where (SAG1)?MAX represents a maximum gradient of a gradient (SAG1)? of a sag amount SAG of the aspherical surface at the light source side within an effective beam diameter.

Abstract: An optical pickup includes: a light source that emits a light beam; an object lens that condenses the light beam on a target recording layer of an optical disk; a lens moving unit; a condensing lens; a hologram element that diffracts, in diffracting a reflected light beam and separating it into reflected zeroth-order and first-order light beams, parts of the reflected first-order light beam in a first direction and sets them as first and second beams, diffracts parts of the reflected first-order light beam in a second direction and sets them as third and fourth beams; and a photodetector that receives the first and second beams and the third and fourth beams and generates light reception signals, and receives interlayer stray light of a part of the light beam reflected by the other recording layers other than the target recording layer and generates a stray light reception signal.

Abstract: An optical information recording reproduction device is disclosed which finds the correlation between the ratio of the minimum pit amplitude to the maximum pit amplitude of an RF signal obtained from the light reflected by the pits recorded on an optical disk in a tracking servo mode and spherical aberration in advance, and stores it. In recoding information on the optical disk, the optical information recording reproduction device calculates the ratio of the minimum pit amplitude to the maximum pit amplitude of the RF signal, and compares the calculation to the stored correlation, and feeds back to an aberration correction optical system and a driving mechanical system to correct the aberration into an aplanatic state.

Abstract: An optical disc apparatus includes: an objective lens that condenses a first light beam, which is emitted from a light source and corresponds to a first optical disc, and that illuminates the first light beam to an unknown disc whose type is unknown; a driving section that drives the objective lens in a focus direction approaching or becoming distant from the unknown disc; a rotation section that rotates the unknown disc; a signal processing section that generates a first reproduction signal indicating a total amount of a first returning light beam generated by reflection of the first light beam from the unknown disc; and a detecting section that detects a first signal recording surface, which corresponds to the first optical disc, from the unknown disc on the basis of the first reproduction signal.

Abstract: Provided are a method and apparatus for recording/reproducing holographic information. The apparatus for recording/reproducing holographic information includes an optical pickup which irradiates light on a holographic information storage medium and receives irradiated light, wherein the optical pickup comprises a focusing optical system having a numerical aperture (NA) during recording that is lower than the NA during reproduction.

Abstract: An objective optical element for use in an optical pickup apparatus, includes two or more optical elements having a first surface having a first phase difference providing structure and a second surface having a second phase difference providing structure, wherein each of the first and second phase difference providing structures emit a diffracted light flux corresponding to each of the entering first-third light fluxes, or emit a transmitting light flux which is not applied a diffractive action corresponding to each of the entering first-third light fluxes, and the first-third light fluxes enter into the objective optical element as an almost infinite parallel light flux for information reproducing and/or recording on the first-third optical information recording media respectively.

Abstract: An optical pickup device includes an optical part module having a light emitting device and an optical pickup case to which the optical part module is fixed by way of an adhesive, in which the optical part module is adhesively fixed by disposing a bonding surface of the optical part module to the optical pickup case at least at two positions on lateral surfaces of the optical part module putting an optical axis therebetween, and a bonding distance L in the lateral surface between the optical part module and the optical pickup is defined as: 40 ?m<L<570 ?m, whereby the optical pickup device can maintain an optimal position at a high positional accuracy without lowering a bonding strength even when a stress due to an external load by bending moment or circumstantial changes is caused to the optical part module, particularly in the case where the optical pickup device is thin.

Abstract: An optical pickup includes a light source emitting a light beam, an objective lens condensing the light beam emitted from the light source onto an optical disc, at least one divergent angle conversion lens (collimator lens) disposed between the light source and the objective lens and changing a divergent angle of the incident light beam, a driving unit (collimator lens driving mechanism) configured to drive the divergent angle conversion lens in a direction of an optical axis, an optical detection device (optical detector) detecting a return light beam reflected at the optical disc, and an environmental change detecting unit (temperature sensor) configured to detect change in environmental temperature, wherein the objective lens is made of a refractive element having, on one surface thereof, a diffraction structure in a stepped shape or a blazed sectional shape, which generates diffraction light providing a spot adapted to perform satisfactory recording and/or reproducing, the objective lens satisfying certai

Abstract: Provides a coupling lens which, when used in combination with an objective lens for a plurality of types of optical discs such as a high density disc, DVD, CD or the like, is capable of compensating for various types of aberrations including those caused by wavelength changes and thus providing good recording or reproduction characteristics with a good wavelength dispersion compensation ability; and an optical head and an optical disc apparatus (drive). A coupling lens is incorporated into an optical head for collecting laser light emitted from a plurality of light sources and having different wavelengths on an information recording face of different types of optical information recording mediums respectively. The coupling lens comprises a first lens and a second lens which are substantially in close contact with each other such that optical axes thereof match each other and designed such that the laser light having different wavelengths are refracted by the close contact face.

Abstract: An optical pickup includes an actuator having an objective lens and an optical base on which the actuator is supported. The actuator includes a yoke having an opening, a first straight section and an opposing second straight section, the opening being interposed between the straight sections, the first and second straight sections having a first and a second bent section, respectively, as an extension of each bent section. The yoke is formed as coving the actuator with the straight sections so that the objective lens is exposed through the opening without being obstructed by the optical base. The first bent section has one contact section whereas the second bent section has two contact sections. The optical base includes an ark-like support section. The optical base supports the actuator in such a way that the contact sections are made to have contact with the ark-like support section.

Abstract: A connection structure of Flexible printed circuits comprising: first and second Flexible printed circuits, respectively, including a base formed of a resin, a plurality of wiring patterns arranged side by side on the base, a cover formed of a resin to cover opposite sides of the wiring patterns to the base, and a connection portion in which the plurality of wiring patterns are not covered by the cover, the connection portions of the first and second Flexible printed circuits being connected with each other. The wiring patterns in the connection portions include a large width portion which is larger in width than the wiring patterns covered by the cover. The large width portions on the first Flexible printed circuit and the large width portions on the second Flexible printed circuit are connected to each other by means of soldering.

Abstract: An optical pickup includes: a light source that emits first light; an objective lens that condenses the first light and allows it to irradiate a track having formed therein a recording mark for intercepting the first light in a uniform recording layer of an optical information recording medium; and a light receiving section that receives transmitted light which has transmitted through the track.

Abstract: In a lens holding member for holding a solid immersion lens, when a difference-in-level portion and/or slant face is constructed at least on a part of the objective side surface, a tilt margin which can be applied to a near field optical recording and reproduction solid immersion lens can be maintained. In a focusing lens using such lens holding member, the optical pickup apparatus and the optical recording and reproducing apparatus, stable transportation between the lens and the optical recording medium can be improved.

Abstract: An optical information apparatus according to the present invention includes: an optical system that includes a solid immersion lens (SIL) 11 and that produces near-field light to be incident on an optical disc 10; a first actuator for displacing the SIL 11; a second actuator 29 for varying the distance between the optical disc 10 and the first actuator 12 by moving the first actuator 12; a gap detecting section 18 for outputting a gap signal 19 representing the magnitude of the gap 17 between the SIL 11 and the optical disc 10; and a gap control system for controlling the first actuator 12 in response to the gap signal 19 such that the gap is maintained at a predetermined setting. The gap control system works so as to control the second actuator 29 in accordance with a signal representing the magnitude of displacement of the SIL 11 caused by the first actuator 12.

Abstract: Influences of reflected light, which result in crosstalk from adjacent layers in a multi-layered optical disk, are mitigated. In an astigmatic optical system of an optical pickup, a first composite segmented wave plate having a segmentation direction that is in the same direction as the focal line that is close to the astigmatic optical system, a second composite segmented wave plate of the same segmentation direction, and an analyzer are inserted.

Abstract: An optical pickup apparatus reads an information signal recorded on a recording surface of an optical disk along a track by projecting a light beam. Said optical pickup apparatus has: an objective lens for converging said light beam onto said recording surface; an objective lens moving device for moving said objective lens in a radial direction of said optical disk; and a divisional photosensing device for receiving return light reflected by said optical disk, in a plurality of divided regions.

Abstract: [Problems] In an objective lens driving device used for an optical disc and the like, a moving speed of the objective lens is changed corresponding to amount of vertical deviation of the optical disc, and when the vertical deviation is small, time for aligning the focus is reduced. [Means for Solving Problems] In a case that an objective lens is moved from a bottom limit to an upper limit in a specific range for aligning the focus, when the objective lens is positioned nearer a point (basic focusing position) where light is focused on an optical disc 11 having no vertical deviation than a position away from the basic focusing position, the servo signal processor 5 moves the objective lens faster.

Abstract: An optical pickup device includes: a first light source for emitting recording laser light; a second light source for emitting reproducing laser light having a wavelength different from a wavelength of the recording laser light; an objective lens for converging the recording laser light and the reproducing laser light. A quarter wavelength plate is disposed between the first light source and the second light source, and the objective lens. A wavelength-selective polarized beam splitter is disposed between the quarter wavelength plate, and the first light source and the second light source. The reproducing laser light alone out of the recording laser light and the reproducing laser light reflected on recording medium is guided to a photodetector.

Abstract: A servo objective lens and a recording/reproducing objective lens are commonly held on a holder. The servo objective lens and the recording/reproducing objective lens are integrally displaced, thereby pulling servo light onto a servo layer. Upon the pulling, focus positions of recording light and reproducing light follow a focus position of the servo light. As a result, the focus positions of recording light and reproducing light are set close to the servo layer. Thereafter, an optical element for displacing the focus positions of recording light and reproducing light in the optical axis direction is driven to pull the recording light and the reproducing light onto a targeted recording layer.

Abstract: An optical reading/writing apparatus has an optical head that includes a collimator and a lens. For efficient and reliable focusing control for writing an empty optical disk, calibration of focus offset and spherical aberration is executed by setting a boundary and performing data-reading in an OPC area only with combinations of focus offset and spherical aberration within the boundary. Accordingly, an optimum combination of focus offset and spherical aberration is determined for focusing compensation in subsequent writing operation of the empty disk.

Abstract: An optical pickup apparatus is provided with an optical system for guiding a laser light emitted from a laser light source to an objective lens and also for guiding the laser light reflected by a recording medium to a photodetecting section as a convergent light. The photodetecting section is provided with first and second photodetectors disposed at positions at which a first part of the target laser light and a second part different from the first part are respectively received, the positions being separated further from the optical system than a convergence position of a target laser light reflected by an irradiation-target recording layer, out of the laser light reflected by the recording medium, and a third photodetector disposed at a position closer to the optical system than the convergence position of the target laser light, the position being bridging more over the second part than the first part.

Abstract: An optical disk reproduction apparatus according to the present invention is an optical disk reproduction apparatus capable of reading information from the NBCA of an optical disk 101 having an NBCA, and includes: an optical pickup 103 having an objective lens 120 for converging a light beam onto the optical disk 101, a lens actuator 170 for controlling a position of the objective lens 120, and a photodetector for generating an electrical signal from at least a portion of the light beam having been reflected by the optical disk 101; a transport mechanism 106 for moving the optical pickup 103 along a radial direction of the optical disk; and an NBCA in/out determination section 104 for, based on electrical signal, determining whether an irradiated position of the light beam on the optical disk 101 is located within the NBCA or not.

Abstract: An optical disc apparatus controls a relative position of an optical pickup with respect to a surface of an optical disc medium according to an output signal output from the optical pickup according to information recorded on the optical disc medium to implement servo control for maintaining a state where the information is readable, acquires an evaluation value for information reading accuracy when the servo control is implemented, and calculates a set value of a parameter to be set for the implementation of the servo control based on evaluation values respectively acquired for at least three set values of the parameter while changing the set value of the parameter for the servo control. The optical disc apparatus determines the set value to be set for further acquiring the evaluation value according to the evaluation values acquired for at least two set values of the parameter.

Abstract: An optical information recording/reproducing device is provided with a first light source 20a for emitting recording light 22a, a second light source 20b for emitting reproducing light 22b, an objective lens 6 for focusing the emitted lights from the both light sources 20a, 20b on an information recording medium including a recording region 3 capable of three-dimensional recording and photodetectors 19a, 19b for detecting reflected lights 7a?, 7b? from the information recording medium, and records information on recording layers 1a to 1e utilizing a nonlinear absorption phenomenon. At the objective lens 6, an average rim intensity of the recording light 7a is lower than that of the reproducing light 7b.

Abstract: [Problems] An optical head device and an optical information recording or reproducing apparatus are provided to detect an excellent track error signal for two-layer optical recording medium. [Means for Solving Problems] Reflecting light of a main beam and sub-beams reflected from a disc is diffracted by a diffractive optical element (9a) and then received by a photodetector. The diffractive optical element (9a) is divided into regions (13a) to (13d) by two lines in parallel with radial and tangential directions passing through an optical axis of incident light. Diffracting gratings pitches at the regions (13a) to (13d) become wider in order.

Abstract: An optical disc apparatus includes an optical pickup for outputting an output signal according to reflected light from an optical disc medium and a comparison signal output unit for outputting a comparison signal indicating whether a level of the output signal is higher than a threshold value, relatively moves an objective lens with respect to a surface of the medium within a predetermined range to measure a maximum level of the output signal, sets a value determined according to the maximum level as a threshold value used by the comparison signal output unit, and measures a level of a reflected signal corresponding to reflected light from each of a plurality of signal surfaces based on the output signal in a time period in which the comparison signal indicates that the level of the output signal is higher than the set threshold value, while moving the objective lens.

Abstract: An optical information recording medium, which has recording layers that include substrates of the same thickness and that correspond to laser light at two difference wavelength, has excellent compatibility. An optical disk, in which recoding or reproduction is performed from one plane through the substrate, has two recoding layers, and the recording density of a first layer is different from the recording density of a second layer. First recording layer 101 and second recording layer 102 are stacked on substrate 1. The laser beam for recording or reproduction is incident through substrate 1. Structurally, the disk is formed by laminating two recording layers on the side opposite to the laser beam incident side. Intermediate layer 103 which is transparent to a second laser beam is formed between the first and second layers. Laser beam with different wavelengths is used to record or reproduce the first and second layers.