Thu, 16 Feb 2017 08:00:00 ESTMethods, apparatuses and systems for detecting defective sectors on a recording medium, the method including calculating a servo gain for each servo sector of a track of a recording medium of a storage device; determining whether the servo gain of each servo sector exceeds a threshold value; and upon determining that the servo gain of a servo sector exceeds the threshold value, determining data sectors included in the servo sector to be defective sectors.
Thu, 16 Feb 2017 08:00:00 ESTEmbodiments disclosed herein generally relate to contact at the disk by the recording head in a hard disk drive. In one embodiment, a direct current is applied to an element in a HAMR head. An alternating current is then applied to the element over top of the direct current to cause the HAMR head to dither. By monitoring the head signal at the dither frequency, a touchdown or contact of a NFT on a disk may be detected based upon variations in the produced signal.
Thu, 16 Feb 2017 08:00:00 ESTEmbodiments disclosed herein generally relate to a HAMR head. The HAMR head includes a main pole, a waveguide and a NFT disposed between the main pole and the waveguide. The NFT includes an antenna, and a portion of the antenna is disposed at a media facing surface. By increasing the volume of the antenna extending from the MFS, the temperature of the NFT during operation is reduced.
Thu, 16 Feb 2017 08:00:00 ESTA main pole has a front end face including a first end face portion and a second end face portion. A plasmon generator has a near-field light generating surface. A surrounding layer has a first surrounding layer end face and a second surrounding layer end face located on opposite sides of the first end face portion in the track width direction. A gap film has a first gap film end face and a second gap film end face located on opposite sides of the near-field light generating surface in the track width direction. Each of the first and second gap film end faces includes a portion located between the first and second surrounding layer end faces, but does not include any portion interposed between the first surrounding layer end face and the first end face portion or between the second surrounding layer end face and the first end face portion.
Thu, 16 Feb 2017 08:00:00 ESTAccording to one embodiment, a failure prognosis device includes circuitry configured to determine whether a sign of failure exists in a head, based on a signal quality value and a floating quantity of the head, the signal quality value being based on an error between a reproducing signal acquired from the head when reading data stored on a storage surface of a disk and a predetermined target signal, and output a determination result.
Thu, 09 Feb 2017 08:00:00 ESTEmbodiments of the present invention provide a method for monitoring components in a library by tracking the movement of library components. By tracking the movement of library components, the degradation of library components can be monitored and the reliability of library components determined, allowing unreliable components to be bypassed or replaced, enhancing the reliability of the library and preventing data loss.
Thu, 09 Feb 2017 08:00:00 ESTAn information recording method of the present disclosure is an information recording method for recording information on a write-once information recording medium, including one or more recording layers, each of the recording layers being spiral-shaped on which a land track and a groove track are alternately repeated as recording tracks, each of the recording tracks being divided into blocks, each of the blocks being a minimum unit in which recording is performed. The information recording method includes: recording the information on the information recording medium in a unit of each of the blocks; and controlling recording on the information recording medium. In the control step, switching is performed whether to perform recording in a block to be recorded in which the information is to be recorded next among the blocks based on recording conditions of the recording tracks adjacent on both sides of the block to be recorded.
Thu, 02 Feb 2017 08:00:00 ESTA method and apparatus for detecting tightness of a pick-up head, and a method and apparatus for controlling the moving of the pick-up head are disclosed. The method for detecting the tightness of the pick-up head includes moving the pick-up head to an inner area of the disc reading device when then disc reading device is powered on, moving the pick-up head to an outer area of the disc reading device within a predetermined time period, moving the pick-up head from the outer area of the disc reading device to the inner area at a constant speed by a first fixed force, and recording the moving duration for moving the pick-up head from the outer area of the disc reading device to the inner area at the constant speed.
Thu, 02 Feb 2017 08:00:00 ESTAn apparatus includes a waveguide that delivers energy from an energy source, a write pole located proximate the waveguide at a media-facing surface, and a near-field transducer located proximate the write pole in a down track direction. The near-field transducer includes an enlarged portion and a peg extending from the enlarged portion towards the media-facing surface. The peg comprises a taper facing away from the write pole, and the taper causes a reduced down track dimension of the peg near the media-facing surface.
Thu, 02 Feb 2017 08:00:00 ESTAn apparatus includes a slider of a recording head comprising a plurality of electrical bond pads coupled to bias sources and a ground pad. Each of a plurality of electrical components of the slider is coupled to at least one of the electrical bond pads. At least one of the electrical bond pads is a shared electrical bond pad coupled to at least two of the electrical components. At least one diode is coupled to at least one of the electrical bond pads and at least one of the electrical components.
Thu, 26 Jan 2017 08:00:00 ESTA recording head is configured to write and read data sectors to and from a recording medium, such as a heat-assisted recording medium. A read channel is coupled to the recording head. Phase-locked loop (PLL) circuitry of the read channel is configured to detect a change in a phase error at a location of the data sector. The phase error change may be indicative of a mode-hop that occurred while writing the data sector to the medium. The PLL circuitry is configured to determine a phase offset using the phase error. A controller is configured to effect re-reading of the data sector location using the phase offset to recover the data sector location.
Thu, 26 Jan 2017 08:00:00 ESTMethods and apparatus for recording and retrieval of optically readable data employ a recording medium (100) which comprises an optically active material (108) able to induce a change in properties of the medium in the presence of optical radiation having a first characteristic, such as a first optical frequency, and wherein the change in properties can be inhibited by optical radiation having a second characteristic, such as a second optical frequency. During recording, a region of the recording medium (100) is irradiated with a first beam (506) of optical radiation having the first characteristic, the beam having a sufficient intensity within a central portion of the irradiated region and being of sufficient duration to cause an optically induced change in properties of the recording medium. Simultaneously, the region of the recording medium (100) is irradiated with a second beam (508) of optical radiation having the second characteristic, the second beam having a local intensity minimum within the central portion of the irradiated region, and a local intensity maximum in at least one portion of the irradiated region adjacent to the central portion which is sufficient to inhibit the optically induced change in properties of the recording medium. A similar method is employed for retrieval, however the intensity of the first beam (506) is reduced to prevent changes in material properties within the recording medium (100).
Thu, 26 Jan 2017 08:00:00 ESTAn information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.
Thu, 26 Jan 2017 08:00:00 ESTProvided herein is an apparatus including a substrate and a magnetic recording layer over the substrate. In addition, a thermochromic layer is over the substrate, wherein the thermochromic layer includes a first optical absorbance at a first temperature and a second optical absorbance at a second temperature.
Thu, 26 Jan 2017 08:00:00 ESTMethods, systems, and computer program product embodiments for improving track-follow control in a tape storage system, by a processor device, are provided. In one embodiment, a method comprises, using an accelerometer to dynamically detect device vibration for determining whether to implement a vibration compensation control mechanism.
Thu, 26 Jan 2017 08:00:00 ESTA turntable device, comprising: a base and an arm. The base may comprise a pad and a spindle. The arm may comprise: a housing; one or more buttons; a spindle engagement portion; a stylus cartridge; a power supply; one or more wireless communication devices; a linear actuator; a motor; and a vertical solenoid. The base may receive a phonographic record, and the spindle engagement portion may engage with the spindle, such that the arm is entirely supported above said base via said spindle and only the spindle.
Thu, 19 Jan 2017 08:00:00 ESTEmbodiments disclosed herein generally relate to a method for forming a HAMR head. The method includes depositing a drop-on-demand mask on a portion of a surface of a slider using a drop-on-demand tool. The surface of the slider includes at least a portion of an NFT. A first protective layer is deposited over a remaining portion of the surface of the slider and over the drop-on-demand mask. The drop-on-demand mask and a portion of the first protective layer disposed on the drop-on-demand mask are removed, exposing at least the portion of the NFT. A second protective layer is deposited on the first protective layer and at least the exposed portion of the NFT. By using the drop-on-demand tool to deposit the drop-on-demand mask, the alignment between the drop-on-demand mask and the portion of the NFT is less stringent, and the drop-on-demand mask can be easily removed using a wiping tool.
Thu, 12 Jan 2017 08:00:00 ESTAn optical recording medium includes a plurality of information signal layers on which information signals are to be optically recorded. Among the plurality of information signal layers, the information signal layer closest to the light-receiving surface has a reflectance of more than 4%.
Thu, 12 Jan 2017 08:00:00 ESTA magnetic write head has a plated coil with narrow pitch and is suitable for writing at high frequencies on magnetic media with high coercivity. The narrow pitch is obtained without such disadvantages as overplating that has adversely affected prior art attempts to produce such narrow pitches. The process that produces the magnetic write head is characterized by an RIE plasma etch using O2/N2 to etch plating trenches into a baked layer of photoresist with the ratio of gases being 5/45 sccm so that a dilute O2 concentration does not create unwanted side etching of the plating trenches. In addition, a Cu seed layer is coated with an insulating layer of Al2O3 which redeposits on the trench sidewalls to inhibit redeposition of any Cu from the seed layer and prevent outward growth of the plated Cu that would result in overplating.
Thu, 12 Jan 2017 08:00:00 ESTA device that includes a near field transducer (NFT); at least one cladding layer adjacent the NFT; and a carbon interlayer positioned between the NFT and the at least one cladding layer.
Thu, 05 Jan 2017 08:00:00 ESTA servo control system according to the present invention includes a servo control device for driving a driven body that operates periodically using a servomotor; and a learning controller for generating correction data based on a location deviation with respect to a uniform command pattern, and storing the correction data in delay memory and correcting the location deviation. The delay memory includes first memory having a short access delay time and second memory having a long access delay time. The servo control device includes a switching unit for assigning one of the first memory and the second memory to the learning controller, depending on a learning period according to the command pattern.
Thu, 05 Jan 2017 08:00:00 ESTA method, apparatus, and system are provided for implementing in-situ monitoring of head overcoat burnishing and early detection of head failure in a hard disk drive (HDD). A voltage is applied across a slider-disk interface between the slider body and the disk. Realtime monitoring of electrical current flowing across the slider-disk interface is performed for determining an amount of burnishing of the slider.
Thu, 29 Dec 2016 08:00:00 ESTA data storage device testing system may be configured with at least a test slot, a loader assembly, and an exchange assembly. The loader assembly can be positioned to respectively engage and disengage a test deck with the test slot. The exchange assembly may be configured to open an access port portion of the test deck and subsequently replace a tested data storage component housed within the first test deck with an untested data storage component.
Thu, 29 Dec 2016 08:00:00 ESTA heat assisted magnetic recording (HAMR) writer is described. The HAMR writer is coupled with a laser that provides energy having a first polarization state. The HAMR writer has an air-bearing surface (ABS) configured to reside in proximity to a media during use, a plurality of waveguides, a main pole and at least one coil. The main pole writes to the media and is energized by the coil(s). The waveguides receive the energy from the laser and direct the energy toward the ABS. The waveguides include an input waveguide and an output waveguide. The input waveguide is configured to carry light having the first polarization state. The output waveguide is configured to carry light having a second polarization state different from the first polarization state. The waveguides are optically coupled and configured to transfer the energy from the first polarization state to the second polarization state.
Thu, 29 Dec 2016 08:00:00 ESTA method, apparatus, and system for implementing head degradation detection and prediction for hard disk drives (HDDs) are provided. Statistical parameter stability tests are used that are calculated as Confidence Intervals (CIs) from HDD parameter measurements. HDD parameters include, for example, change or delta in fly height (dFH), magnetic resistor resistance (MRR) head values, servo variable gain amplifier (SVGA) readback amplitude values, that are used in conjunction with two or more confidence level indicators and an Auto-Regressive Integrated Moving-Average (ARIMA) (p, d, q) predictor for head degradation detection and field failure prediction.
Thu, 22 Dec 2016 08:00:00 ESTA recording/reproducing device and a recording/reproducing method, which are capable of improving reliability of data while securing compatibility with a file format employed in a recording medium are provided. Provided is a reconstruction method of reproduction data acquired from a reproducing device that reproduces data from a recording medium in which the data is recorded, performs error correction using a second error correction code specified in a file format employed in the recording medium, and outputs reproduction data, and the reconstruction method of the reproduction data includes obtaining reproduction data from the reproducing device, reading a first error correction code different from the second error correction code from the reproduction data, and performing error correction on the reproduction data using the first error correction code and reconstructing user data.
Thu, 22 Dec 2016 08:00:00 ESTAn optical encoder disk comprising an opaque disk, an outer track adjacent a peripheral edge of the disk, an inner index track defined by a first pattern of radial light-blocking elements subtending an arc within an annular band interposed between the outbound track and an axis of the disk, and an opaque support pattern of non-radial elements located within the annular band outside of the arc in which the index track is located formed of substantially non-radial elements. The inner index track further includes pattern apertures formed through the disk between the light-blocking elements so that light emitted on one face of the disk passes through the pattern apertures and falls upon photodetectors located adjacent an opposite face of the disk.
Thu, 22 Dec 2016 08:00:00 ESTAn optical disc including at least three layers of recording layers that each record information in an information track. The recording layer includes: an inner circumferential side region positioned on the inner circumferential side; a data region which is positioned to the outer circumferential side of the inner circumferential side region and records content information; and an outer circumferential side region positioned to the outer circumferential side of the data region. The content information is recorded in the data region of the three or more layers, and a point on an upper layer and a point on a lower layer one layer below the upper layer at which playback switches from content information of the upper layer being played back in an inner circumferential direction to content information of the lower layer, are set to be more to the outside than an innermost circumferential position of the data region.
Thu, 22 Dec 2016 08:00:00 ESTA system, according to one embodiment, includes a near field transducer; an adhesion layer on a media facing side of the near field transducer, the adhesion layer comprising Ni and Cr; and a protective layer on a media facing side of the adhesion layer. Other systems and methods are described in additional embodiments.
Thu, 15 Dec 2016 08:00:00 ESTVarious devices and systems may benefit from enhanced reading of optical media. For example, certain computer systems may benefit from array reading of optical media. An apparatus may include, for example, an array of optical sensors. The array of optical sensors may be configured to read a plurality of parallel linear strips of data from an optical medium.
Thu, 15 Dec 2016 08:00:00 ESTIn recording technologies for batch formation of a plurality of recording bits in a recording medium by forming a plurality of optical spots using an ultrashort pulse laser and a spatial optical modulator, the hatch recordable hit number has an upper limit, resulting in restricted recording speed. The intensity of the optical spot is corrected to increase the batch recordable bit number for increasing the recording speed.
Thu, 15 Dec 2016 08:00:00 ESTA device including a magnetic structure, the magnetic structure having a substrate adjacent surface and a second, opposing surface, the magnetic structure having a near field transducer (NFT), wherein the NFT includes gold or an alloy thereof, and is positioned at the second surface an overcoat structure; and a film structure, the film structure positioned between the magnetic structure and the overcoat structure, the film structure having a total thickness of not greater than about 100 Å, and the film structure including: a first interfacial structure having a first and a second opposing surface; a second interfacial structure having a first and a second opposing surface; and an intermediate structure wherein the first surface of the first interfacial structure is positioned adjacent the NFT of the magnetic structure, and the second surface of the second interfacial structure is positioned adjacent the overcoat structure, and the intermediate structure is positioned between the first interfacial structure and the second interfacial structure, and wherein the first interfacial structure includes one or more rare earth elements, one or more alkaline earth metals, one or more alkali metals, or a combination thereof.
Thu, 08 Dec 2016 08:00:00 ESTA test deck may be employed as part of a data storage component testing system. A test deck can consist of at least a bottom cover mating to a top cover to define an enclosed testing region configured to house a data storage medium, transducing head, and head suspension. The top cover may have an access port occupied by a door providing access to the enclosed testing region.
Thu, 08 Dec 2016 08:00:00 ESTAn optical information recording/reproducing device that uses a signal beam and a reference beam to record digital information on an optical information storage medium by angle multiplexing using holography includes a light source unit generating a reference beam and a signal beam, and a recording angle control unit controlling an angle of the reference beam irradiated on the optical information storage medium in an angle direction in which the angle multiplexing recording is performed. The reference beam is irradiated on an unrecorded portion of the optical information storage medium when an incident angle of the reference beam is being changed by the recording angle control unit, and thereafter, the signal beam and the reference beam are irradiated on the optical information storage medium to record the digital information.
Thu, 01 Dec 2016 08:00:00 ESTData can be encoded in physical medium and represented by shapes having many various physical attributes. In various examples, data points are encoded and represented by the physical shape, color, size, and/or structure of objects. In one embodiment, holes in memory surface substrates represent data. Various attributes of such holes, including depth, profile size, profile shape, and/or angle can represent data.
Thu, 01 Dec 2016 08:00:00 ESTDevices having air bearing surfaces (ABS), the devices include a near field transducer (NFT) that includes a disc configured to convert photons incident thereon into plasmons; and a peg configured to couple plasmons coupled from the disc into an adjacent magnetic storage medium, wherein the disc includes a disc material and the peg includes a peg material, wherein the disc material is different from the peg material and wherein the disc material has a first real part of the permittivity and a peg material has a second real part of the permittivity and the second real part of the permittivity is not greater than the first real part of the permittivity.
Thu, 01 Dec 2016 08:00:00 ESTDevices having an air bearing surfaces (ABS), the devices including a near field transducer (NFT) that includes a disc having a front edge; a peg, the peg having a front surface at the air bearing surface of the apparatus, an opposing back surface, a top surface that extends from the front surface to the back surface, two side surfaces that expend from the front surface to the back surface and a bottom surface that extends from the front surface to the back surface; and a barrier layer, the barrier layer separating at least the back surface of the peg from the disc and the barrier layer having a thickness from 10 nm to 50 nm.
Thu, 01 Dec 2016 08:00:00 ESTMethods of forming a NFT the methods including forming a hard mask positioned over at least a portion of the rod, the hard mask including at least one layer; patterning a resist mask over the hard mask, the resist mask having an edge positioned over at least a portion of the rod; etching a portion of the hard mask to expose a back edge of the rod and to form a back edge of the hard mask, wherein the back edge of the rod is equivalent to the back edge of the peg; and wherein a forward portion of the rod which is the portion of the rod forward of the back edge is covered by the hard mask; forming a disc mask including a void configured to form a disc of a NFT, the disc mask being formed over at least a portion of the hard mask so that the exposed back edge of the rod is within the void configured to form the disc; etching an area exposed in the void of the disc mask to remove both a rear portion of the rod and the surrounding dielectric up to the back edge of the hard mask edge; depositing a disc material in the etched void, wherein the back edge of the hard mask defines the front edge of the disc and the back edge of the rod is in contact with the front edge of the disc; and polishing the deposited disc material to form a top surface substantially planar with the top of the forward rod portion.
Thu, 01 Dec 2016 08:00:00 ESTDevices having air bearing surfaces (ABS), the devices including a near field transducer (NFT) that includes a disc configured to convert photons incident thereon into plasmons; and a peg configured to couple plasmons coupled from the disc into an adjacent magnetic storage medium, wherein at least one of a portion of the peg, a portion of the disc, or a portion of both the peg and the disc include a multilayer structure including at least two layers including at least one layer of a first material and at least one layer of a second material, wherein the first material and the second material are not the same and wherein the first and the second materials independently include aluminum (Al), antimony (Sb), bismuth (Bi), boron (B), barium (Ba), calcium (Ca), cerium (Ce), chromium (Cr), cobalt (Co), copper (Cu), erbium (Er), gadolinium (Gd), gallium (Ga), germanium (Ge), gold (Au), hafnium (Hf), indium (In), iridium (Ir), iron (Fe), lanthanum (La), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), niobium (Nb), osmium (Os), palladium (Pd), platinum (Pt), rhenium (Re), rhodium (Rh), ruthenium (Ru), scandium (Sc), silicon (Si), silver (Ag), strontium (Sr), tantalum (Ta), thorium (Th), tin (Sn), titanium (Ti), vanadium (V), tungsten (W), ytterbium (Yb), yttrium (Y), zirconium (Zr), or combinations thereof.
Thu, 01 Dec 2016 08:00:00 ESTDevices that have an air bearing surface (ABS), the device includes a near field transducer (NFT) that includes a disc configured to convert photons incident thereon into plasmons; and a peg configured to couple plasmons coupled from the disc into an adjacent magnetic storage medium, wherein the disc includes a disc material that includes gold or an alloy thereof and the peg includes a peg material, wherein the disc material is different from the peg material and wherein the peg material has a real part of the permittivity that is not greater than that of gold.
Thu, 01 Dec 2016 08:00:00 ESTA near-field transducer includes first and second stacked base portions having a common outline shape. The second base portion is proximate alight delivery structure. A peg extends from the first base portion towards a media-facing surface. The peg includes a material that is more thermally robust than a plasmonic material of the base portion. The peg has a peg thickness that is less than a thickness of the first base portion. The first base portion has a first recess proximate the peg. The first recess separates the first base portion from the media-facing surface and exposes at least a top side of the peg.
Thu, 01 Dec 2016 08:00:00 ESTEmbodiments disclosed herein generally relate to a HAMR head. The HAMR head includes a main pole, a waveguide and a NFT disposed between the main pole and the waveguide. The NFT includes an antenna, and the antenna is made of a compound that has a composition that varies based on the location within the antenna. In one embodiment, the antenna has a surface at a media facing surface (MFS) and the surface has an apex, and the composition of the compound varies from the apex in a direction away from the apex. The apex has the highest temperature during the operation of the HAMR head, and having a composition that is thermally stable at the apex helps achieve higher reliability.
Thu, 24 Nov 2016 08:00:00 ESTA holographic light-emitting module includes a light source module and a light shape control module. The light source module is configured to provide a signal light beam and a reference light beam, in which polarizations of the signal light beam and the reference light beam are orthogonal. The light shape control module is configured to receive the signal light beam and the reference light beam propagated from the light source module, in which the signal light beam and the reference light beam are modulated and emitted by the light shape control module The reference light beam is surrounded by the signal light beam and located at a center of the signal light beam, and the signal light beam and the reference light beam are partially overlapped.
Thu, 24 Nov 2016 08:00:00 ESTAn apparatus comprises a spindle to rotate a magnetic recording medium and a magnetic field generator to expose a track of the medium to a DC magnetic field. The magnetic field generator is configured to saturate the track during an erase mode and reverse the DC magnetic field impinging the track during a writing mode. A laser arrangement heats the track during the erase mode and, during the writing mode, heats the track while the track is exposed to the reversed DC magnetic field so as to write a magnetic pattern thereon. A reader reads the magnetic pattern and generates a read signal. A processor is coupled to the reader and configured to measure one or more magnetic properties of the track using the read signal. The apparatus can further comprise a Kerr sensor that generates a Kerr signal using the magnetic pattern.
Thu, 24 Nov 2016 08:00:00 ESTA heater power of a heat-assisted magnetic recording head is set to an initial power to induce an initial head-medium clearance. For a plurality of iterations, a heater power at an optimum laser power is determined that achieve a target clearance. If differences in the heater power and optimum laser power between the two subsequent iterations are below a threshold, the iterations are stopped and the heater power and the optimum laser power for one of the two subsequent iterations is used as an operational heater power and laser power for the heat-assisted magnetic recording head.
Thu, 24 Nov 2016 08:00:00 ESTA write-once type information recording medium according to one aspect of the present disclosure includes at least one recording layer. In the information recording medium, the at least one recording layer has a spiral shape in which a land track and a groove track are alternately arranged as a recording track, the recording track is divided into blocks each of which being minimum unit in which recording is performed, and the information recording medium includes a management information area where management information is recorded and a user data area where user data is recorded. Each of the management information areas of both the land track and the groove track on each recording layer of the at least one recording layer is disposed at a same distance from the center of the information recording medium.
Thu, 24 Nov 2016 08:00:00 ESTA thermally-assisted magnetic recording head includes a main pole, a plasmon generator, and first and second side shields. The main pole has a front end face located in the medium facing surface. The plasmon generator has a near-field light generating surface located in the medium facing surface. The front end face of the main pole includes a first end face portion, and a second end face portion greater in width than the first end face portion. The first and second side shields have first and second side shield end faces located on opposite sides of at least part of the near-field light generating surface and at least part of the first end face portion in the track width direction.
Thu, 17 Nov 2016 08:00:00 ESTAn optical device, such as an optical storage medium, comprises a layer of material in the solid state that has a refractive index that is switchable between at least two stable values by applied light. A reflector is spaced apart from the layer of material by a solid spacer layer transmissive to light.
Thu, 17 Nov 2016 08:00:00 ESTAn optical information storage medium includes a multilayer film that includes a plurality of extruded alternating active data storage layers and buffer layers, which separate the active data storage layers. The active data storage layers and buffer layers have thicknesses that allow the active data storage layers to be writable by non-linear or threshold writing processes to define data voxels within the active data storage layers that are readable by an optical reading device.
Thu, 17 Nov 2016 08:00:00 ESTA reference beam adjusting method for reproducing information recorded on an optical information recording medium by utilizing interference of a signal beam with a reference beam includes a step of changing the wavelength of the reference beam; a step of changing the angle of the reference beam to the optical information recording medium; a step of detecting a brightness distribution of the reproduction image from the optical information recording medium; a step of calculating a gravity center dispersion in the brightness distribution of the reproduction image; and a step of controlling the angle and wavelength of the reference beam based on the gravity center dispersion.