Abstract: An aspect of the invention provides an image reading apparatus including: first and second light emitters that emit lights; a light guide unit that guides the lights emitted from the first and second light emitters to irradiate a document with the light; a photoelectric conversion unit that converts reflected light from the document into an image signal; and a control unit that controls the first light emitter to emit light for a first time period in a unit time period and controls the second light emitter to emit light for a second time period misaligned from the first time period in the unit time period.

Abstract: An imaging lens comprises a first, a second, a third, and a fourth lens group from an object toward an image. The first lens group includes a first lens that is a convex meniscus lens with a convex surface on the object side. The second lens group includes a second lens having a positive refractive power, and a third lens bonded to the second lens and having a negative refractive power. The third lens group includes a fourth lens having a negative refractive power, and a fifth lens bonded to the fourth lens and having a positive refractive power. The fourth lens group includes a sixth lens having a positive refractive power. The imaging lens satisfies the condition 0.10<D/f<0.19 where D denotes a sum of an air gap between the first lens and the second lens and an air gap between the fifth lens and the sixth lens, and f denotes a focal length of the entirety of the imaging lens with respect to an e-ray.

Abstract: A graphical scanner for scanning a graphical image includes a source for producing an optical beam, a monochromator for dividing the optical beam into a plurality of component beams for hyperspectral bandpasses, a director for directing the component beams to illuminate portions of the graphical image, a sensor for measuring a light intensity for the one or illuminated portions, and a translator for transforming the measured light intensities for each of the one or more portions into hyperspectral traces each representing a spectral power distribution. The translator further transforms the hyperspectral traces into one or more device-independent representations of color.

Abstract: In order to enable a user to easily and quickly set the processing mode, the user interface device sets the processing mode for job execution in an image processing apparatus. This user interface device includes specifying means that specifies the processing modes presented to the user prior to processing mode setting as presentation processing modes, generating means that generates presentation preview images indicating processing results when the image data is processed using the presentation processing modes, display means that displays the generated presentation preview images, and setting means that sets in the image processing apparatus the processing modes corresponding to the displayed presentation preview images.

Abstract: An imaging apparatus capable of performing image conversion such as white balance with a simple operation to obtain image data suited to user's preference, includes an imaging section, an image divider, a calculator, and an image converter. The imaging section images a subject to generate image data. The image divider divides a whole region of the generated image data into plural regions, and outputs first data including data in at least one of the divided regions and second data including data in at least one of other divided regions. The calculator calculates a first set value (for example, for correcting white balance of the image data) based on the first data, and a second set value based on the second data. The image converter generates first converted image data (for example, with corrected white balance) based on the first set value, and generates second converted image data based on the second set value.

Abstract: An image display body in which a decorative effect is obtained more effectively by an optical diffraction structure. In an image display body, an optical diffraction structure portion constituted by the optical diffraction structure in a halftone dot state is provided in a colored region on a base material. In the image display body, a dot area percent of a halftone dot a constituting the optical diffraction structure portion to the colored region ranges from 15% to 60%, an area of each halftone dot a is smaller than 0.25 mm2. The halftone dots 21a are diffused by an error diffusion method.

Abstract: A multicolor hologram (e.g., a two-color hologram) is replicated (copied) into a photosensitive layer by masking to produce a copy (replicate) of the hologram in a manner such that the copy is an accurate and true replication of the hologram (e.g., master hologram), and the copy is characterized to possess a high brightness level and color fidelity comparable to that of the multicolor hologram that was replicated. Both flood and scan modes can be employed in the replication.

Abstract: There is provided an optical device, comprising a display source; a light-diffuser; an imaging optical module, and an output aperture from the optical device characterized in that the light diffuser is an angular, non-uniform diffuser of light for increasing a portion of light emerging from the display source that passes through the output aperture. A method for improving the brightness of an optical display is also provided.

Abstract: An optical scanning device is provided with a scanning unit including an oscillating element which is elastically and rotatably supported so as to rotatably oscillate, a light beam incident on the scanning unit being deflected to scan as the oscillating element oscillates, a scanning signal generating unit which generates a scanning signal, the scanning signal including a sawtooth wave part and a corrective wave part which is formed based on a resonance frequency intrinsic to the scanning unit, and a driving unit which drives the scanning unit to oscillate the oscillating element in accordance with the scanning signal.

Abstract: A scanning display device is disclosed. The scanning display device includes: first to M-th scan mirrors (where M is an integer of at least 2), each of which scans a light signal in a first direction; and a scanning unit for scanning the light signal scanned by each of the first to M-th scan mirrors in a second direction, wherein a m-th scan mirror (where 1?m?M?1) scans the light signal in the first direction, and a n-th scan mirror (where 2?n?M) adjacent to the m-th scan mirror scans the light signal scanned by the m-th scan mirror in the first direction.

Abstract: A micromechanical device and system utilizing a supplemental reset pulse to ensure deflectable members deflect to the desired position. After loading data into a micromechanical device, a reset pulse is used to position the deflectable member to a position indicated by the data. A supplemental reset pulse is then applied to ensure the deflectable member is driven to the position indicated by the data. The method and system are also used to ensure the deflectable members are driven to a neutral position.

Abstract: An iterferometric modulator array is configured to reflect a broad band spectrum of optical wavelengths by arranging a reflector and a partially transparent substrate in a non-parallel relationship.

Abstract: An actuator, includes: a weight part; a supporting part supporting the weight part; a connecting part coupling the weight part rotatable to the supporting part and having an elastic part; a driving member for driving and rotating the weight part; and a semiconductor circuit for driving the weight part. The driving member is operated to torsionally deform the elastic part and rotate the weight part. The elastic part has a first silicon part that is mainly made of silicon and a first resin part that is mainly made of resin and coupled to the first silicon part. The supporting part has at least a second silicon part made mainly of silicon and coupled to the first silicon part of the elastic part. The semiconductor circuit is provided on the second silicon part of the supporting part.

Abstract: The present invention discloses a structure and method for realizing electromagnetically-induced transparency. In the present invention, a first split-ring resonator and a second split-ring resonator form a resonance structure. The first split-ring resonator and the second split-ring resonator are made of a conductive material. The first split-ring resonator has a “U” shape with a containing space. The second split-ring resonator has a “rectangular loop” shape with a gap or has a “U” shape with an opening. The second split-ring resonator is inserted into the containing space with the gap or opening arranged inside the containing space and faced downward to form the resonance structure. The resonance structures are periodically arranged on a chip to form an array. Thereby, different-frequency electromagnetic waves can be used to generate electromagnetically-induced transparency via regulating the dimensions of the resonance structure.

Abstract: A photochromic optical article comprises a substrate, and a photochromic coating coated on an outer surface of the substrate and having at least two photochromic layers. Each of the photochromic layers has a composition that contains a carrier and at least one photochromic dye. The compositions of the photochromic layers are different from each other.

Abstract: An electrophoretic display device is described. The device includes a substrate, first electrodes, an electrophoretic film having electrophoretic particles, and second electrodes. The substrate is has a plurality of pixel regions. First electrodes are disposed respectively on each pixel region, and include first patterns separated from one another and second patterns connected to the first patterns. The second electrode is disposed on the electrophoretic film. The area of one of the electrodes, opposing the other of the electrodes has apertures formed therein, reducing the contact area between the electrode and the electrophoretic film.

Abstract: Provided is an electrochromic device (ECD) that includes: a first transparent electrode having a first substrate having thereon a first electrically conductive layer; a second transparent electrode having a second substrate having thereon a second electrically conductive layer; a first polymeric layer on the first transparent electrode, wherein the first polymeric layer includes a cathodic electrochromic polymer and a first non-electrochromic polymeric matrix; a second polymeric layer on the second transparent electrode, wherein the second polymeric layer includes an anodic electrochromic polymer and a second non-electrochromic polymeric matrix; and an electrolyte layer disposed between the first polymeric layer and the second polymeric layer. Also provided is a process of producing the ECDs, as well as the electrochromic layers themselves.

Abstract: An electrochromic device including: (a) a first substantially transparent substrate having an electrically conductive material associated therewith; (b) a second substrate having an electrically conductive material associated therewith; (c) an electrochromic medium contained within a chamber positioned between the first and second substrates which includes: (1) a solvent; (2) an anodic material; and (3) a cathodic material, wherein both of the anodic and cathodic materials are electroactive and at least one of the anodic and cathodic materials is electrochromic; (d) wherein a seal member, the first substrate, the second substrate, and/or the chamber includes a plug associated with a fill port; and (e) wherein the plug is at least partially cured with an antimonate photo initiator and/or is one- or two-part plug which comprises a resin or mixture of resins that are substantially insoluble and/or substantially immiscible with an associated electrochromic medium while in the uncured state.

Abstract: A delay-line demodulator for demodulating a differential quadrature phase shift keying (DQPSK) signal is provided. The demodulator includes two Mach-Zehnder interferometers individually comprising two waveguides having different lengths therebetween and through which a light signal branched from the DQPSK signal propagates, respectively. A phase of the light signal propagating at one of the waveguides is delayed as compared to a phase of the light signal propagating at another one of the waveguides, wherein a divergence amount of polarization is adjusted by driving sets of heaters that are facing each other and sandwiching a half wavelength plate therebetween.

Abstract: Systems and methods for coherent beam combination of lasers are provided. In one embodiment, a method for coherent beam combination is provided. The method comprises providing a plurality of secondary laser signals from a primary laser signal, amplifying the plurality of secondary signals along respective amplifier arms to provide a plurality of amplified output signals, providing a frequency-shifted reference beam from the primary laser signal, generating a plurality of optically heterodyne detected (OHD) beat signals based on combining respective amplified output signals of the plurality of amplified output signals with the frequency-shifted reference beam, and adjusting path lengths of respective amplifier arms based on respective amplitudes of the plurality of OHD beat signals to control the path length of respective amplifier arms to within a coherence length of the primary laser signal.

Abstract: An objective for imaging specimens is disclosed. The objective receives light energy from a light energy source configured to provide light energy in a wavelength range of approximately 480 to 660 nanometers, employs a Mangin mirror arrangement in conjunction with an immersion liquid to provide a numerical aperture in excess of 1.0 and a field size in excess of 0.05 millimeters, where every element in the objective has a diameter of less than approximately 40 millimeters.

Abstract: The size and production costs of an optical microscope apparatus capable of blocking light or maintaining the specimen environment are reduced. The provided optical microscope apparatus includes a microscope that has a stage for mounting a specimen (A), a transmission-illumination optical system, and a detection optical system; and a housing that surrounds the microscope, wherein the housing includes a fixed housing, and a movable housing, wherein, among optical parts constituting the transmission-illumination optical system and the image-forming optical system, at least some optical parts disposed above the stage are movable, and wherein a switching mechanism is provided, the switching mechanism being configured to retract the optical parts away from above the stage when the movable housing is disposed in an open position relative to the fixed housing and to substantially align the optical axes of both optical systems when the movable housing is disposed in a closed position relative to the fixed housing.

Abstract: An apparatus for imaging cells including a culture chamber, in which a cultivation sub-structure is placed, imaging optics, and actuators for providing the relative movement of the cultivation substructure and the imaging optics in such a way that the imaging optics is used to image different sites in the substructure. The cultivation substructure is isolated as a subchamber of its own that is separate from the culture chamber, and imaging is carried out by moving the imaging optics and the subchamber in relation to each other.

Abstract: An optical device may include at least one optical element and a coupling section adapted to control relative movement between the at least one optical element and the coupling section. The coupling section may include an engaging element and a detent mechanism adapted to adjustably lock the at least one optical element in a plurality of rotational positions. The rotational positions may include rotational positions around a first axis that is substantially perpendicular to a second axis of the at least one optical element, the second axis being a substantially longitudinal axis of the at least one optical element.

Abstract: A floor projection screen to be installed in front of department stores, shops, shopping malls, and a method for manufacturing the same are disclosed. The floor projection screen is formed by overlapping a hard screen material, which is obtained by mixing white cement with a light diffuser such as glass beads, silica, etc. having a particle of 400 to 800 mesh, or by mixing plastic resin with white cement, calcium material, pigments, etc., and a soft material such as urethane, rubber, or non-woven fabrics, thereby achieving vivid imaging, an anti-skid function, and durability for friction.

Abstract: An optical diffusing sheet is provided, which prevents deterioration in image quality which might result from warping of the sheets due to environmental changes, and is capable of, even if a substrate is broken by an accident, preventing scattering of pieces of the broken substrate. An optical diffusing sheet is used in a transmission type screen that emits imaging light projected from an incident side to an emergent side. The optical diffusing sheet includes a highly rigid substrate layer with a light-transmissibility and a high rigidity, and a plurality of layers laminated on the highly rigid substrate layer. The plurality of layers includes at least a pair of anti-scattering layers disposed on opposite sides of the highly rigid substrate layer for preventing scattering of the highly rigid substrate layer. At least one layer of the two or more layers includes an optical diffusing element that diffuses imaging light.

Abstract: An optical element having a function of splitting incident light into polarized beams includes a substrate transparent for the incident light; a diffractive structure that includes a plurality of concave portions and a plurality of convex portions alternately arranged with each other, each of the plurality of concave portions and convex portions having a rectangular sectional shape and that is provided on a first surface of the substrate; and a grid that includes a plurality of fine lines extending in a single direction and that is provided across a top surface of the diffractive structure on the first surface of the substrate, wherein conditions: d<? and ?/n<??? are satisfied when ? represents a wavelength of the incident light; d represents a distance between the neighboring fine lines; ? represents a distance between the convex portions; and n represents a refractive index of a material forming the substrate.

Abstract: An eyepiece system has a lens group S1 in which a lens L1 having a negative refractive index and refractive power and a lens L2 having a positive refractive index and refractive power are joined, so that the lens group S1 as a whole has a positive refractive index and refractive power; and a multi-layer (stacked) diffraction optical element PF. In an optical system positioned between an image surface I and an eye point EP, the position of a diffraction plane on the optical axis is between EF in FIG. 1. In FIG. 1, EF is the range in which the value ra of the ratio between a distance (DH2) between the diffraction plane (C) and a principal point (H2) near the diffraction plane and a distance (DH1H2) between principal points is 0.5 or less in both directions from the principal points H1, H2.

Abstract: A lens unit includes a lens array, a first light blocking member, and a second light blocking member. The lens array includes a plurality of lens pairs arranged in a substantially linear arrangement. Each of the lens pairs includes a first lens for forming an inverted reduced-size image of an object and a second lens for forming an inverted enlarged-size image of the inverted reduced-size image. The first light blocking member is disposed between the first lenses and the second lenses, and includes first apertures. The second light blocking member includes second apertures arranged in a substantially linear arrangement corresponding to an arrangement interval of the lens pairs, and having different opening portion shapes depending on a position of the lens pairs in an optical axis direction of the lens pairs. The second light blocking member is disposed at least between the first lenses and an object plane or the second lenses and an image plane.

Abstract: An optical element includes: an element body including a resin containing a polymer having an alicyclic structure. The optical element is treated by one of heat treatment and wet-heat treatment for 15 hours or longer at a temperature lower by 10° C. to 30° C. than a glass transition temperature of the resin after being formed by injecting the resin in a mold. The optical element body has a length along an optical axis of the optical element in a range of 0.5 to 3 mm, and a length in a perpendicular direction to the optical axis in a range of 3 to 5 mm.

Abstract: The invention relates to an optical system for the projection of digital image data comprising a fixed focal length lens and a pivotable focal length extender. The principal field of application of the invention is digital cinema projection, usually employing the wide-screen format 1.9:1 or the Cinemascope format 2.37:1 (width:height). For format changeover during projection, two different fixed focal lengths are realized by the insertion or removal of the focal length extender (1755) into the lens. The projection lens according to the invention has more favorable optical properties than the conventional zoom lenses, such as a minimal chromatic transverse aberration, high telecentricity, very small distortions and a small volume and weight.

Abstract: A small projection lens includes a first lens, which is a biconvex lens, an aperture, an aperture diaphragm (or an aperture), a second lens, which is a negative meniscus lens having a concave surface facing a magnification side, a third lens, which is a positive meniscus lens having a convex surface facing a reduction side, and a fourth lens, which is a biconvex lens having aspheric surfaces at both sides on an optical axis, arranged in this order from the magnification side. A minimum portion of the length of all lens elements of the small projection lens in a diametric direction vertical to the optical axis is equal to or less than 15 mm, and the small projection lens satisfies the following conditional expression: 2.5<?/S<10.0 (where S indicates the maximum length of a magnification-side image (inch) and ? indicates a magnifying power).

Abstract: A wide field video endoscope objective and method of assembly the objective including four groups with five lenses, a mechanical housing containing the entire image forming elements, a aperture stop, a centering member and a retainer sleeve. The centering member is at first centered over the photo sensitive area of the chip and bonded to the surface of the cover glass. The retainer sleeve slides over said centering member and is glued to the centering member and the housing of the video chip. The objective housing with the optical elements is screwed on the centering member to adjust for focusing.

Abstract: A wide angle hybrid refractive-diffractive endoscope objective is provided. The objective comprises a negative meniscus lens having a first surface and a second surface; a stop adjacent to the negative meniscus lens; a positive lens adjacent to the negative lens and having a first surface and a second surface; and a hybrid refractive-diffractive element adjacent to the positive lens and having a first surface and a second surface, wherein one of the first surface, or the second surface comprises a diffractive surface, wherein the objective has an effective focal length in a range from about 0.8 mm to about 1.6 mm.

Abstract: An illuminator (10) for producing a radiation spot (120) on a workpiece (110) comprises a laser light source (20) and a beam-shearing optical system (30). Fine structure (160) generated by an integrator (80) of laser light source (20) in integrated beams (90) as a result of path length differences among coherent light beams (70) from emitters (60) of lasers (40) is sheared by the inclusion of beam-shearing optical system (30) into illuminator (10). Beam-shearing optical system (30) allows illuminator (10) to produce a radiation spot (120) in which the fine structure (160) is spread so that scanning of radiation spot (120) does not produce the striations (140) in scanned patch (170) that are obtained with prior art illuminators.

Abstract: A zoom lens includes, in order from the object side thereof, a first lens unit G1 having a positive refracting power, a second lens unit G2 having a negative refracting power, and a third lens unit G3 having a positive refracting power, wherein zooming is performed by changing distances between the lens units, the second lens unit has two negative lens elements and one positive lens element, and the lens element located closest to the object side is a negative lens element. The zoom lens satisfies the following conditions: 0.60<?d2G/Imw<1.95??(1-1) and 1.830<N2ave<2.000??(1-2), where the term “lens element” refers to an optical member that satisfies 0.1<L/Imw.

Abstract: A zoom lens system including, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a negative refractive power; an aperture stop; and a fourth lens unit having a positive refractive power and including a front lens subunit and a rear lens subunit in which Abbe numbers of lenses in the rear lens subunit satisfy the following expression, 0.400<?m/(?rp??rn)<0.630, where ?m represents the Abbe number of the material of a first positive lens having the largest dispersion of the positive lenses included in the rear lens subunit, ?rp represents the average Abbe number of materials of positive lenses other than the first positive lens in the rear lens subunit, and ?rn represents the average Abbe number of materials of negative lenses in the rear lens subunit.

Abstract: A two-lens type optical lens system for taking image consists two lens elements with refractive power, from the object side: a positive first lens element with a convex object-side surface and a concave image-side surface, both the object-side surface and the image-side surface of the first lens element being aspheric; a positive second lens element with a concave object-side surface and a convex image-side surface, both the object-side surface and the image-side surface of the second lens element being aspheric, and an aperture stop located in front of the first lens element. A focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the optical lens system is f, a radius of curvature of the object-side surface of the second lens element is R3, and they satisfy the relations: f/f1>0.9; (f/f1)>(f/f2)>0.35; and 1/R3<?0.01 mm?1.

Abstract: Disclosed herein is a light quantity adjusting device including: first and second diaphragm blades shiftably provided to adjust a size of a diaphragm aperture; a neutral density filter blade provided shiftably in the same direction as the first and second diaphragm blades and having a neutral density filter adapted to cover the diaphragm aperture to reduce a quantity of light passing through the diaphragm aperture; and a drive mechanism adapted to shift the first and second blades and the neutral density filter blade; wherein the drive mechanism is configured to include an actuator, a first cam groove, a second cam groove, a third cam groove, an arm, a first cam-pin, and a second cam-pin.

Abstract: An objective lens system for endoscope comprising at least a first negative lens element, a second positive lens element, an aperture stop, and a cemented lens component consisting of a third negative lens element and a fourth positive lens element, and being configured so as to satisfy the conditions (2), (5) and (4) or the conditions (2), (3) and (4) which are mentioned below, whereby the lens system corrects lateral chromatic aberration and longitudinal chromatic aberration with a good balance, favorably corrects aberrations such as chromatic aberration and has a compact composition or a short total length. D2/f<0.9??(2) |f/(f1×?1)+f/(f2×?2)|<0.025??(5) 1.5<|(f4×?1)/(f3×?3)|??(4) |f/(f5×?5)?f/(f1×?1)?f/(f2×?2)|<0.025.

Abstract: A second optical element is bonded to a first optical element by forming the second optical element larger in diameter than the first optical element by pressing a second optical element material against the first optical element under a condition free from restriction to at least part of the second optical element material in the direction orthogonal to a direction in which the second optical element material is pressed.

Abstract: A lens drive device has (i) an objective lens and (ii) a lens holder, to a side face of which coils for drive control are attached. The surface where the coils are adhered, or the side surface, is an irregular surface where a recess/projection section for restricting the direction of flow of an adhesive is formed. The coils and the lens holder are integrally formed together by the adhesive with the recess/projection section in between.

Abstract: A lens barrel includes a rotational ring, first and second movable members linearly movable having first and second followers, respectively; and first and second guide grooves formed on the rotational ring, the first and second followers being slidably engaged therein, respectively. The first movable member has a non-linear moving path. The first guide groove includes an inclined linear lead groove. The lens barrel includes a complementary cam mechanism for controlling the rotational ring to define a non-linear moving path of the first movable member via a cam track of the complementary cam mechanism and a track of the linear lead groove. The second guide groove includes first and second lead groove portions extending parallel to the linear lead groove at different positions in the optical axis direction, and a differential groove portion extending in the circumferential direction which connect the first and second lead groove portions.

Abstract: In one embodiment, an actuator for positioning of mirrors in an optical system is provided and includes an actuator base and a reaction mass assembly. The reaction mass assembly includes a reaction mass support member having biasing features formed as a part thereof and a reaction mass that is coupled to the biasing features such that the reaction mass is suspended on biasing elements in six degrees of freedom (DOF). The support member is fixedly connected to the actuator base; however, the reaction mass is not directly attached to the actuator base but rather is supported in the reaction mass support member in a manner that allows it to have six DOF.

Abstract: A swinging and tilting mechanism includes a lens, a lens holding frame that holds the lens, a fixed member, and an operation member. The fixed member includes a rotation support portion that rotatably supports the lens holding frame in at least one side surface in one direction perpendicular to an optical axis of an optical system, and a tilting support portion that supports the lens holding frame tiltably in a direction of the optical axis in at least one side surface in another direction perpendicular to the optical axis and the one direction. The operation member rotates the lens holding frame supported by the fixed member with the rotation support portion used as a support point, and tilts the same along the tilting support portion.

Abstract: Disclosed is a lens driving apparatus. The lens driving apparatus comprises a base, a yoke coupled to the base, having an upper surface formed with a hole, a closed side surface, and an opened bottom surface, a bobbin movably installed in an inner portion of the yoke, a lens module coupled to the bobbin to go in and out the hole according to movement of the bobbin, a magnet fixed to an inner portion of the yoke, a coil fixed to an outer portion of the bobbin while facing the magnets, and springs coupled to the bobbin to provide restoration force to the bobbin.

Abstract: An enhanced oscillation test for detecting off track writing associated with a read/write head writing, on a magnetic media, a measurement track. Once the measurement track is written, a series of seek, write, and read operations is performed, e.g., between various origin tracks and the tracks adjacent to the measurement track, in order to detect any off track write problems. If a measurement track read operation fails a certain number of times, then an error code is generated which indicates an off track write problem.

Abstract: A data storage system includes a storage medium having a plurality of data sectors and a head that communicates with the data storage medium. The head produces a readback signal when reading information from the data storage medium. A computation unit extracts a distortion component of the readback signal and generates a position error signal from the distortion component.

Abstract: A magnetic recording medium and a method of fabricating the same are provided. The magnetic recording medium in which a position for magnetic recording is patterned with a magnetic material, includes a magnetic recording layer which includes a data area having a plurality of data tracks, and a servo area having a servo burst for following the data tracks, wherein the servo burst includes a plurality of bursts disposed in a zigzag structure along a downtrack direction, and each of the bursts includes a plurality of burst pieces having different coercivities from each other. The magnetic recording medium is subjected to two servo-recording processes, so that a signal similar to an alternative signal written in a burst having a burst pattern used in a related art continuous medium can be obtained.

Abstract: Embodiments of the present invention provide a magnetic disk drive in which the error correction capability of ECC is improved without sacrificing the storage capacity. In one embodiment, a data track adopts a format structure in which no data-to-data gap area is formed in data sectors. When one of the data sectors is updated in a state in which the rotational speed of a magnetic disk does not satisfy specified conditions, a leading end area of a succeeding data sector or a trailing end area of a preceding data sector is overwritten by the data sector. If a read error occurs in the overwritten data sector, ERP steps are executed to perform read retry so that the read error is recovered by means of on-the-fly ECC or erasure correction. In the case of the erasure correction, an erasure pointer equivalent to the maximum number of overwritten bytes is set.