Abstract: An objective optical system is disclosed that is suitable for a high-precision endoscope that performs focusing by moving a single lens component. The objective optical system includes, in order from the object side, a front lens group, a middle lens group, and a rear lens group. The middle lens group is composed of two or more lens components, at least two of which have positive refractive power, and the lens component that is moved for focusing is in the middle lens group. Additionally, the objective optical system satisfies two specified conditions, and other conditions may apply.

Abstract: A zoom lens includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power. The first to third lens units are arranged in that order from an object side toward an image side, and change the distances therebetween during zooming. The following conditions are satisfied: 0.70<f2/?{square root over ((fW·fT))}<0.95, and 2.9<(?2T·?3W)/(?2W·?3T)<3.7 where fW and fT respectively represent the focal lengths of the entire zoom lens at a wide angle end and a telephoto end, f2 represents the focal length of the second lens unit, ?2W and ?2T respectively represent the imaging magnifications of the second lens unit at the wide angle end and the telephoto end, and ?3W and ?3T respectively represent the imaging magnifications of the third lens unit at the wide angle end and the telephoto end.

Abstract: The invention relates to a slimmed-down, small-format, high-zoom-ratio bent type zoom optical system that can be tucked away in a lens mount and an imaging system incorporating the same. The bent type zoom optical system or taking system comprises, in order from its object side, a first lens group G1 of positive refracting power, a second lens group G2 of negative refracting power and a reflecting mirror R located on an image side with respect to the second lens group G2 for bending an optical axis at substantially right angles upon zooming. Between the reflecting mirror R and an imaging plane I there are a plurality of lens groups G2 and G4 interposed. For zooming, while the spacing between the first G1 and the second lens group G2 varies, at least one lens group of the plurality of lens groups G2 and G4 lying on the imaging plane side of the reflecting mirror R moves.

Abstract: Lens barrel 3 includes a stationary frame 20, a drive frame 30, a rotation cam frame 70, and a first lens frame 60. The drive frame 30 is supported by the stationary frame 20 to be movable in a Y axis direction along an optical axis of an imaging optical system O and rotatable around the optical axis in response to a drive force. The rotation cam frame 70 is supported by the drive frame 30 to be movable in the Y axis direction relative to the drive frame 30 in response to the drive force. The first lens frame 60 supports a first lens group G1 included in the imaging optical system O, and is supported by the rotation cam frame 70 to be movable in the Y axis direction relative to the rotation cam frame 70 in response to the drive force.

Abstract: An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens having a positive refractive power and having a convex surface on the object side; a second lens having a negative refractive power and having a concave surface on the object side; a third lens having a positive refractive power in the vicinity of an optical axis thereof; and a fourth lens of a meniscus lens having a negative refractive power and having a convex surface on the object side, the imaging lens satisfying the specific conditional expressions.

Abstract: The present invention provides an image pickup lens for forming an image of an object on a photoelectrical converter of a solid-state image pickup element. The image pickup lens includes: an aperture stop; a first lens having a positive refractive power and having a meniscus shape whose surface facing the object side is convex; a second lens having a negative refractive power whose surface facing an image side of the image pickup lens is concave; and a third lens having a positive refractive power and having a meniscus shape whose surface facing the object side is convex. Each of the first lens, the second lens, and the third lens includes an aspheric optical surface. The image pickup lens satisfies predetermined conditions according to a focal length of the first lens, and a refractive power of an air lens formed from surfaces of the second lens and the third lens.

Abstract: There is provided an objective lens for an optical pick-up. The objective lens is formed to be a single-element plastic lens having a first surface and a second surface. The first surface is configured to have, within an effective diameter, an inflection point at which a second derivative of a sag of the first surface takes a value of 0. Further, the objective lens having a numerical aperture larger than or equal to 0.75.

Abstract: It is to provide an imaging lens and an imaging device including the imaging lens in which the imaging lens can maintain excellent optical performance, while achieving sufficient reduction in size and weight. The imaging lens comprises, in order from an object side to an image surface side, a diaphragm, a first lens that is a biconvex lens having a positive power, a second lens having a negative power, a third lens having a positive power, and a fourth lens that is a biconcave lens, wherein a condition expressed by 0.7?FL/f1?3.0 (where, FL: focal distance of the entire lens system, and f1: focal distance of the first lens) is to be satisfied.

Abstract: An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens having a convex surface on the object side and having a positive power; a second lens having a concave surface on the object side and having a negative power; a third lens having a positive power; and a fourth lens having a convex surface on the object side near a paraxial axis and having a meniscus shape. The imaging lens satisfies conditional expressions specified in the specification.

Abstract: The invention provides a mechanical viewing structure or theater for viewing small screens associated with personal electronic devices. The viewing structure is made of four semi-rigid trapezoid shaped walls joined together to form a hollow trapezoidal viewing structure that optionally is collapsible. The viewing structure has a larger opening that is fitted with a magnifying screen and a smaller opening adapted to be placed above the screen of the personal electronic device and magnify that image for the viewer. The invention also includes a projector that may be releasably attached to the viewing structure to allow an image present on the personal electronic device to be projected onto a remote surface, such as a wall or ceiling.

Abstract: A highly precision, super stable, structure compact and fully lockable ball joint mechanism optical mounts are presented. Both stationary plate and movable plate have a partial-spherical hole or conical hole. Facing spacing aligns the bases of the partial-spherical holes or conical holes; a space adjustable cavity is formed. An external-spherical circumference shape optical element carrier plate fits and mates in the space adjustable combined cavity forms a ball joint mechanism, or an external-column circumference and edges chamfered optical element carrier plate fits and mates in the space adjustable combined internal-spherical shaped cavity forms an angle tilt-able and around axis swivel-able joint pair mechanism. A removable tooling for exporting a tilting and rotating movement to the optical element carrier plate are presented. Locking ring pushes the movable plate to adjust the combined cavity and locking the optical element carrier plate and to lock optical element that is carried thereby.

Abstract: A lens actuator is provided for moving a movable part including a lens, with respect to a fixed part in the optical axis direction of the lens. The lens actuator includes (a) a magnet disposed on the surface of the movable part facing the fixed part and magnetized in the optical axis direction, (b) a coil disposed on the surface of the fixed part facing the magnet, and (c) a pair of magnetic materials disposed on both sides of the magnet in the optical axis direction, to direct magnetic flux from the magnet toward the coil.

Abstract: An arrangement for a micro-mechanical beam includes a support structure to provide an increase in bending stiffness of the micro-mechanical beam without significantly influencing torsional stiffness, where the support structure is configured to directly attach to the micro-mechanical beam.

Abstract: An external rearview mirror assembly is fixedly secured to a motor vehicle. The external rearview mirror assembly includes a mounting bracket which is fixedly secured to the motor vehicle. An arm is pivotally secured to the mounting bracket. The arm defines an elongated channel having an upper arm surface, a lower arm surface, and an intermediate arm surface disposed between the upper and lower arm surfaces. A case frame extends between a bracket and a distal end. The case frame defines an elongated channel for receiving the elongated channel therein. A mirror is movaably secured to the distal end of the case frame to provide a view rearward of the motor vehicle.

Abstract: A color wheel includes a motor, a filter and a dark slide. The motor has an adhering section and the filter is affixed to the motor by the adhering section. The filter has a first surface facing the motor and a second surface opposite to the first surface. The dark slide is affixed to the filter on the second surface. The dark slide matches the location and shape of the adhering section to block light from projecting onto the adhering section. The thermal expansion coefficients of the dark slide and the filter are substantially identical to avoid damage from thermal stress caused by heating and cooling. An assembling tool and an assembling method are also provided in the embodiments.

Abstract: An optical device, a method of manufacturing the optical device, a replica substrate for manufacturing the optical device, and a method of producing the replica substrate are disclosed. The optical device includes a base, and a plurality of structures arranged at a fine pitch equal to or shorter than a wavelength of visible light on a surface of the base. Each of the structures is composed of protuberance. The structures have a depth distribution.

Abstract: A servo system for detecting and demodulating servo data is disclosed. In illustrated aspects, a demodulation circuit or portion includes a correlator component configured to output a correlation of a sequence of equalized channel samples with a sequence of correlator weight derived based on at least one mapped channel sequence. A decision component, for example a threshold detector uses the correlation results to output a data bit symbol based upon the correlation of the sequence of equalized channel samples to the at least one mapped channel sequence.

Abstract: A method of forming a servo sync mark patterns on a disk is disclosed wherein alternating even-numbered and odd-numbered tracks are marked with a first servo sync mark pattern on the even-numbered tracks, and a second servo sync mark pattern, different from the first servo mark pattern, on the odd-numbered tracks. A write operation is controlled in an HDD in relation to either a first sync mark pattern or a second sync mark pattern read from a servo region of a current track and an expected sync mark pattern associated with a target track indicated by the write operation.

Abstract: A magnetic microstructure comprising (i) a magnetic storage layer having a magnetic easy axis perpendicular to a film plane of the storage magnetic layer; (ii) a magnetic assist layer having a magnetic easy axis in the film plane; and (iii) a phase transition interlayer between the magnetic storage layer and the magnetic assist layer. The phase transition layer comprises a material, such as FeRh, that switches from antiferromagnetic at ambient to ferromagnetic at a transition temperature that is greater than ambient, but below the Curie temperature. When the phase transition interlayer is in antiferromagnetic phase, there exists little magnetic coupling between the storage and assist layers. When the interlayer changes to ferromagnetic phase, the interlayer couples the magnetic moments of the storage and assist layer ferromagnetically.

Abstract: A storage drive implements a method for a BEMF voltage reduction during a deceleration period of an electric motor of the storage drive. In operation, the electric motor is disconnected from a power supply during an entirety of the deceleration period of the electric motor to prevent any flow of a BEMF current into the power supply, and the electric motor is connected to a power return during a segment or an entirety of the deceleration period of the electric motor to dissipate any BEMF voltage within the electric motor.

Abstract: A drive apparatus that handles and operates a recording medium attached with a memory tag, the drive apparatus include: a recording medium mounting part on which the recording medium is mounted; an information readout part configured to read information out of a memory tag attached to a recording medium before the recording medium is mounted on the recording medium mounting part; a determining part configured to determine whether the recording medium can be handled and operated based on the information read out by the information readout part; and an informing part configured to inform a determined result determined by the determining part.

Abstract: An emergency unload verification device verifies whether or not a control unit to control an emergency unload operation in a storage apparatus is abnormal. A storage section stores previous waveform information of a control signal to be sent out by the control unit for controlling the emergency unload operation. A waveform comparing section compares a waveform information of a control signal, sent out by the control unit for controlling the emergency unload operation when the emergency unload operation is executed, with the waveform information stored into the storage section. An abnormality determining section determines whether or not the control circuit is abnormal on the basis of the comparison result of the waveform comparing section.

Abstract: A tape drive having a reel release sensing procedure and system is provided. In one example, the tape drive includes a motor coupled to a reel driver for driving a reel of a storage device, a sensor for detecting movement associated with the reel driver, and a controller. The controller operates to activate the motor to rotate the reel driver prior to coupling the tape to a drive leader. The controller further determines if the reel driver moved in response to activating the motor based on a signal from the sensor, and causes the tape to be loaded into the drive if the reel moved (or moved more than a predetermined amount/distance). For example, the controller may determine the reel is released if the reel driver moved in response to activating the motor and is not released otherwise.

Abstract: A method of recording bits on a ferroelectric medium using a scanning probe or a small conductive structure and a recording medium thereof, in which bit sizes can be decreased to increase data recording density as well as to reduce losses in reproduction signals. The method includes applying switching voltages to a lower electrode of the ferroelectric medium and the probe so as to write bits while approaching the probe to or bringing the probe into contact with a surface of the ferroelectric medium; and applying a base bias voltage, which is equal or smaller in magnitude and opposite in sign to the switching voltages between the switching voltages to make the probe equipotential with an upper portion of the record medium.

Abstract: According to one embodiment, a disk drive includes a head, a shock sensor, and a controller. The head has a heating element for controlling the spacing between a disk medium and the head. When the shock sensor detects an impact applied to the disk drive, the controller controls the heating element, increasing the spacing between the head and the disk medium.

Abstract: The present invention is a servo signal recording method for recording a servo signal on a magnetic tape having a data band and a servo band, wherein erasure is performed based on a pulse having a duty ratio varied so that a driving time of the AC erasing head with respect to one polarity is longer than a driving time thereof with respect to the other polarity, and then, the servo band is magnetized so as to have a magnetization direction opposite to magnetization direction caused by the erasure to record a servo signal in the servo band. According to this configuration, the influence of an information recording signal recorded on the surface of a magnetic recording medium on a reproduction output is reduced, whereby the reproduction output of a servo signal can be enhanced easily.

Abstract: Hard disk drive (HDD) including humidity sensor measuring interior and second humidity sensor measuring exterior with door actuator controlling door for mass transfer between interior and exterior based upon determination of whether or not to transfer. HDD may further include and use temperature sensors for interior and/or exterior to further control door. An embedded circuit and processor at least partly implementing these operations. External cover including door and door actuator, possibly second sensors. Manufacturing methods and these items as their products.

Abstract: The transfer apparatus is directed toward electrical transfer components providing an electrical connection to a rotating object. The transfer apparatus includes a stator base mounted proximate to the rotating object. An axle rotatably mounts at least one conductive disk to the stator base. The conductive disk is held against the rotating object. As the rotating object rotates about a first axis, the conductive disk is made to rotate about a second axis, the second axis otherwise maintaining a static position. A rotationally immobile contact is maintained in substantial electronic contact with the conductive disk whereby a lead wire may be connected to the immobile contact.

Abstract: A spindle motor includes a spindle motor hub that supports one or more disks, and has a contact area reduction portion that minimizes the area of contact between the hub and a disk when the disk is mounted to the hub. The spindle motor hub includes a hub body having a cylindrical sidewall that includes a contact section around which the disk extends and a non-contact section. The non-contact section is constituted by the contact area reduction portion. An outer diameter of the cylindrical hub body at the contact section is greater than an outer diameter of the cylindrical hub body at the contact area reduction portion of the non-contact section.

Abstract: A perpendicular magnetic recording (PMR) head is provided which records data in a PMR medium. The PMR head includes a main pole having an end portion disposed on an air bearing surface (ABS) that is opposite to the PMR medium; a return yoke spaced apart from the main pole; a sub-yoke starting from the other end portion and extending away from the PMR medium, so as to magnetically connect the main pole with the return yoke; and a coil disposed to enclose the sub-yoke.

Abstract: In a patterned perpendicular magnetic recording medium, embodiments of the present invention provide a magnetic head in which magnetic field to be applied to adjacent tracks can be suppressed and a recording device equipped with the magnetic head. In one embodiment of the present invention, a sum of a width Pw of a main pole of a magnetic head and distances between right and left magnetic substances on a width-directional side of tracks and the main pole, so-called widths of side gap lengths s_g1—1 and s_g1—2 is, in a magnetic recording medium having a soft-magnetic underlayer, made to be not more than a sum of a width w_land of a convexity or land of the soft-magnetic underlayer and widths w_groove—1 and w_groove—2 of concavities or grooves adjacent to the land on both its sides.

Abstract: There is a thin-film magnetic head provided, which comprises a perpendicular recording head portion including a thin-film coil adapted to generate a magnetic flux, and a main magnetic pole layer that extends rearward from a recording medium opposite plane facing a recording medium and has a main magnetic pole adapted to release a magnetic flux produced at the thin-film coil toward the recording medium. A given concave groove form that is more constricted as the lower end draws nearer is provided at or near the flare point of the front end of the main magnetic pole, so that the flow of the magnetic flux through the main magnetic pole is focused on the upper end edge (gap portion), thereby improving overwrite performance and holding back the occurrence of pole erasure.

Abstract: An integral recording head, for use in a linear tape drive system, includes a circumferentially grooved roller guide assembly and a recording head actuator assembly. The circumferential groove feature is incorporated on the surfaces of the roller guide assembly, and provides a substantial frictional contact force that acts to reduce the lateral motion, and further attenuates high frequency lateral disturbances of the magnetic tape. The reduced high frequency content of the lateral disturbances significantly improves the ability of the actuator to achieve a desired track following control. The grooved roller guide assembly is formed integrally of two solid cylindrical contact surfaces separated by a circumferential slot that accommodates the recording head actuator assembly.

Abstract: The present invention relates to an object storage device having shaking function having a vertically situated storage cassette, which has multiple object storage points situated one on top of another, and having a drive unit functionally connected to the storage cassette via a first drive connection, comprising at least one drive element for performing a shaking movement of the storage cassette. The present invention also relates to a climatic cabinet having such an object storage device.

Abstract: Embodiments of the present invention provide a perpendicular magnetic recording medium having an improved writing property due to the exchange spring effect and capable of stable production. According to one embodiment, a perpendicular magnetic recording medium includes a non-magnetic substrate; an adhesion layer; a soft magnetic underlayer; a seed layer; and intermediate layer; a magnetic recording layer at least including a perpendicular recording layer, a writing assist layer, and a magnetic coupling layer disposed between the perpendicular recording layer and the writing assist layer; a protective layer, and a lubrication layer, in which the saturation magnetization of the magnetic coupling layer is lower than the saturation magnetization of the writing assist layer, the saturation magnetization of the magnetic coupling layer is 300 kA/m (300 emu/cc) or lower, and the thickness of the magnetic coupling layer is 1 nm or more and 3 nm or lower.

Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.

Abstract: A head slider for a magnetic disk drive is provided. The head slider includes a leading edge, a trailing edge and a ramp structure for deflecting impact of the slider with a disk defect, the ramp structure comprising a leading end and a trailing end wherein the ramp structure is higher with respect to the air bearing surface at the trailing end than the leading end and wherein the trailing end of the ramp structure is proximate the trailing end of the slider.

Abstract: A microactuator substrate. The substrate includes a stroke amplifier for generating an amount of amplified motion converted from a force received thereon. The substrate also includes a rotating device coupled to the stroke amplifier and comprising supporting rotational springs. The rotating device is separate and independent from the stroke amplifier and has a center of rotation substantially proximal to a center of mass of an object disposable thereon. The rotating device causes a rotation in a portion of the substrate upon receiving said amplified motion. The substrate further includes a piezoelectric (PZT) actuator that is coupled to the stroke amplifier and is for generating the force. The stroke amplifier and the rotating device are integrated within the substrate.

Abstract: In general, this invention is directed to a rail and slider system having residential and commercial organizational applications. In one aspect, the system comprises at least one rail and a slider mounted on the rail for sliding movement along the rail. The rail and slider have teeth which releasably engage with one another for locking the slider at selected positions along the rail. A spring device on the slider urges the slider toward a locked position. The slider is manually movable against the urging of the spring device from its locked position to an unlocked position in which the teeth on the arms and the tracks are disengaged to permit sliding movement of the slider along the rail to a different selected position. Various items can be attached to the slider, e.g., a funnel-shaped holder and shelf bracket.

Abstract: A slider assembly used in a direct access storage device includes electrically conductive bond pads formed on the slider body. A rigid and electrically non-conductive material surrounds and abuts the bond pads. The material and the bond pads form a planar surface. The material prevents the bond pads from migrating and shorting, so that the bond pads can be placed closer together.

Abstract: According to an aspect of an embodiment, a method for manufacturing a magnetic head support having a piezoelectric device on a metal plate member comprises the steps of: providing a metal plate member; forming a piezoelectric layer of a piezoelectric material on the plate member at an elevated temperature; forming a first electrode layer of an electrical conducting material on the piezoelectric layer; and bending the metal plate member at a bending portion adjacent to the piezoelectric layer while the temperature is lowered from the elevated temperature after forming the piezoelectric layer.

Abstract: An integrated lead head suspension flexure including a plurality of integrated leads each including at least one lead portion unbacked by the flexure spring metal layer and configured to be substantially inline with the general plane of the spring metal layer. The leads are disposed on a dielectric layer including an unbacked dielectric layer portion having a surface positioned between the major surfaces of the spring metal layer.

Abstract: An FPC holding mechanism of an actuator assembly of a hard disk drive (HDD) includes an FPC holder protruding from an arm-mold of the actuator assembly, and an FPC clip that is mounted to the FPC holder so as to be rotatable relative to the FPC holder. The FPC holder defines a guide groove into which the FPC is inserted and a first side support plate facing one side surface of the FPC. The FPC clip includes a second side support plate juxtaposed with the first side support plate and facing the other side surface of the FPC, and at least two clip arms extending in a horizontal direction over upper and lower edges of the FPC, respectively. At least one of the clip arms has a hook that is hooked onto the first side support plate. The FPC holding mechanism thus prevents a portion of the FPC from moving in vertical and horizontal directions.

Abstract: An actuator latch system of an HDD retains a swing arm in place when the magnetic head of the HDD is parked. The actuator latch system includes a rotatable latch lever that has a hook designed to absorb shock when the hook engages the swing arm. A rear end of the swing arm has a corner portion where first and second surfaces of the rear end of the swing arm meet at a point of inflection. The hook has a first portion, a second portion, and a third portion extending between and connecting the first and second portions. Inner surfaces of the first, second, and third portions delimit a slot. The inlet of the slot has a width that is less than a width of the corner portion.

Abstract: An actuator latch apparatus usable with a hard disk drive apparatus includes a latch lever disposed on a base to pivot thereon and having a first latch prevention portion to prevent pivoting of an actuator arm in a direction, the actuator arm having a bobbin formed at a rear end portion thereof, and a bobbin protruding portion having a first catch portion provided at the bobbin and an auxiliary catch portion provided at the bobbin separated from the first catch portion to lock with the first latch prevention portion when the first catch portion is not caught by the first latch prevention portion.

Abstract: A latching mechanism for a flex cable bracket. The latching mechanism includes a position limiter. The position limiter prevents movement of an actuator assembly installed thereon. The latching mechanism also includes a spring clip. The spring clip has spring functionality and a cantilever beam to retain the actuator assembly when installed thereon. The latching mechanism further includes an orientation position limiter. The orientation position limiter prevents a rocking motion of the actuator assembly. The position limiter and the spring clip and the orientation position limiter are integrated into structure of the flex cable bracket.

Abstract: A voice coil motor for use in a disk drive device suitable for causing rotation of a head gimbal assembly connected to a first end of the voice coil motor is provided. At least one protrusion may protrude from a second end of the voice coil motor, with the second end of the voice coil motor being opposed to the first end. The voice coil motor may be rotatable to move a head connected to the head gimbal assembly for a read and/or write operation and for parking. The protrusion may be disposed on the voice coil motor so as to cooperate with a single pin to define first and second maximum positions beyond which the voice coil motor cannot rotate. In certain example embodiments, the first maximum position may be a load position limit beyond which the voice coil motor cannot rotate during a read/write operation, and the second maximum position may be a park position limit beyond which the voice coil motor cannot rotate when the head is parked.

Abstract: An apparatus and method for a microactuator having a bonding pad having a solder ball retainer to decrease instances of solder ball movement. The method provides a substrate for the microactuator. A conductive layer above the substrate is provided. A bonding pad having a solder ball retainer is provided and disposed above the conductive layer. The bonding pad having a solder ball retainer provides reduced instances of movement of a solder ball disposed therewithin prior to and during a reflow process performed on the solder ball.

Abstract: The tunnel magnetoresistance effect film is a highly practical tunnel magnetoresistance effect film having a characteristic of serviceable negative MR ratio, which can be used at room temperature. The tunnel magnetoresistance effect film comprises: a tunnel barrier layer; and magnetic layers sandwiching the tunnel barrier layer. One of the magnetic layers is composed of FeN.

Abstract: Provided are a perpendicular magnetic write head capable of achieving the high performance and stability in the writing performance, and a method of manufacturing the same. On a trailing side of a main magnetic pole layer, disposed are a gap layer extending backward from an air bearing surface and an auxiliary magnetic pole layer extending backward from a position recessed from the air bearing surface. The auxiliary magnetic pole layer is partially overlapped on the gap layer. In case the auxiliary magnetic pole layer is formed using etching method in the process of manufacturing the perpendicular magnetic write head, the gap layer has a function as an etching stopper layer so that the main magnetic pole layer is protected; thereby the already-formed main magnetic pole layer is not subjected to etching.