WO2006048581A1 - Dispositif d'enregistrement et/ou de lecture a tetes magnetiques multiples azimutees - Google Patents
Dispositif d'enregistrement et/ou de lecture a tetes magnetiques multiples azimutees Download PDFInfo
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- WO2006048581A1 WO2006048581A1 PCT/FR2005/050920 FR2005050920W WO2006048581A1 WO 2006048581 A1 WO2006048581 A1 WO 2006048581A1 FR 2005050920 W FR2005050920 W FR 2005050920W WO 2006048581 A1 WO2006048581 A1 WO 2006048581A1
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- recording
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B5/584—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on tapes
Definitions
- the subject of the present invention is a device for recording and / or reading with multiple magnetic heads with azimuth gaps as well as a method for producing such a device.
- This device with multiple magnetic heads finds its application in the magnetic recording and / or the reading of data on any magnetic recording medium that is magnetic or magneto-optical and more particularly on magnetic tape.
- magnetic medium has been used and this includes magnetic media and magneto-optical media.
- magnetic tracks it includes the tracks of a magnetic medium and those of a magneto-optical medium.
- the end applications of tape storage are typically archiving and backing up computer or more generally digital data.
- This data may be, for example, data from databases, digitized films, audio or computer files often from computers or digital devices such as camcorders, video recorders or servers. These data are often called "multimedia" and have an industrial, professional or consumer background.
- the helical recording in which one or more pairs of magnetic heads, mounted on a cylindrical drum rotating at high speed, write and read magnetic tracks in the form of portions of helices on a magnetic tape slowly scrolling while winding and sliding around the drum,
- FIG. 1 gives a schematic representation of this type of recording.
- a bar 1 of magnetic heads 3 spaced a step D is arranged along a generatrix of a fixed cylindrical support 2 (drum).
- Each magnetic head 3 comprises two pole pieces 3.1, 3.2 separated by a gap 3.3 non-magnetic. Subsequently, when we talk about the air gap of a pair of polar parts, it is about the air gap between two polar parts of a pair.
- the magnetic recording medium 4 to be read or recorded moves linearly close to the bar 1.
- This type of recorder has the advantage of being relatively simple mechanically (fixed or weakly moving magnetic heads) and allows, thanks to its multiple magnetic heads, high data rates.
- US-A-5,452,165 overcomes some of these difficulties.
- the magnetic heads 13.1, 13.2 are arranged one after the other on the same support 12 (a bar) which is oriented along a longitudinal axis x '(referred to as the longitudinal axis of the succession of magnetic heads inclined at an angle ⁇ (called tilt angle) relative to a longitudinal axis x of tracks 15 of the magnetic recording medium 14.
- Magnetic heads 13.1, 13.2 make it possible to simultaneously record and / or read information bits on several adjacent tracks in an inclined manner with opposite azimuth angles + ⁇ and - ⁇ from one magnetic head to the next. These azimuth angles are measured with respect to a normal to the longitudinal axis x 'of the heads 13.1 or 13.2.
- Two successive magnetic heads 13.1, 13.2 each have a gap 13.a, 13.b which is shifted by + ⁇ or - ⁇ respectively with respect to the plane perpendicular to the general direction x 'of the magnetic heads.
- These azimuth angles when they are different, make it possible to minimize the crosstalk between two successive tracks. This configuration makes it possible to tighten the distance between tracks so as to make them joined or almost contiguous.
- the distance D between magnetic heads is reduced by the use of solenoid-shaped coils (not shown) as recording and / or reading means.
- the solenoid-shaped windings reduce the inter-track distance compared to conventional planar windings.
- the width of the track 15 which cooperates with the magnetic head 13.1 and T2 is called the width of the track 15 which cooperates with the magnetic head 13.2.
- the magnetic heads of the same bar are made simultaneously.
- the azimuth angle must be realized with a very high precision.
- the azimuth angle is 20 degrees (in absolute value) plus or minus 0.15 °. It is very difficult to make these opposing azimuth angles with such precision in a batch process. It is also difficult to master from one magnetic head to another, the length of the gap, and the width of the pole pieces.
- Patent application FR-A-2 774 797 also discloses a recording and / or reading device with multiple azimuth magnetic heads.
- This device comprises several assembled supports on which are distributed heads magnetic.
- This device does not provide that the supports have an angle of inclination with respect to the tracks. It therefore does not make it possible to make "massively parallel" magnetic heads, making heads for reading or writing n tracks requiring n assembled supports, which in practice limits n to 2, 3 or 4 for reasons of efficiency.
- the constraints during the assemblies lead to a weakening of the recording and / or reading device.
- This device also does not provide heads cooperating with overlapping tracks, as is done today in the industry, because the distance, normal to the supports, between two pairs of pole pieces belonging to two consecutive supports is greater or equal to zero. This configuration does not allow the recording and / or playback device to adapt to various recording standards.
- the present invention relates to a device for recording and / or reading a magnetic medium with magnetic tracks, comprising a plurality of magnetic heads each comprising a pair of pole pieces separated by a nonmagnetic air gap having a given azimuth angle.
- the pairs of pole pieces are distributed over several integral supports, the gaps of pairs of pole pieces on the same support all having the same azimuth angle.
- At least two supports comprise pairs of pole pieces whose air gaps have different azimuth angles, each support having a given angle of inclination with respect to the magnetic tracks.
- pairs of pole pieces on the same support all have the same width.
- angles of inclination can be, for at least two supports, for example consecutive, equal or different.
- consecutive supports When they are parallel, consecutive supports define a polar inter-piece distance which is the distance between face planes facing polar pieces located on the consecutive supports.
- Magnetic shielding and / or magnetoresistive reading means may be placed in a space corresponding to the inter-piece polar distance.
- the inter-piece distance polar [tg ( ⁇ ). (T + D) J- (Pl + P2) with ⁇ inclination angle of the supports relative to the tracks, T longitudinal pitch of the pairs of pairs of pole pieces placed on the same support, D longitudinal shift relative to the supports between two pairs of consecutive pole pieces placed on two consecutive supports, Pl width of pairs of pole pieces on a first support, P2 width of the pole pieces on a second support consecutive to the first support.
- Two pairs of pole pieces belonging to different media, for example consecutive, can cooperate with two consecutive magnetic tracks for reading or recording.
- Two consecutive supports can form a common support on which two sets of pairs of pole pieces are placed on either side of a electrically insulating layer of the common support.
- an SOI (silicon on insulator) type substrate could be used as a common support.
- the pairs of pole pieces of a support may be those of magnetic heads for reading or recording.
- the recording and / or reading device may comprise at least one block of supports for recording and at least one block of supports for reading, these blocks being arranged one after the other in the direction magnetic tracks.
- it may comprise at least one block of one or more media for recording and at least one block of one or more media for reading, the supports of these blocks being secured to each other.
- a block for reading can be separated from a block for recording by a shielding screen.
- the magnetic shielding and / or the magnetoresistive reading means may be contained in an inter-support layer placed in the space corresponding to the inter-piece distance polar, this inter ⁇ support layer separating a support of a reading block of a support of a recording block.
- the recording and / or reading device comprises, for each magnetic head, a magnetic circuit integrating a pair of pole pieces and possibly a magnetic flux guide, this magnetic circuit cooperating with recording and / or reading means.
- a magnetic flux guide may comprise several parts: the core of a solenoid winding, pads, a rear magnetic piece, a magnetoresistive sensor flux guide.
- the recording and / or reading means may be inductive or magnetoresistive.
- Signal processing circuits may cooperate with the recording and / or reading means.
- the present invention also relates to a method for producing a recording and / or reading device on a magnetic magnetic strip medium. It comprises the following steps: on a first substrate forming several first pairs of pole pieces of first magnetic heads, these pole pieces being separated by a non-magnetic gap having the same first azimuth angle; on a second substrate forming several second pairs of pole pieces of second magnetic heads, these pole pieces being separated by a non-magnetic gap having the same second azimuth angle; assembling the first substrate to the second substrate by positioning them so that the first azimuth angle and second azimuth angle are different after assembly; embodiment of recording and / or reading means and possibly magnetic flux guides capable of cooperating each with a pair of pole pieces of the first pairs of pole pieces and / or second pairs of pole pieces; substrate treatment to give them a given angle of inclination with respect to the magnetic tracks.
- the assembly of the first and second substrates can take place before or after the treatment.
- the recording and / or reading means and the possible magnetic flux guides may be made on at least one third substrate which is positioned and assembled with the first substrate and / or the second substrate.
- a step of reducing the thickness of at least substrates may be provided before assembly.
- the first substrate can be assembled to a first third substrate after turning one of them, the second substrate is assembled to another third substrate after turning one of them, the first substrate is assembled to the second substrate.
- a step of reducing the thickness of at least one of the substrates can be provided before assembly.
- a step of inserting the wedges and / or a layer between polar pieces can also be provided.
- the recording and / or reading means and the possible magnetic flux guides may be made on one and / or the other of the first and second substrates. This realization can take place before or after their assembly.
- the treatment may consist in performing a grinding of the substrates before or after assembly or in assembling the substrates or one or more parts of the substrates in the same mechanical support conferring the inclination to the substrates.
- the angle of inclination of the first substrate may be different from that of the second substrate.
- the method may comprise a step of providing in the second substrate pairs of magnetic connection pads for magnetically connecting each of the recording and / or reading means or a flux guide to a pair of pole pieces of the first substrate.
- the pair of pole pieces of the first substrate are coupled to recording and / or reading means or a flux guide of one of the third substrates
- the pairs of polar pieces of the second substrate are coupled to recording and / or reading means or a flux guide of the other third substrate.
- the first and second substrates can be assembled to each other after turning one of them.
- a step of thinning at least one of the substrates may be provided before and / or after assembly.
- Positioning is done with aligned substrates.
- first box by anisotropic etching in the first or second substrate, it is possible to form a non-magnetic layer on the first or the second substrate, the first box of material can be filled.
- magnetic can be achieved by isotropic etching a second box adjacent to the first box, can fill the second box of magnetic material.
- This non-magnetic layer having a substantially uniform thickness lines the flanks of the first boxes.
- the non-magnetic material may advantageously be formed by surface oxidation of the first or second substrate.
- a pair of boxes in the second substrate can be made by isotropic etching, between two pairs of pole pieces of the second substrate and the pair of boxes of magnetic material can be filled.
- Surface planarization can be carried out after any one of the magnetic material filling steps.
- the first substrate and / or the second substrate may be formed of electrically insulating material located between two layers, one of the layers comprising the boxes being monocrystalline, the other possibly being removed later.
- the first substrate and / or the second substrate may be formed of an electrically insulating material located between a layer of wear resistant material and a layer of monocrystalline material having the wells.
- the assembly can be done by gluing, by molecular assembly, by anodic assembly or by fusible beads.
- the third substrate within which the recording and / or reading means and the possible magnetic flux guides may be optionally multilayered with a layer of electrically insulating material.
- the third substrate in which the recording and / or reading means and the possible magnetic flux guides will be present may comprise a layer of wear-resistant material possibly covered with electrically insulating material.
- a step of producing signal processing means may be provided, they cooperate with the reading and / or recording means.
- FIG. 1 shows a recording and / or linear reading device of the prior art
- Figure 2 shows a recording and / or reading device as shown in US-A-5 452 165
- Figures 3 to 7 show several variants of a recording device and / or reading according to the invention
- Figures 8A, 8B show a side view and a view in space of a recording device and / or reading whose method of production will be described later
- FIGS. 9A to 9D illustrate steps of realization on a first substrate of first pairs of polar pieces of a recording and / or reading device according to the invention
- FIGS. HA to HE illustrate embodiments of a third magnetic circuit substrate (in part) and means for recording and / or reading a recording device and / or reading device according to the invention, the figure HE being a sectional side view of the figure HD;
- Figs. 12A, 12B illustrate the steps of assembling the third substrate to the structure of Fig. 10D; FIG.
- FIG. 13 illustrates the grouping on the same mechanical support of two groups of magnetic heads, these groups of magnetic heads having the same angle of inclination with respect to the tracks of the magnetic recording medium.
- FIGS. 14A to 14H illustrate steps of making a variant of a recording and / or reading device according to the invention in which during assembly a reversal of 180 ° on two axes was carried out;
- FIGS. 15A and 15B illustrate steps of making another variant of a recording and / or reading device according to the invention;
- FIG. 16 shows a view in space of a variant of a reading device according to the invention in which the reading means are formed of magneto-resistive bars;
- FIGS. 17A, 17B illustrate steps for producing the reading device illustrated in FIG. 16, FIG.
- FIG. 17C illustrating another variant of a reading device according to the invention
- Figure 18 shows two substrates carrying pairs of pole pieces about to be assembled by fusible beads which allows precise alignment of the substrates.
- Identical, similar or equivalent parts of the different figures bear the same numerical references so as to facilitate the passage from one figure to another.
- a magnetic head device according to the invention will now be described with reference to FIG.
- This device is intended for recording and / or reading information on magnetic tracks carried by a magnetic medium.
- This magnetic medium is represented as a band but other forms would be possible for example a disk.
- the example which will be described applies to a linear magnetic or magneto- optical recording, but such a recording and / or reading device could be used in the context of a helical recording.
- a magnetic head conventionally comprises a magnetic magnetic flux closing circuit terminating on a pair of polar parts separated by a non-magnetic gap.
- This magnetic circuit may include, in addition to pairs of pole pieces, a magnetic flux guide.
- the magnetic flux guide is absent and the pairs of pole pieces have a shape suitable for this magnetic flux guide function.
- Recording and / or reading means cooperate with the magnetic circuit, it can be at least one winding which surrounds the magnetic flux guide, if any, for the inductive recording heads and / or reading or a magnetoresistance for the magnetic read heads.
- This magnetoresistance can be inserted into the flux guide at an air gap thereof, it can advantageously take the form of a bar made of material with giant magnetoresistance GMR (abbreviation Anglo-Saxon Giant Magneto Resistance) or magnetoresistance TMR tunnel effect. In the absence of a flux guide, the magnetoresistance cooperates directly with a pair of pole pieces.
- the device according to the invention comprises several magnetic heads 30.1 to 30.4, 31.1 to 31.4 which are each materialized by a pair of pole pieces separated by a gap el, e2 nonmagnetic.
- the device also comprises several integral supports 1001, 1002 and the pairs of pole pieces of the magnetic heads are distributed one after the other on these supports 1001, 1002.
- the device also comprises between two supports 1001, 1002, at the least one inter-support layer 33, 34 for separating the pairs of pairs of pole pieces by a distance d well adjusted. This distance d separates from the facing planes facing the pole pieces located on consecutive supports. She is normal to these supports.
- first pairs of pole pieces of the magnetic heads 30.1 to 30.4 are supported by the first support 1001 and second pairs of pole pieces of the magnetic heads 31.1 at 31.4 are supported by the second support 1002. It is of course conceivable to use more than two assembled supports, after alignment, between the inter-support layers 33, 34. If there are more than two supports, it will be possible to thin one of the first two before assembling the third as we will see later.
- the supports 1001, 1002 are substantially planar, the pairs of pole pieces 30.1 to 30.4, 31.1 to 31.4 of the magnetic heads rest on a main face of the corresponding support which is substantially flat.
- the pairs of pole pieces of the magnetic heads are placed on two faces facing the supports. Other configurations are possible.
- the magnetic heads are azimuthed, this means that each gap el, e2 has a given azimuth angle relative to a perpendicular to the main face of the support 1001, 1002.
- the pairs of pole pieces 30.1 to 30.4 or 31.1 to 31.4 placed on the same support 1001, 1002 respectively have all the same azimuth angle respectively.
- This azimuth angle is referenced ⁇ 1 for the pairs of pole pieces of the support 1001 and ⁇ 2 for the pair of pole pieces of the support 1002.
- This azimuth angle is between + 90 ° and -90 ° limits excluded compared to a normal to the support.
- a magnetic flux guide and / or a magnetoresistive element may rest on a main face of a support 1001 or 1002, coming from press the pair of polar pieces concerned.
- the assemblies of supports will be cut to reveal the functional faces of the pole pieces, that is to say the faces perpendicular to the main faces of the initial supports, which come into contact with the magnetic recording medium.
- Each magnetic head is intended to cooperate with a magnetic recording medium 35 oriented substantially parallel to the functional faces of the pole pieces and therefore substantially perpendicular to the main face of the support 1001, 1002.
- This magnetic medium 35 comprises numerous magnetic recording tracks 36 on which the magnetic heads are intended to write or read information. These tracks 36 are created by the magnetic recording heads.
- the tracks 36 have an angle of inclination ⁇ with respect to the main surface of the supports 1001, 1002 or with respect to the length of the magnetic heads.
- the supports 1001, 1002 have the same angle inclination ⁇ relative to the general direction of the magnetic recording tracks 36.
- the edges of the supports are therefore not parallel to the direction of the tracks 36.
- the inclination angle ⁇ is non-zero and between ⁇ 90 ° .
- P2 denote the width of all the pole pieces 31.1 to 31.4 on the second support 1002. This width P2 is counted perpendicular to the main face of the support 1002 on which the inter-support layer 34 is located.
- Polar pieces on the same support have the same width.
- this distance d is the distance between face planes facing pairs of polar pieces located on consecutive supports. This distance is non-zero. This distance d gives another degree of freedom to adjust the interpiste distance or even the overlap of the recorded tracks.
- D denote the longitudinal offset with respect to the supports between two pairs of polar pieces 30.1, 31.1 consecutive placed on consecutive supports 1001, 1002.
- This longitudinal offset is defined between the abscissae of the centers of the air gaps along the axis ox '.
- P1, P2 respectively the width of the pole pieces of a support, measured along the axis oy '.
- the supports 1001, 1002 have the same angle of inclination ⁇ with respect to the general direction of the tracks.
- the angle of inclination ⁇ can be obtained for example by means of a mechanical machining of the supports.
- the polar inter-piece distance makes it possible, in particular, to adjust the longitudinal offset D to a value making it possible both to meet a standard (positioning the tracks cooperating with a support relative to the neighboring support) and to allow easy technological fabrication in optimizing the compactness of the magnetic heads of two consecutive media.
- the magnetic circuit and the means of reading and / or recording adapting to pairs of polar pieces impose geometric constraints.
- Tl denote the width of the tracks 36 which cooperate with the pairs of pole pieces 30.1 to 30.4 which are on the first support 1001 and T2 the width of the tracks 36 which cooperate with the pairs of pole pieces 31.1 to 31.4 which are on the second support 1002.
- the width of the tracks is measured perpendicular to the ox axis.
- Tl Pl.cos ( ⁇ 1 - ⁇ ) / cos ( ⁇ 1)
- T2 P2.cos ( ⁇ 2 + ⁇ ) / cos ( ⁇ 2)
- T1 T2.
- the object of the invention is to enable the manufacture of magnetic heads adapting to various standards.
- the invention may make it possible to produce magnetic heads cooperating with non-contact tracks and / or of different widths.
- the supports 1001, 1002 can be physically distinct and then assembled by stacking them or else they can be combined, for example as in FIG. 7.
- the support is multilayer, it can be for example a substrate of the type SOI (semiconductor on insulator) or more generally an XOI type substrate where X represents a monocrystalline material.
- the pole pieces are on both sides of the insulation layer.
- the outer layers common support can be likened to two supports assembled to each other.
- the magnetic heads dedicated to the recording are preferably magneto-resistor type MR, giant magnetoresistance GMR or magnetoresistance TMR tunnel while the magnetic write heads are preferably inductive magnetic heads.
- the recording and / or reading device may comprise a first block B1 comprising magnetic recording heads 41 and a second block B2 comprising magnetic read heads 42, these two blocks B1, B2 being placed one after the other. the other in the axial direction of the tracks 47 of the magnetic recording medium 44 and being separated in this example by a magnetic shielding screen 43.
- One of the blocks (for example Bl) is dedicated to the writing of information on the magnetic recording medium 44 and the other (eg B2) on reading written information.
- Each of these blocks B1, B2 comprises several supports 45.1, 45.2, 46.1, 46.2 respectively on which are arranged a succession of pairs of pole pieces separated by a nonmagnetic gap, each gap materializing a magnetic head 41, 42 respectively in the figure.
- RWW read while write
- FIG. 5 Instead of the writing blocks B1 and B2 reading one another in the axial direction of the tracks 47 of the magnetic recording medium 44, they are stacked .
- a write block B1 formed of several adjacent superposed supports 45.1, 45.2 can be combined with a reading block B2 also formed of several adjacent superposed supports 46.1, 46.2.
- the supports 45.1, 45.2 of the writing block B1 carry pairs of polar pieces of magnetic writing heads 41 and the supports 46.1, 46.2 of the reading block B2 comprise pairs of polar pieces of magnetic read heads 42.
- the device recording and playback is a WWRR device (W for recording and R for playback).
- the azimuth angles of the magnetic heads 41, 42 of a block B1, B2 are identical from one block to another to cooperate. They are different from one medium to another in the same block.
- Magnetic heads 41 or 42 belonging to the same block B1 or B2 have their pairs of pole pieces placed on adjacent supports 45.1, 45.2 or 46.1, 46.2. Note in the example of Figure 5 that in the same block, the magnetic heads whose pairs of pole pieces are carried by a first support have a first azimuth angle and the magnetic heads whose pairs of pole pieces are carried by another support have another azimuth angle different from the first azimuth angle.
- the different supports 45.1, 45.2, 46.1, 46.2 are here all separated from each other by an inter-support layer 48 of thickness d to mechanically maintain the supports at a precise distance from each other.
- the inter-support layer 48 for separating the blocks B1, B2 can advantageously have a magnetic shielding to reduce crosstalk and / or magneto-resistive reading means.
- FIG. 6 shows another variant in which the supports 45.1, 45.2, 46.1, 46.2 are always superimposed but now the supports 45.1, 45.2 or 46.1, 46.2 of a block B1 or B2 are no longer neighbors.
- the supports 45.1, 45.2 of a block B1 and the supports 46.1, 46.2 of the other block B2 are alternated.
- the azimuth angles of the magnetic heads whose pairs of pole pieces are placed on adjacent supports 45.1, 46.1 are identical.
- These magnetic heads belong to different Bl, B2 blocks.
- the azimuth angles of the magnetic heads whose pairs of pole pieces are on supports belonging to the same block are different.
- the supports 45.1, 46.1, 45.2, 46.2 are separated by an inter-support layer 48. In this example, each of these layers may advantageously comprise a magnetic shielding.
- FIG. 6 it is considered that a WRWR stack of write, read, write and read heads was made from the top.
- the recording and / or reading device according to the invention is not limited to operating with a magnetic recording medium on which the recording is linear as illustrated in the figures which have just been described.
- Such a recording and / or reading device can also be applied to a magnetic medium on which the recording is helical as illustrated in FIG. 7. It is a device with quadruple magnetic heads, for example, dedicated to recording and / or reading.
- the different elements represented in this figure bear the same references as in FIGS. previously described. It is assumed that references 45.1 and 45.2 are layers of different crystalline orientations. These two layers are separated by an electrically insulating layer 48.
- This recording and / or reading device can be made by assembling two stacked supports as seen above, but it can also be performed on a common support 45, for example of the SOI type. or more generally a support comprising an electrically insulating layer sandwiched between two monocrystalline layers.
- the different recording magnetic tracks referenced 47 are now inclined with respect to the general direction of the magnetic recording medium 44 (here helical type). These tracks 47 were parallel to the general direction of the magnetic recording medium 44 (linear type) in FIGS. 4 to 6.
- the inter-support layer 33, 34, 48 may be composed of an insulator, for example silicon oxide (SiO 2 ), silicon nitride (Si 3 N 4 ), alumina (Al 2 O 3 ), zirconia ( ZrO 2 ), silicon carbide (SiC), AlSiC (mixture of alumina and silicon carbide), titanium carbide (TiC), AlTiC (mixture of alumina and titanium carbide) or any other insulant having a good resistance to wear.
- This layer can be made in one or more times, for example by a deposition process using microelectronic equipment or micro or nano technology for example sputtering type (PVD, PECVD ).
- the thickness of an SOI / XOI substrate will be adjusted by the substrate manufacturer by any method of this type of industry.
- brackets 1001 and 1002 of Figure 3 on either side of the inter layer ⁇ support 33, 34, it is possible to realize the inter layer ⁇ support on one, the other or both supports 1001, 1002 with, for example, mechano-chemical planarization steps and appropriate surface preparations for subsequent assembly with precise positioning.
- the inter-support distance will then of course be the sum of the thicknesses deposited on each support 1001 and 1002.
- Each of these thicknesses may optionally contain one or more magnetic screens and / or magnetoresistive elements (GMR or more generally XMR) embedded in the insulation 33, 34 (deposited and / or etched by appropriate micro ⁇ technology equipment).
- GMR magnetoresistive elements
- the magnetic heads are made collectively, pairs of pole pieces are distributed over several supports.
- the sectional figures are made at the pairs of pole pieces.
- the magnetic heads are made on substrates, they correspond to the supports that have been described previously.
- FIGS. 9A-9D which describe a first embodiment of a recording and / or reading device substantially similar to that shown in Figures 8A, 8B.
- the magnetic heads are shown from the side, we can see for each of the functional face of its pair 41, 42 of polar parts separated by the air gap el, e2. It is this face that will fly over the magnetic recording medium (not shown).
- the recording and / or reading device comprises two supports each carrying three magnetic heads.
- FIG. 8B The view of FIG. 8B is in three dimensions and one sees for each magnetic head its magnetic circuit with a magnetic flux guide cl, c2 which connects the two pole pieces 41.1, 41.2, 42.1, 42.2 of a head 41, 42.
- This magnetic flux guide c1, c2 may comprise two legs Jl.l, Jl.2, J2.1, J2.2 magnetically connected on one side to a pole piece 41.1, 41.2, 42.1, 42.2 and the other to a single magnetic rear part al, a2 closing.
- the connection between the legs j1.l, jl.2, J2.1, j2.2 and the pole pieces 41.1, 41.2, 42.1, 42.2 can be direct or be done via magnetic pads p2.1, p2.
- the magnetic circuit could be a monolithic magnetic circuit, substantially in the form of a horseshoe or the like, each end of which would be formed by a pole piece.
- FIG. 8B also shows recording and / or reading means taking the form of solenoid windings sl.l, si.2, s2.1, s2.2 which cooperate with the legs j1.l, jl.2. , J2.1, j2.2 flow guides cl, c2.
- FIG. 9A It starts from a first substrate 100 with an electrically insulating layer 102 sandwiched between two outer layers 101, 103 of which at least one is made of monocrystalline material.
- SOI substrate silicon on insulator
- the other outer layer 101 may be made of a material resistant to wear, this material can be neither semiconductor nor monocrystalline. It may be made for example of zirconia ZrO 2 , silicon carbide and alumina AlSiC, titanium carbide and alumina AlTiC, alumina Al 2 O 3 or other. This outer layer 101 is advantageously thicker than that which is monocrystalline.
- first flared boxes 104 to house one of the pole pieces of each first pair of pole pieces to be on this first substrate ( Figure 9A).
- This etching may be an anisotropic wet chemical etching adapted to silicon, for example in a KOH potash bath.
- the inclination of one of the flanks of each first box conditions the value of the azimuth angle. This inclination takes advantage of the monocrystalline nature of the substrate, the anisotropic etching taking place along a crystallographic plane of the substrate. In silicon, it is the ⁇ 111> family planes that limit the etching edges. These substrates are commercially available. This process is described, for example, in document FR-A-2 664 729.
- the layer of electrically insulating material 102 of the substrate 100 serves as a stop layer during the etching of the first boxes 104.
- the thickness of the monocrystalline layer 103 of the substrate 100 determines the width of the pole pieces of the pairs lying on this first substrate. We choose its thickness accordingly.
- a layer 105 of non-magnetic material is formed on the first substrate 100, it lines with a substantially uniform thickness the sides of the first boxes 104.
- the first boxes are made of silicon, it is possible to carry out a thermal oxidation surface of the first substrate 100 thus worked (FIG. 9A).
- the desired thickness of the non-magnetic material could have been deposited on the flanks of the first caissons.
- the non-magnetic layer 105 for example made of silicon oxide, which lines one of the flanks of each of the first first caissons will constitute the azimuth air gap and each of the first pair of polar parts on the substrate 100.
- a magnetic material 106 is deposited, for example by electrolysis, in the first boxes 104.
- the magnetic material may or may not be laminated, for example an alloy of NiFe, CoFe or CoFeX where X represents an appropriate material such as Cr, Cu or other.
- the surface of the substrate 100 thus worked is optionally planarized so that the oxide is flush and the magnetic material has the desired thickness ( Figure 9B).
- This magnetic material forms a first pole piece 106 of each first pair of pole pieces.
- Isotropic is then etched second boxes 107 to accommodate the other pole piece of each first pair of pole pieces to be on the first substrate 100 (Figure 9C).
- These second boxes 107 are contiguous to the first boxes 104 and are all on the same side of these first boxes 104. In the example, they are on the left of the first boxes 104. They could be on the right. The angle of azimuth would then be different, it would be another plane of the family ⁇ 111>.
- the monocrystalline material of the outer layer 103 which is close to the gap is removed by etching.
- the nonmagnetic material of the air gap el serves as a flank for these second caissons 107.
- the depth of these second caissons is substantially the same as that of the first caissons because the insulating layer 102 serves as a stop layer.
- These second boxes 107 are filled with magnetic material 108, for example by electrolysis, and a planarization step is completed as previously described (FIG. 9D).
- This magnetic material 108 forms a second pole piece of each first pair of pole pieces.
- This planarization step makes it possible to finally adjust the width of the pole pieces. It makes it possible to give pairs of pole pieces a very good alignment on their upper face (in the figure).
- first boxes 114 which are filled with magnetic material 116 by providing a step of forming a non-magnetic layer 115, for example by a surface thermal oxidation in the case of first caissons 114 dug in silicon, before filling and planarization as described in FIGS. 9A and 9B.
- Second boxes 117 are made by isotropic etching as described in FIG. 9C.
- the second boxes 117 adjoin the first boxes 114 and are, in this example, all on the same side of these first boxes 114 on the left as in Figure 9C. They could be on the right, this depends in particular on the final azimuth angle of pairs of polar pieces located on the second substrate.
- the position of the second caissons 117 depends mainly on the relative movement that one wishes to perform during the reversal of one of the substrates relative to the other at the time of assembly. The sign of the azimuth angle can thus change during the subsequent step of assembling the first substrate to the second substrate depending on the type of reversal performed.
- pairs of third boxes 118 are made to house pairs of magnetic connection pads 120 each intended to magnetically connect a part. polar of a first pair of pole pieces located on the first substrate to the magnetic circuit finalized later.
- These third boxes 118 are positioned so that the magnetic pads of a pair are magnetically connected to the pole pieces 108, 106 of a first pair of pole pieces when the first substrate 100 and the second substrate 110 are aligned and assembled. to one another after reversal.
- a rotation of 180 ° in the plane of the substrate may optionally be introduced in addition to turning over so that the desired azimuth angles on the two substrates are obtained.
- the second and third caissons 117 and 118 may be made by isotropic etching of the monocrystalline layer 113 of the second substrate 110, fourth compartments 121 rear to house the rear closure magnetic pieces 122 each of which is a part of the flow guide of a magnetic head of the recording and / or reading device.
- These fourth boxes 121 are positioned so that the closing rear magnetic parts 122 are opposite first and second pairs of pole pieces. They can therefore advantageously be made at the same level as the second pairs of polar pieces.
- FIG. 10B shows, in partial top view, pairs of magnetic studs 120 and rear magnetic closing pieces 122.
- FIG. 10B it is assumed that the first and second substrates (not visible) have been assembled. and positioned appropriately.
- These second boxes 117, third boxes 118 and fourth boxes 121 of magnetic material are filled as described in FIG. 9D and a planarization of the surface is carried out.
- the magnetic material will form the second pole pieces 119 of the second pairs of pole pieces as well as the connection pads 120.
- the azimuth angle of the air gaps el, e2 of the first and second pair of pole pieces has been suitably adjusted by the choice of the crystallographic orientation of the monocrystalline layers 103, 113. These azimuth angles can be opposed if wish that in final after assembly of the substrates these are opposed. It has also been desired to adjust the width of the pole pieces which is not necessarily equal from one substrate to another.
- the first substrate 100 and the second substrate 110 will be positioned and assembled by their worked faces, after one of them has been turned over and possibly 180 ° rotation of one of the substrates around a transverse axis of said substrate. .
- the assembly can be done by any technique known to those skilled in the art in the field of micro-technologies and in particular electromechanical microsystems (MEMS).
- MEMS electromechanical microsystems
- Advantageous assembly methods are bonding with glue, anodic bonding, and direct bonding as described in FR-A-2,774,797 or microbead bonding. (English bail bonding or flip chip bonding).
- a preparation of the surfaces to be assembled possibly including a mechano-chemical planarization may be necessary depending on the type of assembly used. This planarization will be carried out in particular in the case of a molecular bonding.
- Figure 10C illustrates the two substrates 100, 110 about to be assembled. It can be discerned that the planarized oxide 105, which contributes to the molecular bonding, remains partially on the surface. This oxide remains only between the caissons filled with magnetic material. It is advantageous, before using the assembly to deposit on the surface of at least one of the substrates 100, 110, an insulating layer 50 (for example silicon oxide) and / or a magnetic shielding layer to adjust the distance of inter ⁇ polar part.
- the material of the insulating layer 50 may advantageously be in a material resistant to wear so as to limit the wear of the recording device and / or reading. His choice may also facilitate the assembly of substrates.
- the shielding layer may advantageously leave openings in the shielding layer at the magnetic pads 120, the shielding layer is located on one and / or the other of the substrates.
- the overturning of one of the substrates 100 or 110 may result in the change of sign of the azimuth angle of the pairs of polar pieces that are on this substrate. It depends on how you do it. If there is both reversal and 180 ° rotation of the substrate around a transverse axis there will be sign change.
- the untreated layer 111 of the second substrate 110 will then be removed. This elimination may be carried out selectively, for example by etching with, for example, potassium hydroxide KOH, or by chemical-mechanical etching with a stop on the layer.
- buried insulator 112 (FIG. 10D). If necessary, it may be necessary to thin the buried insulating layer 112 to make appear or almost appear the second pairs of pole pieces 116, 119 and the pairs of magnetic pads 120.
- the rest of the flow guide of each of the magnetic heads that is to say in this example the magnetic legs, and the recording means and / or reading. If in Figure 10A, the rear magnetic closing parts have not been made, the flow guide will be substantially shaped horseshoe. The method employed is inspired by that described in the patent application FR-A-2,745,111.
- the recording and / or reading means are solenoid-type windings which surround the magnetic circuit at the level of the legs or branches of the horseshoe.
- Figures HA to HD are sections along a leg of the magnetic circuit.
- a third substrate 130 with a base layer 131 (for example semiconductor) covered with a layer of electrically insulating material 132. It could very well use a bulk substrate (in English bulk) for the layer 131 or a wear-resistant material optionally covered with an insulator.
- a base layer 131 for example semiconductor
- a wear-resistant material optionally covered with an insulator.
- first parallel grooves 134 directed substantially perpendicular to the axis of the magnetic cores, are etched. solenoids. These cores correspond to legs J1, J1, J2.1, J2.2 illustrated in Figure 8B.
- first furrows 134 are filled by depositing, for example by electrolysis, a conductive material 135, for example copper-based (FIG. HA).
- This conductive material 135 forms conductor portions of the first layer of conductors.
- a planarization is then carried out, for example mechanical or preferably mechano-chemical, to remove the superfluous conductive material 135 located above the grooves 134.
- An electrically insulating layer 136 for example silicon oxide, for example by PECVD, is deposited over the entire planarized surface with a thickness greater than that desired for the legs.
- the insulating layer 136 is etched to reveal caissons 133 at the legs of the magnetic circuit that is to be made.
- the bottom of these boxes 133 has a sufficient thickness to electrically isolate the conductors of the first layer of conductors of the magnetic circuit.
- a magnetic material 137 optionally laminated as indicated above for producing the pole pieces ( Figure HB). The surface obtained is planarized as explained above.
- An electrically insulating layer 138 is deposited on the planarized surface (for example silicon oxide by PECVD).
- Wells 139 are etched in the insulating layers 138 and 136 until they reach the ends of the conductors 135 of the first layer of conductors.
- These wells 139 are filled, for example by electrolysis, with conductive material 140, for example copper-based (FIG. HC). Planarize the resulting surface. This conductive material forms the lateral conductors 140 of the solenoids.
- FIG. HD then produces a second horizontal sheet (in the figure) of solenoid conductors by depositing a layer of electrically insulating material 141 on the surface of the structure obtained, by etching second grooves 142 in this material, the ends of which the lateral conductors 140 thus produced.
- the second grooves are not quite parallel to the first grooves 134, one of their end is shifted by one step so as to make the solenoid.
- the second grooves 142 are filled with conductive material 143 based on copper deposited for example by electrolysis. Planarize the resulting surface.
- the conductive material 143 forms the conductors of the second conductor ply of the solenoids.
- the conductive material 143 is covered with a layer of electrically insulating material 144. It is intended to make contact resumptions at the ends of the conductor of the solenoids (not visible).
- Figure HE illustrates, with a different scale and in side view with respect to FIG HD, the configuration of the third substrate 130 ready to be assembled to the structure formed by the first substrate 100 and the second substrate 110.
- the third substrate may optionally accommodate signal processing means delivered or acquired by the magnetic heads.
- Positioning is aligned and assembles the third substrate 130 and the structure shown in Figure 10D, after turning one of them.
- the assembly can be done by one of the methods described above.
- the third substrate 130 has been assembled by molecular bonding or other, with alignment so that the magnetic circuits 137 are magnetically connected each with a pair of pole pieces 106, 108, 116, 119, this connection being making either directly or indirectly via the magnetic pads 120. It remains only to eventually totally or partially eliminate the base layer 131 of the third substrate 130 ( Figure 12B), for example by complete or local selective etching of the material of this base layer 131 with a stop on the insulating layer 132. It is then possible to perform contact pickups through the insulating material of the layer 132 for the supply or detection of the signal of the means recording and / or reading (the solenoids formed by 135, 140, 143 in this particular case).
- the non-worked layer 101 of the first substrate 100 may advantageously be made of a material resistant to wear for example AlTiC, ZrO 2 , AlSiC.
- the structure obtained in FIG. 12B is then processed so as to give the substrates a given angle of inclination ⁇ with respect to the magnetic tracks of the magnetic recording substrate.
- This treatment can consist of an integration of one or more blocks (bars or chips) of magnetic heads on a common mechanical support.
- the mechanical support includes in particular bars, chips, etc.
- One or more of these blocks 300, 301 are mounted on the same mechanical support 350. This step is known by the English name of "back-end” or "packaging”.
- the mechanical support 350 will advantageously be made of a wear-resistant material such as, for example, AlTiC (titanium carbide and alumina) which is commonly used by manufacturers of linear magnetic heads.
- the contour of the mechanical support 350 is then rectified, for example at its faces 351, so that the substrates 100, 110 may have a desired angle of inclination ⁇ relative to the tracks 47 of the magnetic support of FIG. recording 44.
- FIG. 12A could be directly corrected before or after the chip blanking in order to reveal the angle of inclination ⁇ , especially if it is small, on the external faces of the substrates 100 and 110. in this case, electrical contact resumption will be advantageously by local etching.
- a second embodiment of a recording and / or reading device according to the invention will be described. In this configuration, there are no pairs of magnetic connection pads.
- first substrate 150 formed of a stack with an electrically insulating layer 152 buried between, for example, two outer layers for example semiconductors 151, 153, at least one of which is monocrystalline
- the procedure is as described in FIGS. FIGS. 9A to 9D for making first pairs of pole pieces 106, 108 (FIG. 14A).
- the substrate 150 may be of the SOI type.
- the rear closure magnetic parts may be made as described in FIGS. 10A, 10B.
- a second substrate 160 formed of a stack with an electrically insulating layer 162 sandwiched between two outer layers, for example semiconductors 161, 163 at least one of which is monocrystalline, the procedure is as described in FIGS. 9A to 9D to achieve second pairs of pole pieces 116, 119 (FIG. 14B)
- the second substrate 160 may be of the SOI type
- the magnetic pads are not produced
- the rear closure magnetic pieces may be made as described in FIGS. 10A, 10B.
- the first substrate 150 and the second substrate 160 are positioned and assembled by their worked faces, after turning one of them, taking care when positioning them to align by placing the first pairs of pole pieces 106, 108. and second pairs of pole pieces 116, 119 alternately longitudinally (Fig. 14C). Assembly and alignment can be done as previously described in Figure 1OC.
- An insulating layer 50 can be made between the two substrates possibly containing a magnetic shielding screen. It is deposited on at least one of the substrates.
- the intact outer layer 161 and the buried electrically insulating layer 162 (at least partly) of one of the substrates 160, for example the second substrate (FIG. 14C) can be eliminated.
- the elimination of the outer layer 161 can be done for example by chemical etching (with for example potassium hydroxide KOH) or mechanochemical and that of the buried insulating layer 162 for example by ion milling or other dry etching.
- a thin insulating layer can remain, its moderate thickness allowing magnetic continuity.
- This electrically insulating layer is even particularly advantageous in some cases, because it allows a magnetic decoupling between the various elements and a reduction of effects due to eddy currents.
- a third substrate 170 (formed of a base layer 171, for example a semiconducting and / or wear-resistant layer covered with an electrically insulating layer 172) is made on a first substrate 171) of the first flux guides 173 of the magnetic circuits and the first recording and / or reading means 174, for example of the solenoid type as described in FIGS. HA to HE, these first flux guides 173 and these first recording and / or reading means 174 being intended for cooperate with the first pairs of polar pieces or the second pairs of polar pieces. In the example described, these are the second pairs of pole pieces 116, 119.
- This third substrate 170 is therefore equipped with fewer flux guides than in the previous embodiment.
- FIG. 14E the third substrate 170 and the structure illustrated in FIG. 14C are positioned and assembled after reversing one of them, taking care to align them. This assembly can be done as described in Figure 12A.
- the first flux guides 173 placed on the third substrate 170 are then each magnetically connected to one of the second pair of pole pieces 116, 119 on the second substrate 160.
- the flow guides and the recording and / or reading means would be deposited directly on one of the substrates 150, 160 worked.
- the two substrates can be assembled as in FIG. 14C after removal of the non-worked support layers with advantageous use of a superstrate.
- the layer of non-worked material 151 and the buried insulating layer 152 (at least partly) of the first substrate 150 are then eliminated.
- the elimination of the layer 151 may be carried out for example by chemical etching (with, for example, potassium hydroxide KOH) or mechano-chemical and that of the buried insulating layer 152, for example by ion milling or other dry etching (FIG. 14F).
- These second magnetic circuits 183 and these second recording and / or reading means 184 are intended to cooperate with the other pairs of pole pieces, in the example with the first pairs of pole pieces 106, 108.
- the fourth substrate 180 and the structure illustrated in FIG. 14F are positioned and assembled after reversing one of them. This positioning is done with alignment for example as described in Figure 12A.
- the second magnetic circuits placed 183 on the fourth substrate 108 are then each magnetically connected to one of the first pairs of pole pieces 106, 108 on the first substrate 150.
- Repetitions of electrical contacts (not shown) of the recording and / or reading means can be done using an intra-connection technology or for example by local etching (dry or wet).
- First pairs of pole pieces 106, 108 and possibly rear magnetic pieces are made on a first substrate 150, for example as described in FIGS. 9A to 9D, 10A and 10B.
- a second substrate 180 are made first flux guides 183 of the magnetic circuits and first recording and / or read means 184 as described for example in FIG. 14G.
- Alignment is positioned and the first substrate 150 and the second substrate 180 are assembled after turning one of them so that each of the first flux guides 183 is magnetically connected to one of the first pairs of pole pieces 106. 108.
- Such a first structure is illustrated in FIG. 15A.
- a second pair of polar pieces 116, 119 and possibly rear magnetic pieces and a fourth substrate 170 of the second flux guides 173 and second recording and / or recording means are produced in the same manner on a third substrate 160. reading 174. Positioning with alignment and assembling the third substrate
- the unworked layer 151 is eliminated,
- Repetitions of electrical contacts (not shown) of the recording and / or reading means can be done using an intra-connection technology or for example by local etching (dry or wet). It is then possible to mount one or more chips of multiple magnetic heads on the same mechanical support as described in FIG. 13. The rectification is then also carried out as explained in the description of this FIG. 13.
- Fig. 16 which is similar to Fig. 8B, except that each magnetic circuit cooperates with a giant magneto-resistance bml, bm2 bar instead of a solenoid.
- first and second pairs of pole pieces 106, 108, 116, 119 located respectively on a first and a second substrate 100, 110, these two substrates 100, 110 having been assembled together.
- pairs of magnetic connection pads 120 and possibly magnetic rear closure parts are also been made (FIG. 17A).
- flux guides 200 of the magnetic circuits are made at least partly on a third substrate 130.
- the reading means 201 formed for each of the magnetic circuits, a bar for example magneto-resistance, giant magnetoresistance (or optionally with tunneling magnetoresistance with a slightly different process) are produced by deposition of a suitable magnetoresistive layer on insulating material and then etching to a desired contour, with elimination of the superfluous material and finally deposition of an insulating layer.
- Each bar 201 is possibly in the vicinity of an air gap (not visible in Figure 17B but visible in Figure 16) of a flow guide. The gap is visible in Figure 16.
- the flux guides 200 could be omitted, the magnetoresistance bars 201 could cooperate with the pairs of pole pieces to then form the complete magnetic circuits.
- each magnetic circuit is connected magnetically to a first pair of polar parts or to a second pair of polar pieces.
- FIG 17C shows in section another variant of a reading device according to the invention.
- the reading means are of the magnetoresistive type and take the form of magneto-resistance bars. They are referenced 201 and are distributed in the layer 50 and in the layer 1300. There is no longer any need for pairs of magnetic connection pads since the magnetoresistance bars 201 of the layer 50 cooperate directly with the pairs of pole pieces 106. , 108 of the first substrate 100, while the magneto-resistance bars 201 of the layer 1300 cooperate directly with the pair of pole pieces 116, 119 of the second substrate 110.
- Signal processing means 302 for example preamplifier circuits, multiplexers, demultiplexers, cooperate with the reading means 201.
- FIG. 18 schematically illustrates a recording and reading device according to the invention in which a first substrate 210 carrying first pairs of pole pieces 211 of magnetic heads will be assembled to a second substrate 220 carrying second pairs of pole pieces 221. magnetic heads by balls 230 fusible alloy.
- the steps of these methods can be combined with one another.
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Magnetic Heads (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP05819213A EP1810284A1 (fr) | 2004-11-04 | 2005-11-02 | Dispositif d'enregistrement et/ou de lecture a tetes magnetiques multiples azimutees |
JP2007539622A JP2008519385A (ja) | 2004-11-04 | 2005-11-02 | 多数の方位角制御された磁気ヘッドを備えた記録および/または読取デバイス |
US11/718,458 US20090067088A1 (en) | 2004-11-04 | 2005-11-02 | Recording and/or playback device comprising multiple azimuth magnetic heads |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR0452528 | 2004-11-04 | ||
FR0452528A FR2877485A1 (fr) | 2004-11-04 | 2004-11-04 | Dispositif d'enregistrement et/ou de lecture a tetes magnetiques multiples azimutees |
Publications (1)
Publication Number | Publication Date |
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WO2006048581A1 true WO2006048581A1 (fr) | 2006-05-11 |
Family
ID=34953616
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/FR2005/050920 WO2006048581A1 (fr) | 2004-11-04 | 2005-11-02 | Dispositif d'enregistrement et/ou de lecture a tetes magnetiques multiples azimutees |
Country Status (5)
Country | Link |
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US (1) | US20090067088A1 (fr) |
EP (1) | EP1810284A1 (fr) |
JP (1) | JP2008519385A (fr) |
FR (1) | FR2877485A1 (fr) |
WO (1) | WO2006048581A1 (fr) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US10718826B2 (en) * | 2014-12-02 | 2020-07-21 | Texas Instruments Incorporated | High performance fluxgate device |
US9852747B1 (en) * | 2016-09-22 | 2017-12-26 | International Business Machines Corporation | Segmented magnetic recording write head for writing timing-based servo patterns |
US9934804B1 (en) | 2016-09-22 | 2018-04-03 | International Business Machines Corporation | Segmented magnetic recording write head for detection-based servo pattern writing |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4439793A (en) * | 1981-10-22 | 1984-03-27 | Fuji Photo Film Co., Ltd. | Thin film head array |
US5293285A (en) * | 1992-06-01 | 1994-03-08 | Storage Technology Corporation | Apparatus and media for recording data on two sides of a magnetic tape |
US5452165A (en) * | 1994-03-16 | 1995-09-19 | International Business Machines Corporation | Close packed magnetic head linear array |
US5883760A (en) * | 1992-10-20 | 1999-03-16 | Mitsubishi Denki Kabushiki Kaisha | Magnetic structure and magnetic head using the same |
FR2774797A1 (fr) * | 1998-02-11 | 1999-08-13 | Commissariat Energie Atomique | Procede de realisation d'un ensemble a plusieurs tetes magnetiques et ensemble a tetes multiples obtenu par ce procede |
-
2004
- 2004-11-04 FR FR0452528A patent/FR2877485A1/fr not_active Withdrawn
-
2005
- 2005-11-02 JP JP2007539622A patent/JP2008519385A/ja active Pending
- 2005-11-02 EP EP05819213A patent/EP1810284A1/fr not_active Withdrawn
- 2005-11-02 US US11/718,458 patent/US20090067088A1/en not_active Abandoned
- 2005-11-02 WO PCT/FR2005/050920 patent/WO2006048581A1/fr active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4439793A (en) * | 1981-10-22 | 1984-03-27 | Fuji Photo Film Co., Ltd. | Thin film head array |
US5293285A (en) * | 1992-06-01 | 1994-03-08 | Storage Technology Corporation | Apparatus and media for recording data on two sides of a magnetic tape |
US5883760A (en) * | 1992-10-20 | 1999-03-16 | Mitsubishi Denki Kabushiki Kaisha | Magnetic structure and magnetic head using the same |
US5452165A (en) * | 1994-03-16 | 1995-09-19 | International Business Machines Corporation | Close packed magnetic head linear array |
FR2774797A1 (fr) * | 1998-02-11 | 1999-08-13 | Commissariat Energie Atomique | Procede de realisation d'un ensemble a plusieurs tetes magnetiques et ensemble a tetes multiples obtenu par ce procede |
Also Published As
Publication number | Publication date |
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EP1810284A1 (fr) | 2007-07-25 |
FR2877485A1 (fr) | 2006-05-05 |
JP2008519385A (ja) | 2008-06-05 |
US20090067088A1 (en) | 2009-03-12 |
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