Patent Application
20100196739
The present invention relates to a magnetic head, a manufacturing method therefor and a magnetic tape device.
Recently, the importance of data backup for data erasure problem has increased with increase in volume of data to be stored in an information processing device such as a server. As a device for backing up large-volume data, there has been widely used a magnetic tape device exemplified by LTO (Liner Tape-Open). In the case of LTO, as much as 1.6 Tbytes data can be recorded on a half-inch width magnetic tape at a transmission rate of 120 Mbytes/sec or more.
The magnetic tape device is provided with a magnetic head for recording data on a magnetic tape or reading data recorded on the magnetic tape. The magnetic head is of the linear recording type, wherein since data is to be recorded and reproduced at every track defined along a longitudinal direction of the magnetic tape, a plurality of recording and reproducing elements for each track are arranged along a magnetic tape width direction. Typically, the magnetic head has recording and reproducing elements for 16 channels.
In the production of the magnetic head, accordingly, even when only one element for one channel is malfunctioning, the entire device becomes a defective product. Hence, if there is adopted a method of integrally obtaining a magnetic head from a wafer, including a portion where the recording and reproducing elements do not exist, the yield will be extremely lowered.
On the other hand, instead of the above method, there is another method, in which after obtaining a substrate that includes the recording and reproducing elements for all the tracks from a wafer, separately-formed two auxiliary members that do not include the recording and reproducing elements are adhered to its two end faces, respectively, in the tape width direction. This method is very advantageous in view of production efficiency since the number of substrates that can be obtained from a single wafer can be increased.
In the case of adopting this manufacturing method, however, when the substrate and the auxiliary members are adhered together, height positions of the TBSs (Tape Bearing Surfaces) are required to correspond with a high accuracy, making it difficult to further improve production efficiency. If their height positions are different from each other, there will be a problem that the tape bearing surface has steps, resulting in increasing the frictional heat between the magnetic tape and the magnetic head, and in addition, the steps of the tape bearing surface may cause a large space between the magnetic tape and the magnetic head, causing a problem of reducing power of reading or writing signals, so-called spacing loss.
In order to solve the above problems, there may be adopted a method of stabilizing contact between the magnetic tape and the magnetic head, for example, by applying a guide member to the magnetic head as disclosed in Japanese Unexamined Utility-Model Application Publication No. 5-73728, but eventually, it is less-than-effective because high accuracy is required for formation of a groove in the guide member and adhesion to the magnetic head.
It is an object of the present invention to provide a magnetic head which can be kept in stable contact with a magnetic tape and has improved production efficiency, a manufacturing method therefor, and a magnetic tape device.
In order to solve the above problems, the magnetic head according to the present invention comprises a substrate and two auxiliary members, having a tape bearing surface to be in sliding contact with a magnetic tape.
Reproducing and recording elements in alignment with each other along a tape running direction are arranged in the substrate along a tape width direction.
The two auxiliary members are joined to two ends, respectively, of the substrate, constituting the tape bearing surface together with the substrate.
The substrate or the two auxiliary members are formed with slopes extending from join-faces between the substrate and the two auxiliary members to the tape bearing surface to make clearances for the magnetic tape.
When kept in contact with the magnetic tape, the magnetic head with the slopes formed in the substrate or the two auxiliary members makes clearances. The clearances are formed along the tape running direction as two grooves in the tape bearing surface and generate negative pressure as the magnetic tape runs, so that the magnetic tape can be drawn to the clearances by atmospheric pressure. Hence, the running magnetic tape can be suitably kept in parallel with the tape bearing surface.
In addition, since the clearances are formed at the boundaries between the substrate and the two auxiliary members in the tape bearing surface, the tape bearing surface does not have any step between the substrate and the two auxiliary members. Accordingly, the above-described problems of frictional heat and spacing loss can be avoided. Thus, the magnetic head according to the present invention can be kept in stable contact with the magnetic tape at the tape bearing surface.
In the magnetic head according to the present invention, moreover, since the above-described high-accuracy adjustment of the substrate and the two auxiliary members for the height position of the tape bearing surface is no more required because of having the clearances, the production efficiency can be improved.
The method for manufacturing a magnetic head according to the present invention is a method for manufacturing a magnetic head with a tape bearing surface to be in sliding contact with a magnetic tape, as described above.
In the manufacturing method, prior to constituting the tape bearing surface by joining two auxiliary members to two ends, respectively, of a substrate whose reproducing and recording elements in alignment with each other along a tape running direction are arranged along a tape width direction, the substrate or the two auxiliary members are formed with slopes extending from join-faces between the substrate and the two auxiliary members to the tape bearing surface to make clearances for the magnetic tape.
Since the foregoing magnetic head can be obtained according to the magnetic head manufacturing method of the present invention, it is obvious that it can obtain the same effects as above.
The magnetic tape device according to the present invention comprises a magnetic tape driving means and a magnetic head.
The magnetic tape driving means is adapted to run a magnetic tape along a tape running direction.
The magnetic head is the foregoing magnetic head, and the tape bearing surface is adapted to be kept in sliding contact with the magnetic tape for writing data on the magnetic tape with the recording element and reading data from the magnetic tape with the reproducing element.
Since the magnetic tape device of the present invention includes the foregoing magnetic head, it is obvious that it can obtain the same effects as above.
The other objects, constructions and advantages of the present invention will be further detailed below with reference to the attached drawings. However, the attached drawings show only illustrative examples.
a-13d show steps of a method for manufacturing a magnetic head according to the present invention.
The motors 4a, 4b being a magnetic tape driving means make the pair of reels 2a, 2b rotate through a power transmission system such as gears, whereby the magnetic tape 6 runs along tape running direction D1, D2. The motors 4a, 4b can be driven in either rotation direction, and when the magnetic tape 6 runs in the tape running direction D1, the pair of reels 2a, 2b are rotated such that the magnetic tape 6 is unwound from the reel 2a and taken up by the reel 2b. When the magnetic tape 6 runs in the tape running direction D2, the pair of reels 2a, 2b are rotated by the motors 4a, 4b such that the magnetic tape 6 is unwound from the reel 2b and taken up by the reel 2a. The running magnetic tape 6 is guided by the plurality of guide pins 3.
The magnetic head 1 is positioned such that it can be pressed against the magnetic tape 6 between the pair of reels 2a, 2b. The magnetic head 1 has a tape bearing surface 100 in sliding contact with the magnetic tape 6, writing data on the magnetic tape 6 with a recording element Ew and reading data from the magnetic tape 6 with a reproducing element Er.
The recording element Ew is an electromagnetic conversion element that converts an input electrical signal and applies a signal magnetic field to the magnetic tape 6 for writing data. On the other hand, the reproducing element Er is a MR element having TMR (Tunnel Magneto Resistance) effect or GMR (Giant Magneto Resistance) effect and perceives a signal magnetic field from the magnetic tape 6 and converts it to an electrical signal for reading data. The recording elements Ew and the reproducing elements Er are formed within the magnetic head 1 but partially exposed on the tape bearing surface 100.
The controller 5 is a control circuit board or the like which, according to an operation from the outside, controls not only the rotation of the motors 4a, 4b but also writing operation on the magnetic tape 6 with data output to the recording element Ew of the magnetic head 1 and reading operation from the magnetic tape 6 with data input from the reproducing element Er of the magnetic head 1.
The magnetic head 1 includes first and second head portions 11a, 11b having the recording and reproducing elements Ew, Er and first and second closures 12a, 12b of a rectangular prism shape having the same width as the head portions 11a, 11b. It should be noted that the first and second head portions 11a, 11b have the same structure and the first and second closures 12a, 12b also have the same structure. The magnetic head 1 is composed such that the first and second head portions 11a, 11b are joined to the first and second closures 12a, 12b, respectively, and the first and second closures 12a, 12b are further joined to each other in face-to-face relationship.
In the substrate 112, the reproducing and recording elements Er, Ew in alignment with each other along the tape running direction D1, D2 are arranged along a tape width direction D3. At both ends of the array of the reproducing elements Er and at both ends of the array of the recording elements Ew, moreover, there are arranged servo elements Es for detecting the position with respect to the magnetic tape 6. The reproducing, recording and servo elements Er, Ew Es are disposed corresponding to tracks 61 to 67 defined along the tape width direction D3 of the magnetic tape 6 for performing reading from and writing on the corresponding tracks 61 to 67. It should be noted that the configuration of the tracks 61 to 67 is not limited to the illustrated one.
When the magnetic tape 6 runs along the tape running direction D1, the first head portion 11a has the reproducing element Er on the leading side and the recording element Ew on the tracking side, while the second head portion 11b has the reproducing element Er on the tracking side and the recording element Ew on the leading side. When the magnetic tape 6 runs along the tape running direction D2, on the other hand, the first head portion 11a has the reproducing element Er on the tracking side and the recording element Ew on the leading side, while the second head portion 11b has the reproducing element Er on the leading side and the recording element Ew on the tracking side.
In other words, one of the substrates 112 is disposed such that the reproducing element Er is located on the leading side with respect to the tape running direction D1, D2, and the other of the substrates 112 is disposed downstream of the one of the substrates 112 in the tape running direction D1, D2 such that the recording element Ew is located on the leading side with respect to the tape running direction D1, D2.
With the two head portions 11a, 11b being thus provided, during the writing operation, data can be written by the upstream side recording elements Ew of either one of the first and second head portions 11a, 11b, depending on the tape running direction D1, D2, while the written data can be read by the downstream side reproducing elements Er and checked by the controller 5 to confirm the normality of the writing operation. For example, when the magnetic tape 6 runs along the tape running direction D1, data is written by the recording elements Ew of the first head portion 11a, while the written data is read by the reproducing elements Er of the second head portion 11b.
The two auxiliary members 111 are joined to two ends, respectively, of the substrate 112, constituting the tape bearing surface 100 together with the substrate 112. That is, the two auxiliary members 111 are joined to two end faces C1 of the substrate 112 in the tape width direction D3.
The two auxiliary members 111 are formed with slopes P extending from join-faces C2 between the substrate 112 and the two auxiliary members 111 to the tape bearing surface 100 to make clearances S for the magnetic tape 6. Concretely, the slope P is formed into a rectangular shape extending from the join-face C2 to the tape bearing surface 100. Accordingly, the clearance S is a space in the shape of a triangular prism whose height direction is taken along the tape running direction D1, D2.
When kept in contact with the magnetic tape 6, the magnetic head 1 with the slopes P formed in the substrate 112 or the two auxiliary members 111 makes the clearances S. The clearances S are formed along the tape running direction D1, D2 as two grooves in the tape bearing surface 100, and as the magnetic tape runs, they generate negative pressure, so that the magnetic tape 6 can be drawn to the clearances S by atmospheric pressure (see suction F in
In addition, since the clearances S are formed at the boundaries between the substrate 112 and the two auxiliary members 111 in the tape bearing surface 100, the tape bearing surface 100 does not have any step between the substrate 112 and the two auxiliary members 111. Accordingly, the above-described problems of frictional heat and spacing loss can be avoided. Thus, the magnetic head 1 according to the present invention can be kept in stable contact with the magnetic tape 6 at the tape bearing surface 100.
In the present embodiment, therefore, the magnetic tape 6 can be kept in close contact with the reproducing and recording elements Er, Ew more reliably by projecting the substrate 112 from the two auxiliary members 111 toward the magnetic tape 6.
Moreover, since the clearances S are formed at two locations of the tape bearing surface 100 in the tape width direction D3, the suction F acts over the tape width direction D3, whereby the magnetic tape 6 can be stably held particularly in the tape width direction D3. With this, there can be obtained an effect that the magnetic tape 6 can be suitably prevented from rolling or the like.
Furthermore, the above-described closures 12a, 12b are joined to one end face of the substrate 112 and the two auxiliary members 111 in the tape running direction D1, D2, closing an open side of the clearance S. With this, the suction F for the magnetic tape 6 becomes more stable.
In the magnetic head 1 according to the present invention, still furthermore, since the above-described high-accuracy adjustment of the substrate 112 and the two auxiliary members 111 for the height position of the tape bearing surface 100 is no more required because of having the clearances S, the production efficiency can be improved.
The above effects can be similarly obtained by a magnetic tape device that is provided with the magnetic head 1 according to the present invention.
The magnetic head 1 according to the present invention is not limited to the above embodiment. Other embodiments of the magnetic head 1 will be described hereinbelow.
In the present embodiment, the slope P is formed such that the depth of the clearance S as measured from the running plane of the magnetic tape 6 varies in the tape running direction D1, D2 (i.e., the direction from the reproducing element Er to the recording element Ew). The slope P is formed such that the distance from the magnetic tape 6 (i.e., the distance in the direction Z in the drawings) increases along the tape running direction D1, D2, so that the clearance S is widened along the tape running direction D1, D2. Concretely, the slope P is formed into a triangular shape with one corner taken as vertex, wherein the clearance S has a triangular pyramid shape widening along the tape running direction D1, D2.
Here, as shown in
Therefore, the cross-sectional area of the clearance S along the tape width direction D3 decreases in the direction from the recording element Ew to the reproducing element Er, causing a difference in the suction F for the magnetic tape 6 between the reproducing element Er side and the recording element Ew side, depending on the tape running direction D1, D2.
In the case of the tape running direction D1, more specifically, the suction F in the first head portion 11a is stronger at the recording element Ew side than at the reproducing element Er side, while the suction F in the second head portion 11b is stronger at the reproducing element Er side than at the recording element Ew side. In the case of the tape running direction D2, on the other hand, the suction F in the first head portion 11a is stronger at the reproducing element Er side than at the recording element Ew side, while the suction F in the second head portion 11b is stronger at the recording element Ew side than at the reproducing element Er side.
These effects are very effective in the above-described writing operation including subsequent data confirmation. This is because in each of the head portions 11a, 11b, the magnetic tape 6 can be drawn more strongly to the functioning one of the reproducing and recording elements Er, Ew, depending on the tape running direction D1, D2, so that the writing operation can be performed more reliably.
The slope P of the substrate 112 has a triangular shape extending from each end face C4, i.e., a face joined to a join-face C5 of the auxiliary member 115 to the tape bearing surface 100. Accordingly, the clearance S has a triangular pyramid shape widening along the tape running direction D1, D2. With the head portions 11a, 11b being disposed as shown in
For the substrates 112, 114 and the auxiliary members 111, 113, 115 described above, moreover, the optimum dimensions will be described below.
(1) Dimensions of the rectangular prism of the substrates 112, 114:
(2) Dimensions of the rectangular prism of the auxiliary members 111, 113, 115:
(3) Cut-off portion (i.e., portion indicated by dotted lines) of the auxiliary member 111 shown in
(4) Cut-off portion (i.e., portion indicated by dotted lines) of the auxiliary member 113 shown in
(5) Cut-off portion (i.e., portion indicated by dotted lines) of the substrate 114 shown in
Next will be described a method for manufacturing the foregoing magnetic head 1.
The method for manufacturing a magnetic head according to the present invention is a method for manufacturing a magnetic head with the tape bearing surface 100 to be in sliding contact with the magnetic tape 6, as described above.
In the manufacturing method, prior to constituting the tape bearing surface 100 by joining the two auxiliary members 111 to the two ends Cl, respectively, of the substrate 112 whose reproducing and recording elements Er, Ew in alignment with each other along the tape running direction D1, D2 are arranged along the tape width direction D3, as shown in
As means for forming the slope P, there may be adopted cutting or polishing. In the auxiliary member 113 shown in
As means for joining together the substrate 112 and the two auxiliary members 111, there may be adopted an adhesive. Moreover, as has been described above, it is desirable that the substrate 112 and the two auxiliary members 111 are joined together such that the substrate 112 projects from the two auxiliary members 111 toward the magnetic tape 6.
After the substrate 112 and the two auxiliary members 111 are joined together, as shown in
Since the foregoing magnetic head 1 can be obtained according to the magnetic head manufacturing method of the present invention, it is obvious that the same effects can be obtained as above.
The present invention has been described in detail above with reference to preferred embodiments. However, obviously those skilled in the art could easily devise various modifications of the invention based on the technical concepts underlying the invention and teachings disclosed herein.
