1. Field of the Invention
The present invention generally relates to a magnetic head assembly, a manufacturing method thereof, a flexure, and a magnetic disk apparatus, especially to a magnetic head assembly having a signal wiring portion disposed on a surface of a support of a head slider, a manufacturing method thereof, a flexure, and a magnetic disk apparatus.
2. Description of the Related Art
In recent years, miniaturization of magnetic head assemblies for performing recording/reproduction on a magnetic disk have made progress according as magnetic disk apparatuses have higher density and miniaturized sizes. As shown in
In order to connect the element portion 101 of the head slider 102 to the Cu wiring 104a, a head terminal 105 is disposed on the head slider 102 and a flexure terminal 106 is disposed on the Cu wiring 104a. Conventionally, the head terminal 105 and the flexure terminal 106 are electrically connected using gold ball bonding referred to as GBB (see Parent Document 1, for example). The gold ball bonding is a type of an ultrasonic welding method where the flexure 103 and the head slider 102 must be firmly fixed upon bonding in order to certainly propagate ultrasonic waves. Stress applied on this occasion may easily deform the flexure 103 and poses a problem in that a yield of the magnetic head assembly 100 is reduced. In order to solve this problem, junction techniques referred to as solder ball bonding (SSB), for example, have been introduced instead of the gold ball bonding, by which a solder ball is melted and solidified so as to form a junction portion 108 and the head terminal 105 and the flexure terminal 106 are electrically connected (refer to Parent Document 2 or 3, for example).
Parent Document 1: Japanese Laid-Open
Patent Application No. 2005-276436
Parent Document 2: Japanese Laid-Open
Patent Application No. 2005-123581
Parent Document 3: Japanese Laid-Open
Patent Application No. 2005-81406
As shown in
In the SSB, a solder ball is heated to a high temperature, namely, about 200° C. and melted so as to form the junction portion 108. The volume of solder is shrunk upon solidification and stress is generated such that the head terminal 105 and the flexure terminal 106 are brought close to each other. Thus, a connection portion between the attachment portion 109 of the head slider 102 and the body of the flexure 103 is deformed and raised relative to the body of the flexure 103. In accordance with this, a relative angle of the head slider 102 is changed with respect to the body of the flexure 103. This poses a problem in that levitation characteristics of the head slider 102 are deteriorated and levitation height thereof is changed, thereby reducing recording/reproduction characteristics or causing damage to a magnetic disk upon loading/unloading and reducing performance and reliability of a magnetic disk apparatus.
It is a general object of the present invention to provide an improved and useful magnetic head assembly, a manufacturing method thereof, a flexure, and a magnetic disk apparatus using a magnetic head assembly in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide a magnetic head assembly, a manufacturing method thereof, a flexure, and a magnetic disk apparatus using a magnetic head assembly that controls deformation of the flexure and has good levitation characteristics.
According to one aspect of the present invention, there is provided a magnetic head assembly comprising: a head slider having an element portion including a recording element or a reproduction element; a flexure for supporting the head slider; and a signal wiring portion disposed on a surface of the flexure, the signal wiring portion transmitting recording current signals or reproduction signals, wherein the flexure has a slider attachment portion supported by the flexure on an end portion and capable of warping and a flexure terminal portion disposed on the end portion side relative to an attachment position of the head slider on the slider attachment portion, the flexure terminal portion being electrically connected to the signal wiring portion, the head slider is fixed on a surface of the slider attachment portion and has a slider terminal portion disposed on a side surface on the end portion side, the slider terminal portion being electrically connected to the element portion, the slider terminal portion is electrically connected to the flexure terminal portion using a joint portion, and the flexure terminal portion is disposed separably from the surface of the flexure.
According to the present invention, when forming the joint portion for connecting the slider terminal portion of the head slider to the flexure terminal portion, stress is generated such that the slider terminal portion and the flexure terminal portion are brought close to each other due to the volume shrinkage of molten solder upon solidification. In accordance with this stress, the flexure terminal portion is separated from the surface of the flexure and absorbs the stress. Thus, the stress does not affect the flexure, especially the flexure attachment portion, and the warping of the flexure attachment portion is prevented. Therefore, the flexure attachment portion is held at a desired relative angle relative to the flexure, so that it is possible to provide a magnetic head assembly with good levitation characteristics.
According to another aspect of the present invention, there is provided a method of manufacturing a magnetic head assembly including: a head slider having an element portion including a recording element or a reproduction element; a flexure including a metallic plate and supporting the head slider; and a signal wiring portion disposed on a surface of the flexure, the signal wiring portion transmitting recording current signals or reproduction signals, wherein the flexure has a slider attachment portion supported by the flexure on an end portion and capable of warping and a flexure terminal portion disposed on the end portion side relative to an attachment position of the head slider on the slider attachment portion, the flexure terminal portion being electrically connected to the signal wiring portion, the head slider is fixed on a surface of the slider attachment portion and has a slider terminal portion disposed on a side surface on the end portion side, the slider terminal portion being electrically connected to the element portion, and the slider terminal portion is electrically connected to the flexure terminal portion using a joint portion, the method comprising the steps of: forming an insulating layer on an area where the signal wiring portion on a surface of the metallic plate is formed; forming a flexure terminal portion and a signal wiring layer on the insulating layer; forming, between the surface of the metallic plate and the insulation layer or between the insulating layer, the flexure terminal portion, and the signal wiring layer, a sacrifice layer on an area including an area where the flexure terminal portion is formed; and removing the sacrifice layer after the insulating layer or the signal wiring layer is formed on an upper side of the sacrifice layer.
According to the present invention, the sacrifice layer is formed between the surface of the metallic plate and the insulating layer, or in an area including an area where the flexure terminal portion is formed, between the insulating layer, the flexure terminal portion, and the signal wiring layer, thereby providing the aforementioned magnetic head assembly.
According to yet another aspect of the present invention, there is provided a magnetic disk apparatus comprising one of the magnetic head assemblies mentioned above, an actuator mechanism for supporting the magnetic head assembly, and a magnetic disk recorded and reproduced by the element portion of the magnetic head assembly.
According to the present invention, a magnetic head assembly having good levitation characteristics is included, so that it is possible to provide a magnetic disk apparatus with superior reliability.
According to the present invention, it is possible to provide a magnetic head assembly, a manufacturing method thereof, a flexure, and a magnetic disk apparatus using a magnetic head assembly that controls deformation of the flexure and has good levitation characteristics.
Other objects, features and advantage of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.
In the following, embodiments of the present invention will be described with reference to the accompanying drawings.
With reference to
The magnetic disk 12 is capable of employing what is called an in-plane magnetic recording medium or a vertical magnetic recording medium, for example. The magnetic disk 12 has a known structure and may be capable of recording and reproducing using the magnetic head assembly 20.
In the housing 11, there is disposed an R/W amplifier 18 for inputting/outputting a recording current and reproduction signals to the magnetic head assembly 20 via an FPC 16 (Flexible Print Circuit). The R/W amplifier 18 is connected to an electronic board (not shown in the drawings) disposed on a back side of the housing 11. The electronic board includes a recording/reproduction controlling circuit, a magnetic head position controlling circuit, a spindle motor controlling circuit, and the like (not shown in the drawings). In the following, the magnetic head assembly 20 will be described in detail.
With reference to
A sheet metal including stainless steel and the like is used for the load beam 21. The load beam 21 has the base plate 22 on a base thereof by fitting, for example, in an integrated manner and is fixed on the arm 15 shown in
The flexure 23 employs a sheet metal including stainless steel and the like and has a function of a leaf spring. In the flexure 23, a base 23c is fixed on the load beam 21 and a flexure tip portion 23b includes a free end with the fixed portion as a fulcrum.
A boundary between a flexure body portion 23a and the flexure tip portion 23b is represented by line P-P as shown in
Also, the flexure 23 has the slider attachment portion 26 formed on the flexure tip portion 23b and the head slider 24 is bonded on the surface of the slider attachment portion 26.
The head slider 24 includes a pad 30 for receiving pressure from an air flow generated on a medium facing surface 24a in accordance with a rotation of a magnetic disk (not shown in the drawings) and an element portion 31 performing recording/reproduction on an air flow side.
The element portion 31 includes a recording element for converting recording current signals to a recording magnetic field and a reproduction element for detecting a signal magnetic field from a magnetic disk and converting to reproduction signals, the elements being not distinctively shown in the drawings due to minute sizes thereof. The head slider 24 has a slider terminal portion 32 disposed on a side surface of the flexure tip portion 23b. The slider terminal portion 32 is for supplying the recording current signals to the recording element and extracting the reproduction signals from the reproduction element. In this case, the slider terminal portion 32 has four pad electrodes 32a, for example.
The slider attachment portion 26 is connected to the flexure tip portion 23b. Both sides in X axis direction and a side relative to the base 23c in Y axis direction are separated from the flexure body portion 23a with an opening portion 23-1. In other words, the slider attachment portion 26 has a cantilever structure supported by the flexure tip portion 23b. The slider attachment portion 26 has such a structure, so that the flexure tip portion 23b of the slider attachment portion 26 is capable of deformation in accordance with levitation force generated in the head slider 24.
With reference to
On a surface of the flexure 23, the signal wiring portion 25 includes an insulating layer 36, a Cu wiring layer 38, and a protective film 39 in this order in a laminated manner. The insulating layer 36 of the signal wiring portion 25 may include resin having a thickness of 10 μm, for example. Examples of resin preferable for the insulating layer 36 include polyimide resin or polyester resin. The insulating layer 36 has almost an entire portion thereof firmly adhered to the surface of the flexure 23.
The Cu wiring layer 38 includes a Cu film having a thickness of 10 μm and a width of about 20 μm to 60 μm, for example. Although four signal wires and earthing wires are shown as an example of the Cu wiring layer 38, the layer is not limited to this example. In addition, the Cu wiring layer 38 may include a Cu alloy film or a metallic material with good conductivity besides the Cu film.
The protective film 39 includes resin having a thickness of 5 μm, for example, and the same material as selected in the insulating layer 36. The protective film 39 is formed such that it covers the Cu wiring layer 38 and substantially overlaps the insulating layer.
In the signal wiring portion 25, an HGA terminal portion 35 is disposed, including a pad electrode electrically connected to the Cu wiring layer 38 on the base of the magnetic head assembly 20. The HGA terminal portion 35 is connected to the FPC 16 shown in
On the other hand, in the signal wiring portion 25, a flexure terminal portion 29 is disposed as a terminal on the head slider 24. The flexure terminal portion 29 is disposed on the flexure tip portion 23b relative to the attachment position of the head slider 24 of the slider attachment portion 26. The flexure terminal portion 29 includes an insulating layer 36a formed on the slider attachment portion 26 and the surface of the flexure tip portion 23b, a pad electrode 29a formed thereon, and the Cu wiring layer 38 connected to the pad electrode 29a. In this case, the flexure terminal portion 29 has four pad electrodes 29a, for example.
In magnetic head assembly 20 in the first example, the insulating layer 36a of the flexure terminal portion 29 is separated from the slider attachment portion 26 and the surface of the flexure tip portion 23b. The insulating layer 36a is a portion of the insulating layer 36 of the signal wiring portion 25 mentioned above and is shown in a hatching area of slant lines in
A solder joint portion 40 electrically connects the pad electrode 29a of the flexure terminal portion 29 to the pad electrode 32a of the slider terminal portion 32. Materials for solder of the solder joint portion 40 are not particularly limited. Examples that may be used include an alloy in which Sn, Ag, Cu, Bi, Zn, In, and the like are added in a compound and unleaded solder having Sn—Ag—Cu (eutectic point is 218° C., for example).
The volume of the solder is shrunk upon solidification from a liquid status and stress is generated between the slider terminal portion 32 and the flexure terminal portion 29 such that they are brought close to each other. The head slider 24 is firmly adhered to the slider attachment portion 26, so that the head slider 24 bears the stress from the solder joint portion 40 using an elastic force of the slider attachment portion 26.
On the other hand, the insulating layer 36a of the flexure terminal portion 29 is separated from the surface of the flexure 23 (the slider attachment portion 26 and the flexure tip portion 23b), so that the insulating layer 36a is readily capable of deformation such as being raised in accordance with the stress from the solder joint portion 40. Thus, the insulating layer 36a is separated from the surface of the flexure 23 and absorbs the stress of the solder joint portion 40. Accordingly, warping of the slider attachment portion 26 can be prevented and a relative angle of the slider attachment portion 26 relative to the flexure body portion 23a is not changed, thereby preventing negative effects on the levitation characteristics caused when the volume of the solder of the solder joint portion 40 is shrunk upon solidification.
As mentioned above, the magnetic head assembly 20 in the first example is formed such that the insulating layer 36a of the flexure terminal portion 29 is separated from the surface of the flexure 23. Thus, when the solder of the solder joint portion 40 is solidified, the insulating layer 36 of the flexure terminal portion 29 experiences deformation such as being raised from the surface of the flexure 23, so that the stress generated by the volume shrinkage of the solder is absorbed. In accordance with this, it is possible to prevent the stress from warping the head slider 24 of the slider attachment portion 26 to the flexure tip portion 23b relative to the attachment position via the slider terminal portion 32. As a result, a desired relative angle between the slider attachment portion 26 and the flexure 23 is maintained. Therefore, a desired relative angle between the head slider 24 and the flexure 23 is maintained and good levitation characteristics of the magnetic head assembly 20 are secured. Further, reliability of the magnetic disk apparatus 10 using the magnetic head assembly 20 is secured.
Next, a method of manufacturing the magnetic head assembly in the first example is described.
The method of manufacturing the magnetic head assembly in the first example substantially includes a base plate forming step, a load beam forming step, a flexure forming step, a head slider forming step, and an assembly step. In the following, the assembly step including the flexure forming step and the forming of signal wiring is described. Other steps mentioned above may employ known forming steps.
FIGS. 7 to 11 are diagrams showing a portion of the method of manufacturing the magnetic head assembly in the first example. Each A of FIGS. 7 to 11 shows a plan view, and B shows a cross-sectional view taken along line D-D shown in each A. In addition, line D-D shown in each A of FIGS. 7 to 11 indicates the same line as line C-C shown in
First, in steps of
Specifically, the forming of the sacrifice layer 43 includes the steps of forming a resist pattern having an area of an opening for forming the sacrifice layer 43 in advance, accumulating materials for the sacrifice layer on the opening portion in a plating method, a deposition method, or a sputtering method, and removing the resist film and the Cu film disposed thereon at one time by a lift-off method. In addition, the sacrifice layer 43 may be formed on an entire surface of the metallic thin belt 42 in advance and an area other than the sacrifice layer 43 shown in
Next, in steps of
Specifically, the forming of the insulating layers 34 and 36 includes the steps of coating a polyimide resin solution onto an entire surface of the metallic thin belt 42 and drying the entire surface. Then, the polyimide resin is formed into a predetermined shape by dry etching such as reactive ion etching. The insulating layers 34 and 36 formed in this manner are firmly adhered to the sacrifice layer 43 and the metallic thin belt 42.
Next, in steps of
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The steps of
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Following the steps of
Next, the following steps will be described with reference to
Next, a solder ball including Sn—Ag'Cu is used and the flexure terminal portion 29 is connected to the slider terminal portion 32 by soldering.
In this manufacturing method, the sacrifice layer 43 is formed such that it includes the area where the flexure terminal on the surface of the metallic thin belt 42 is formed. The insulating layer 36 of the signal wiring portion 25 is formed on the sacrifice layer 43 and then the sacrifice layer 43 is removed. Thus, the insulating layer 36a of the flexure terminal portion 29 is configured to be separate from the surface of the flexure. Further, it is possible to prevent negative effects such as erosion provided to the Cu wiring layer 38 by the etching processing of the sacrifice layer 43.
Next, other example of the method of manufacturing the magnetic head assembly in the first example will be described. Description of steps other than a flexure forming step is omitted, since the steps other than the flexure forming step are the same as in the aforementioned method of manufacturing the magnetic head assembly in the first example. Moreover, plan views for the manufacturing steps are omitted, since the plan views are substantially the same as those shown in
In the steps of
Next, in steps of
Next, in steps of
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In steps of
In this manufacturing method, the sacrifice layer 43 is formed such that it includes the area where the flexure terminal portion on the surface of the metallic thin belt 42 is formed, the insulating layer 36 of the signal wiring portion 25 is formed on the sacrifice layer, the Cu wiring layer 38 and the like is formed, and then the sacrifice layer 43 is removed. Thus, the insulating layer 36a of the flexure terminal portion 29 is configured to be separate from the surface of the flexure. Further, it is possible to prevent negative effects such as erosion provided to the Cu wiring layer 38 by the etching processing of the sacrifice layer 43.
Moreover, in this manufacturing method, the sacrifice layer 43 is removed after the protective film 39 of the signal wiring portion 25 is formed. Thus, when forming the pad electrode 29a of the flexure terminal portion 29 and the Cu wiring layer 38 connecting to the pad electrode 29a, the forming can be performed while the insulating layer 36a is fixed on the metallic thin belt 42 via the sacrifice layer 43. Therefore, when forming the pad electrode 29a of the flexure terminal portion 29 and the Cu wiring layer 38, positioning accuracy thereof is improved.
In the aforementioned manufacturing method, the step of removing the sacrifice layer 43 may be performed before the step of forming the protective film 39.
Next, description is given regarding an example of the magnetic disk apparatus 10 according to the first embodiment shown in
In a magnetic head assembly 20A in the second example, the insulating layer 36 of the flexure terminal portion 29 is firmly adhered to the surface of the flexure 23 and the pad electrode 29a of the flexure terminal portion 29 and the Cu wiring layer 38 connected thereto are disposed separately from the insulating layer 36. Further, the protective film 39 is disposed on the surface of the Cu wiring layer 38.
In the solder joint portion 40, the flexure terminal portion 29 is electrically connected to the slider terminal portion 32 using solder. Since the volume of solder of the solder joint portion 40 is shrunk upon solidification, stress is generated such that the slider terminal portion 32 and the flexure terminal portion 29 are brought close to each other. In this case, the pad electrode 29a of the flexure terminal portion 29 and the Cu wiring layer 38 are raised and absorbs the stress since they are separate from the insulating layer 36. In accordance with this, it is possible to prevent the slider attachment portion 26 from being raised from the flexure body portion 23a and a desired relative angle between the slider attachment portion 26 and the flexure body portion 23a is maintained. Thus, good levitation characteristics of the head slider 24 are maintained. Further, it is possible to prevent the deterioration of the performance and reliability of the magnetic disk apparatus 10 using the magnetic head assembly 20A. In addition, the protective film 39 may be formed on the entire surface of the Cu wiring layer 38 in the flexure terminal portion 29.
Next, description will be given regarding other example of the method of manufacturing the magnetic head assembly in the second example. Description of steps other than a flexure forming step is omitted, since the steps other than the flexure forming step are the same as in the aforementioned method of manufacturing the magnetic head assembly in the first example.
In steps of
In steps of
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Next, in steps of
Next, in steps of
In this manufacturing method, the pad electrode 29a of the flexure terminal portion 29 and the Cu wiring layer 38 are configured to be separate from the insulating layer 36a. Also, in this manufacturing method, the sacrifice layer 43 is removed after the signal wiring portion 25 is formed. Thus, when forming the pad electrode 29a of the flexure terminal portion 29 and the Cu wiring layer 38, the forming can be performed while the insulating layer 36 is firmly adhered to the metallic thin belt 42. Therefore, when forming the pad electrode 29a of the flexure terminal portion 29 and the Cu wiring layer 38, positioning accuracy thereof is improved.
A magnetic disk apparatus according to a second embodiment of the present invention concerns a magnetic disk apparatus including a lamp-type loading/unloading mechanism.
With reference to
In the magnetic head assembly 60 in the third example, a lift tab 61 is disposed at the tip portion 23b thereof and the base of the lift tab 61 is supported by the load beam 21. In addition, the lift tab 61 is not directly connected to a flexure 63.
The lamp 51 is disposed on the outside of the magnetic disk 12. The lamp 51 includes resin, for example. A slope-like lift tab sliding portion 51a is formed such that it extends in the periphery of the magnetic disk 12 and comes away from a surface of the magnetic disk 12 in the vertical direction from the magnetic disk 12 side to the outer side thereof.
The magnetic head assembly 60 is unloaded such that the head slider 24 in a levitation status is forcedly separated from the magnetic disk 12 when the lift tab 61 is entrained in the lift tab sliding portion 51a of the lamp 51 upon withdrawing to an outer area of the magnetic disk 12. Also, when the magnetic head assembly 60 is loaded from an unloaded status, the lift tab 61 is slid down the lift tab sliding portion 51a, whereby the head slider 24 is loaded on the magnetic disk 12.
With reference to
The protective film 62 is formed on the surface of the flexure tip portion 23b substantially along an outline of a protrusion 23d. The protective film 62 has a film thickness of 5 μm, for example. Materials of the protective film 62 are selected from the same resin materials as in the insulating layer 36, namely, polyimide resin, for example.
The protective film 62 is formed separately from the insulating layer 36a of the flexure tip portion 23b. On the other hand, the insulating layer 36a of the flexure terminal portion 29 is separated from the surface of the flexure 63. This structure is the same as that of the flexure of the magnetic head assembly in the first example. Thus, the insulating layer 36a is separated from the protective film 62, so that the flexure terminal portion 29 is capable of absorbing stress in the same manner as in the magnetic head assembly in the first example when the volume of the solder of the solder joint portion 40 is shrunk.
With reference to
Further, the flexure is in contact with the flexure entraining portion 51b via the protective film 62. Thus, direct contact between the metallic protrusion 23d and the resin flexure entraining portion 51b is prevented and the generation of dust through the abrasion of the flexure entraining portion 51b can be prevented.
As mentioned above, the magnetic head assembly 60 in the third example includes the lift tab 61 and the protective film 62 is formed on the surface of the flexure 63 of the flexure tip portion 23b. Thus, the flexure tip portion 23b is brought into contact with the flexure entraining portion 51b of the lamp 51 via the protective film 62, so that the generation of dust can be prevented. Further, the protective film 62 is separated from the insulating layer 36a of the flexure terminal portion 29, so that it is also possible to prevent the warping of the slider attachment portion 26 resulting from stress generated when the volume of the solder of the solder joint portion 40 is shrunk upon solidification.
In addition, the method of manufacturing the magnetic head assembly 60 in the third example is substantially the same as that of the aforementioned magnetic head assembly 60 in the first example, so that description thereof is omitted. However, it is preferable to form the protective film 62 in the same steps as those of the insulating layer 36 in terms of simplification.
Next, description is given regarding an example of the magnetic disk apparatus according to the second embodiment including a magnetic head assembly in a fourth example. The magnetic disk apparatus has the same structure as that of the magnetic head apparatus shown in
With reference to FIGS. 20 to 22 along with
In the magnetic head assembly 60A, the pad electrode 29a and the Cu wiring layer 38 of the flexure terminal portion 49 are disposed separately from the insulating layer 66. This is substantially the same structure as that of the magnetic head assembly 20A in the second example shown in
Further, as shown in
As mentioned above, in the magnetic head assembly 60A in the fourth example, the insulating layer 66 of the signal wiring portion 25 is formed continuously to the surface of the protrusion 23d of the flexure tip portion 23b. Thus, the flexure tip portion 23b is brought into contact with the flexure entraining portion 51b of the lamp 51 via the insulating layer 66, so that it is possible to prevent the generation of dust. Further, when the solder of the solder joint portion 40 is solidified, the magnetic head assembly 60A in the fourth example is deformed such that the pad electrode 29a and the Cu wiring layer 38 of the flexure terminal portion 49 are raised from the insulating layer 66, thereby absorbing the stress generated by the volume shrinkage of the solder. Thus, it is also possible to prevent the warping of the slider attachment portion 26 resulting from the stress.
The method of manufacturing the magnetic head assembly 60A in the fourth example is substantially the same as that of the magnetic head assembly 60A in the first example, so that description thereof is omitted. However, the steps of forming the insulating layer 66 are substantially the same as those of the insulating layer 36 of the magnetic head assembly 60 in the first example.
Although the element portion of the magnetic head slider of the magnetic head assembly in the first example to the fourth example is described as having the recording element and the reproduction element, only either one of the recording element and the reproduction element may be included.
The present invention is not limited to the specifically disclosed embodiment, and variations and modifications may be made without departing from the scope of the present invention.
The present application is based on Japanese priority application No. 2006-068125 filed Mar. 13, 2006, the entire contents of which are hereby incorporated herein by reference.
Number | Date | Country | Kind |
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2006-068125 | Mar 2006 | JP | national |