JP2007095275A - Micro-actuator provided with electric spark preventing structure, magnetic head assembly and disk device using it and manufacturing method of micro-actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To design a micro-actuator capable of preventing electric sparks, of which a frame is formed to be thin and which is produced at a low cost in a manufacturing process of a high degree of freedom. <P>SOLUTION: The micro-actuator has a metal frame having two side arms and at least one support arm for connecting the two side arms, and the two side arms are arranged in parallel at a distance so as to hold a magnetic head slider loaded on the support arm with each other. An independent layer is provided on each of the side arms of the metal frame, and a piezoelectric element is joined to the independent layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a disk device capable of recording data, and more particularly to a microactuator provided in a disk device having an electrical spark prevention structure. Moreover, it is related with the manufacturing method.

  The disk device is an information storage device using a magnetic disk for storing data. The disk device in the conventional example is configured as shown in FIG. First, a conventional disk device includes a casing 701 that houses a plurality of circular disks 702 each having a plurality of tracks (not shown) formed concentrically on each surface by magnetic coating. The disk 702 is mounted on a spindle motor 703 that selectively rotates the disk 702. A drive arm 704 is provided in the casing 701, and this drive arm 704 is controlled to drive a head gimbal assembly 705 (HGA) with respect to the disk 702 by a voice coil motor 707 (VCM). The Then, the microactuator equipped with the magnetic head slider is moved so that the magnetic head slider crosses between the tracks on the surface of the disk 702 in order to record and reproduce data on the disk at the position moved by the HGA 705. .

  However, due to the large inertial force of the VCM 707, the following performance of the disk device is limited, and it is difficult to realize quick and minute positioning control of the magnetic head slider. This affects the increase in the recording capacity of the hard disk device.

  In order to solve the above problem, a microactuator having a piezoelectric element (PZT) is used to correct a positional deviation (off-track) of the magnetic head slider. This PZT microactuator has components having a frequency higher than that of the VCM, and corrects the positional deviation of the magnetic head slider so as to correct an error caused by the VCM. The PZT microactuator can move the magnetic head slider within a range smaller than the width of the recording track, thereby reducing the TPI (track-per-inch) representing the recording density of the disk drive by 50%. Increase. Therefore, the recording density of the disk surface and the drive performance of the disk drive are improved, and for example, the head seeking time and settling time are also reduced.

  Here, FIG. 11 shows an HGA 277 in a conventional example. The HGA 277 includes a suspension 213 that supports a PZT microactuator 205 on which a magnetic head slider 203 is mounted. The suspension 213 includes conductive traces 210a and 210b, which are connected to the magnetic head slider 203 and the PZT microactuator 205, respectively.

  Next, FIG. 12 shows a PZT microactuator 205 having a metal frame 230. The metal frame 230 includes two side arms 211 and 212, and a top support arm 215 and a bottom support arm 216 that connect the two side arms 211 and 212 at both ends, respectively. Further, the two side arms 211 and 212 are arranged in parallel with an appropriate interval so that the magnetic head slider 203 can be mounted and held on the top support arm 215 between them. The top support arm 215 and the bottom support arm 216 are arranged in parallel to each other, and the top support arm 215 is parallel to the surface of the magnetic head slider. Further, the two PZT elements 207 and 208 are mounted on the outer surfaces of the two side arms for driving, for example, with epoxy or the like. Referring to FIG. 14, the two PZT elements 207 and 208 are each formed in a multilayer structure in which a piezoelectric member layer 225 and two electrodes 223 and 224 are stacked on each other. Two electrical connection terminals 220 and 221 are provided to be joined to the electrodes 223 and 224, respectively.

  As shown in FIG. 13, in the PZT microactuator 205, the bottom support arm 216 is joined to the tongue surface (not shown) of the suspension 213 of the HGA 277 by epoxy or laser welding. Then, on one side (outer surface) side of each PZT element 207, 208, for example, a large number of electric bonding balls 209 a used for gold ball bonding (GBB) and solder ball bonding (SBB) are formed on the side arm 211 of the microactuator 205. , 212 are connected to the electrical connection terminals 220, 221 of the PZT elements 207, 208 laminated on the conductive trace 210a. Further, a metal ball 209b used in GBB or SBB electrically connects the magnetic head slider 203 and the conductive trace 210b for electrical connection of the recording / reproducing element. When the driving power is supplied via the conductive trace 210a, the PZT elements 207 and 208 on the side arms 211 and 212 expand and contract, and the side arms 211 and 212 are bent in the same lateral direction. Give rise to This bending deformation causes shear deformation of the metal frame 230, and the rectangular metal frame 230 can be deformed into a substantially parallelogram. Then, since the magnetic head slider 203 is attached to the top support arm 215 on the deforming side of the parallelogram, the magnetic head slider 203 is moved in the lateral direction. Thus, micro head positioning can be realized.

JP 2002-133803 A

  However, as shown in FIG. 15, when a voltage is applied to operate the microactuator 205, the bottom surfaces of the PZT elements 207 and 208 are electrodes to which an operating voltage is applied, and the bonding epoxy is very thin (5 μm Since the metal frame 230 is a common ground on the top), an electrical spark 303 can occur.

  As described above, when the surrounding conditions change while the microactuator is operating, an electric spark problem occurs between the metal frame 230 and the PZT elements 207 and 208. Therefore, a microactuator for a disk drive capable of preventing electric spark and a manufacturing method thereof are desired.

  In addition, in order to obtain sufficient rigidity to support the flying magnetic head slider, it is necessary for the frame to have a sufficient thickness. For example, this makes it possible to manufacture the frame by etching or molding. And molding becomes difficult. In addition, a thick frame material is difficult to manufacture and is expensive.

  For this reason, in the present invention, a microactuator that can prevent electric sparks while maintaining the same performance as the conventional example, has a thinner frame, and has a low-cost and highly flexible manufacturing process. Its purpose is to design.

  A main aspect of the present invention relates to a method and a structure for preventing an electric spark of a microactuator when the microactuator mounted on a disk drive is operated. Another embodiment of the present invention relates to a microactuator having a structure for preventing an electric spark. Furthermore, the present invention relates to a head gimbal assembly (HGA) equipped with a microactuator having the above electric spark prevention structure, and a disk device.

  The microactuator according to the present invention includes a metal frame having two side arms and at least one support arm for connecting the two side arms, and the two side arms are supported in parallel. The magnetic head sliders mounted on the arms are arranged so as to be able to hold each other. An independent layer is provided on each side arm of the metal frame, and a piezoelectric element is joined to the independent layer. Therefore, when a voltage for driving the microactuator is applied, the metal frame is mounted away from the piezoelectric element, so that the occurrence of electric spark can be prevented.

In the present invention, the independent layer is an insulating layer (for example, a polymer compound) laminated on each side arm of the metal frame. In the present invention, the independent layer is a spacer (for example, for use in mounting a piezoelectric element on each side arm of the metal frame and maintaining a predetermined distance between each side arm and the piezoelectric element. An epoxy layer having glass or SiO ₂ ). In the present invention, the independent layer is a base layer (for example, ceramic or silicon) formed on the piezoelectric element. In the present invention, the independent layer is a bottom layer of a piezoelectric element having a multilayer structure, and is an inactive layer having no polarity.

  Furthermore, since the metal plate is used to form the main part of the microactuator, the microactuator can be improved in shape and size. Therefore, a microactuator having a sufficient stroke can be designed. Furthermore, since the metal plate can be processed easily and accurately, a low-cost and highly flexible manufacturing process can be realized.

  Furthermore, a method of manufacturing a microactuator having an electric spark prevention structure according to another aspect of the present invention includes two side arms and at least one support arm that connects the two side arms. A step of providing a metal frame spaced apart so that the side arm can hold the magnetic head slider mounted on the support arm in parallel with each other, and an independent layer provided on each side arm of the metal frame And a step of bonding and providing a piezoelectric element to the independent layer.

  In the present invention, the independent layer is formed by laminating an insulating layer on each side arm of the metal frame. The independent layer is formed by using an epoxy having a spacer to mount a piezoelectric element on each side arm of the metal frame. Furthermore, the independent layer is formed by providing a base layer formed on the surface of the piezoelectric element joined to each side arm of the metal frame. The independent layer is formed by providing an inert layer on the bottom layer of the multilayered piezoelectric element joined to each side arm of the metal frame, and joins the piezoelectric element to the inert layer facing the metal frame. You may have a process.

  A head gimbal assembly (HGA) according to another embodiment of the present invention includes a magnetic head slider, a microactuator, and a suspension that supports the magnetic head slider and the microactuator. The microactuator has two side arms. And at least one support arm for connecting the two side arms, and the two side arms can hold the magnetic head slider mounted on the support arm in parallel with each other. It is arranged with an interval, and further includes an independent layer provided on each side arm of the metal frame, and a piezoelectric element joined to the independent layer.

Furthermore, a disk device according to another aspect of the present invention includes a head gimbal assembly including a microactuator, a magnetic head slider, and a suspension that supports the microactuator and the magnetic head slider;
A drive arm coupled to the head gimbal assembly;
A disc,
A spindle motor for rotating the disk,
The microactuator includes a metal frame having two side arms and at least one support arm connecting the two side arms, and the two side arms are mounted in parallel and on the support arm. Are further provided so as to be able to hold each other, and further includes an independent layer provided on each side arm of the metal frame and a piezoelectric element joined to the independent layer.

  As described above, when the present invention is compared with the conventional example, since the conventional device has the piezoelectric element directly mounted on the metal frame, the problem of electric spark is likely to occur. Since it is formed in between, it is possible to prevent the occurrence of the electric spark described above.

  Hereinafter, the features and advantages of the present invention, as well as some of the essence of the present invention, will be described with reference to the drawings and the like in the embodiments described later.

  The PZT microactuator in the first embodiment of the present invention is configured as shown in FIGS. 1 and 2, and a magnetic head slider is mounted on the PZT microactuator. The PZT microactuator is indicated by reference numeral 205a, and the magnetic head slider is indicated by the same reference numeral 203 as in the above-described prior art FIG. Here, in order to distinguish between different configurations and members that are similar to the prior art, the endings of the same reference numerals are denoted by “a”, while the first embodiment of the present invention and the prior art are shown. When the same configuration or member is shown in both, the same reference numerals are used.

  The PZT microactuator 205a in this embodiment includes a metal frame 230 having two side arms 211 and 212, and a top support arm 215 and a bottom support arm 216 that connect the vicinity of both ends of the two side arms 211 and 212, respectively. It is equipped with. The two side arms 211 and 212 are arranged in parallel and spaced from each other so that the magnetic head slider mounted on the top support arm 215 can be held between them. The top support arm 215 and the bottom support arm 216 are parallel to each other, and the top arm 215 is disposed in parallel to the surface of the magnetic head slider 203. For example, an insulating layer 307 made of a polymer compound is provided on the outer surface of the metal frame 230, specifically, on the outer surfaces of the side arms 211 and 212. At this time, two piezoelectric (PZT) elements 207 and 208 are mounted on the insulating layers 307 of the side arms 211 and 212 by epoxy 308, respectively.

  FIG. 2A shows the assembled microactuator 205a. Referring to FIG. 2B, which is a cross-sectional view taken along the line AA of this figure, the insulating layer 307 includes side arms 211, 212. And the PZT elements 207 and 208 and bonded by epoxy 308. Each PZT element 207, 208 has a multilayer structure in which piezoelectric member layers 225 and two electrodes 223, 224 are alternately stacked, and two electrical connection terminals 220, 221 are connected to each electrode 223, 224 are connected to each other (see FIG. 1).

  As described above, in this embodiment, since the insulating layer 307 is provided between the PZT elements 207 and 208 and the metal frame 230, the metal frame 230 (ground side) is insulated from the PZT elements 207 and 208 (voltage application side). It is in the state that was done. Therefore, even when a voltage for driving the PZT microactuator 205a is applied, no electric spark is generated.

  In addition, since the metal plate is used for the main part of the microactuator that provides mechanically high strength, it becomes very easy to handle the microactuator during the assembly of the HGA. Also, by using a metal plate to form the main part of the microactuator, the microactuator can be improved in its outer shape and / or its size. Therefore, a microactuator having a sufficient stroke can be designed. Furthermore, since the metal plate is easy to machine and has high accuracy, a highly flexible manufacturing process can be realized at low cost.

  Referring to FIGS. 3 to 4, the PZT microactuator in the second embodiment of the present invention is configured as indicated by reference numeral 205b. The PZT microactuator 205b in this embodiment is an improvement of the PZT microactuator 205a shown in FIGS. 1 and 2 in the first embodiment and has the same configuration, but differs in the following points. .

The microactuator 205b in the present embodiment is not provided with the insulating layer 207 laminated on the outer surface of each side arm 211, 212 in the first embodiment. Instead, for example, an epoxy 403 having a spacer 406 such as glass or SiO ₂ (silicon dioxide) is used to mount the PZT elements 207 and 208 on the two side arms 211 and 212. Since the spacer 406 forms and maintains a predetermined interval between the PZT elements 207 and 208 and the metal frame 230 (ground side), the occurrence of electric sparks can be prevented.

  4A shows the assembled microactuator 205b. Referring to FIG. 4B, which is a cross-sectional view taken along the line BB of this figure, the epoxy 403 having the spacer 406 is attached to the metal frame. PZT elements 207 and 208 are placed on the side arms 211 and 212 of 230. Therefore, even when a voltage for driving the PZT microactuator 205b is applied, the electric spark problem does not occur.

  Referring to FIGS. 5 to 6, the PZT microactuator in the third embodiment of the present invention is configured as indicated by reference numeral 205c. The PZT microactuator 205c in this embodiment is an improvement of the PZT microactuator 205a shown in FIGS. 1 and 2 in the first embodiment, and has the same configuration, but differs in the following points. .

  The microactuator 205c in the present embodiment is not provided with the insulating layer 207 laminated on the outer surface of each side arm 211, 212 in the first embodiment. Instead, the PZT elements 207 and 208 are formed with a base layer (insulating layer) 504 made of ceramic or silicon, for example, and mounted on the outer surface of the side arms 211 and 212 of the metal frame 230 by an epoxy 309. Has been.

  6 (a) shows the assembled microactuator 205c. Referring to FIG. 6 (b), which is a cross-sectional view taken along the line C-C of this figure, the underlayer 504 has PZT elements 207, 208. And the side arms 211 and 212 (common ground side). As a result, it is possible to effectively prevent the occurrence of electric spark when the microactuator 205c is operated, and the effect can be increased.

  Referring to FIG. 7B, the PZT microactuator in the fourth embodiment of the present invention is configured as indicated by reference numeral 205d. The PZT microactuator 205d in this embodiment is an improvement of the PZT microactuator 205a shown in FIGS. 1 and 2 in the first embodiment and has the same configuration, but differs in the following points. .

  The microactuator 205c in the present embodiment is not provided with the insulating layer 207 laminated on the outer surface of each side arm 211, 212 in the first embodiment. Instead, PZT elements 207a and 208a having slightly different configurations from the PZT elements 207 and 208 in the first embodiment are provided. The PZT elements 207a and 208a in this embodiment have a multilayer structure in which PZT member layers 607 and two electrodes 604 and 605 are alternately stacked as shown in FIG. An inactive layer having no polarity is formed on the (lowermost layer), and itself is maintained inactive. When the PZT elements 207a and 208a are mounted on the outer surfaces of the side arms 211 and 212 of the metal frame 230, since the piezoelectric member is ceramic, the PZT elements 207a and 208a and the side arms (common ground) are used. It is possible to prevent electricity from flowing between 211 and 212. As a result, it is possible to effectively prevent the occurrence of electric spark when the microactuator 205d is operated, and the effect can be increased.

  In the present invention, the structure of the metal frame 230 is not limited to the structure shown in the figure. For example, the metal frame 230 is configured to have only one support arm that connects the two side arms 211 and 212, or the top support. The arm 215 and the bottom support arm 216 may be formed in other structures and shapes.

  A fifth embodiment of the present invention is a head gimbal assembly (HGA) 300, which includes a suspension 301 that supports a magnetic head slider 203 and a PZT microactuator 205a, as shown in FIG. The PZT microactuator 205a can be physically and electrically mounted on the suspension 301. However, the HGA in this embodiment may include the PZT microactuators 205b, 205c, and 205d disclosed in the embodiments 2, 3, and 4 instead of the PZT microactuator 205a disclosed in the first embodiment.

  In this embodiment, the suspension 301 includes a base plate, a hinge, and a flexure and a load beam that are assembled together. As a matter of course, the suspension is configured to be mountable on the PZT microactuator in the present invention.

  The sixth embodiment of the present invention is a disk device as shown in FIG. This disk device is constructed by assembling a housing 108, a disk 101, a spindle motor 102, and a VCM 107 equipped with the HGA 300 disclosed in the fifth embodiment. The configuration and assembly process of the disk device are known to those skilled in the art, and further detailed description is omitted.

  Although the present invention has been described with reference to the above-described embodiments, the present invention is not limited to such contents, and includes various improvements and equivalent modifications that are included in the scope of the idea of the present invention.

  The microactuator of the present invention can be used by being mounted on a head gimbal assembly mounted on a disk device, and has industrial applicability.

FIG. 3 is a perspective view showing a configuration of a microactuator before assembly equipped with a magnetic head slider in Example 1. FIG. 2A is a perspective view showing a configuration when the microactuator disclosed in FIG. 1 is assembled. FIG. 2B is a cross-sectional view taken along the line AA in FIG. 2A and shows the internal configuration of the side arm and the piezoelectric element. It is a perspective view which shows the structure of the micro actuator before an assembly equipped with the magnetic head slider in Example 2. FIG. FIG. 4A is a perspective view showing a configuration when the microactuator disclosed in FIG. 3 is assembled. FIG. 4B is a cross-sectional view taken along line BB in FIG. 4A, and is a diagram illustrating an internal configuration of the side arm and the piezoelectric element. It is a perspective view which shows the structure of the micro actuator before an assembly equipped with the magnetic head slider in Example 3. FIG. FIG. 6A is a perspective view showing a configuration when the microactuator disclosed in FIG. 5 is assembled. FIG. 6B is a cross-sectional view taken along the line C-C in FIG. 6A and shows the internal configuration of the side arm and the piezoelectric element. FIG. 7A is a cross-sectional view showing the configuration of the piezoelectric element of the microactuator in the fourth embodiment. FIG. 7B is a perspective view showing the configuration of the microactuator before assembly equipped with the magnetic head slider in the fourth embodiment. It is a perspective view which shows the structure of HGA equipped with the microactuator in this invention. It is a perspective view which shows the structure of the disk apparatus carrying the HGA disclosed in FIG. It is a figure which shows the structure of the disk apparatus in a prior art example. It is a figure which shows the structure of HGA in a prior art example. It is a figure which shows the structure of the PZT microactuator in a prior art example. It is an enlarged view of the tongue surface vicinity of HGA in a prior art example. It is sectional drawing of the PZT element of the microactuator in a prior art example. It is a figure for demonstrating the problem of the electric spark in the microactuator in a prior art example.

Explanation of symbols

101 disk 102 spindle motor 107 VCM
108 Housing 203 Magnetic head slider 205a, 205b, 205c, 205d PZT microactuator 207, 208, 207a, 208a Piezoelectric element 211, 212 Side arm 215 Top support arm 216 Bottom support arm 220, 221 Electrical connection terminals 223, 224, 604 605 Electrodes 225 and 607 Piezoelectric member layer 230 Metal frame 300 HGA
301 Suspension 307 Insulating layer 308, 309, 403 Epoxy 406 Spacer 504 Underlayer

Claims (22)

A metal frame having two side arms and at least one support arm connecting the two side arms,
The two side arms are arranged in parallel and at a distance so as to hold a magnetic head slider mounted on the support arm.
An independent layer equipped on each side arm of the metal frame;
A piezoelectric element bonded to the independent layer;
A microactuator characterized by comprising:   The microactuator according to claim 1, wherein the independent layer is an insulating layer stacked on each side arm of the metal frame.   3. The microactuator according to claim 2, wherein the insulating layer is made of a polymer compound.   The independent layer is an epoxy layer having a spacer used for mounting the piezoelectric element on each side arm of the metal frame and maintaining a predetermined interval between the side arm and the piezoelectric element. The microactuator according to claim 1, 2 or 3. The spacers are formed by glass or SiO _2, the micro-actuator according to claim 4, wherein a.   6. The microactuator according to claim 1, 2, 3, 4 or 5, wherein the independent layer is a base layer formed on the piezoelectric element.   7. The microactuator according to claim 6, wherein the underlayer is made of ceramic or silicon.   8. The micro of claim 1, 2, 3, 4, 5, 6 or 7, wherein the independent layer is a bottom layer of the piezoelectric element having a multilayer structure, and is an inert layer having no polarity. Actuator. A method of manufacturing a microactuator having an electric spark prevention structure,
Two side arms and at least one support arm connecting the two side arms, the two side arms holding the magnetic head slider mounted between the two side arms in parallel and on the support arms Providing a metal frame spaced as possible, and
Forming an independent layer provided on each side arm of the metal frame;
Bonding and providing a piezoelectric element to the independent layer;
A method of manufacturing a microactuator, comprising:   10. The method of manufacturing a microactuator according to claim 9, wherein the independent layer is formed by laminating an insulating layer on each side arm of the metal frame.   11. The microactuator according to claim 9, wherein the independent layer is formed by using an epoxy having a spacer to mount the piezoelectric element on each side arm of the metal frame.   12. The micro of claim 9, 10 or 11, wherein the independent layer is formed by providing an underlayer formed on a surface of the piezoelectric element joined to each side arm of the metal frame. Actuator manufacturing method. The independent layer is formed by providing an inactive layer on a bottom layer of the piezoelectric element having a multilayer structure joined to each side arm of the metal frame,
Bonding the piezoelectric element to the inert layer facing the metal frame;
13. The method of manufacturing a microactuator according to claim 9, 10, 11 or 12. A magnetic head slider;
A microactuator,
A suspension for supporting the magnetic head slider and the microactuator,
The microactuator includes a metal frame having two side arms and at least one support arm connecting the two side arms, and the two side arms are mounted in parallel and on the support arm. The magnetic head sliders are arranged at intervals so as to hold each other, and further, an independent layer provided on each side arm of the metal frame, and a piezoelectric element joined to the independent layer, Prepared,
A head gimbal assembly characterized by that.   The head gimbal assembly according to claim 14, wherein the independent layer is an insulating layer stacked on each side arm of the metal frame.   The head gimbal assembly according to claim 15, wherein the insulating layer is made of a polymer compound.   The independent layer is an epoxy layer having a spacer used for mounting the piezoelectric element on each side arm of the metal frame and maintaining a predetermined interval between the side arm and the piezoelectric element. The head gimbal assembly according to claim 14, 15 or 16. The head gimbal assembly according to claim 17, wherein the spacer is made of glass or SiO ₂ .   The head gimbal assembly according to claim 14, 15, 16, 17 or 18, wherein the independent layer is a base layer formed on the piezoelectric element.   20. The head gimbal assembly according to claim 19, wherein the underlayer is made of ceramic or silicon.   21. The head according to claim 14, 15, 16, 17, 18, 19, or 20, wherein the independent layer is a bottom layer of the piezoelectric element having a multilayer structure and is an inert layer having no polarity. Gimbal assembly. A head gimbal assembly comprising a microactuator, a magnetic head slider, and a suspension for supporting the microactuator and the magnetic head slider;
A drive arm coupled to the head gimbal assembly;
A disc,
A spindle motor that rotationally drives the disk,
The microactuator includes a metal frame having two side arms and at least one support arm connecting the two side arms, and the two side arms are mounted in parallel and on the support arm. The magnetic head sliders are arranged at intervals so as to hold each other, and further, an independent layer provided on each side arm of the metal frame, and a piezoelectric element joined to the independent layer, Prepared,
A disk device characterized by the above.

Images