Disk device

Abstract

To provide a disk device in which peeling of a flexible printed circuit board may be suppressed.SOLUTION: A disk device includes a magnetic disk, a magnetic head, a first flexible printed circuit board, and a second flexible printed circuit board FPC 19. The first flexible printed circuit board has a plurality of first terminals. The second flexible printed circuit board has a surface, a plurality of second terminals arranged on the surface and respectively connected to the plurality of first terminals by a joint body, and a first solid ground covering at least one of the plurality of second terminals in a direction orthogonal to the surface. Each of the plurality of second terminals includes a first lead terminal. The first solid ground is separated from at least a part of the first lead terminal in the direction along the surface.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a disk drive. [Background technology]

[0002] A disk device such as a hard disk drive (HDD) has a magnetic disk and a magnetic head that reads and writes information from and to the magnetic disk. For example, multiple flexible printed circuits (FPCs) electrically connect the magnetic head to a control device that controls the HDD. The two FPCs are connected to each other by soldering the terminals of one FPC to the terminals of the other FPC. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 64-064389 Summary of the Invention [Problem to be solved by the invention]

[0004] When the terminals of two FPCs are joined by solder, the solder is heated, for example, by laser light. If the area around the terminals is excessively heated through the solder, there is a risk that the FPC will peel off.

[0005] One example of a problem to be solved by the present invention is to provide a disk drive that can prevent peeling of a flexible printed circuit board. [Means for solving the problem]

[0006] According to one embodiment, a disk drive includes a magnetic disk, a magnetic head, a first flexible printed circuit board, and a second flexible printed circuit board. The magnetic head is configured to read and write information from and to the magnetic disk. The first flexible printed circuit board has a plurality of first terminals, and the magnetic head is mounted on the first flexible printed circuit board, with at least one of the first terminals being electrically connected to the magnetic head. The second flexible printed circuit board has a surface, a plurality of second terminals provided on the surface, each of which is joined to a corresponding one of the first terminals by a conductive adhesive, and a first solid ground covering at least one of the second terminals in a direction perpendicular to the surface. The second terminals include a first lead terminal through which an electrical signal representing information read by the magnetic head from the magnetic disk flows. The first solid ground is spaced apart from at least a portion of the first lead terminal in a direction along the surface. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an exemplary perspective view that schematically illustrates a hard disk drive according to one embodiment. [Figure 2] FIG. 2 is an exemplary diagram that schematically illustrates the FPC and the flexure of the above embodiment. [Figure 3] FIG. 3 is an exemplary plan view that schematically illustrates a part of the FPC and a part of the flexure according to the embodiment. [Figure 4] FIG. 4 is an exemplary plan view schematically illustrating a portion of the FPC of the above embodiment. [Figure 5] FIG. 5 is an exemplary cross-sectional view schematically illustrating a part of the FPC and a part of the flexure of the above embodiment taken along line F5-F5 in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment will be described below with reference to FIGS. 1 to 5. In this specification, components according to the embodiment and descriptions of the components may be described using multiple expressions. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. Furthermore, the components may also be described using expressions different from those in this specification.

[0009] 1 is an exemplary perspective view showing a hard disk drive (HDD) 1 according to one embodiment. The HDD 1 is an example of a disk device. Note that the disk device is not limited to the HDD 1, and may be another disk device such as a hybrid hard disk drive.

[0010] 1, the HDD 1 includes a housing 11, multiple magnetic disks 12, a spindle motor 13, a clamp spring 14, multiple magnetic heads 15, an actuator assembly 16, a voice coil motor (VCM) 17, a ramp load mechanism 18, and a flexible printed circuit board (FPC) 19. The FPC 19 is an example of a second flexible printed circuit board.

[0011] The housing 11 has a plate-shaped bottom wall 11a and side walls 11b protruding from the outer edge of the bottom wall 11a. The housing 11 further has a cover attached to the side wall 11b to cover the inside of the housing 11. The housing 11 houses at least a portion of a magnetic disk 12, a spindle motor 13, a clamp spring 14, a magnetic head 15, an actuator assembly 16, a VCM 17, a ramp load mechanism 18, and an FPC 19.

[0012] The magnetic disk 12 is, for example, a disk having a magnetic recording layer provided on at least one of its upper and lower surfaces. The diameter of the magnetic disk 12 is, for example, 3.5 inches, but is not limited to this example.

[0013] The spindle motor 13 supports and rotates a plurality of magnetic disks 12 stacked at intervals. A clamp spring 14 holds the plurality of magnetic disks 12 on the hub of the spindle motor 13.

[0014] The magnetic head 15 records and reproduces information on the recording layer of the magnetic disk 12. In other words, the magnetic head 15 reads and writes information from and to the magnetic disk 12. The magnetic head 15 is supported by an actuator assembly 16.

[0015] The actuator assembly 16 is rotatably supported by a support shaft 21 disposed at a position separated from the magnetic disk 12. The VCM 17 rotates the actuator assembly 16 and places it at a desired position. When the magnetic head 15 moves to the outermost periphery of the magnetic disk 12 as a result of the rotation of the actuator assembly 16 by the VCM 17, the ramp load mechanism 18 holds the magnetic head 15 at an unload position separated from the magnetic disk 12.

[0016] A printed circuit board (PCB) is attached to the outside of the bottom wall 11a of the housing 11. A control device for controlling the spindle motor 13, the magnetic head 15, and the VCM 17 is mounted on the PCB.

[0017] The control device includes various electronic components, such as a read / write channel (RWC), a hard disk controller (HDC), a processor, RAM, ROM, a buffer memory, and a servo combo IC. The control device is electrically connected to the magnetic head 15 and the VCM 17 via the FPC 19.

[0018] The actuator assembly 16 includes an actuator block 31, a plurality of arms 32, and a plurality of head suspension assemblies 33. The head suspension assemblies 33 may also be referred to as head gimbal assemblies (HGA).

[0019] The actuator block 31 is rotatably supported on the support shaft 21 via, for example, a bearing. The multiple arms 32 protrude from the actuator block 31 in a direction substantially perpendicular to the support shaft 21. Note that the actuator assembly 16 may be divided, and multiple arms 32 may protrude from each of the multiple actuator blocks 31.

[0020] The arms 32 are arranged at intervals in the direction in which the support shaft 21 extends. Each arm 32 is formed in a plate shape that can enter between adjacent magnetic disks 12. The arms 32 extend approximately parallel to one another.

[0021] The voice coil of the VCM 17 is provided on a protrusion that protrudes from the actuator block 31. The VCM 17 has a pair of yokes, a voice coil disposed between the yokes, and a magnet provided on the yoke.

[0022] The head suspension assemblies 33 are attached to the tip portions of the corresponding arms 32 and protrude from the arms 32. As a result, the plurality of head suspension assemblies 33 are arranged at intervals in the direction in which the support shafts 21 extend.

[0023] FIG. 2 is an exemplary diagram schematically illustrating the FPC 19 and flexure 43 of this embodiment. Each of the multiple head suspension assemblies 33 includes the base plate 41 and load beam 42 shown in FIG. 1, and the flexure 43, preamplifier 44, and HDI sensor 45 shown in FIG. 2. Furthermore, the magnetic head 15 is attached to the head suspension assembly 33. The flexure 43 is an example of a first flexible printed circuit board and may also be referred to as a relay FPC. The preamplifier 44 may also be referred to as a head IC or a head amplifier.

[0024] 1 is formed in a plate shape and is attached to the tip of the arm 32. The load beam 42 is formed in a plate shape that is thinner than the base plate 41. The load beam 42 is attached to the tip of the base plate 41 and protrudes from the base plate 41.

[0025] 2, the flexure 43 is formed in a long, narrow strip shape. However, the shape of the flexure 43 is not limited to this example. The flexure 43 is a laminated plate having, for example, a metal plate (backing layer) such as stainless steel, an insulating layer formed on the metal plate, a conductive layer formed on the insulating layer and constituting a plurality of wirings (wiring patterns), and a protective layer (insulating layer) covering the conductive layer. The flexure 43 has a first mounting portion 51, a second mounting portion 52, and an intermediate portion 53.

[0026] The first mounting portion 51 is provided at one end of the flexure 43. The second mounting portion 52 is provided at the other end of the flexure 43. The intermediate portion 53 extends between the first mounting portion 51 and the second mounting portion 52.

[0027] The first mounting portion 51 is attached to the base plate 41 and the load beam 42. The first mounting portion 51 is located on the load beam 42 and has a displaceable gimbal portion (elastic support portion). The magnetic head 15 is mounted on the gimbal portion.

[0028] The intermediate portion 53 projects outward from the first mounting portion 51 along the side edge of the base plate 41. The intermediate portion 53 extends outside the base plate 41, along the side edge of the arm 32, toward the actuator block 31.

[0029] The second mounting portion 52 is formed in a rectangular shape extending in the longitudinal direction of the intermediate portion 53. The second mounting portion 52 has a plurality of pads 55. The pads 55 are an example of first terminals. The pads 55 are arranged at intervals in the longitudinal direction of the second mounting portion 52 and form flying leads.

[0030] The flexure 43 further has a plurality of wirings 56. The pads 55 and wirings 56 are provided on the conductive layer of the flexure 43. The wirings 56 pass through the intermediate portion 53 and extend between the first mounting portion 51 and the second mounting portion 52. The plurality of wirings 56 electrically connect at least one of the plurality of pads 55 to a read element, a write element, a heater, or other components of the magnetic head 15. In other words, the wirings 56 extend between the pads 55 and electrodes connected to the magnetic head 15, and form at least a part of an electrical path between the pads 55 and the magnetic head 15.

[0031] 3 is an exemplary plan view schematically illustrating a part of the FPC 19 and a part of the flexure 43 according to this embodiment. As shown in FIG. 3, the FPC 19 has a joint portion 61, an extension portion 62, and a plurality of protrusions 63.

[0032] The joint 61 is attached to the actuator block 31 by, for example, a plurality of screws 65. The joint 61 has a plurality of insertion holes 66 through which the screws 65 pass. The extension 62 extends between the joint 61 and the PCB on which the control device is mounted. A plurality of protrusions 63 protrude from the joint 61.

[0033] The second mounting portions 52 of the multiple flexures 43 are attached to the joints 61 of the FPC 19. The FPC 19 electrically connects the PCB on which the above-mentioned control device is mounted to the flexures 43. That is, the control device is electrically connected to the magnetic head 15 via the PCB, the FPC 19, and the flexures 43.

[0034] Fig. 4 is an exemplary plan view schematically illustrating a portion of the FPC 19 of this embodiment. Fig. 5 is an exemplary cross-sectional view schematically illustrating a portion of the FPC 19 of this embodiment and a portion of the flexure 43 along line F5-F5 in Fig. 4.

[0035] 5, the FPC 19 has, for example, a base layer 71, two conductive layers 72 and 73, and two cover layers 74 and 75. An adhesive layer is interposed between the multiple layers of the FPC 19. However, the FPC 19 is not limited to this example and may have fewer or more layers.

[0036] The base layer 71 and the cover layers 74, 75 are, for example, flexible and insulating films made of synthetic resin such as polyester or polyimide. The base layer 71 has two surfaces 71a, 71b provided on opposite sides to each other. The surface 71b faces the actuator block 31.

[0037] The conductive layers 72 and 73 are made of a conductive metal such as copper. The conductive layer 72 is laminated on a surface 71a of the base layer 71. The conductive layer 73 is laminated on a surface 71b of the base layer 71. Therefore, the base layer 71 is located between the two conductive layers 72 and 73.

[0038] The cover layer 74 is laminated on the surface 71a of the base layer 71 and the conductive layer 72. That is, the cover layer 74 covers at least a portion of the surface 71a of the base layer 71 and at least a portion of the conductive layer 72.

[0039] The cover layer 75 is laminated on the surface 71b of the base layer 71 and the conductive layer 73. That is, the cover layer 75 covers at least a portion of the surface 71b of the base layer 71 and at least a portion of the conductive layer 73. Therefore, the base layer 71 is located between the two cover layers 74, 75. For the sake of explanation, the cover layer 74 is omitted from FIG. 4.

[0040] At the joint 61, a metal plate (backing layer) made of aluminum or the like is attached to the cover layer 75 of the FPC 19. This makes the joint 61 substantially flat. The joint 61 is attached to the actuator block 31 via the metal plate. As shown in FIG. 1, the extension 62 can bend to absorb displacement of the joint 61 that accompanies rotation of the actuator assembly 16.

[0041] 3, the joint 61 of the FPC 19 has a surface 61a and two edges 61b and 61c. The surface 61a is one surface of the joint 61 and is formed, for example, by the cover layer 74, and the conductive layer 72 and base layer 71 exposed by a hole in the cover layer 74. Note that the surface 61a may also be formed by other parts.

[0042] Assuming that the surface 61a is flat as shown in several drawings including FIG. 3, the X-axis, Y-axis, and Z-axis are defined herein for convenience. The X-axis, Y-axis, and Z-axis are perpendicular to one another. The X-axis is aligned along the width of the surface 61a. The Y-axis is aligned along the length of the surface 61a. The Z-axis is aligned perpendicular to the surface 61a.

[0043] Furthermore, in this specification, the X direction, Y direction, and Z direction are defined. The X direction is a direction along the X axis, and includes the +X direction indicated by the X axis arrow and the -X direction opposite to the X axis arrow. The Y direction is a direction along the Y axis, and includes the +Y direction indicated by the Y axis arrow and the -Y direction opposite to the Y axis arrow. The Z direction is a direction along the Z axis, and includes the +Z direction indicated by the Z axis arrow and the -Z direction opposite to the Z axis arrow.

[0044] The X direction and the Y direction are directions along the surface 61a. The X direction and the Y direction intersect each other (orthogonal in this embodiment). The Z direction is a direction perpendicular to the surface 61a. The X direction is an example of a second direction. The Y direction is an example of a first direction and a third direction. In the following description, the arrangement of each element in a direction along the surface 61a is equivalent to the arrangement of each element when viewed in a direction perpendicular to the surface 61a.

[0045] The joint 61 may bend so that the surface 61a is curved or uneven. In this case, the X direction is the width direction of the joint 61 along the surface 61a, and the Y direction is the length direction of the joint 61 along the surface 61a.

[0046] Edge 61b of joint 61 is provided at the end of joint 61 in the +Y direction. Edge 61c of joint 61 is provided at the end of joint 61 in the -Y direction. The two edges 61b, 61c extend approximately parallel in the X direction. Multiple protrusions 63 protrude from edge 61b approximately in the +Y direction. Multiple protrusions 63 are arranged at intervals from one another in the X direction. Extension 62 extends from edge 61c approximately in the -Y direction.

[0047] 4, in the joint 61, the conductive layer 72 has a plurality of connection pads 81, a plurality of mounting pads 82, a plurality of wirings 83, and a plurality of solid grounds 84. The solid ground 84 is an example of a second solid ground. The solid ground 84 may also be referred to as a solid pattern or a ground plane.

[0048] The connection pads 81 and the mounting pads 82 are provided on the surface 61a. Specifically, as shown in Fig. 5, the connection pads 81 and the mounting pads 82 are exposed to the outside of the FPC 19 through a plurality of holes 74a provided in the cover layer 74. In this way, the connection pads 81 and the mounting pads 82 are provided on the surface 61a.

[0049] 4, the connection pads 81 are closer to the edge 61b of the joint portion 61 than the mounting pads 82. The mounting pads 82 are located between the connection pads 81 and the extension portion 62. In addition, the connection pads 81 are closer to the edge 61b of the joint portion 61 than the screws 65.

[0050] In the example of Fig. 3, the multiple connection pads 81 are arranged in six rows in the Y direction. In other words, the multiple connection pads 81 form six rows L. In the example of Fig. 3, each row L includes six of the multiple connection pads 81 arranged in the Y direction. Note that the number of rows L of connection pads 81 and the number of multiple connection pads 81 included in each row L are not limited to this example.

[0051] In each row L, the connection pads 81 are arranged at intervals in the Y direction. The connection pads 81 are also arranged at intervals in the X direction. The number of connection pads 81 in each row L corresponds to, for example, the function of the magnetic head 15.

[0052] 4, hereinafter, the connection pads 81 included in each row may be individually referred to as connection pads 81A, 81B, 81C, 81D, 81E, and 81F. In other words, each of the plurality of connection pads 81 includes a plurality of connection pads 81A, 81B, 81C, 81D, 81E, and 81F.

[0053] The connection pad 81B is an example of a write terminal, the connection pad 81E is an example of an HDI terminal, and the connection pad 81F is an example of a first lead terminal.

[0054] The multiple connection pads 81A, 81B, 81C, 81D, 81E, and 81F are arranged in order in the Y direction. The connection pad 81A is closer to the edge 61b of the bonding portion 61 than the other multiple connection pads 81B, 81C, 81D, 81E, and 81F. The connection pad 81F is closer to the edge 61c of the bonding portion 61 than the other multiple connection pads 81A, 81B, 81C, 81D, and 81E.

[0055] The multiple connection pads 81A are arranged in the X direction at intervals. The multiple connection pads 81B are spaced apart from the multiple connection pads 81A in the -Y direction and are arranged in the X direction at intervals. Similarly, the multiple connection pads 81C, 81D, 81E, and 81F are spaced apart from adjacent multiple connection pads 81 in the -Y direction and are arranged in the X direction at intervals.

[0056] One connection pad 81A and the corresponding connection pads 81B, 81C, 81D, 81E, and 81F are arranged at approximately the same position in the X direction. Note that the positions in the X direction of the corresponding connection pads 81A, 81B, 81C, 81D, 81E, and 81F may be different from one another. Also, the number of connection pads 81 in each row L may be different.

[0057] As shown in FIG. 5, each of the multiple connection pads 81 of the FPC 19 is bonded to a corresponding one of the multiple pads 55 of the flexure 43 by solder 87. The solder 87 is conductive and is an example of a bonding material. The solder 87 may be leaded solder or lead-free solder. The conductive adhesive is not limited to the solder 87 and may be, for example, silver paste, brazing filler metal, or a conductive adhesive.

[0058] 3, the second mounting portion 52 of the flexure 43 extends in the Y direction across the edge 61b of the joint portion 61 and covers the corresponding row L of connection pads 81. The pads 55 of one flexure 43 are connected to the connection pads 81 included in one row L.

[0059] The preamplifier 44 is mounted on the surface 61a of the joint 61. Specifically, electrodes of the preamplifier 44 are joined to the multiple mounting pads 82, for example, by soldering. That is, the multiple mounting pads 82 are connected to the preamplifier 44. Therefore, the multiple connection pads 81 are located between the edge 61b and the preamplifier 44 in the direction along the surface 61a.

[0060] 4, each of the plurality of wirings 83 connects a corresponding one of the plurality of connection pads 81B, 81C, 81D, 81E, and 81F to a corresponding one of the plurality of mounting pads 82. Note that the electrical path between the connection pad 81 and the mounting pad 82 may include the wiring 83, a wiring included in the conductive layer 73, and a via.

[0061] The preamplifier 44 is electrically connected to the magnetic head 15 through the mounting pads 82, the wiring 83, the connection pads 81, the solder 87, the pads 55, and the wiring 56. Meanwhile, the connection pads 81A are connected to each other by, for example, other wiring 89, and are also connected to the PCB via a driver mounted on, for example, the FPC 19.

[0062] The preamplifier 44 is electrically connected to the write element of the magnetic head 15 through the connection pad 81B. That is, the connection pad 81B is assigned to an electrical signal (write signal) of information that the magnetic head 15 writes to the magnetic disk 12.

[0063] The preamplifier 44 amplifies the write signal output by the control device. The preamplifier 44 outputs the amplified write signal to the write element of the magnetic head 15 through the connection pad 81B. The write element writes information to the magnetic disk 12 based on the write signal. In this way, the write signal flows from the preamplifier 44 to the magnetic head 15 through the connection pad 81B.

[0064] The preamplifier 44 is electrically connected to the heater of the magnetic head 15 through the connection pad 81C. The heater of the magnetic head 15 adjusts the temperature of the magnetic head 15, thereby adjusting the positions of the write element and read element of the magnetic head 15 relative to the magnetic disk 12.

[0065] The preamplifier 44 is electrically connected through the connection pad 81D to the microwave-assisted magnetic recording (MAMR) element of the magnetic head 15. The MAMR element of the magnetic head 15 superimposes microwaves on the recording magnetic field of the write element and applies them to the magnetic disk 12.

[0066] The preamplifier 44 is electrically connected to the HDI sensor 45 built into the magnetic head 15 through the connection pad 81E. That is, the connection pad 81E is electrically connected to the HDI sensor 45. The HDI sensor 45 built into the magnetic head 15 is mounted on the flexure 43.

[0067] The HDI sensor 45 has, for example, a thermocouple, and detects contact between the magnetic disk 12 and the magnetic head 15 and outputs an electric signal (detection signal). For example, the resistance value of the thermocouple changes in response to heat generated by contact between the magnetic disk 12 and the magnetic head 15. The HDI sensor 45 outputs a detection signal corresponding to the resistance value of the thermocouple. However, the HDI sensor 45 is not limited to this example. The detection signal passes through the connection pad 81E and is transmitted to the control device via the preamplifier 44.

[0068] The preamplifier 44 is electrically connected to the read element of the magnetic head 15 through the connection pad 81F. That is, the connection pad 81F is assigned to the electrical signal (read signal) of information read by the magnetic head 15 from the magnetic disk 12.

[0069] The read element of the magnetic head 15 inputs a read signal to the preamplifier 44 through the connection pad 81F. The preamplifier 44 amplifies the read signal and transmits it to the control device. In this way, the read signal flows from the magnetic head 15 to the preamplifier 44 through the connection pad 81F.

[0070] The control device is electrically connected to a Gimbal Micro Actuator (GMA) through the connection pad 81A. That is, the connection pad 81A is assigned to the GMA. The control device, for example, drives the GMA to deform the load beam 42 and fine-tune the position of the magnetic head 15.

[0071] The solid ground 84 is a metal film that extends along the surface 61a. The solid ground 84 is set to ground potential. The solid ground 84 is spaced apart from the connection pads 81, the mounting pads 82, and the wiring 83 in the direction along the surface 61a. Note that the solid ground 84 may be connected to the connection pads 81, the mounting pads 82, and the wiring 83 that are assigned to the ground.

[0072] The solid ground 84 is disposed, for example, between two adjacent columns L in an area where no wiring 83 is provided. In other words, at least a portion of the solid ground 84 is located between two of the multiple connection pads 81 in the direction along the surface 61a. Note that the solid ground 84 may be provided in another position.

[0073] The solid ground 84 is closer to the edge 61b than to the edge 61c of the joint 61. The solid ground 84 is spaced apart from the protrusion 63. The solid ground 84 may be provided in an area closer to the edge 61c than to the edge 61b, or may be provided on the protrusion 63.

[0074] In the joint 61, the conductive layer 73 has a solid ground 91. The solid ground 91 is an example of a first solid ground. The solid ground 91 is a metal film that extends along the surface 61a. The solid ground 91 is set to the ground potential.

[0075] The solid ground 91 covers the multiple connection pads 81A, 81C, and 81D in the Z direction. In other words, the solid ground 91 overlaps the multiple connection pads 81A, 81C, and 81D in the Z direction.

[0076] Furthermore, the solid ground 91 covers the mounting pads 82 and wiring 83 connected to the connection pads 81A, 81C, and 81D in the Z direction. The solid ground 91 also covers the solid ground 84 in the Z direction. In this way, the solid ground 91 covers at least one of the multiple connection pads 81, at least one of the multiple mounting pads 82, and at least one of the multiple wiring 83 in the Z direction.

[0077] In the Y direction, a portion of the solid ground 91 is located between the connection pad 81A and the edge 61b of the joint 61. The end of the solid ground 91 in the +Y direction is located near the edge 61b. In addition, in the Y direction, another portion of the solid ground 91 is located between the connection pad 81F and the edge 61c of the joint 61. The end of the solid ground 91 in the -Y direction is located near the edge 61c.

[0078] A plurality of holes 92, a plurality of first openings 93, and a plurality of second openings 94 are provided in the solid ground 91. The holes 92, the first openings 93, and the second openings 94 are holes that penetrate the solid ground 91 in the Z direction. The first openings 93 and the second openings 94 may be cutouts.

[0079] The multiple holes 92 include multiple holes 92B and 92E. Each of the multiple holes 92B overlaps in the Z direction with at least a portion of the corresponding connection pad 81B and with at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81B. In other words, each of the multiple holes 92B has a portion that overlaps in the Z direction with at least a portion of the corresponding connection pad 81B, a portion that overlaps in the Z direction with at least a portion of one mounting pad 82, and a portion that overlaps in the Z direction with at least a portion of one wiring 83.

[0080] In other words, in the direction along the surface 61a, at least a portion of the connection pad 81B and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81B are located inside the edge of the hole 92B. As described above, the solid ground 91 is spaced apart in the direction along the surface 61a from at least a portion of the connection pad 81B and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81B.

[0081] Each of the multiple holes 92E overlaps in the Z direction with at least a portion of a corresponding connection pad 81E and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81E. In other words, in the direction along the surface 61a, at least a portion of the connection pad 81E and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81E are located inside the edge of the hole 92E. Therefore, the solid ground 91 is separated in the direction along the surface 61a from at least a portion of the connection pad 81E and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81E.

[0082] Furthermore, each of the multiple holes 92E overlaps in the Z direction with at least a portion of the corresponding connection pad 81F and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81F. In other words, in the direction along the surface 61a, at least a portion of the connection pad 81F and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81F are located inside the edge of the hole 92E. Therefore, the solid ground 91 is separated in the direction along the surface 61a from at least a portion of the connection pad 81F and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81F.

[0083] The wiring 83 connected to the connection pad 81F is an example of a lead wiring. The mounting pad 82 connected to the connection pad 81F via the wiring 83 is an example of a second lead terminal. Note that a hole different from the hole 92E may overlap in the Z direction with at least a portion of the corresponding connection pad 81F and at least a portion of the mounting pad 82 and wiring 83 connected to the connection pad 81F.

[0084] Instead of the holes 92, notches or areas between the two divided solid grounds 91 may be provided. The notches or areas overlap in the Z direction with at least parts of the corresponding connection pads 81 and at least parts of the mounting pads 82 and wiring 83 connected to the connection pads 81.

[0085] As described above, the solid ground 91 is at least partially separated from the predetermined wiring 83 and the connection pads 81 (81B, 81E, 81F) and mounting pads 82 connected to the predetermined wiring 83 in the direction along the surface 61a. The solid ground 91 is also separated from at least a portion of each of the connection pads 81B, 81E, 81F in the multiple rows L in the direction along the surface 61a. That is, in any of the rows L, at least a portion of the connection pads 81B, 81E, 81F is not covered by the solid ground 91. The solid ground 91 may cover at least one of the connection pads 81B, 81E, 81F in the multiple rows L in the Z direction.

[0086] Also, one of the plurality of connection pads 81 may be electrically connected to a heat-assisted magnetic recording (HMAR) element. A solid ground 91 covers the one of the plurality of connection pads 81 in the Z direction.

[0087] The first opening 93 is located between one of the plurality of connection pads 81 and the preamplifier 44 in the direction along the surface 61a. That is, an imaginary line connecting a point on one of the plurality of connection pads 81 and a point on the preamplifier 44 in the direction along the surface 61a crosses the first opening 93.

[0088] The second opening 94 is located between one of the multiple connection pads 81 that is closest to the insertion hole 66 in the direction along the surface 61a and the insertion hole 66. In other words, an imaginary line connecting a point on one of the multiple connection pads 81 that is closest to the insertion hole 66 in the direction along the surface 61a and a point on the insertion hole 66 crosses the second opening 94.

[0089] The solid ground 91 is spaced apart from the plurality of protruding portions 63 in the direction along the surface 61a. Therefore, both the solid grounds 84 and 91 are spaced apart from the protruding portions 63. The solid ground 91 may be provided on the protruding portions 63. Also, a conductor such as wiring 89 may be provided on the protruding portions 63.

[0090] The joint 61 further includes a plurality of vias 99. The vias 99 are, for example, through holes. Each of the vias 99 penetrates the base layer 71 and connects the solid ground 91 to a corresponding one of the solid grounds 84.

[0091] During the above assembly of the HDD 1, the pads 55 of the flexure 43 are joined to the connection pads 81 of the FPC 19 by solder 87. For example, a paste containing solder 87 is applied to one of the pads 55 and the connection pads 81. Next, the second mounting portion 52 of the flexure 43 and the joint portion 61 of the FPC 19 are overlapped, and the paste is applied to the other of the pads 55 and the connection pads 81.

[0092] Next, for example, laser light is irradiated onto the paste through the hole 43a provided in the flexure 43 in Fig. 5. This melts the paste, and the pad 55 and the connection pad 81 are joined by the solder 87.

[0093] When the paste is irradiated with laser light, the paste (solder 87) is heated, and the surrounding area of the paste is also heated. For example, heat is transferred from the solder 87 to the connection pad 81, and the portion of the FPC 19 surrounding the connection pad 81 is heated.

[0094] In the FPC 19, each of the metal conductive layers 72 and 73 has a higher thermal conductivity than both the base layer 71 and the cover layers 74 and 75. In other words, the conductive layers 72 and 73 easily dissipate heat. Therefore, in the FPC 19, the high-density portions of the conductive layers 72 and 73 more easily dissipate heat than the low-density portions of the conductive layers 72 and 73.

[0095] The density of the wiring 83 is high around the preamplifier 44 in the joint 61 of the FPC 19. On the other hand, the density of the wiring 83 is low around the edge 61b of the joint 61. Therefore, many wirings 83 can dissipate heat around the preamplifier 44.

[0096] Generally, when the density of the conductive layers 72 and 73 is low around the edge 61b of the joint 61, the area around the edge 61b is less able to dissipate heat. Therefore, when the area around the edge 61b is irradiated with laser light under the same conditions as the area around the preamplifier 44, the area around the edge 61b may be excessively heated. If the FPC 19 is excessively heated, for example, the conductive layers 72 and 73 may peel off from the base layer 71.

[0097] On the other hand, in this embodiment, solid grounds 84 and 91 are provided around the edge 61b. For example, the solid ground 91 covers the connection pad 81A located near the edge 61b in the Z direction. This makes it easier for heat to escape from the area around the edge 61b, and the thermal conductivity of the area around the edge 61b and the area around the preamplifier 44 is more uniform. Therefore, even if the area around the edge 61b is irradiated with laser light under the same conditions as the area around the preamplifier 44, excessive heating can be suppressed.

[0098] The first opening 93 penetrates the solid ground 91, thereby preventing heat conduction across the first opening 93. The first opening 93 is located between the connection pad 81 and the preamplifier 44, thereby reducing the amount of heat conducted from around the connection pad 81 to around the preamplifier 44. Therefore, the first opening 93 can prevent the temperature from rising easily around the connection pad 81F, which is relatively close to the preamplifier 44.

[0099] The second opening 94 penetrates the solid ground 91, thereby preventing heat conduction across the second opening 94. Furthermore, the screw 65 is made of metal and has a larger volume than the conductive layers 72 and 73. This allows heat to easily escape from the area around the screw 65. The second opening 94 is located between the connection pad 81 and the insertion hole 66, thereby reducing the amount of heat conducted from around the connection pad 81 to around the screw 65. As a result, the second opening 94 can prevent the area around the connection pad 81F closest to the insertion hole 66 from becoming too hot.

[0100] The plurality of protrusions 63 have a large surface area per volume and can easily dissipate heat. Since the solid grounds 84 and 91 are spaced apart from the protrusions 63, it is possible to prevent the temperature around the plurality of protrusions 63 from rising.

[0101] If the solid ground 91 covers the connection pads 81, the mounting pads 82, and the wiring 83 in the Z direction, parasitic capacitance may occur, and impedance may be generated in the connection pads 81, the mounting pads 82, and the wiring 83. This impedance may affect the electrical signals flowing through the connection pads 81, the mounting pads 82, and the wiring 83.

[0102] On the other hand, in this embodiment, the solid ground 91 is spaced apart in the direction along the surface 61a from at least a portion of the connection pads 81B, 81E, and 81F and from at least a portion of the corresponding mounting pads 82 and wiring 83. In other words, the solid ground 91 does not cover at least a portion of the conductors through which the write signal, the detection signal, and the read signal flow.

[0103] The solid ground 91 does not cover the connection pad 81B, the corresponding mounting pad 82, and the wiring 83, and therefore can suppress the influence of parasitic capacitance on the write signal. The solid ground 91 does not cover the connection pad 81E, the corresponding mounting pad 82, and the wiring 83, and therefore can suppress the influence of parasitic capacitance on the detection signal. Furthermore, the solid ground 91 does not cover the connection pad 81F, the corresponding mounting pad 82, and the wiring 83, and therefore can suppress the influence of parasitic capacitance on the read signal.

[0104] The solid ground 91 may entirely cover in the Z direction the connection pads 81B and 81E, the corresponding mounting pads 82, and the wiring 83. For example, if the effect of impedance on the light signal and the detection signal is small, the solid ground 91 entirely covers in the Z direction the connection pads 81B and 81E, the corresponding mounting pads 82, and the wiring 83, making it easier for heat to escape.

[0105] In this embodiment, the solid ground 91 is spaced apart from the entire wiring 83 connected to the connection pad 81F in the direction along the surface 61a. On the other hand, the solid ground 91 may cover a portion of the wiring 83 connected to the connection pads 81B and 81E in the Z direction. For example, a portion connecting one portion of the solid ground 91 to another portion may extend so as to cross a portion of the wiring 83 connected to the connection pad 81B. This allows the solid ground 91 to suppress a difference in potential between that portion of the solid ground 91 and the other portion.

[0106] In the HDD 1 according to the present embodiment described above, the FPC 19 has a surface 61a, a plurality of connection pads 81 provided on the surface 61a, and a solid ground 91. Each of the plurality of connection pads 81 is bonded to a corresponding one of the plurality of pads 55 by solder 87. The solid ground 91 covers at least one of the plurality of connection pads 81 in the Z direction perpendicular to the surface 61a. This allows the solid ground 91 to dissipate heat transferred from the solder 87 heated by a heat source such as laser light to the connection pad 81 when the connection pad 81 is bonded to the pad 55 by the solder 87. Therefore, the HDD 1 can prevent the FPC 19 from peeling due to excessive heating of the connection pads 81. The plurality of connection pads 81 also includes a connection pad 81F. An electrical signal (read signal) representing information read by the magnetic head 15 from the magnetic disk 12 flows through the connection pad 81F. The solid ground 91 is spaced apart from at least some of the connection pads 81F in a direction along the surface 61a. Generally, when a solid ground is placed close to a conductor, such as a terminal or wiring through which an electrical signal flows, impedance is generated in the conductor, affecting the electrical signal. If impedance is generated in the connection pads 81F through which a read signal flows, the impedance may affect the reading and writing of information in the HDD 1. On the other hand, even if impedance is generated in the connection pads 81C and 81D, the impact on the reading and writing of information in the HDD 1 is minimal. In the HDD 1 of this embodiment, the solid ground 91 is spaced apart from the connection pads 81F, thereby preventing impedance from being generated in the connection pads 81F due to the proximity of the connection pads 81F and the solid ground 91. Therefore, the HDD 1 uses the solid ground 91 to prevent peeling of the FPC 19 and also prevents the solid ground 91 from affecting the read signal, thereby preventing a degradation in the performance of the HDD 1.

[0107] In the HDD 1 according to the present embodiment described above, the FPC 19 includes a surface 61a, a plurality of connection pads 81 provided on the surface 61a, a plurality of mounting pads 82 provided on the surface 61a, a plurality of wirings 83, and a solid ground 91. Each of the connection pads 81 is bonded to a corresponding one of the pads 55 by solder 87. The wirings 83 connect the connection pads 81 to the mounting pads 82. The solid ground 91 covers at least one of the connection pads 81, at least one of the mounting pads 82, and at least one of the wirings 83 in the Z direction perpendicular to the surface 61a. This allows the solid ground 91 to dissipate heat transferred from the solder 87 heated by a heat source such as laser light to the connection pads 81 when the connection pads 81 are bonded to the pads 55 by the solder 87. Therefore, the HDD 1 can prevent the FPC 19 from peeling off due to excessive heating of the connection pads 81. The preamplifier 44 is also connected to the multiple mounting pads 82. The solid ground 91 is at least partially separated along the surface 61a from one of the multiple wirings 83 and one of the multiple connection pads 81 and one of the multiple mounting pads 82 connected to that one of the multiple wirings 83. In the HDD 1 of this embodiment, the solid ground 91 is separated from the interconnected connection pads 81, mounting pads 82, and wirings 83, thereby preventing impedance from occurring in these connection pads 81, mounting pads 82, and wirings 83. Therefore, in the HDD 1, the solid ground 91 prevents peeling of the FPC 19 and prevents the solid ground 91 from affecting the electrical signals flowing through the connection pads 81, mounting pads 82, and wirings 83, thereby preventing a degradation in performance of the HDD 1.

[0108] An electrical signal (write signal) of information written by the magnetic head 15 to the magnetic disk 12 flows through the connection pad 81B. The solid ground 91 is spaced apart from the connection pad 81B in the direction along the surface 61a. By spacing the solid ground 91 away from the connection pad 81B, the HDD 1 can prevent impedance from being generated in the connection pad 81B due to the proximity of the connection pad 81B and the solid ground 91. Therefore, the HDD 1 can prevent peeling of the FPC 19 due to the solid ground 91 and can also prevent the solid ground 91 from affecting the write signal, thereby preventing a decrease in performance of the HDD 1.

[0109] The HDI sensor 45 is mounted on the flexure 43 and detects contact between the magnetic disk 12 and the magnetic head 15 to output an electrical signal (detection signal). The connection pad 81E is electrically connected to the HDI sensor 45. The solid ground 91 is spaced apart from the connection pad 81E in the direction along the surface 61a. By spacing the solid ground 91 away from the connection pad 81E, the HDD 1 can prevent impedance from being generated in the connection pad 81E due to proximity between the connection pad 81E and the solid ground 91. Therefore, the HDD 1 can prevent peeling of the FPC 19 due to the solid ground 91 and can prevent the solid ground 91 from affecting the detection signal, thereby preventing a decrease in performance of the HDD 1.

[0110] The multiple connection pads 81 form multiple rows L. Each of the multiple rows L includes two or more of the multiple connection pads 81 arranged in the Y direction along the surface 61a. Each of the multiple rows L includes a connection pad 81F. The solid ground 91 is spaced apart from at least a portion of each of the connection pads 81F in the multiple rows L in the direction along the surface 61a. This allows the solid ground 91 to suppress impedance from occurring in each of the connection pads 81F in the multiple rows L.

[0111] The FPC 19 has a mounting pad 82 connected to the preamplifier 44 and a wiring 83 connecting the connection pad 81F and the mounting pad 82. The solid ground 91 is spaced apart from at least a portion of the mounting pad 82 and the wiring 83 in the direction along the surface 61a. This prevents the HDD 1 of this embodiment from generating impedance in the connection pad 81F, the wiring 83, and the mounting pad 82 due to the proximity of the connection pad 81F, the wiring 83, and the mounting pad 82 to the solid ground 91. This effectively prevents the solid ground 91 from affecting the read signal, thereby preventing a degradation in the performance of the HDD 1.

[0112] A hole 92 is provided in the solid ground 91. In the direction along the surface 61a, at least a portion of the connection pad 81F, the wiring 83, and the mounting pad 82 are located inside the edge of the hole 92. In other words, the solid ground 91 is present around the connection pad 81F, the wiring 83, and the mounting pad 82. This allows the solid ground 91 to more effectively dissipate heat when the connection pad 81 is bonded to the pad 55. Therefore, the HDD 1 can prevent the FPC 19 from peeling off due to excessive heating of the connection pad 81.

[0113] A first opening 93 is provided in the solid ground 91. The first opening 93 is located between one of the multiple connection pads 81 and the preamplifier 44 in the direction along the surface 61a. The first opening 93 can reduce heat transfer between the connection pad 81 and the preamplifier 44 through the solid ground 91. This allows the HDD 1 of this embodiment to reduce temperature imbalances among the multiple connection pads 81 when the connection pads 81 are bonded to the pads 55. Therefore, the HDD 1 can prevent peeling of the FPC 19 due to excessive heating of some of the connection pads 81.

[0114] The FPC 19 has an edge 61b extending in the X direction along the surface 61a and a protrusion 63 extending along the surface 61a and protruding from the edge 61b in the Y direction, which intersects the X direction. A plurality of connection pads 81 are positioned between the edge 61b and the preamplifier 44 in the direction along the surface 61a. The solid ground 91 is spaced apart from the protrusion 63 in the direction along the surface 61a. The protrusion 63 protruding from the edge 61b dissipates heat more easily than the joint 61 of the FPC 19, which includes the edge 61b. Because the solid ground 91 is spaced apart from the protrusion 63, excessive heat dissipation from the protrusion 63 is suppressed. Therefore, the HDD 1 of this embodiment can reduce temperature imbalances in the FPC 19 when the connection pads 81 are bonded to the pads 55. Therefore, the HDD 1 can suppress peeling of the FPC 19 due to excessive heating of some connection pads 81.

[0115] The FPC 19 includes a base layer 71 and a conductive layer 72 laminated on the base layer 71. The conductive layer 72 includes a plurality of connection pads 81 and a solid ground 84 spaced apart from the connection pads 81 in a direction along the surface 61a. At least a portion of the solid ground 84 is located between two of the connection pads 81 in a direction along the surface 61a. That is, the solid ground 84 is provided near the connection pads 81. This allows the solid ground 84 to dissipate heat from the connection pads 81 when the connection pads 81 are bonded to the pads 55. Therefore, the HDD 1 can prevent the FPC 19 from peeling off due to excessive heating of the connection pads 81.

[0116] The FPC 19 has a via 99 that connects the solid ground 91 and the solid ground 84. This allows the HDD 1 of this embodiment to have the solid ground 91 and the solid ground 84 at the same potential. Therefore, the HDD 1 can prevent the solid ground 91 and the solid ground 84 from functioning as an antenna, generating unwanted impedance, or generating noise, thereby preventing a decrease in performance of the HDD 1.

[0117] The FPC 19 is provided with a through-hole 66 through which the screw 65 passes. A second opening 94 is provided in the solid ground 91. The second opening 94 is located between the through-hole 66 and one of the connection pads 81 that is closest to the through-hole 66 in the direction along the surface 61a. The second opening 94 can reduce heat transfer through the solid ground 91 between the connection pad 81 and the screw 65 passing through the through-hole 66. This reduces temperature imbalances among the connection pads 81 when the connection pads 81 are bonded to the pads 55 in the HDD 1 of this embodiment. Therefore, the HDD 1 can prevent peeling of the FPC 19 due to excessive heating of some of the connection pads 81.

[0118] In the above description, suppression is defined as, for example, preventing an event, action, or effect from occurring or reducing the magnitude of an event, action, or effect.

[0119] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0120] 1...hard disk drive (HDD), 12...magnetic disk, 15...magnetic head, 19...flexible printed circuit board (FPC), 43...flexure, 44...preamplifier, 45...HDI sensor, 55...pad, 61a...surface, 61b...edge, 63...protrusion, 65...screw, 66...through hole, 71...base layer, 72...conductive layer, 81, 81A, 81B, 81C, 81D, 81E, 81F...connection pad, 82...mounting pad, 83...wiring, 84...ground plane, 87...solder, 91...ground plane, 92, 92B, 92E...hole, 93...first opening, 94...second opening, 99...via, L...row.

Claims

1. A magnetic disk, a magnetic head configured to read and write information from and to the magnetic disk; a first flexible printed circuit board having a plurality of first terminals, the magnetic head being mounted thereon, and at least one of the plurality of first terminals being electrically connected to the magnetic head; a second flexible printed circuit board having a surface, a plurality of second terminals provided on the surface and each of which is joined to a corresponding one of the plurality of first terminals by a conductive bonding material, and a first solid ground covering at least one of the plurality of second terminals in a direction perpendicular to the surface; Equipped with the plurality of second terminals include a first lead terminal through which an electrical signal of information read by the magnetic head from the magnetic disk flows; the first solid ground is spaced apart from at least a portion of the first lead terminal in a direction along the surface; Disk device.

2. the plurality of second terminals include a write terminal through which an electrical signal of information to be written by the magnetic head onto the magnetic disk flows; the first solid ground is spaced apart from the light terminal in a direction along the surface; 2. The disk device according to claim 1.

3. an HDI sensor that detects contact between the magnetic disk and the magnetic head and outputs an electrical signal; Further comprising: the plurality of second terminals include an HDI terminal electrically connected to the HDI sensor; the first solid ground is spaced apart from the HDI terminal in a direction along the surface; 3. The disk device according to claim 1 or 2.

4. the plurality of second terminals form a plurality of rows, each row including two or more of the plurality of second terminals arranged in a first direction along the surface; each of the plurality of rows includes the first lead terminal; the first solid ground is spaced apart from at least a portion of the first lead terminals of each of the plurality of rows in a direction along the surface; 4. A disk device according to claim 1.

5. a preamplifier mounted on the second flexible printed circuit board, which outputs an electrical signal of information to be written to the magnetic disk by the magnetic head, and receives an electrical signal of information read from the magnetic disk by the magnetic head, from the magnetic head; Further comprising: the second flexible printed circuit board has a second lead terminal connected to the preamplifier and a lead wiring connecting the first lead terminal and the second lead terminal, the first solid ground is spaced apart from the second lead terminal and at least a part of the lead wiring in a direction along the surface; 5. A disk device according to claim 1.

6. a hole is provided in the first solid ground; In a direction along the surface, at least a portion of the first lead terminal, the lead wiring, and the second lead terminal is located inside an edge of the hole.

6. The disk device according to claim 5.

7. A magnetic disk, a magnetic head configured to read and write information from and to the magnetic disk; a first flexible printed circuit board having a plurality of first terminals, the magnetic head being mounted thereon, and at least one of the plurality of first terminals being electrically connected to the magnetic head; a second flexible printed circuit board having a surface, a plurality of second terminals provided on the surface, each of which is joined to a corresponding one of the plurality of first terminals by a conductive bonding material, a plurality of third terminals provided on the surface, a plurality of wirings connecting the plurality of second terminals and the plurality of third terminals, and a first solid ground covering at least one of the plurality of second terminals, at least one of the plurality of third terminals, and at least one of the plurality of wirings in a direction perpendicular to the surface; a preamplifier connected to the plurality of third terminals, for outputting to the magnetic head an electrical signal of information to be written to the magnetic disk by the magnetic head, and for receiving from the magnetic head an electrical signal of information read from the magnetic disk by the magnetic head; Equipped with the first solid ground is at least partially separated from one of the plurality of wirings, and one of the plurality of second terminals and one of the plurality of third terminals connected to the one of the plurality of wirings, in a direction along the surface; Disk device.

8. 8. A disk device according to claim 5, wherein the first solid ground has a first opening located between one of the plurality of second terminals and the preamplifier in a direction along the surface.

9. the second flexible printed circuit board has an edge extending in a second direction along the surface, and a protrusion protruding from the edge in a third direction along the surface and intersecting the second direction; the plurality of second terminals are located between the edge and the preamplifier in a direction along the surface; the first solid ground is spaced apart from the protrusion in a direction along the surface; 9. A disk device according to claim 5.

10. the second flexible printed circuit board has a base layer and a conductive layer laminated on the base layer, the conductive layer has the plurality of second terminals and a second solid ground spaced apart from the plurality of second terminals in a direction along the surface; at least a portion of the second solid ground is located between two of the plurality of second terminals in a direction along the surface; 10. A disk device according to claim 1.

11. 11. The disk drive of claim 10, wherein the second flexible printed circuit board has a via that connects the first solid ground and the second solid ground.

12. The second flexible printed circuit board is provided with insertion holes through which screws pass, a second opening is provided in the first solid ground, the second opening being located between the insertion hole and one of the plurality of second terminals that is closest to the insertion hole in a direction along the surface; 12. A disk drive according to claim 1.

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