Disk drive

Abstract

To provide a disk drive that can improve the reliability of flexible printed circuit boards. [Solution] A disk device according to one embodiment comprises a magnetic disk, a magnetic head, a flexible printed circuit board, and an electronic component. The flexible printed circuit board has a first insulating layer, a first conductive layer provided on a first surface of the first insulating layer, a second conductive layer provided on a second surface of the first insulating layer, a second insulating layer covering the second surface and the second conductive layer, and a first adhesive layer adhering the second insulating layer to the second surface and the second conductive layer. The first conductive layer has a first land. A plurality of first through holes are provided in a first portion of the second conductive layer that overlaps the first land via the first insulating layer. The first adhesive layer adheres to the second surface through the plurality of first through holes. The electronic component has a first pin bonded to the first land.

Description

Technical Field

[0001] Embodiments of the present invention relate to a disk device.

Background Art

[0002] A disk device such as a hard disk drive has a flexible printed circuit board (FPC) and electronic components mounted on the FPC. For example, pins of the electronic components are joined to pads provided on the FPC.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when a moment (torque) that rotates (twists) on the surface of the FPC occurs in an electronic component, a force in the direction along the surface acts on the FPC in the vicinity of the land. The force acts on the adhesive portion between the insulating layer and the conductive layer of the FPC, which may reduce the reliability of the FPC.

[0005] An example of the problem to be solved by the present invention is to provide a disk device that can improve the reliability of a flexible printed circuit board.

Means for Solving the Problems

[0006] A disk device according to one embodiment comprises a magnetic disk, a magnetic head, a flexible printed circuit board, and electronic components. The magnetic head is configured to read and write information to the magnetic disk. The flexible printed circuit board is electrically connected to the magnetic head. The electronic components are mounted on the flexible printed circuit board. The flexible printed circuit board has a first insulating layer, a first conductive layer provided on a first surface of the first insulating layer, a second conductive layer provided on a second surface of the first insulating layer located opposite the first surface, a second insulating layer covering the second surface and the second conductive layer, and a first adhesive layer adhering the second insulating layer to the second surface and the second conductive layer. The first conductive layer has first lands. A plurality of first through holes are provided in a first portion of the second conductive layer that overlaps the first lands via the first insulating layer. The first adhesive layer adheres to the second surface through the plurality of first through holes. The electronic component has a first pin bonded to the first land. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is an illustrative perspective view showing a disassembled HDD according to the first embodiment. [Figure 2] Figure 2 is an illustrative plan view schematically showing the FPC of the first embodiment. [Figure 3] Figure 3 is an illustrative cross-sectional view schematically showing a portion of the HDD of the first embodiment. [Figure 4] Figure 4 is an illustrative plan view schematically showing the second connection portion of the FPC of the first embodiment. [Figure 5] Figure 5 is an exemplary cross-sectional view schematically showing the second connection and relay connector of the first embodiment along the line F5-F5 in Figure 4. [Figure 6] Figure 6 is an illustrative cross-sectional view schematically showing a part of the HDD according to the second embodiment. [Modes for carrying out the invention]

[0008] (First Embodiment) The first embodiment will be described below with reference to Figures 1 to 5. Note that in this specification, the components of the embodiment and their descriptions may be described using multiple expressions. The components and their descriptions are examples and are not limited by the expressions used herein. Components may also be identified by names different from those used herein. Furthermore, components may also be described using expressions different from those used herein.

[0009] In the following explanation, “suppress” is defined, for example, to prevent the occurrence of an event, action, or effect, or to reduce the degree of an event, action, or effect. Also, in the following explanation, “restrict” is defined, for example, to prevent movement or rotation, or to permit movement or rotation within a predetermined range while preventing movement or rotation beyond that predetermined range.

[0010] Figure 1 is an exemplary perspective view showing a disassembled hard disk drive (HDD) 10 according to the first embodiment. The HDD 10 is an example of a disk device and may also be referred to as an electronic device, storage device, external storage device, or magnetic disk device. Note that the disk device is not limited to the HDD 10.

[0011] As shown in each drawing, the X, Y, and Z axes are defined herein for convenience. The X, Y, and Z axes are orthogonal to each other. The X axis is provided along the width of the HDD 10. The Y axis is provided along the length of the HDD 10. The Z axis is provided along the thickness of the HDD 10.

[0012] Furthermore, the X, Y, and Z directions are defined herein. 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 which is the opposite direction of 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 which is the opposite direction of 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 which is the opposite direction of the Z-axis arrow.

[0013] As shown in Figure 1, the HDD 10 comprises a housing 11, a plurality of magnetic disks 12, a spindle motor 13, a head stack assembly (HSA) 14, a voice coil motor (VCM) 15, a ramp load mechanism 16, and a printed circuit board (PCB) 17. The magnetic disks 12 may also be referred to as disks, media, or platters.

[0014] The housing 11 includes a base 21, an inner cover 22, and an outer cover 23. Note that the housing 11 is not limited to this example. The base 21 is formed in the shape of a roughly rectangular box open in the +Z direction. The base 21 houses a plurality of magnetic disks 12, a spindle motor 13, an HSA 14, a VCM 15, and a ramp load mechanism 16.

[0015] The base 21 has a bottom wall 25 and side walls 26. The bottom wall 25 is formed in the shape of a roughly rectangular (quadrilateral) plate, positioned roughly perpendicular to the Z direction. The side walls 26 protrude from the edge of the bottom wall 25 in the direction roughly +Z and are formed in the shape of a roughly rectangular frame.

[0016] The inner cover 22 is attached, for example, by screws to the end of the side wall 26 in the +Z direction and closes the base 21. The outer cover 23 covers the inner cover 22 and is attached, for example, by welding to the end of the side wall 26 in the +Z direction.

[0017] The inner cover 22 is provided with a vent hole 27. Further, the outer cover 23 is provided with a vent hole 28. Components are attached inside the base 21. After the inner cover 22 and the outer cover 23 are attached to the base 21, the air inside the housing 11 is exhausted from the vent holes 27 and 28. Further, a gas different from air is filled inside the housing 11.

[0018] The gas filled inside the housing 11 is, for example, a low-density gas having a lower density than air, an inert gas with low reactivity, or the like. For example, helium is filled inside the housing 11. Note that other fluids may be filled inside the housing 11.

[0019] The vent hole 28 of the outer cover 23 is blocked by a seal 29. The seal 29 hermetically seals the vent hole 28 and restricts the fluid filled inside the housing 11 from leaking from the vent hole 28 to the outside of the housing 11.

[0020] The plurality of magnetic disks 12 are formed in a disk shape arranged substantially parallel to the bottom wall 25. The plurality of magnetic disks 12 are arranged at intervals in the Z direction. The spindle motor 13 supports the plurality of magnetic disks 12. The plurality of magnetic disks 12 are held, for example, by a clamp spring on the hub of the spindle motor 13. The spindle motor 13 rotates the plurality of magnetic disks 12.

[0021] A support shaft 31 spaced apart from the magnetic disk 12 is provided on the housing 11. The support shaft 31 extends, for example, in the +Z direction from the bottom wall 25 of the housing 11. The HSA 14 is supported by the support shaft 31 so as to be rotatable around the support shaft 31.

[0022] The HSA 14 has a carriage 35, a plurality of head gimbal assemblies (HGAs) 36, and a flexible printed circuit board (FPC) 37. The carriage 35 has an actuator block 41 and a plurality of arms 42.

[0023] The actuator block 41 is supported on the support shaft 31 via bearings so that it can rotate around the support shaft 31, for example. Multiple arms 42 protrude substantially parallel to the actuator block 41.

[0024] Multiple arms 42 are arranged with spacing in the Z direction. Each of the multiple arms 42 can enter the gap between two adjacent magnetic disks 12 among the multiple magnetic disks 12.

[0025] The VCM15 comprises a voice coil attached to the carriage 35, a pair of yokes, and magnets provided on the yokes. The VCM15 rotates the carriage 35 around the support shaft 31.

[0026] Each of the HGA36 units has a base plate 45, a load beam 46, a flexure 47, and a magnetic head 48. The base plate 45 is attached to the end of the arm 42. The load beam 46 is formed to be thinner than the base plate 45 and extends from the base plate 45.

[0027] The flexiser 47 is formed in a long, narrow strip shape. However, the shape of the flexiser 47 is not limited to this example. The flexiser 47 is a type of FPC having a metal plate such as stainless steel (backing layer), an insulating layer (base layer) formed on the metal plate, a conductive layer formed on the insulating layer and constituting multiple wires (wiring patterns), and an insulating layer (cover layer) covering the conductive layer.

[0028] A gimbal section (elastic support section) is provided at one end of the flexure 47, which is located on the load beam 46 and is displaceable. The magnetic head 48 is mounted on the gimbal section of the flexure 47. The magnetic head 48 records and reproduces information on the recording layer of the magnetic disk 12. In other words, the magnetic head 48 reads and writes information to the magnetic disk 12.

[0029] The VCM 15 rotates the carriage 35 to position the magnetic head 48 at the desired location on the magnetic disk 12. Once the magnetic head 48 has moved to the outermost edge of the magnetic disk 12, the ramp load mechanism 16 holds the magnetic head 48 in an unloaded position, separated from the magnetic disk 12.

[0030] The FPC 37 is connected to the other end of the flexure 47. For example, multiple flexures 47 are connected to the FPC 37. This allows the FPC 37 to be electrically connected to multiple magnetic heads 48 via the wiring of the multiple flexures 47.

[0031] PCB17 is a rigid substrate, such as a glass epoxy substrate, and is a multilayer substrate or a build-up substrate. PCB17 is placed outside the housing 11 and attached to the bottom wall 25 of the base 21. PCB17 is attached to the bottom wall 25 by, for example, multiple screws.

[0032] The HDD10 further includes, for example, an interface (I / F) connector 51, a controller 52, and a relay connector 53. The relay connector 53 is an example of a first connector. The I / F connector 51, the controller 52, and the relay connector 53 are mounted on the PCB 17. Other components may also be mounted on the PCB 17.

[0033] The I / F connector 51 is a connector compliant with an interface standard such as Serial ATA (SATA) and is connected to the I / F connector of the host computer. The controller 52 is, for example, a system-on-a-chip (SoC) and has a read / write channel (RWC), a hard disk controller (HDC), and a processor.

[0034] The PCB 17 is electrically connected to various components located inside the housing 11 via the relay connector 53. For example, the PCB 17 is electrically connected to the spindle motor 13, VCM 15, FPC 37, flexi 47, and magnetic head 48.

[0035] Figure 2 is a schematic plan view illustrating an FPC 37 of the first embodiment. As shown in Figure 2, the FPC 37 is formed in a roughly L-shaped strip when removed from other parts and in a natural state where no external forces are acting on it. Note that the shape of the FPC 37 is not limited to this example. The FPC 37 has a first connecting portion 61, a second connecting portion 62, and an intermediate portion 63.

[0036] The first connection portion 61 is provided, for example, at one end of the FPC 37 in the direction in which the FPC 37 extends. The first connection portion 61 is attached to the actuator block 41, for example, by a screw. The first connection portion 61 is connected to a plurality of flexures 47.

[0037] The second connecting portion 62 is provided, for example, at the other end of the FPC 37 in the direction in which the FPC 37 extends. The second connecting portion 62 is attached, for example, to the bottom wall 25 of the housing 11 by screws.

[0038] The intermediate section 63 is provided between the first connecting section 61 and the second connecting section 62. The intermediate section 63 extends in a strip shape and flexes between the first connecting section 61 and the second connecting section 62 in accordance with the rotation of the actuator block 41.

[0039] Figure 3 is an exemplary cross-sectional view schematically showing a part of the HDD 10 of the first embodiment. As shown in Figure 3, the HSA 14 further includes a relay connector 65, a relay device 66, and a reinforcing plate 67. The relay connector 65 is an example of an electronic component and a second connector.

[0040] The relay connector 65 is mounted on the second connection portion 62 of the FPC 37. Therefore, the relay connector 65 is housed in the enclosure 11. The relay connector 65 is, for example, a compression connector. Note that the relay connector 65 may be other connectors such as stacking connectors. Also, the electronic component is not limited to the relay connector 65, but may be other electronic components. The relay connector 65 has a case 71 and a plurality of pins 72. The case is an example of an insulating material.

[0041] The case 71 is made of an insulating material such as synthetic resin. The case 71 is formed, for example, in a substantially rectangular parallelepiped shape extending in the X direction. The case 71 has a bottom surface 71a, a top surface 71b, and two sides 71c and 71d. Note that the terms "top" and "bottom" in this embodiment are for convenience based on Figure 3 and do not limit the direction, position, or mode of use.

[0042] The bottom surface 71a is formed to be substantially flat and faces the +Z direction. The bottom surface 71a faces the second connection portion 62 of the FPC 37. The top surface 71b is located on the opposite side of the bottom surface 71a and faces the -Z direction. The two sides 71c and 71d are located on opposite sides of each other. Side 71c faces the -Y direction. Side 71d faces the +Y direction.

[0043] Figure 4 is an exemplary plan view schematically showing the second connection portion 62 of the FPC 37 in the first embodiment. Figure 5 is an exemplary cross-sectional view schematically showing the second connection portion 62 and the relay connector 65 of the first embodiment along the line F5-F5 in Figure 4.

[0044] As shown in Figure 5, each of the multiple pins 72 is held in the case 71 by, for example, fitting into a groove in the case 71. As shown in Figure 4, the multiple pins 72 are arranged to form two rows L1 and L2. The multiple pins 72 forming row L1 are arranged at approximately equal intervals in the X direction. Row L2 is spaced apart from row L1 in the +Y direction. The multiple pins 72 forming row L2 are arranged at approximately equal intervals in the X direction.

[0045] As shown in Figure 5, each of the multiple pins 72 has a joint portion 75 and a contact portion 76. The joint portion 75 is provided at one end of the pin 72. The contact portion 76 is provided at the other end of the pin 72.

[0046] The joints 75 of the multiple pins 72 forming row L1 each protrude from the side surface 71c of the case 71. The joints 75 of the multiple pins 72 forming row L2 each protrude from the side surface 71d of the case 71. In addition, the contact portions 76 of the multiple pins 72 each protrude from the top surface 71b of the case 71.

[0047] The relay device 66 shown in Figure 3 has, for example, a PCB. The relay device 66 is attached to the bottom wall 25 of the base 21 so as to hermetically seal the through hole H provided in the bottom wall 25. In this way, the relay device 66 is installed in the housing 11.

[0048] The contact portion 76 of the pin 72 makes contact with a pad provided on the surface of the relay device 66. This electrically connects the relay device 66 and the relay connector 65. Furthermore, the terminals of the relay connector 53, which acts as a compression connector, make contact with the relay device 66. This electrically connects the relay connector 53 and the relay device 66. If the relay connector 53 is a stacking connector, the relay device 66 has a stacking connector that is connected to the relay connector 53.

[0049] PCB17 is electrically connected to FPC37 through relay connector 53, relay device 66, and relay connector 65. As a result, controller 52 is electrically connected to magnetic head 48 through PCB17, relay connector 53, relay device 66, relay connector 65, FPC37, and flexi 47.

[0050] The reinforcing plate 67 is made of a metal such as aluminum or a synthetic resin, and is formed in the shape of a plate. However, the reinforcing plate 67 is not limited to this example. The reinforcing plate 67 is attached to the second connection portion 62 of the FPC 37. The second connection portion 62 is located between the relay connector 65 and the reinforcing plate 67.

[0051] The reinforcing plate 67 has higher rigidity than the FPC 37. Therefore, the reinforcing plate 67 improves the rigidity of the second connection portion 62. At least a portion of the intermediate portion 63 is not attached to the reinforcing plate 67 and can bend.

[0052] As shown in Figure 5, the FPC 37 has a base layer 81, two conductive layers 82 and 83, two cover layers 84 and 85, and two adhesive layers 86 and 87. Note that in Figure 4, the cover layer 84 and adhesive layer 86 are omitted for illustrative purposes.

[0053] Base layer 81 is an example of a first insulating layer. Conductive layer 82 is an example of a first conductive layer. Conductive layer 83 is an example of a second conductive layer. Cover layer 84 is an example of a third insulating layer. Cover layer 85 is an example of a second insulating layer. Adhesive layer 86 is an example of a second adhesive layer. Adhesive layer 87 is an example of a first adhesive layer.

[0054] The base layer 81 and the cover layers 84 and 85 are made of an insulating synthetic resin such as polyimide (PI). However, the base layer 81 and the cover layers 84 and 85 may be made of other resins.

[0055] As shown in Figure 5, the base layer 81 has a first surface 81a and a second surface 81b. The first surface 81a faces approximately in the -Z direction. The first surface 81a faces the relay connector 65. The second surface 81b is located on the opposite side of the first surface 81a and faces approximately in the +Z direction. The second surface 81b faces the reinforcing plate 67.

[0056] The conductive layers 82 and 83 are made of a conductive metal such as copper. However, the materials for the conductive layers 82 and 83 are not limited to this example. The conductive layers 82 and 83 each form the wiring pattern of the FPC 37.

[0057] The conductive layer 82 is provided on the first surface 81a of the base layer 81. The conductive layer 82 has a plurality of pads 91 and a plurality of wirings 92. The pads 91 may also be referred to as lands, electrodes, or terminals.

[0058] The pad 91 is an electrode provided on the second connection portion 62. As shown in Figure 4, each of the multiple pads 91 is formed in a substantially rectangular shape, for example. Note that the shape of the pad 91 is not limited to this example.

[0059] The conductive layer 82 further has a plurality of other pads provided on the first connection portion 61 and joined to the flexure 47. Each of the plurality of wirings 92 connects at least two of the plurality of pads 91 provided on the second connection portion 62 and the plurality of other pads provided on the first connection portion 61. The conductive layer 82 may also connect the pads 91 to other pads, for example, joined to the VCM 15.

[0060] The multiple pads 91, like the multiple pins 72, are arranged to form two rows L3 and L4. The multiple pads 91 forming row L3 are arranged at approximately equal intervals in the X direction. Row L4 is spaced apart from row L3 in the +Y direction. The multiple pads 91 forming row L4 are arranged at approximately equal intervals in the X direction.

[0061] As shown in Figure 5, each of the multiple pads 91 is electrically and mechanically joined to one of the corresponding joints 75 among the multiple pins 72 by solder S. In this way, the relay connector 65 is mounted on the second connection part 62 of the FPC 37.

[0062] As shown in Figure 4, the multiple pads 91 include, for example, pads 91A, 91B, and 91C. Similarly, the multiple pins 72 include pins 72A, 72B, and 72C. Pad 91A is an example of a first land. Pad 91B is an example of a second land. Pad 91C is an example of a third land. Pin 72A is an example of a first pin. Pin 72B is an example of a second pin. Pin 72C is an example of a third pin.

[0063] Pin 72A is one of several pins 72 located at the end of row L1. Pad 91A is one of several pads 91 located at the end of row L3. Pin 72A is joined to pad 91A by solder S.

[0064] Pin 72B is one of several pins 72 located in row L1. Pad 91B is one of several pads 91 located in row L3. Pin 72B is joined to pad 91B by solder S.

[0065] Pin 72C is one of several pins 72 located in row L2. Pad 91C is one of several pads 91 located in row L4. Pin 72C is joined to pad 91C by solder S.

[0066] Pin 72C and pad 91C are electrically connected to the magnetic head 48 via wiring 92 and flexure 47. Pin 72C and pad 91C transmit read or write signals.

[0067] The read signal is an electrical signal corresponding to the information read by the magnetic head 48 from the magnetic disk 12. The write signal is an electrical signal corresponding to the information written by the magnetic head 48 to the magnetic disk 12. In other words, the relay connector 65 receives the read signal from the magnetic head 48 to pin 72C, or outputs the write signal from pin 72C to the magnetic head 48. An electronic component such as an amplifier may be provided in the electrical path between pin 72C and the magnetic head 48.

[0068] Pin 72A and pad 91A are, for example, set to ground potential or transmit electrical signals different from the write and read signals. These different electrical signals include, for example, the output signal of a contact sensor, the control signal of a laser element in heat-assisted magnetic recording (HAMR), the control signal of an oscillator in microwave-assisted magnetic recording (MAMR), or the control signal of a heater. Pin 72A and pad 91A may also transmit other electrical signals.

[0069] Pin 72B and pad 91B are set to ground potential. A portion of the wiring 92 connected to pad 91B overlaps with the case 71 of the relay connector 53 and forms a ground plane. Note that pins 72A, 72B, 72C and pads 91A, 91B, 91C are not limited to the above examples.

[0070] The multiple wires 92 include, for example, multiple wires 92A and multiple wires 92B. Wire 92A is an example of a second wire. Wire 92B is an example of a first wire. Each of the multiple wires 92A is thinner than each of the multiple wires 92B. One of the multiple wires 92A is connected to pad 91A. One of the multiple wires 92B is connected to pad 91B.

[0071] The width of the wiring 92A along the first surface 81a is smaller than the width of the pad 91 along the first surface 81a. The width of the wiring 92B along the first surface 81a is, for example, approximately the same as the width of the pad 91 along the first surface 81a, or partially thicker. The widths of the wirings 92A and 92B are not limited to this example.

[0072] As shown in Figure 5, the conductive layer 83 is provided on the second surface 81b of the base layer 81. As shown in Figure 4, the conductive layer 83 has a ground plane 95. The conductive layer 83 may also have other patterns, such as wiring.

[0073] The ground plane 95 is set to, for example, the ground potential. In this embodiment, the ground plane 95 is spaced apart from the portion of the base layer 81 that overlaps with the case 71 of the relay connector 65. That is, the ground plane 95 in this embodiment does not overlap with the case 71. However, the ground plane 95 may overlap with the case 71.

[0074] In this embodiment, the conductive layer 83, including the ground plane 95, is spaced apart from the portion of the base layer 81 that overlaps with the pad 91C. Furthermore, the conductive layer 83 is spaced apart not only from the pad 91C, but also from the portion of the base layer 81 that overlaps with the pad 91 that transmits read or write signals. In other words, the conductive layer 83 in this embodiment does not overlap with the pad 91 that transmits read or write signals. Note that the conductive layer 83 is not limited to this example.

[0075] As shown in Figure 5, the cover layer 84 covers the first surface 81a of the base layer 81 and the wiring 92 of the conductive layer 82. The cover layer 85 covers the second surface 81b of the base layer 81 and the conductive layer 83. Therefore, the base layer 81 and the conductive layers 82 and 83 are located between the two cover layers 84 and 85.

[0076] The adhesive layers 86 and 87 are, for example, epoxy adhesives. However, the adhesive layers 86 and 87 may also be adhesives made of other resins, such as acrylic adhesives. Adhesive layer 86 adheres the cover layer 84 to the first surface 81a and the wiring 92. Adhesive layer 87 adheres the cover layer 85 to the second surface 81b and the conductive layer 83.

[0077] Multiple through-holes are provided in the cover layer 84 and the adhesive layer 86. The cover layer 84 and the adhesive layer 86 expose multiple pads 91 to the outside of the FPC 37 through these through-holes. As a result, the joint portion 75 of the pin 72 can be joined to the pads 91 by solder S. The cover layer 85 is bonded to the reinforcing plate 67, for example, by adhesive.

[0078] The ground plane 95 of the conductive layer 83 has a plurality of mesh portions 100. Each of the plurality of mesh portions 100 is a part of the ground plane 95 and is meshed. That is, each of the plurality of mesh portions 100 is provided with a plurality of through holes 101. Each of the plurality of through holes 101 penetrates the ground plane 95 in approximately the Z direction. As shown in Figure 4, each of the plurality of through holes 101 is approximately rhomboid. Note that the through holes 101 may have other shapes, or may have shapes different from each other.

[0079] The multiple mesh sections 100 include, for example, multiple mesh sections 100A, 100B, and 100C. Mesh section 100A is an example of a first section. Mesh section 100B is an example of a second and third section. Mesh section 100C is an example of a second and fourth section.

[0080] The mesh portion 100A is the part of the ground plane 95 that overlaps with the pad 91A via the base layer 81. That is, the contour of the mesh portion 100A is approximately equal to the contour of the pad 91A. For this reason, the width of the mesh portion 100A along the first surface 81a is greater than the width of the wiring 92A along the first surface 81a. Multiple through holes 101 are provided in the mesh portion 100A. Multiple through holes 101 in the mesh portion 100A are an example of multiple first through holes.

[0081] The mesh portion 100B is the part of the ground plane 95 that overlaps with the pad 91B via the base layer 81. Therefore, the mesh portion 100B is also the part of the ground plane 95 that is spaced apart from the mesh portion 100A. Multiple through holes 101 are provided in the mesh portion 100B. The multiple through holes 101 in the mesh portion 100B are an example of multiple second through holes and multiple third through holes.

[0082] The multiple mesh sections 100 include not only mesh sections 100A and 100B, but also multiple portions of the ground plane 95 that overlap the pads 91 via the base layer 81. In this embodiment, all of the multiple pads 91 that overlap the ground plane 95 via the base layer 81 overlap the through holes 101 via the base layer 81. Note that at least a portion of the ground plane 95 that overlaps the pads 91 via the base layer 81 does not have to be a mesh section 100.

[0083] The mesh portion 100C is the part of the ground plane 95 that overlaps with the wiring 92B via the base layer 81. Therefore, the mesh portion 100C is also the part of the ground plane 95 that is spaced apart from the mesh portion 100A. Multiple through holes 101 are provided in the mesh portion 100C. The multiple through holes 101 in the mesh portion 100C are an example of multiple second through holes and multiple fourth through holes.

[0084] As shown in Figure 5, the adhesive layer 87 adheres to the second surface 81b of the base layer 81 through the multiple through holes 101. That is, the adhesive layer 87 adheres to the second surface 81b of the base layer 81 through the multiple through holes 101 of each of the mesh portions 100A, 100B, and 100C. In this case, the adhesive layer 87 is provided inside each of the multiple through holes 101 and on the second surface 81b of the base layer 81. In this embodiment, the adhesive layer 87 fills the inside of the multiple through holes 101.

[0085] The adhesive layer 87 adheres to the surface 95a of the ground plane 95 and to the inner surface 95b of the ground plane 95 that defines the through-holes 101. However, the adhesive layer 87, made of a resin such as epoxy, is less likely to form a chemical bond with the ground plane 95, which is made of a metal such as copper, compared to when it adheres to a resin. For this reason, the adhesive layer 87 adheres weakly to the surface 95a and inner surface 95b of the ground plane 95.

[0086] On the other hand, the adhesive layer 87 readily forms a chemical bond with the base layer 81, which is made of a resin such as PI. As a result, the adhesive layer 87 can be firmly bonded to the second surface 81b of the base layer 81.

[0087] Furthermore, as the adhesive layer 87 adheres to the inner surface 95b that defines the multiple through holes 101, a large contact area is provided between the adhesive layer 87 and the ground plane 95. In addition, because the adhesive layer 87 penetrates into the multiple through holes 101, an anchoring effect is generated. As a result, the overall adhesive strength between the adhesive layer 87 and the ground plane 95 is improved.

[0088] As described above, the adhesive layer 87 can adhere relatively strongly to the ground plane 95 and holds the ground plane 95 to the second surface 81b of the base layer 81 through the through holes 101. As a result, the ground plane 95 is difficult to peel off from the adhesive layer 87 and also difficult to peel off from the second surface 81b of the base layer 81.

[0089] In this embodiment, multiple mesh sections 100 of the ground plane 95 are meshed and provided with multiple through holes 101. On the other hand, other parts of the ground plane 95 are not meshed. However, other parts of the ground plane 95 may be meshed, or the entire ground plane 95 may be meshed.

[0090] The relay connector 65 may experience mounting misalignment, for example, when it is mounted on the FPC 37 or connected to the relay device 66. This mounting misalignment may generate a moment (torque) around the center C in Figure 4 in the relay connector 65. The center C is, for example, a virtual axis of rotation extending approximately in the Z direction. That is, a moment may be generated in the relay connector 65 in a direction along the first surface 81a of the base layer 81. Furthermore, warping of the FPC 37 and the relay connector 65 may also generate a moment around the center C in the relay connector 65.

[0091] The relay connector 65 generates a moment around the center C, thereby acting a force around the center C on the FPC 37 via solder S from, for example, pin 72. Pins 72 located at the ends of rows L1 and L2 are further from the center C than the other pins 72. As a result, a relatively large force acts from, for example, pin 72A on the FPC 37 near pad 91A.

[0092] A force around the center C generates torsional stress in the adhesive portion between the second surface 81b of the base layer 81 and the ground plane 95. If the adhesive force between the second surface 81b and the ground plane 95 is weak, the ground plane 95 may peel off from the second surface 81b due to this torsional stress. However, the adhesive layer 87 of this embodiment firmly holds the ground plane 95 to the second surface 81b.

[0093] Furthermore, the adhesive layer 87 adheres to the second surface 81b through the multiple through holes 101. In this case, the adhesive layer 87 is provided inside each of the multiple through holes 101 and on the second surface 81b of the base layer 81. The adhesive layer 87 adheres to the inner surface 95b of each of the multiple through holes 101. Therefore, the adhesive layer 87 supports the inner surface 95b of the ground plane 95 that defines the through holes 101, and restricts the movement of the ground plane 95 relative to the second surface 81b in the direction along the second surface 81b (X direction and Y direction). As a result, the FPC 37 of this embodiment can prevent the ground plane 95 from peeling off from the second surface 81b.

[0094] Furthermore, during the manufacturing of the FPC37, the cover layer 85 and the adhesive layer 87 may contain moisture. This moisture may expand when heated in the furnace during solder reflow, for example, and could cause the ground plane 95 to peel off from the second surface 81b. However, the ground plane 95 of this embodiment can facilitate the discharge of this moisture.

[0095] For example, the ground plane 95 does not overlap with the case 71 and pad 91C of the relay connector 65. In addition, the ground plane 95 is provided with multiple through holes 101. As a result, moisture from the cover layer 85 and adhesive layer 87 can be discharged from the FPC 37 through the through holes 101 and the parts that do not overlap with the case 71 and pad 91C. Therefore, the FPC 37 of this embodiment can prevent the ground plane 95 from peeling off from the second surface 81b due to moisture.

[0096] The following is an example of a method for mounting the relay connector 65 to the FPC 37. Note that the method for mounting the relay connector 65 to the FPC 37 is not limited to the method described below, and other methods may be used. First, solder paste (solder S) is supplied to a plurality of pads 91, for example, by printing or coating.

[0097] Next, the relay connector 65 is mounted on multiple pads 91. The reinforcing plate 67 supports the relay connector 65 via the FPC 37, thereby suppressing deformation of the FPC 37 during mounting.

[0098] Next, the FPC 37 is heated in a reflow oven, and the solder paste melts. This joins the joint 75 of the pin 72 to the pad 91. At this time, flux mixed with the solder S or supplied separately may leak out of the solder S.

[0099] Next, the FPC37 is cleaned, for example, by ultrasonic cleaning. For example, the FPC37 is placed in a tank filled with cleaning solution. The cleaning solution flows through the gap G between the FPC37 and the case 71 of the relay connector 65, and can remove substances that may contaminate the HDD10, such as flux.

[0100] The ground plane 95 overlaps with at least one of the multiple pads 91. Therefore, the ground plane 95 can prevent the pads 91 from sinking so that the case 71 moves closer to the FPC 37. Thus, the gap G is kept relatively large, and the cleaning fluid can easily flow through the gap G.

[0101] For example, the cleaning solution transmits ultrasonic waves. These ultrasonic waves lift the flux present in the gap G away from the FPC 37. Subsequently, the FPC 37 is removed from the cleaning solution. At this time, the cleaning solution, along with the flux, is discharged from the gap G. With this, the mounting of the relay connector 65 to the FPC 37 is completed.

[0102] In the HDD 10 according to the first embodiment described above, the magnetic head 48 is configured to read and write information to the magnetic disk 12. The FPC 37 is electrically connected to the magnetic head 48. The relay connector 65 is mounted on the FPC 37. The FPC 37 has a base layer 81, conductive layers 82, 83, a cover layer 85, and an adhesive layer 87. The conductive layer 82 is provided on the first surface 81a of the base layer 81. The conductive layer 83 is provided on the second surface 81b of the base layer 81, which is located on the opposite side of the first surface 81a. The cover layer 85 covers the second surface 81b and the conductive layer 83. The adhesive layer 87 adheres the cover layer 85 to the second surface 81b and the conductive layer 83. The conductive layer 82 has a pad 91A. A plurality of through holes 101 are provided in the mesh portion 100A of the conductive layer 83 that overlaps the pad 91A via the base layer 81. The adhesive layer 87 adheres to the second surface 81b through a plurality of through holes 101. The relay connector 65 has pins 72A bonded to the pad 91A.

[0103] Generally, the metal material for the conductive layers 82 and 83 and the resin material for the base layer 81, cover layers 84 and 85, and adhesive layers 86 and 87 do not form chemical bonds as easily as when two resins adhere to each other, resulting in weaker adhesion. For example, when the relay connector 65 generates a moment on the surface of the FPC 37 that causes it to rotate (twist) relative to the FPC 37, a force acts near the pad 91A of the FPC 37 in a direction along the surface. This force also acts on the adhesive portion between the second surface 81b of the base layer 81 and the conductive layer 83. However, in this embodiment, the adhesive layer 87 adheres to the second surface 81b through a plurality of through holes 101 provided in the conductive layer 83. Therefore, the adhesive layer 87 can hold the conductive layer 83 to the second surface 81b more firmly than if it simply adhered to the second surface 81b around the conductive layer 83. Therefore, the FPC 37 can prevent the conductive layer 83 from peeling off from the second surface 81b due to the above force. In addition, during the manufacturing of the FPC 37, moisture mixed inside the cover layer 85 and adhesive layer 87 can be released to the outside through the through hole 101. Therefore, the FPC 37 can prevent the conductive layer 83 from peeling off from the second surface 81b due to the above moisture. As described above, the HDD 10 of this embodiment can improve the reliability of the FPC 37.

[0104] Multiple through-holes 101 are provided in the mesh portion 100B of the conductive layer 83 that is separated from the mesh portion 100A. The adhesive layer 87 adheres to the second surface 81b through the multiple through-holes 101. That is, the adhesive layer 87 can more firmly hold not only the vicinity of the pad 91A but also other parts of the conductive layer 83 to the second surface 81b. Therefore, the FPC 37 can suppress the peeling of the conductive layer 83 from the second surface 81b.

[0105] The conductive layer 83 has a ground plane 95. The ground plane 95 has a mesh portion 100A. Specifically, multiple through holes 101 are provided in the portion of the ground plane 95 that overlaps with the pad 91A via the base layer 81. The adhesive layer 87 adheres to the second surface 81b through the multiple through holes 101, thereby more firmly holding the ground plane 95 to the second surface 81b. Therefore, in this embodiment, the HDD 10 can provide the ground plane 95 over a wider area of ​​the second surface 81b, and consequently improve transmission characteristics such as the impedance of the conductive layer 82.

[0106] The conductive layer 82 has a pad 91B. Multiple through holes 101 are provided in the mesh portion 100B of the ground plane 95 that overlaps with the pad 91B via the base layer 81. The adhesive layer 87 adheres to the second surface 81b through the multiple through holes 101. The relay connector 65 has a pin 72B joined to the pad 91B. That is, the adhesive layer 87 can hold the portion of one ground plane 95 near the pad 91A on the second surface 81b through the through holes 101, and can also hold the portion of the same ground plane 95 near the pad 91B on the second surface 81b through the through holes 101. By holding the ground plane 95 on the second surface 81b at multiple positions, the adhesive layer 87 can more reliably suppress the ground plane 95 from peeling off the second surface 81b. Therefore, in this embodiment, the HDD 10 can provide the ground plane 95 over a wider area of ​​the second surface 81b.

[0107] The conductive layer 82 has wiring 92B. Multiple through holes 101 are provided in the mesh portion 100C of the ground plane 95 that overlaps with the wiring 92B via the base layer 81. The adhesive layer 87 adheres to the second surface 81b through the multiple through holes 101. That is, the adhesive layer 87 can hold the portion of one ground plane 95 near the pad 91A to the second surface 81b through the through holes 101, and can also hold the portion of the same ground plane 95 near the wiring 92B to the second surface 81b through the through holes 101. By holding the ground plane 95 to the second surface 81b at multiple positions, the adhesive layer 87 can more reliably suppress the peeling of the ground plane 95 from the second surface 81b. Therefore, in this embodiment, the HDD 10 can provide the ground plane 95 over a wider area of ​​the second surface 81b.

[0108] The housing 11 houses the magnetic disk 12, magnetic head 48, FPC 37, and relay connector 65. The PCB 17 is located outside the housing 11. The relay connector 53 is mounted on the PCB 17. The relay device 66 is provided in the housing 11 and is electrically connected to the relay connector 53. The relay connector 65 is electrically connected to the relay device 66. The PCB 17 is electrically connected to the FPC 37 through the relay connector 53, the relay device 66, and the relay connector 65. For example, when the relay connector 65 is connected to the relay device 66, if the relay connector 65 generates a moment on the surface of the FPC 37 that causes it to rotate (twist) relative to the FPC 37, a force acts in the vicinity of the pad 91A of the FPC 37 in a direction along the surface. However, as described above, the FPC 37 of this embodiment can suppress the peeling of the conductive layer 83 from the second surface 81b due to this force.

[0109] The relay connector 65 has a case 71 and a plurality of pins 72 that protrude from the case 71 and are arranged to form a row L1. Pin 72A is included in the plurality of pins 72 and is located at the end of row L1. For example, if the relay connector 65 generates a moment on the surface of the FPC 37 that causes it to rotate (twist) relative to the FPC 37, the displacement of the pin 72A at the end of the row will be greater than the displacement of the other pins in the center of the row. As a result, a large force acts near the pad 91A of the FPC 37. However, as described above, the FPC 37 of this embodiment can suppress the peeling of the conductive layer 83 from the second surface 81b due to this force.

[0110] The HDD 10 of this embodiment has, for example, 10 or more magnetic disks 12. In this case, the number of HGA 36s increases, and the number of pins 72 on the relay connector 65 increases. The number of pins 72 also increases due to the increased functionality of the HDD 10. When the number of pins 72 increases, the distance between the center and the end pins 72A of the relay connector 65 increases, and the displacement of the pins 72A becomes greater. However, as described above, the FPC 37 of this embodiment can suppress the delamination of the conductive layer 83 from the second surface 81b in the vicinity of the pins 72A and pads 91A.

[0111] The conductive layer 82 has a pad 91C. The conductive layer 83 is spaced apart from the portion of the base layer 81 that overlaps with the pad 91C. The relay connector 65 has a pin 72C bonded to the pad 91C. The relay connector 65 is electrically connected to the magnetic head 48 and outputs a write signal corresponding to the information that the magnetic head 48 writes to the magnetic disk 12 from the pin 72C to the magnetic head 48, or inputs a read signal corresponding to the information that the magnetic head 48 reads from the magnetic disk 12 to the pin 72C. In other words, the conductive layer 83 does not cover the pad 91C through which the write signal or read signal is transmitted. As a result, the HDD 10 of this embodiment can suppress the conductive layer 83 from affecting the transmission of the write signal or read signal. Furthermore, during the manufacturing of the FPC 37, moisture mixed inside the cover layer 85 and adhesive layer 87 can be released to the outside through the portion of the base layer 81 that is not covered by the conductive layer 83. Therefore, the FPC37 can prevent the conductive layer 83 from peeling off from the second surface 81b due to the above-mentioned moisture.

[0112] The relay connector 65 has a case 71. Pins 72A protrude from the case 71. The conductive layer 83 has a ground plane 95 spaced apart from the portion of the base layer 81 that overlaps with the case 71. That is, the ground plane 95 does not cover the case 71. As a result, during the manufacturing of the FPC 37, moisture mixed inside the cover layer 85 and adhesive layer 87 can be released to the outside through the portion of the base layer 81 that is not covered by the ground plane 95. Therefore, the FPC 37 can prevent the conductive layer 83 from peeling off from the second surface 81b due to the moisture.

[0113] (Second embodiment) A second embodiment will be described below with reference to Figure 6. In the following description of the embodiments, components having the same function as those already described will be denoted by the same reference numerals as those previously described, and their description may be omitted. Furthermore, multiple components denoted by the same reference numerals do not necessarily share all functions and properties, and may have different functions and properties depending on the embodiment.

[0114] Figure 6 is an exemplary cross-sectional view schematically showing a part of the HDD 10 according to the second embodiment. As shown in Figure 6, the conductive layer 82 of the second embodiment has at least one mesh portion 200. The mesh portion 200 is a portion of the conductive layer 82 spaced apart from the pads 91. For example, the mesh portion 200 is a ground plane. The mesh portion 200 may be other portions such as wiring 92.

[0115] The mesh portion 200 is meshed. That is, the mesh portion 200 is provided with a plurality of through holes 201. The plurality of through holes 201 is an example of a plurality of fifth through holes. Each of the plurality of through holes 201 penetrates the mesh portion 200 in approximately the Z direction.

[0116] The adhesive layer 86 adheres to the first surface 81a of the base layer 81 through multiple through holes 201. The adhesive layer 87 also adheres to the surface 82a of the conductive layer 82 and the inner surface 82b of the conductive layer 82 that defines the through holes 201.

[0117] Similar to adhesive layer 87, adhesive layer 86 weakly adheres to the surface 82a and inner surface 82b of conductive layer 82, while firmly adhering to the first surface 81a of base layer 81. Furthermore, because adhesive layer 86 adheres to multiple inner surfaces 82b, a large contact area is provided between adhesive layer 86 and conductive layer 82. In addition, since adhesive layer 86 penetrates into multiple through holes 201, an anchoring effect is generated. As a result, the overall adhesive strength between adhesive layer 86 and conductive layer 82 is improved.

[0118] In this embodiment, at least one mesh portion 200 of the conductive layer 82 is meshed and provided with a plurality of through holes 201. On the other hand, the other parts of the conductive layer 82 are not meshed. However, the other parts of the conductive layer 82 may be meshed, or the entire conductive layer 82 may be meshed.

[0119] In the HDD 10 of the second embodiment described above, the FPC 37 has a cover layer 84 and an adhesive layer 86. The cover layer 84 covers the first surface 81a and a part of the conductive layer 82. The adhesive layer 86 adheres the cover layer 84 to the first surface 81a and the conductive layer 82. Multiple through holes 201 are provided in the mesh portion 200 of the conductive layer 82 that is spaced apart from the pad 91A. The adhesive layer 86 adheres to the first surface 81a through the multiple through holes 201. Therefore, the adhesive layer 86 can hold the conductive layer 82 to the first surface 81a more firmly than if it were simply adhered to the first surface 81a around the conductive layer 82. Accordingly, the FPC 37 can suppress the conductive layer 82 from peeling off from the first surface 81a. Furthermore, during the manufacturing of the FPC 37, moisture mixed inside the base layer 81, cover layer 85, and adhesive layer 87 can be released to the outside through the through holes 201. Therefore, the FPC 37 can prevent the conductive layer 82 from peeling off from the first surface 81a due to the above-mentioned moisture. As a result, the HDD 10 of this embodiment can improve the reliability of the FPC 37.

[0120] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0121] 10...Hard disk drive (HDD), 11...Enclosure, 12...Magnetic disk, 17...Printed circuit board (PCB), 37...Flexible printed circuit board (FPC), 48...Magnetic head, 53, 65...Intermediate connector, 66...Intermediate device, 71...Case, 72, 72A, 72B, 72C...Pins, 81...Base layer, 81a...First surface, 81b...Second surface, 82, 83...Conductive layer, 84, 85...Cover layer, 86, 87...Adhesive layer, 91, 91A, 91B, 91C...Pads, 92, 92A, 92B...Wiring, 95...Ground plane, 100, 100A, 100B, 100C, 200...Mesh section, 101, 201...Through-hole, L1...Row, S...Solder.

Claims

1. Magnetic disks and A magnetic head configured to read and write information to the magnetic disk, A flexible printed circuit board electrically connected to the magnetic head, Electronic components mounted on the aforementioned flexible printed circuit board, It is equipped with, The flexible printed circuit board comprises a first insulating layer, a first conductive layer provided on a first surface of the first insulating layer, a second conductive layer provided on a second surface of the first insulating layer located opposite the first surface, a second insulating layer covering the second surface and the second conductive layer, and a first adhesive layer adhering the second insulating layer to the second surface and the second conductive layer. The first conductive layer has a first land, A plurality of first through holes are provided in the first portion of the second conductive layer that overlaps the first land via the first insulating layer. The first adhesive layer adheres to the second surface through the plurality of first through holes, The electronic component has a first pin bonded to the first land. Disk drive.

2. A plurality of second through holes are provided in the second portion of the second conductive layer that is spaced apart from the first portion. The first adhesive layer adheres to the second surface through the plurality of second through holes. The disk device according to claim 1.

3. The second conductive layer described above has a ground plane, The ground plane has the first portion, The disk device according to claim 1.

4. The first conductive layer has a second land, A third portion of the ground plane that overlaps with the second land via the first insulating layer is provided with a plurality of third through holes. The first adhesive layer adheres to the second surface through the plurality of third through holes, The electronic component has a second pin bonded to the second land. The disk device according to claim 3.

5. The first conductive layer has a first wiring, A plurality of fourth through-holes are provided in the fourth portion of the ground plane that overlaps with the first wiring via the first insulating layer. The first adhesive layer adheres to the second surface through the plurality of fourth through holes. The disk device according to claim 3.

6. The flexible printed circuit board includes a third insulating layer that covers the first surface and a portion of the first conductive layer, and a second adhesive layer that adheres the third insulating layer to the first surface and the first conductive layer. A plurality of fifth through holes are provided in the portion of the first conductive layer that is spaced apart from the first land. The second adhesive layer adheres to the first surface through the plurality of fifth through holes. The disk device according to claim 1.

7. The magnetic disk, the magnetic head, the flexible printed circuit board, and the housing that houses the electronic components, A circuit board located outside the aforementioned housing, A first connector mounted on the aforementioned circuit board, A relay device provided in the housing and electrically connected to the first connector, Furthermore, it is equipped with, The electronic component has a second connector electrically connected to the relay device. The disk device according to claim 1.

8. The aforementioned electronic component has an insulating member and a plurality of pins that protrude from the insulating member and are arranged to form a row, The first pin is included in the plurality of pins and is located at the end of the row. The disk device according to claim 1.

9. The first conductive layer has a third land, The second conductive layer is spaced apart from the portion of the first insulating layer that overlaps with the third land. The electronic component has a third pin bonded to the third land, is electrically connected to the magnetic head, outputs a write signal from the third pin to the magnetic head corresponding to information written by the magnetic head to the magnetic disk, or receives a read signal from the magnetic head to the third pin corresponding to information read by the magnetic head from the magnetic disk. The disk device according to claim 1.

10. The aforementioned electronic component has an insulating member, The first pin protrudes from the insulating member, The second conductive layer has a ground plane spaced apart from the portion of the first insulating layer that overlaps with the insulating member. The disk device according to claim 1.

11. The first conductive layer has a second wiring connected to the first land, The width of the first portion along the first surface is greater than the width of the second wiring along the first surface. The disk device according to claim 1.

Images