Flexible printed circuit offset finger reinforcement

Abstract

The present invention is entitled "Flexible Printed Circuit Offset Finger Reinforcement". A hard disk drive flexible printed circuit (FPC) is disclosed that includes a plurality of fingers extending from a main portion, wherein each finger has a thermally conductive reinforcement, at least one wiring layer on the reinforcement, and a cover film over the at least one wiring layer, wherein a centroid of the reinforcement is offset from a centerline of the cover film. Thus, using the heat dissipation properties of the reinforcement, the temperature difference between the upper and lower electrical pads of the FPC resulting from a thermal-based interconnection process can be reduced, and the temperature on the FPC fingers becomes more uniform, damage to the FPC is prevented, and solder yield is improved.

Description

Technical Field

[0001] Embodiments of the present invention may generally relate to hard disk drives, and more specifically to a method for providing substantially uniform temperature across a flexible printed circuit (FPC) electrical pad during interconnection processes. Background Technology

[0002] A hard disk drive (HDD) is a non-volatile storage device housed in a protective casing that stores digitally encoded data on one or more disks with magnetic surfaces. When an HDD is in operation, each magnetic recording disk is rapidly rotated by a spindle system. Read / write heads (or "transducers") positioned above specific locations on the disk by actuators read data from and write data to the magnetic recording disk. The read / write heads use magnetic fields to write data onto and read data from the surface of the magnetic recording disk. The write head operates by utilizing current flowing through its coils, thereby generating a magnetic field. Electrical pulses are sent to the write head in different modes of positive and negative current. The current in the coils of the write head generates a localized magnetic field in the gap between the head and the disk, which in turn magnetizes a small area on the recording medium.

[0003] To write data to or read data from a medium, the read / write head must receive instructions from the controller. Therefore, the head is electrically connected to the controller in some way so that it not only receives instructions to read / write data, but can also send information back to the controller about the data read and / or written. Typically, flexible printed circuits (FPCs) are used to electrically transmit signals from the read / write head to other electronics within the HDD via a tail. The FPC and tail are usually located in the comb or "E-block" section of the head stack assembly (HSA) (see, for example...). Figure 1 The components are welded together at the carriage 134. To connect them to the solder, the suspension electrical pads and FPC electrical pads are heated. If the soldering temperature is too low, the solder may not melt, while if the soldering temperature is too high, these components may be damaged by heat. Therefore, it is desirable to heat these components evenly to avoid significant temperature differences between the various pads. Otherwise, the corresponding electrical interconnects may be damaged, which could lead to impaired data flow to / from the read / write head.

[0004] Any method described in this section is a feasible method, but not necessarily one that has been previously conceived or implemented. Therefore, unless otherwise stated, no method described in this section should be considered prior art simply because it is included in this section. Attached Figure Description

[0005] The embodiments are illustrated in the accompanying drawings by way of example rather than limitation, in which the same reference numerals refer to similar elements and wherein:

[0006] Figure 1This is a plan view of a hard disk drive according to one embodiment;

[0007] Figure 2A This is a perspective view showing the actuator assembly according to one embodiment;

[0008] Figure 2B This is a perspective view illustrating the electrical interconnection between the overhang and the flexible printed circuit (FPC) according to one embodiment;

[0009] Figure 2C It is a floor plan of the FPC according to one implementation scheme;

[0010] Figure 2D It is based on an implementation plan illustration Figure 2C A cross-sectional view of the FPC;

[0011] Figure 3A It is a plan view showing a symmetrical FPC reinforcement according to one embodiment;

[0012] Figure 3B This is a plan view showing an offset FPC reinforcement according to one embodiment;

[0013] Figure 4 This is a plan view showing an offset FPC reinforcement according to one embodiment;

[0014] Figure 5A This is a perspective view showing an asymmetric FPC reinforcement according to one embodiment;

[0015] Figure 5B It is based on an implementation plan illustration Figure 5A A plan view of an asymmetric FPC reinforcement;

[0016] Figure 6 This is a perspective view showing an asymmetric FPC reinforcement according to one embodiment;

[0017] Figure 7 This is a perspective view illustrating an asymmetric FPC reinforcement according to one embodiment; and

[0018] Figure 8 This is a flowchart illustrating a method for manufacturing a flexible printed circuit (FPC) laminate composition according to one embodiment. Detailed Implementation

[0019] Generally, methods for providing substantially uniform temperature across the electrical pads of a flexible printed circuit (FPC) during interconnection processes are described. In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of the embodiments of the invention described herein. However, it will be apparent, however, that the embodiments of the invention described herein can be practiced without these specific details. In other instances, well-known structures and devices may be shown in block diagram form in order to avoid unnecessarily obscuring the embodiments of the invention described herein.

[0020] introduction

[0021] the term

[0022] References to "implementation," "an embodiment," etc., herein are intended to mean that a particular feature, structure, or characteristic described is included in at least one embodiment of the invention. However, instances of such phrases do not necessarily refer to the same embodiment.

[0023] The term "substantially" should be understood as describing features that are mostly or nearly structured, constructed, or dimensionally defined, but in practice, manufacturing tolerances and other factors may cause the structure, configuration, dimensions, etc., to not always or necessarily be as precise as described. For example, describing a structure as "substantially vertical" would give the term its general meaning, implying that the sidewalls are vertical for all practical purposes, but may not be precisely at 90 degrees throughout.

[0024] While terms such as “optimal,” “minimum,” “maximum,” “maximize” may not have certain values ​​associated with them, if used herein, it is intended that those skilled in the art will understand that such terms will encompass values, parameters, measures, etc., that influence in a beneficial direction consistent with the whole of this disclosure. For example, describing the value of something as “minimum” does not require that the value is actually equal to some theoretical minimum (e.g., zero), but should be understood in a practical sense as the corresponding objective being to move that value toward the theoretical minimum in a beneficial direction.

[0025] Context

[0026] At the far end of the suspension, there is a read / write transducer (or "head") for reading and writing data. At the other near end of the suspension, there is a conductive pad (or simply "electrical pad") for electrical connection to a corresponding conductive pad on the flexible printed circuit (FPC). The suspension pad and the FPC pad are typically electrically interconnected with solder (or orthogonal in this case).

[0027] Figure 2AThis is a perspective view illustrating an actuator assembly according to one embodiment. The actuator assembly 200 includes a carriage 201 (see, for example...). Figure 1 The carriage 134 is connected by a pivot bearing assembly (not shown here; see example...) Figure 1 The pivot bearing assembly 152) and the central pivot (not shown here; see example) Figure 1 The actuator assembly 200 is rotatably coupled to a pivot 148 and is rotatably driven by a voice coil motor (VCM) (its voice coil 204 is shown here). The actuator assembly 200 also includes one or more actuator arms 206 (see, for example...). Figure 1 Each actuator arm of the actuator arm is coupled to a suspension assembly 208 (see, for example, arm 132). Figure 1 The lead wire suspension 110c), which houses the read / write head 210 (see, for example...) Figure 1 The read / write head 110a typically includes a forged substrate 208a and a load beam 208b (see example...). Figure 1 The load beam 110d and the tail 208c. Each suspension assembly 208 is electrically connected via the tail 208c to a flexible printed circuit (FPC) 212 coupled to the same carriage 201.

[0028] Figure 2B This is a perspective view illustrating the electrical interconnection between the overhang and the flexible printed circuit (FPC) according to one embodiment. Figure 2B The cantilever 208c is depicted as being mechanically and electrically coupled to the corresponding FPC finger 212a of FPC 212 via solder 211 (or some other electrical connection device). Figure 2A The suspended end 208e of the FPC 212 is electrically connected to the electrical pad 212d of the FPC 212. To recap, by welding and other similar joining techniques, the suspended electrical pad and the FPC electrical pad are heated, and if the welding temperature is too low, the solder may not melt, and if the welding temperature is too high, the FPC may be damaged by heat. Typically, solder reflow, hot air, or lasers can be used to heat the materials in the welding process.

[0029] Various situations may arise that lead to an asymmetrical configuration between the upper electrical pad 212d and its corresponding trace and the lower electrical pad 212d and its corresponding trace, which could result in a significant temperature difference between the upper and lower portions of the FPC finger 212a. For a non-limiting example, in a scenario using a common head slider for both the upper and lower read / write heads, this could cause the head pad layout to be flipped rather than mirrored as with mirrored upper and lower heads, and the corresponding pad layout of the FPC 212, as well as the trace wiring layout of the FPC finger 212a, would not be mirrored between the upper electrical pad 212d and its corresponding trace and the lower electrical pad 212d and its corresponding trace. Therefore, the temperature difference between some pairs of upper and lower pads 212d (e.g., manifested as a temperature difference between the upper and lower portions of the FPC finger 212a) and along one or two rows of pads 212d could become significant enough to affect one or more electrical interconnects and / or the FPC laminate (see, for example...). Figure 2D The degree of harm. Therefore, it is desirable to heat these components evenly to avoid significant temperature differences between the various pads.

[0030] Figure 2C This is a plan view illustrating a flexible printed circuit according to one embodiment. Here, FPC 212 includes a plurality of FPC fingers 212a, each FPC finger including a plurality of electrical pads 212d on each of its upper and lower sides. Each FPC finger 212a typically serves both an upper head (a read / write head facing upwards to serve the bottom surface of the corresponding disk) and a lower head (a read / write head facing downwards to serve the top surface of the same disk), with each corresponding upper and lower head electrically connected to a preamplifier 220 (or further) mounted on FPC 212. The cross-section of the FPC finger 212a is labeled AA.

[0031] Figure 2D It is based on an implementation plan illustration Figure 2C A cross-sectional view of the FPC. Cross-sectional view AA depicts the layers of an FPC such as FPC 212, including a base film 254 (e.g., a polyimide insulating layer) inserted between a top first wiring layer 252 (e.g., including copper traces) and a bottom second wiring layer 256 (e.g., including copper traces). The first wiring layer 252 is covered by a first cover film 250 (e.g., a polyimide insulating layer), and the second wiring layer 256 is covered by a second cover film 258 (e.g., a polyimide insulating layer). Finally, all the aforementioned layers are coupled to and supported by a bottom reinforcing layer 260 (e.g., including aluminum, or some other rigid and durable material). The precise layout of FPC 212 can vary depending on the specific implementation, therefore Figure 2DThe layout is presented as an example. However, the techniques described herein are broadly applicable to alternative FPC layouts that have a metal (or other thermally conductive material) reinforcement layer 260 (or simply "reinforcement 260") beneath the wiring trace layer.

[0032] Offset reinforcement for flexible printed circuit finger components

[0033] Figure 3A This is a plan view illustrating a symmetrical FPC reinforcement according to one embodiment. Here, the FPC finger 312a includes a reinforcement 360 symmetrical to the corresponding cover film 350, as depicted by a single centerline representing the superposition of the centerline 355 of the cover film 350 and the centerline 365 of the reinforcement 360. As described elsewhere herein, the electrical pad 212d ( Figures 2B-2C Some of them are related to FPC finger 212a ( Figure 2B , Figure 2C Significant and undesirable temperature differences may exist between the corresponding traces on the upper portion of the FPC finger 212a and some of the electrical pads 212d and their corresponding traces on the lower portion of the FPC finger 212a, especially in non-limiting scenarios where the FPC finger 212a pad layout differs for the upper and lower heads. Significant and undesirable temperature differences may also exist between some of the electrical pads 212d in any row of pads serving the corresponding upper or lower head.

[0034] Figure 3B This is a plan view showing an offset FPC reinforcement according to one embodiment. According to this embodiment, in order to facilitate the use of FPC 212 (… Figures 2A-2D Different electrical pads (e.g., electrical pad 212d) Figures 2B-2C To improve temperature uniformity between the top and bottom electrical pads 322a, the reinforcement 370 of the FPC finger 322a is displaced or offset from the centerline of the cover film 350. In other words, the reinforcement 370 is formed and positioned asymmetrically relative to the cover film 350, as depicted by the fact that the centerline 355 of the cover film 350 no longer overlaps with the centerline 375 of the reinforcement 370. Therefore, since the thermally conductive reinforcement, such as the reinforcement 370, inherently acts as a heat sink, the amount and location of heat transferred to the reinforcement 370 on the top or upper side of the FPC finger 322a differs from that on the bottom or lower side of the FPC finger 322a (e.g., during the interconnect soldering process with the overhang end 208e). That is, due to the downward displacement of the reinforcement 370, the lower electrical pad 212d becomes hotter. Therefore, the overall temperature gradient between the top and bottom electrical pads 212d can be reduced, and the temperature across the FPC finger 322a is generally more uniform.

[0035] Return to reference Figure 3AIt should be noted that for the FPC finger 312a with symmetrical reinforcement 360, the gap distance (d1) between the top edge 361 of the reinforcement 360 and the top edge 351 of the cover film 350 is the same as the gap distance (d1) between the bottom edge 362 of the reinforcement 360 and the bottom edge 352 of the cover film 350. In contrast, reference... Figure 3B It should be noted that for the FPC finger 322a with offset reinforcement 370, the gap distance (d2) between the top edge 371 of reinforcement 370 and the top edge 351 of cover film 350 is greater than the gap distance (d3) between the bottom edge 372 of reinforcement 370 and the bottom edge 352 of cover film 350.

[0036] It should also be noted that, for Figure 3A The symmetrical reinforcement 360 has its top edge 361 parallel to the top edge 351 of the cover film 350, and its bottom edge 362 is also parallel to the bottom edge 352 of the cover film 350. In a sense, the outline of the reinforcement 360 is "nested" within the outline of the cover film 350. Similarly, for Figure 3B The asymmetric reinforcement 370 has a top edge 371 parallel to the top edge 351 of the cover film 350, and a bottom edge 372 of the reinforcement 370 is also parallel to the bottom edge 352 of the cover film 350.

[0037] Figure 4 This is a front view showing an offset FPC reinforcement according to one embodiment. According to this embodiment, in order to facilitate the use of FPC 212 (… Figures 2A-2D Different electrical pads (e.g., electrical pad 212d) Figures 2B-2C To improve temperature uniformity between the two parts, the top edges 471 of the reinforcement 470 of the FPC finger 412a and the top edges 351 of the cover film 350 of the FPC finger 412a are intentionally shaped to converge or not parallel to each other. Therefore, the gap distance between the top edges 471 of the reinforcement 470 varies or tapers from a first gap distance (d2) at one end of the reinforcement 470 to a second gap distance (d4) at the other end of the reinforcement 470, where (d4) is greater than (d2). Thus, since the thermally conductive reinforcement such as the reinforcement 470 inherently acts as a heat sink, the amount and location of heat transferred to the reinforcement 470 on the top or upper side of the FPC finger 412a differs from that on the bottom or lower side of the FPC finger 412a (e.g., during the interconnection soldering process with the overhang end 208e), i.e., the lower electrical pad 212d becomes hotter due to the downward displacement of the centroid of the reinforcement 470. Therefore, the total temperature gradient between the top electrical pad 212d and the bottom electrical pad 212d can be reduced, and the temperature across the FPC fingers 412a is generally more uniform.

[0038] Figure 3B Implementation plan and Figure 4 The implementation schemes can be combined, whereby the reinforcement 470 is offset from the cover film 350, and the top edge 471 of the reinforcement 470 is not parallel to the top edge 351 of the cover film 350. In this case, Figure 3B and Figure 4 The gap distance (d2) between the two will be equal and Figure 3B and Figure 4 The gap distance (d3) between the two will be equal, and the additional non-parallel top edge 471 will create a second gap distance (d4). However, if implemented alone... Figure 4 The implementation plan, Figure 4 The gap distances (d2) and (d3) will be equal, while the non-parallel top edge 471 will still produce a second gap distance (d4). In all cases, the temperature difference between the top electrical pad 212d and the bottom electrical pad 212d can be reduced accordingly.

[0039] Figure 5A This is a perspective view illustrating an asymmetric FPC reinforcement according to one embodiment, and Figure 5B It is based on an implementation plan illustration Figure 5A Front view of the asymmetric FPC reinforcement. According to this embodiment, in order to facilitate the reinforcement of FPC212 (… Figures 2A-2D Different electrical pads (e.g., electrical pad 212d) Figures 2B-2C To improve temperature uniformity between the top and bottom electrical pads 512a, the reinforcement 570 of the FPC finger 512a includes localized material removal, or cutouts 571. Similarly, the reinforcement 570 is formed asymmetrically or has a different profile relative to the cover film 550. Therefore, since the thermally conductive reinforcement, such as the reinforcement 570, inherently acts as a heat sink, the amount and location of heat transferred to the reinforcement 570 at the top or upper side of the FPC finger 512a differs from that at the bottom or lower side (e.g., during interconnect soldering procedures with the overhang end 208e). Specifically, the lower electrical pad 212d becomes hotter due to the downward displacement of the centroid of the reinforcement 570. Consequently, the overall temperature gradient between the top and bottom electrical pads 212d can be reduced, and the temperature across the FPC finger 512a is generally more uniform. Figure 3B Implementation plan and / or Figure 4 Implementation plan and Figures 5A-5B The implementation schemes can be combined, whereby the reinforcement 570 is offset from the cover film 550, and the cutout 571 of the reinforcement 570 is applied. In all cases, the temperature difference between the top electrical pad 212d and the bottom electrical pad 212d can be reduced accordingly.

[0040] It should be noted that the shape and placement of the notch 571 in the reinforcement 570 can be based on specific design requirements and objectives relative to the location of the temperature gradient that is to be avoided or suppressed, and can vary depending on the specific implementation. That is, the notch 571 can be located on the top or bottom side of the reinforcement 570, and / or the notch 571 can be positioned more towards the narrower end of the reinforcement 570 than the thicker end. Furthermore, the use of the term "notch" is not intended to limit the manner in which the material void represented by the notch 571 is formed, i.e., by a cutting process or even necessarily a material removal process. Rather, the reinforcement 570 can be formed from its source material (e.g., molding or extrusion, etc.) with the material void in the appropriate location. Furthermore, Figure 5A The shape of the cut 571 depicted is for illustrative purposes, as the actual shape of the cut such as the cut 571 can vary depending on the specific implementation, depending on factors such as design requirements and objectives, manufacturing considerations, etc.

[0041] Figure 6 This is a perspective view illustrating an asymmetric FPC reinforcement according to one embodiment. According to this embodiment, in order to facilitate the use of FPC 212 (… Figures 2A-2D Different electrical pads (e.g., electrical pad 212d) Figures 2B-2C To ensure temperature uniformity between the layers, the reinforcement 670 of the FPC finger 612a includes partial material removal, or a notch 671. Here, the notch 671 does not span the entire thickness of the reinforcement 670, but rather creates material voids in the region closest to the cover film 650 (i.e., adjacent to the cover film, but not for other layers of the FPC 612a, e.g., ...). Figure 2D Layers 252-258), and extending only a portion of the thickness of the reinforcement 670 in a direction away from the cover film 650. This cutout 671 can be formed from the source material of the semi-stamped reinforcement 670. Here again, the reinforcement 670 is formed asymmetrically or has a different profile relative to the cover film 650. Therefore, since the thermally conductive reinforcement such as the reinforcement 670 inherently acts as a heat sink, the amount and location of heat transferred to the reinforcement 670 on the top or upper side of the FPC finger 612a differs from that on the bottom or lower side of the FPC finger 612a (e.g., during the interconnect soldering process with the overhang end 208e), that is, the lower electrical pad 212d becomes hotter due to the downward displacement of the centroid of the reinforcement 670. Therefore, the total temperature gradient between the top electrical pad 212d and the bottom electrical pad 212d can be reduced, and the temperature across the FPC finger 612a is generally more uniform. Figure 3B Implementation plan and / or Figure 4 Implementation plan and Figure 6The implementation schemes can be combined, whereby the reinforcement 670 is offset from the cover film 650, and the cutout 671 of the reinforcement 670 is applied. In all cases, the temperature difference between the top electrical pad 212d and the bottom electrical pad 212d can be reduced accordingly.

[0042] It should be noted that the shape and placement of the notch 671 in the reinforcement 670 can be based on specific design requirements and objectives relative to the location of the temperature gradient that is to be avoided or suppressed, and can vary depending on the specific implementation. That is, the notch 671 can be located on the top or bottom side of the reinforcement 670, and / or the notch 671 can be positioned more towards the narrower end of the reinforcement 670 than the thicker end. Furthermore, the use of the term "notch" is not intended to limit the manner in which the material void represented by the notch 671 is formed, i.e., by a cutting process or even necessarily a material removal process. Rather, the reinforcement 670 can be formed from its source material (e.g., molding or extrusion, etc.) with the material void in the appropriate location. Furthermore, Figure 6 The shape of the cut 671 depicted is for illustrative purposes, as the actual shape of the cut such as the cut 671 can vary depending on the specific implementation, depending on factors such as design requirements and objectives, manufacturing considerations, etc.

[0043] Figure 7 This is a perspective view illustrating an asymmetric FPC reinforcement according to one embodiment. According to this embodiment, in order to facilitate the use of FPC 212 (… Figures 2A-2D Different electrical pads (e.g., electrical pad 212d) Figures 2B-2C To improve temperature uniformity between the FPC fingers 712a, the reinforcement 770 includes partial removal of material or through holes 771. Here, the holes 771 may span the entire thickness of the reinforcement 770, or they may be located only in the area closest to the cover film 750 and extend through only a portion of the thickness of the reinforcement 770 in a direction away from the cover film 750. Therefore, since thermally conductive reinforcements such as the reinforcement 770 inherently act as heat sinks, the amount and location of heat transferred to the reinforcement 770 on the top or upper side of the FPC finger 712a differs from that on the bottom or lower side of the FPC finger 712a (e.g., during interconnect soldering procedures with the overhang end 208e). That is, the lower electrical pad 212d becomes hotter due to the downward displacement of the centroid of the reinforcement 770. Therefore, the overall temperature gradient between the top and bottom electrical pads 212d can be reduced, and the temperature across the FPC finger 712a is generally more uniform. Figure 3B Implementation plan and / or Figure 4 Implementation plan and Figure 7The implementation schemes can be combined, whereby the reinforcement 770 is offset from the cover film 750, and the hole 771 of the reinforcement 770 is applied. In all cases, the temperature difference between the top electrical pad 212d and the bottom electrical pad 212d can be reduced accordingly. It should be noted that the placement of the hole 771 of the reinforcement 770 can be based on specific design requirements and objectives relative to the location of the temperature gradient that is to be avoided or suppressed and can vary depending on the specific implementation. That is, the hole 771 can be positioned on the top or bottom side of the reinforcement 770, and / or the hole 771 can be positioned more towards the narrower end of the reinforcement 770 rather than the thicker end.

[0044] In summary, each of the aforementioned implementation schemes characterizes the FPC reinforcement 370 ( Figure 3B ), 470 Figure 4 ), 570 Figures 5A-5B ), 670 Figure 6 ), 770 Figure 7 ) relative to the corresponding covering film 350 ( Figure 3B , Figure 4 ), 550 Figures 5A-5B ), 650 Figure 6 ), 750 Figure 7 The centroid (e.g., centripetal center) of the top electrical pad 212d is shifted, either alone or in combination, using various techniques described. Therefore, the top electrical pad 212d is shifted due to heat-based interconnection processes (e.g., soldering). Figure 2D The temperature difference between the FPC finger and the bottom electrical pad 212d can therefore be reduced, preventing damage to the FPC and improving the soldering yield. Typically, the temperature becomes more uniform across a given FPC finger.

[0045] Methods for manufacturing flexible printed circuits

[0046] Figure 8 This is a flowchart illustrating a method for manufacturing a flexible printed circuit (FPC) laminate composition according to one embodiment.

[0047] At frame 802, a thermally conductive reinforcement is formed, having: an upper side with a top edge, a lower side with a bottom edge, a proximal end, and a distal end narrower than the proximal end. For example, FPC reinforcement 260 ( Figure 2D ), 370 Figure 3B ), 470 Figure 4 ), 570 Figures 5A-5B ), 670 Figure 6 ), 770 Figure 7 It is formed of a thermally conductive material, such as aluminum, as a non-limiting example.

[0048] At frame 804, at least one wiring layer is formed on the reinforcement. For example, a first wiring layer 252 is formed on FPC reinforcements 260, 370, 470, 570, 670, and 770. Figure 2D ) and second wiring layer 256 ( Figure 2D Examples include etching a copper layer as a non-limiting example.

[0049] At frame 806, a cover film is formed over at least one wiring layer, having: an upper side having a top edge, a lower side having a bottom edge, a proximal end, and a distal end narrower than the proximal end. For example, a cover film 250 is formed over the first wiring layer 252 and the second wiring layer 256. Figure 2D ), 350 Figure 3B , Figure 4 ), 550 Figures 5A-5B ), 650 Figure 6 ), 750 Figure 7 ).

[0050] At frame 808, the centroid of the reinforcement is positioned offset from the centerline of the cover film. For example, the centroid of FPC reinforcement 370 is displaced or offset downwards by asymmetrical positioning of reinforcement 370 relative to the centerline of cover film 350. For example, the centroid of FPC reinforcement 470 is displaced or offset downwards by asymmetrical shaping of reinforcement 470 relative to the centerline of cover film 350. For example, the centroid of FPC reinforcement 570 is displaced or offset downwards by a cut 571 of reinforcement 570 relative to the centerline of cover film 550. For example, the centroid of FPC reinforcement 670 is displaced or offset downwards by a partial cut 671 of reinforcement 670 relative to the centerline of cover film 650. For example, the centroid of FPC reinforcement 770 is displaced or offset downwards by a hole 771 of reinforcement 770 relative to the centerline of cover film 750.

[0051] Physical description of illustrative operational scenarios

[0052] The implementation scheme can be used in contexts such as digital data storage devices (DSDs) like hard disk drives (HDDs). Therefore, according to one implementation scheme, Figure 1 A floor plan of a typical HDD 100 is shown to help illustrate how a typical HDD usually operates.

[0053] Figure 1The functional arrangement of components of an HDD 100, including a slider 110b, is shown. The slider 110b includes a magnetic read / write head 110a. The slider 110b and the head 110a can be collectively referred to as the head slider. The HDD 100 includes at least one head gimbal assembly (HGA) 110 with the head slider, a lead suspension 110c typically attached to the head slider via a bend, and a load beam 110d attached to the lead suspension 110c. The HDD 100 also includes at least one recording medium 120 rotatably mounted on a spindle 124 and a drive motor (not visible) attached to the spindle 124 for rotating the medium 120. The read / write head 110a (also referred to as a transducer) includes a write element and a read element for writing and reading information stored on the medium 120 of the HDD 100, respectively. The medium 120 or multiple disk media can be attached to the spindle 124 using a disk clip 128.

[0054] HDD 100 also includes an arm 132, a carriage 134, and a voice coil motor (VCM) attached to HGA 110. The VCM includes an armature 136 containing a voice coil 140 attached to the carriage 134 and a stator 144 containing a voice coil magnet (not visible). The armature 136 of the VCM is attached to the carriage 134 and configured to move the arm 132 and HGA 110 to access the media 120, both mounted together on a pivot 148 with an inserted pivot bearing assembly 152. In the case of an HDD with multiple disks, the carriage 134 may be referred to as an "E-block" or comb because the carriage is arranged to carry a linked array of arms, thus giving it a comb-like appearance.

[0055] An assembly including a head universal joint assembly (e.g., HGA110) to which the head slider is coupled, an actuator arm (e.g., arm 132) and / or load beam to which the bend is coupled, and an actuator (e.g., VCM) to which the actuator arm is coupled, can be collectively referred to as a head stack assembly (HSA). However, an HSA may include more or fewer components than those described above. For example, an HSA may refer to an assembly that also includes electrical interconnect components. Generally, an HSA is an assembly configured to move the head slider to access portions of the medium 120 for read and write operations.

[0056] Further reference Figure 1Electrical signals, including write signals to and read signals from the magnetic head 110a (e.g., current to the voice coil 140 of the VCM), are transmitted by a flexible cable assembly (FCA) 156 (or “flexible cable” or “flexible printed circuit” (FPC)). The interconnect between the flexible cable 156 and the magnetic head 110a may include an arm electronics (AE) module 160, which may have an onboard preamplifier for the read signal and other read and write channel electronics. The AE module 160 may be attached to a carriage 134, as shown. The flexible cable 156 may be coupled to an electrical connector block 164, which in some configurations provides electrical communication via an electrical feedthrough provided by the HDD housing 168. The HDD housing 168 (or “housing base” or “substrate” or simply “base”) together with the HDD cover provides a semi-hermetic (or hermetically hermetic, in some configurations) protective enclosure for the information storage components of the HDD 100.

[0057] Other electronic components, including the disk controller and servo electronics including a digital signal processor (DSP), provide electrical signals to the drive motor, the voice coil 140 of the VCM, and the magnetic head 110a of the HGA 110. The electrical signals provided to the drive motor cause it to rotate, thereby providing torque to the spindle 124, which is then transmitted to the medium 120 attached to the spindle 124. The medium 120 thus rotates in direction 172. The rotating medium 120 forms an air cushion that acts as an air bearing on which the air bearing surface (ABS) of the slider 110b is mounted, allowing the slider 110b to fly above the surface of the medium 120 without contacting the thin magnetic recording layer on which information is recorded. Similarly, in HDDs utilizing gases lighter than air (such as helium used in a non-limiting example), the rotating medium 120 forms an air cushion that acts as a gas or fluid bearing on which the slider 110b is mounted.

[0058] The electrical signal supplied to the voice coil 140 of the VCM enables the head 110a of the HGA 110 to access the track 176 on which information is recorded. Therefore, the armature 136 of the VCM swings through an arc 180, allowing the head 110a of the HGA 110 to access the individual tracks on the medium 120. Information is stored in multiple radially nested tracks on the medium 120, which are arranged in sectors (such as sector 184) on the medium 120. Accordingly, each track is composed of multiple sectorized track portions (or “track sectors”) such as sectorized track portions 188. Each sectorized track portion 188 may include recorded information and a data header containing error correction code information and a servo burst signal pattern, such as the ABCD-servo burst signal pattern (which is information identifying track 176). When accessing track 176, the read element of the head 110a of the HGA 110 reads a servo burst signal pattern, which provides a positioning error signal (PES) to the servo electronics. This controls the electrical signal supplied to the voice coil 140 of the VCM, enabling the head 110a to follow track 176. Upon locating track 176 and identifying a specific sectored track portion 188, the head 110a either reads information from track 176 or writes information to track 176 according to instructions received by the disk controller from an external agent (e.g., the microprocessor of a computer system).

[0059] The electronic architecture of an HDD includes multiple electronic components for performing their respective HDD operating functions, such as a hard disk controller (“HDC”), an interface controller, an arm electronics module, a data channel, a motor driver, a servo processor, a buffer memory, etc. Two or more of these components may be combined on a single integrated circuit board called a “system-on-a-chip” (“SOC”). Several (if not all) of these electronic components are typically arranged on a printed circuit board coupled to the bottom side of the HDD, such as to the HDD housing 168.

[0060] This article references hard drives, such as references Figure 1The HDD 100 shown and described may include an information storage device sometimes referred to as a “hybrid drive.” A hybrid drive generally refers to a storage device that combines the functionality of a conventional HDD (see, for example, HDD 100) with a solid-state storage device (SSD) that uses non-volatile memory (such as flash memory or other solid-state (e.g., integrated circuit) memory) that is electrically erasable and programmable. Because the operation, management, and control of different types of storage media typically differ, the solid-state portion of a hybrid drive may include its own corresponding controller functionality, which may be integrated with the HDD functionality into a single controller. Hybrid drives can be built and configured to operate and utilize the solid-state portion in a variety of ways, such as, as a non-limiting example, using the solid-state memory as cache memory for storing frequently accessed data, for storing I / O-intensive data, etc. Additionally, hybrid drives can be built and configured essentially as two storage devices, namely a conventional HDD and an SSD, in a single housing, with one or more interfaces for host connectivity.

[0061] Expansion and Replacement

[0062] In the foregoing description, embodiments of the invention have been described with reference to numerous specific details, which may vary depending on the specific implementation. Therefore, various modifications and changes can be made without departing from the broad spirit and scope of the embodiments. Accordingly, the invention, and the applicant's intended sole and exclusive indicator of the invention, is the set of claims in the specific form issued by this patent application, including any subsequent amendments. Any definitions of terms expressly set forth herein that are included in these claims shall determine the meaning of those terms as used in the claims. Therefore, any limitations, elements, characteristics, features, advantages, or attributes not expressly cited in the claims shall not in any way limit the scope of these claims. Therefore, this specification and the accompanying drawings are to be considered exemplary rather than restrictive.

[0063] Furthermore, in this description, certain process steps may be shown in a specific order, and alphanumeric labels may be used to identify certain steps. Unless explicitly specified in the specification, the implementation is not necessarily limited to any particular order in which such steps are performed. Specifically, these labels are used only for the convenience of identifying the steps and are not intended to specify or require a particular order in which such steps are performed.

Claims

1. A flexible printed circuit, comprising: Multiple finger-like elements extending from the main portion, each finger-like element comprising: A thermally conductive reinforcement member has: an upper side having a top edge, a lower side having a bottom edge, a proximal end, and a distal end narrower than the proximal end, wherein the proximal end of the thermally conductive reinforcement member is closer to the main portion than the distal end of the thermally conductive reinforcement member. At least one wiring layer, said at least one wiring layer being located above the reinforcement, and A cover film is located above the at least one wiring layer and has: an upper side having a top edge, a lower side having a bottom edge, a proximal end, and a distal end narrower than the proximal end, wherein the proximal end of the cover film is closer to the main portion than the distal end of the cover film; The centroid of the reinforcing member is offset from the centerline of the covering membrane.

2. The flexible printed circuit according to claim 1, wherein the centroid of the reinforcing member is offset from the centerline of the cover film in a direction transverse to the upper and lower sides of the cover film.

3. The flexible printed circuit of claim 2, wherein at least one of the top edge and the bottom edge of the reinforcement is not parallel to at least one of the corresponding top edge or bottom edge of the cover film.

4. The flexible printed circuit of claim 3, wherein at least one of the top edge and the bottom edge of the reinforcement includes a material void forming a non-linear shape with the at least one edge.

5. The flexible printed circuit of claim 1, wherein at least one of the top edge and the bottom edge of the reinforcement is not parallel to at least one of the corresponding top edge or bottom edge of the cover film.

6. The flexible printed circuit of claim 1, wherein at least one of the top edge and the bottom edge of the reinforcing member includes a material void forming a non-linear shape with the at least one edge.

7. The flexible printed circuit of claim 1, wherein at least one of the top edge and the bottom edge of the reinforcing member is formed with a material void, the material void extending through only a portion of the thickness of the reinforcing member in the region closest to the cover film and in a direction away from the cover film.

8. The flexible printed circuit of claim 1, wherein the reinforcement further includes a hole to suppress heat transfer to the reinforcement at the location of the hole.

9. A hard disk drive comprising the flexible printed circuitry of claim 1.

10. A method for manufacturing a flexible printed circuit laminate composition having a plurality of fingers, the method comprising: A thermally conductive reinforcement is formed, the thermally conductive reinforcement having: an upper side having a top edge, a lower side having a bottom edge, a proximal end, and a distal end narrower than the proximal end, wherein the proximal end of the thermally conductive reinforcement is closer to the main portion of the flexible printed circuit laminate composition than the distal end of the thermally conductive reinforcement; At least one wiring layer is formed on the reinforcing member; A cover film is formed above the at least one wiring layer and has: an upper side having a top edge, a lower side having a bottom edge, a proximal end, and a distal end narrower than the proximal end, wherein the proximal end of the cover film is closer to the main portion of the flexible printed circuit laminate composition than the distal end of the cover film; as well as The centroid of the reinforcement is positioned offset from the centerline of the covering film.

11. The method of claim 10, wherein the positioning includes positioning the centroid of the reinforcement off-center from the centerline of the cover film in a direction transverse to the upper and lower sides of the cover film.

12. The method of claim 11, wherein forming the reinforcement comprises forming at least one of the top edge and the bottom edge of the reinforcement as not parallel to the other of the top edge and the bottom edge of the reinforcement and not parallel to at least one of the corresponding top edge or bottom edge of the cover film.

13. The method of claim 12, wherein forming the reinforcement comprises forming at least one of the top edge and the bottom edge of the reinforcement with material voids, the material voids forming a non-linear shape with respect to the at least one edge.

14. The method of claim 10, wherein forming the reinforcement comprises forming at least one of the top edge and the bottom edge of the reinforcement as not parallel to the other of the top edge and the bottom edge of the reinforcement and not parallel to at least one of the corresponding top edge or bottom edge of the cover film.

15. The method of claim 10, wherein forming the reinforcement comprises forming at least one of the top edge and the bottom edge of the reinforcement with material voids, the material voids forming a non-linear shape with respect to the at least one edge.

16. The method of claim 10, wherein forming the reinforcement comprises forming at least one of the top edge and the bottom edge of the reinforcement with material voids, the material voids extending through only a portion of the thickness of the reinforcement in the region closest to the cover film and in a direction away from the cover film.

17. The method of claim 10, wherein forming the reinforcement includes forming the reinforcement to further include a hole to suppress the thermal conductivity of the reinforcement at the location of the hole.

18. A hard disk drive, comprising: Multiple recording media, the multiple recording media being rotatably mounted on a spindle; Multiple magnetic head sliders, each magnetic head slider accommodating a corresponding read / write transducer, the read / write transducer being configured to read from and write to at least one of the multiple recording media; An actuator configured to move the plurality of head sliders to access a portion of the at least one recording medium; A means for transmitting electrical signals to and from the respective magnetic head sliders of the plurality of magnetic head sliders; and A flexible printed circuit, electrically connected to the device for transmitting electrical signals, the flexible printed circuit comprising: Multiple finger-like elements extending from the main portion, each finger-like element comprising: A thermally conductive reinforcement member has: an upper side having a top edge, a lower side having a bottom edge, a proximal end, and a distal end narrower than the proximal end, wherein the proximal end of the thermally conductive reinforcement member is closer to the main portion than the distal end of the thermally conductive reinforcement member. At least one wiring layer, said at least one wiring layer being located above the reinforcement, and A cover film is located above the at least one wiring layer and has: an upper side having a top edge, a lower side having a bottom edge, a proximal end, and a distal end narrower than the proximal end, wherein the proximal end of the cover film is closer to the main portion than the distal end of the cover film. The centroid of the reinforcing member is offset from the centerline of the covering film in a direction transverse to the upper and lower sides of the covering film.

19. The hard disk drive of claim 18, wherein at least one of the top edge and the bottom edge of the reinforcing member is not parallel to at least one of the corresponding top edge or bottom edge of the cover film.

20. The hard disk drive of claim 18, wherein at least one of the top edge and the bottom edge of the reinforcing member is formed with a material void, the material void extending through at least a portion of the thickness of the reinforcing member in the region closest to the cover film and in a direction away from the cover film.

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