Disk device with FPC and chip
A disk device according to one embodiment includes a magnetic disk, a magnetic head, an FPC, and a chip. The FPC includes an insulating layer, a first conductive layer on a first face of the insulating layer, and a second conductive layer on a second face of the insulating layer. The chip is mounted on the FPC. The first conductive layer includes pads. The chip includes terminals connected to the plurality of pads via solder. The second conductive layer includes wires. The plurality of wires include at least either one or two or more first wires or one or two or more pairs of second wires. The first wires each include a first part disposed apart from the pads, and a second part having a larger width than the first part, overlapping one of the pads. The second wires overlap one of the pads.
1 . A disk device comprising:
a magnetic disk;
a magnetic head configured to read and write information from and to the magnetic disk;
a flexible printed circuit board electrically connected to the magnetic head, including
an insulating layer,
a first conductive layer disposed on a first face of the insulating layer, and
a second conductive layer disposed on a second face of the insulating layer, the second face being opposite the first face; and
a chip mounted on the flexible printed circuit board, wherein
the first conductive layer includes a plurality of pads,
the chip includes a plurality of terminals connected to the plurality of pads via solder,
the second conductive layer includes a plurality of wires,
the plurality of wires include at least either one or two or more first wires or one or two or more pairs of second wires,
the one or two or more first wires each include
a first part disposed apart from the plurality of pads along the second face, and
a second part having a larger width than the first part, overlapping one of the plurality of pads with the insulating layer interposed in-between the second part and the one pad, and isolated from the one pad by the insulating layer, and
the one or two or more pairs of second wires each overlap one of the plurality of pads, with the insulating layer interposed in-between the one pad and the second wire pair or pairs.
2 . The disk device according to claim 1 , wherein
the plurality of wires include the one or two or more first wires, and
the second part of at least one of the one or two or more first wires overlaps two adjacent pads among the plurality of pads, with the insulating layer interposed in-between the second part and the two adjacent pads.
3 . The disk device according to claim 2 , wherein
the one or two or more first wires each further include a third part connected to the second part apart from the plurality of pads along the second face,
the first part is connected to the second part,
the second part extends between the first part and the third part, and
the two adjacent pads are juxtaposed with an interval in a direction in which the second part extends.
4 . The disk device according to claim 2 , wherein
the flexible printed circuit board includes a via that connects one of the two adjacent pads and the second part.
5 . The disk device according to claim 1 , wherein
the plurality of wires include the one or two or more first wires, and
the second part has a width equal to or larger than a width of the one pad.
6 . The disk device according to claim 1 , wherein
the plurality of wires include the one or two or more pairs of second wires, and
at least one pair of the one or two or more pairs of second wires extend in parallel, overlapping the one pad.
7 . The disk device according to claim 1 , wherein
the plurality of wires include the one or two or more pairs of second wires, and
of at least one pair of the one or two or more pairs of second wires, a part overlapping the one pad with the insulating layer interposed in-between the part and the one pad is larger in width than a part disposed apart from the plurality of pads along the second face.
8 . The disk device according to claim 7 , wherein
of the one or two or more pairs of second wires, at least one pair of second wires each include
a first edge facing the other second wire,
a second edge opposite the first edge, and
an extended part protruding from the second edge and overlapping the one pad with the insulating layer interposed in-between the extended part and the one pad.
9 . The disk device according to claim 1 , wherein
the chip is electrically connected to the magnetic head, to output a write signal to the magnetic head and receive a read signal from the magnetic head, the write signal representing information to be written to the magnetic disk by the magnetic head, the read signal representing information read from the magnetic disk by the magnetic head.
10 . The disk device according to claim 9 , wherein
the one first wire, the two or more first wires, the one pair of second wires, and the two or more pairs of second wires transmit an electrical signal different from the write signal and the read signal.
11 . The disk device according to claim 1 , wherein
the second conductive layer has a ground plane, and
each of the plurality of pads overlaps the one first wire, one of the two or more first wires, the one pair of second wires, one pair of the two or more pairs of second wires, or the ground plane, with the insulating layer interposed in-between each pad and the one first wire, the one of the plurality of first wires, the one pair of second wires, the one of the two or more of pairs of second wires, or the ground plane.
12 . The disk device according to claim 1 , wherein
the chip has a quadrangular bottom face facing the flexible printed circuit board,
the plurality of pads include four corner pads closest to four corners of the bottom face, and
differences between distances between the four corner pads and the chip and an average value of the distances are within a range of ±8% of the average value.
13 . The disk device according to claim 1 , wherein
the chip has a first lateral face extending in a first direction along the first face, and a second lateral face extending in a second direction along the first face, the second direction intersecting the first direction,
the plurality of pads include a plurality of first pads overlapping the second conductive layer with the insulating layer interposed in-between the first pads and the second conductive layer, the plurality of first pads being arranged symmetrically with respect to a middle of the chip in the first direction, and
the plurality of pads include a plurality of second pads arranged apart from the second conductive layer along the second face and symmetrically with respect to the middle of the chip in the first direction.
14 . The disk device according to claim 13 , wherein
the plurality of first pads are arranged symmetrically with respect to the middle of the chip in the second direction, and
the plurality of second pads are arranged symmetrically with respect to the middle of the chip in the second direction.
15 . The disk device according to claim 1 , wherein
the chip is an amplifier.
16 . A disk device comprising:
a magnetic disk;
a magnetic head configured to read and write information from and to the magnetic disk;
a flexible printed circuit board electrically connected to the magnetic head, including
an insulating layer,
a first conductive layer disposed on a first face of the insulating layer, and
a second conductive layer disposed on a second face of the insulating layer, the second face being opposite the first face; and
an electronic component mounted on the flexible printed circuit board, wherein
the first conductive layer includes a plurality of pads,
the electronic component includes a plurality of terminals connected to the plurality of pads via solder,
the second conductive layer includes a plurality of wires,
the plurality of wires include at least either one or two or more first wires or one or two or more pairs of second wires,
the one or two or more first wires each include
a first part disposed apart from the plurality of pads along the second face, and
a second part having a larger width than the first part, overlapping one of the plurality of pads with the insulating layer interposed in-between the second part and the one pad, and isolated from the one pad by the insulating layer, and
the one or two or more pairs of second wires each overlap one of the plurality of pads, with the insulating layer interposed in-between the one pad and the second wire pair or pairs.