Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Disk record
Reexamination Certificate
2001-12-18
2003-07-15
Nguyen, Hoa T. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Disk record
Reexamination Certificate
active
06594107
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a magnetic disc apparatus and, more particularly, to a thin type of magnetic disc apparatus using a magnetic disk with a small diameter.
2. Description of the Related Art
Not only general-purpose computers and workstations but also personal computers are now equipped with magnetic disc apparatus. As lower-price personal computers have come into wide use, the price of magnetic disc apparatus has fallen remarkably. To offset the lower prices, magnetic recording densities are being increased and the number of disks and heads on magnetic disc apparatus are being reduced to reduce costs. As a result, the storage capacity per unit magnetic disc apparatus has increased.
In this context, the capacities of the magnetic disks used as recording media used in personal computers have been increased to a sufficient degree. On the other hand, the increased capacities of magnetic disc apparatus have allowed huge amounts of information such as motion picture and music data to be handled, so attempts have begun to be made to use magnetic disc apparatus in household electrical information appliances other than personal computers. In particular, demands for diverse applications of magnetic disc apparatus are beginning to grow, as seen in such trends as the use of magnetic disc apparatus to construct databases with massive amounts of information, and the tendency of individual persons to carry these massive amounts of information with them for use at any time and place.
As the magnetic disc apparatus used by individual persons to carry massive amounts of information with them as mentioned above, a magnetic disc apparatus smaller and thinner than the 2.5-inch or 3.5-inch magnetic disc apparatus used in current personal computers is required.
The smaller and thinner size needed for this purpose is achieved in a portable external magnetic disc apparatus as described in JP-A-180426/1997. This portable external magnetic disc apparatus uses a magnetic disk with smaller diameter for lower power consumption and higher portability.
FIG. 8
is a perspective view of a 2.5-inch magnetic disc apparatus mounted on current notebook personal computers. The magnetic disc apparatus shown in
FIG. 8
comprises a case
405
and a cover (omitted in
FIG. 8
) that hermetically enclose the inside; a spindle motor is secured to the case
405
. A magnetic disk
400
is attached to the spindle motor by a clamp
406
, with a spacer disposed between them. A carriage is provided on the case
405
. This carriage has a suspension
402
tipped with a magnetic head
411
for reading and writing information on the magnetic disc
400
. In addition, the carriage has a radial degree of freedom with respect to the magnetic disc
400
, provided by a pivot
412
, and can be driven to a given position on the surface of the magnetic disc
400
by a voice coil motor (VCM)
407
attached to the case
405
.
Signals from the magnetic head
411
are transmitted through a flexible printed circuit (FPC)
403
to a pre-amplifier integrated circuit
404
where they are amplified. A further connector (not shown in
FIG. 8
) conducts the signals to a printed circuit board (PCB)
408
where they are processed by electronic components
409
, and the processed signals are transmitted by an external connector
410
to the outside.
The portable compact magnetic disc apparatus, as mentioned above, also has this basic structure, except that it is thinner than the 2.5-inch magnetic disc apparatus. Current 2.5-inch magnetic disc apparatus has a device thickness of 9.5 mm, while the portable compact magnetic disc apparatus has a minimum device thickness of 5.0 mm.
In 2.5-inch magnetic disc apparatus with a device thickness of 9.5 mm, the thickness of the printed circuit board is about 0.6 mm, the ratio of which to the device thickness is about 6.3%. In a portable compact magnetic disc apparatus with a device thickness of 5 mm, the thickness of the printed circuit board is about 0.4 mm, the ratio of which to the device thickness is about 8.0%. It is clear that the portable magnetic disc apparatus has a higher ratio of the board thickness of the printed circuit board
408
to the device thickness as described above.
The prior art includes a structure, disclosed by JP-A-111290/1992, comprising a layer of insulative material that is provided on the internal surface of a case or a cover, and a circuit pattern that is formed on the layer of insulative material for mounting electronic components, thereby reducing the thickness of a magnetic disc apparatus. In another structure, disclosed by JP-A-176186/1995, a layout of electronic components and connectors are electrically connected to a circuit board, a spindle motor and an actuator are secured to the circuit board, and the circuit board is screwed to a cover, thereby reducing the thickness of a magnetic disc apparatus. The art described in JP-A-115590/1996 provides a structure comprising a circuit board with a hole, and a metal base plate that occupies the hole; the metal base plate has holes for securing the spindle motor and actuator, and for components forming connections between the case and the circuit board, thereby reducing the number of components.
Flexible printed circuit connector joining methods used in current magnetic disc apparatus include a structure disclosed in JP-A-106761/1996 and the structure shown in FIG.
9
.
FIG. 9
is an expanded cross-sectional view through line A—A of an FPC-PCB connector joint part transmitting signals from a magnetic head in the current compact magnetic disc apparatus shown in FIG.
8
.
In
FIG. 9
, the pre-amplifier integrated circuit
500
is soldered to the upper surface of a flexible printed circuit
502
that is connected to the signal-flow path from the magnetic head and supported by a flexible printed circuit plate
501
. The flexible printed circuit
502
bends around to the opposite side of the flexible printed circuit plate
501
and is there connected to a flexible printed circuit connector
505
. The flexible printed circuit connector
505
transmits magnetic head signals through the case
506
to a printed circuit board
503
outside the case
506
. The flexible printed circuit connector
505
makes the signal connections by being pressed against a solder joint part
504
on the printed circuit board
503
. As shown in
FIG. 9
, the case
506
has through-holes for the flexible printed circuit connector
505
, around which a packing or sealing substance is used to form a hermetic seal.
For magnetic disc apparatus that uses a flexible printed circuit to provide power and transmit control signals to a spindle motor, the prior art disclosed by JP-A-185371/1999 uses a connector that clamps around the flexible printed circuit, to which it is connected by clamping pressure.
SUMMARY OF THE INVENTION
Therefore, if a basic structure similar to that of current magnetic disc apparatus is adopted, it is necessary to reduce the thickness of the case and the cover still further to achieve the thin size suitable for portable magnetic disc apparatus. The case, however, has a spindle motor, a carriage, and a voice coil motor attached to it, so it must maintain the stiffness needed to support these system components. Therefore, if the case thickness is reduced, it is possible that the case may be unable to maintain the stiffness and may allow vibration which, when transmitted to the outside, causes noise problems. Another possibility is that the cover may be deformed by external forces, and may come in contact with the magnetic disc.
For the printed circuit board, if the board thickness is reduced, stress concentration at the points where electronic components are soldered onto the printed circuit board may warp the printed circuit board. In that case, the problem of faulty connections arises at the place where the connector that transmits signals from the magnetic head to the printed circuit board is joined to the printed circuit board.
In the current structure, described in JP-A-111290/1992 a
Akagi Kyo
Hayakawa Takako
Saegusa Shozo
Uefune Kouki
Yamaguchi Takashi
Chen Tianjie
Mattingly Stanger & Malur, P.C.
Nguyen Hoa T.
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