Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
1999-07-13
2002-02-26
Letscher, George J. (Department: 2754)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
Reexamination Certificate
active
06351347
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head and, in particular, to a magnetic head with an improved flexible cable junction structure.
2. Description of the Related Art
The general construction of a magnetic head used in a conventional hard magnetic disk device will be described with reference to
FIG. 4. A
load beam
21
, which consists of a stainless steel plate, comprises a rectangular base portion
21
a
situated at the rear end thereof, a flat portion
21
c
connected to the base portion
21
a
through two elastic portions
21
b
and extending to the forward end, and a protruding portion
21
d
outwardly protruding from one side of the base portion
21
a
and situated in the same plane as the base portion
21
a.
There is provided on either side of the flat portion
21
c
a bent portion
21
e
bent downward. A rectangular mount
23
consisting of a stainless steel plate is superimposed on the portion of the upper surface of the base portion
21
a
excluding the protruding portion
21
d
and is fastened thereto by spot welding or the like. Formed at the center of the mount
23
and the base portion
21
a,
which are superimposed one upon the other, is a through-hole
24
for mounting the magnetic head to a drive arm (not shown) of a hard magnetic disk device.
A flexure
25
, which consists of a thin stainless steel plate and which is flexible, comprises a wide portion
25
a
extending over the central portion of the upper surface of the flat portion
21
c
of the load beam
21
from the forward end toward the rear end thereof, a narrow portion
25
b
passing between the two elastic portions
21
b
of the load beam
21
and extending around the outer periphery of the base portion
21
a,
and an end portion
25
c
superimposed on the upper surface of the protruding portion
21
d
of the load beam
21
.
As shown in
FIG. 5
, a slider
27
consisting of a ceramic and substantially formed as a parallelepiped is fastened to a tongue
25
d
provided at the forward end of the flexure and partially cut away. On the forward end surface
27
a
of the slider
27
, a thin-film head element
28
for recording and reproducing information on and from a hard magnetic disk and four connection terminals
29
connected to the head element
28
are formed by a thin-film formation technique. Of the four connection terminals
29
, two serve to transmit recording signals and the other two serve to transmit reproduction signals.
A ground layer
30
consisting of an insulator such as polyimide is provided around the wide portion
25
a
and on the narrow portion
25
b
and the end portion
25
c
of the flexure
25
. Formed on the ground layer
30
are four conductive patterns
31
consisting of nickel- and gold-plated copper.
At the end surface
27
a
of the slider
27
, the forward ends of the four conductive patterns
31
are connected to the connection terminals
29
through balls
32
consisting of a conductive material such as Au. Of the four conductive patterns
31
, two are for recording and the other two are for reproduction according to the functions of the connection terminals
29
.
As shown in
FIG. 6
, on the end portion
25
c
of the flexure
25
, the width of the conductive patterns
31
is enlarged such that their end portions are rectangular, forming four rectangular pads
31
a,
which are arranged in a row from the front side of the flexure
25
.
The conductive patterns
31
are covered with an insulating layer (not shown) consisting of polyimide resin or the like. However, the end portions of the conductive patterns
31
connected to the connection terminals
29
of the head element
28
and the portions thereof on the end portion
25
c
of the flexure
25
are not covered with an insulating layer, the pads
31
a
being exposed on the end portion
25
c.
A flexible cable
33
comprises an insulating substrate
33
a
consisting of polyimide resin or the like, four conductors
33
b
formed thereon and consisting of copper or the like, and an insulating covering sheet
33
c
covering the conductors
33
b.
The end portions of the conductors
33
b
are formed as round bumps
33
e
whose surfaces are solder-plated so as to make it possible to perform soldering connection. The bumps
33
e
are formed in a row from the front side. From the end portion
33
d
of the flexible cable
33
, which is superimposed on the end portion
25
c
of the flexure
25
, the covering sheet
33
c
is removed, so that the surfaces of the bumps
33
e
are exposed.
The bumps
33
e
and the pads
31
a
are joined to each other by pressurizing and heating, with the solder-plated surfaces of the bumps
33
e
and the gold-plated surfaces of the pads
31
a
being opposed to each other. A round through-hole
34
provided in the protruding portion
21
d
and a through-hole
35
provided at the end of the flexible cable
33
are used as a means of positioning for the bumps
33
e
and the pads
31
a
when they are superimposed one upon the other. The round bumps
33
e
are included in the rectangular pads
31
a.
The flexible cable
33
is led out rearward from the end portion
25
c
of the flexure
25
and connected to the main body of the hard magnetic disk device, serving to transmit recording and reproduction signals to the thin-film head element
28
.
The above magnetic head is mounted to a driving arm of a hard magnetic disk device (not shown) by attaching the mount to the driving arm such that the upper surface
27
b
of the slider
27
is opposed to the magnetic recording surface of the magnetic disk. During operation, the slider
27
fixed to the flexure
25
flies over the magnetic recording surface of the magnetic disk at a predetermined distance, and magnetic recording and reproduction are performed on and from the magnetic disk by the head element
28
, with the airflow being followed due to the flexibility of the flexure
25
.
When the flexible cable
33
led out of the conventional magnetic head is deflected during assembly, etc., great distortion occurs to the junction, in particular, between the bumps
33
e
and the pads
31
a
which junction is nearest to the lead-out side of the flexible cable
33
, causing breakage to the junction, with the result that the exchange of information between the head element
28
and the cable
33
is interrupted.
SUMMARY OF THE INVENTION
The present invention has been made with a view toward solving the above problem. Accordingly, it is an object of the present invention to make it possible to prevent occurrence of distortion to the junctions between the bumps
33
e
and the pads
31
a.
To achieve the above object, there is provided, in accordance with the present invention, a magnetic head comprising a flexure having conductive patterns formed thereon, a flexible cable having conductors, a head element provided at the forward end of the flexure and connected to the conductive patterns, pads provided at the rear end of the flexure and connected to the conductive patterns, a dummy pad provided at the rear end of the flexure and not connected to the conductive patterns, bumps provided at the forward end of the flexible cable and adapted to transmit electric signals between the head element and the flexible cable, a dummy bump provided at the forward end of the flexible cable and not adapted to transmit electric signals between the head element and the flexible cable, wherein the forward-end portion of the flexible cable is superimposed on the rear-end portion of the flexure to effect junction between the pads and the bumps and between the dummy pad and the dummy bump, the junction between the dummy pad and the dummy bump being positioned nearer to the flexible cable lead-out side than the junctions between the pads and the bumps.
Further, the dummy bump is not connected to the conductors of the flexible cable.
Furthermore, the area of junction between the dummy bump and the dummy pad is larger than the area of junction between each bump and each pad.
Furthermore, the dummy pad and the dummy bump are formed of
Kurai Haruo
Ohno Yuki
Brinks Hofer Gilson & Lione
Letscher George J.
LandOfFree
Magnetic head does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Magnetic head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic head will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2955576