Dynamic magnetic information storage or retrieval – Head mounting – For adjusting head position
Reexamination Certificate
2002-02-21
2004-09-14
Davis, David (Department: 3652)
Dynamic magnetic information storage or retrieval
Head mounting
For adjusting head position
C029S603060
Reexamination Certificate
active
06791802
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head device comprising a piezoelectric element.
2. Description of the Related Art
FIG. 6
is a plan view showing an example of a conventional hard disk device. The hard disk device shown in
FIG. 6
comprises a magnetic disk
101
, a spindle motor
102
for driving the magnetic disk
101
to rotate, a carriage
103
, a load beam
104
, a slider
105
, and a voice coil motor
106
. A magnetic head device schematically comprises the load beam
104
and the slider
105
.
The base end
104
b
of the load beam
104
serving as a supporting member is connected to the tip
103
a
of the carriage
103
comprising a rigid material, and the slider
105
is mounted at the tip
104
a
of the load beam
104
through a flexure (not shown in the drawing).
The carriage
103
and the load beam
104
are driven in the radial direction of the magnetic disk
101
by the voice coil motor
106
to perform the seek operation of moving a reproducing element and recording element mounted on the slider
105
onto a desired recording track, and the tracking operation of finely controlling the positions of the reproducing element and the recording element to keep them on a center line of the recording track.
Furthermore, a microactuator is mounted on the load beam
104
so that only the tip of the load beam
104
can be moved by the microactuator to perform the tracking operation.
FIG. 7
is a perspective view of the load beam
104
, and
FIG. 8
is a sectional view showing the principal portion of the load beam
104
shown in FIG.
7
.
The load beam
104
is made of a stainless steel leaf spring material, and comprises a fixed base end
111
a
held by the carriage, and an oscillating portion
111
b
oscillatable horizontally relative to the fixed base end
111
a
. The load beam
104
further comprises arms
111
c
formed on both sides of the front end of the fixed base end
111
a
to extend in the longitudinal direction of the fixed base end
111
a
. The oscillating portion
111
b
is connected to the arms
111
c
through elastic supporting portions
111
d.
Furthermore, piezoelectric elements
112
and
113
serving as microactuators are placed over a void
111
e
between the oscillating portion
111
b
and the fixed base end
111
a.
The piezoelectric elements
112
and
113
comprise piezoelectric layers
112
a
and
113
a
made of a piezoelectric material such as lead titanate zirconate (PTZ), and electrode layers
112
b
and
112
c
, and electrode layers
113
b
and
113
c
, respectively, made of gold films formed above and below the piezoelectric layers
112
a
and
113
a.
As shown in
FIG. 8
, the electrode layers
112
c
and
113
c
of the piezoelectric elements
112
and
113
are bonded to the oscillating portion
111
b
and the fixed base end
111
a
with an adhesive resin
115
In
FIG. 7
, reference numeral
121
denotes a slider mounted at the tip of the oscillating portion
111
b
through a flexure (not shown in the drawing).
The piezoelectric elements
112
and
113
are elements which produce strain when a voltage is applied through the electrode layers
112
b
and
112
c
, and the electrode layers
113
b
and
113
c
, respectively.
The piezoelectric layers
112
a
and
113
a
of the piezoelectric elements
112
and
113
are polarized in the thickness direction, but the polarization directions of the piezoelectric elements
112
and
113
are opposite to each other. Therefore, when the same potential is applied to the electrode layers
112
c
and
113
c
, one of the piezoelectric elements extends in the longitudinal direction, while the other piezoelectric element shrinks in the longitudinal direction.
As a result, the elastic supporting portions
111
d
are deformed to change the position of the slider
121
mounted at the tip of the oscillating portion
111
b
. Namely, the slider
121
mounted at the tip of the oscillating portion
111
b
can be finely moved in the track width direction to perform the fine tracking operation.
Particularly, the precision of the tracking operation must be increased as the recording density of the magnetic disk
101
increases. However, the load beam
104
enables the precise tracking operation, and is thus adaptable for improving the recording density.
As the adhesive resin
115
for bonding the piezoelectric elements
112
and
113
and the oscillating portion
111
b
and the fixed base end
111
a
, a thermosetting epoxy resin is conventionally used. The epoxy resin is roughly classified into a one-component type and a two-component type.
However, unlike a photo-curing type, a thermosetting epoxy resin cannot be temporarily hardened by light irradiation, and thus a bonded portion must be fixed by a jig or the like until curing is completed, thereby causing the problem of deteriorating manufacturing efficiency.
With a one-component epoxy resin, a powdery curing agent is added to an epoxy solution as a main agent, and then dispersed in the epoxy solution by heating to start curing. However, the viscosity of the epoxy solution decreases until the temperature is increased to the curing temperature, thereby making the mixed state of the curing agent and the epoxy solution heterogeneous to leave an uncured portion in some cases. The uncured portion causes the occurrence of out gases, spots due to dissolution and re-adhesion of the uncured portion, etc., causing the problem of deteriorating the reliability of a magnetic head device.
With a two-component epoxy resin, unlike the one-component epoxy resin, the uncured portion does not occur. However, the viscosity greatly varies with time during mixing of the main agent and the curing agent, thereby causing the problem of complicating handling of the resin after mixing.
Therefore, in order to solve the above problems, the use of a photo-curing and thermosetting acrylic adhesive resin has recently been investigated. The acrylic adhesive resin is cured by radical polymerization, but peroxide radicals occur due to contact with atmospheric oxygen to cause reaction deactivation inhibition. This causes the problem of increasing the amount of the out gases produced, and deteriorating humidity resistance and heat resistance to deteriorate the reliability of the magnetic head device.
SUMMARY OF THE INVENTION
In consideration of the above-described present conditions, it is an object of the present invention to provide a magnetic head device having excellent reliability and comprising a piezoelectric element and a load beam which are bonded together in a good state without using a jig.
In order to achieve the object, the present invention has the following construction:
A magnetic head device of the present invention comprises a slider comprising a reproducing element for detecting magnetic signals recorded on a recording medium, and a recording element for recording magnetic signals on the recording medium; an elastic supporting member for supporting the slider; and a piezoelectric element mounted on the elastic supporting member, for deforming the elastic supporting member to change the position of the slider, wherein the piezoelectric element and the elastic supporting member are bonded together with a photo-curing and thermosetting epoxy adhesive resin having a Young's modulus of 1 GPa or more at 25° C., and a glass transition temperature of 90° C. or more.
In the magnetic head device of the present invention, the piezoelectric element and the elastic supporting member are bonded together with the photocuring and thermosetting epoxy adhesive resin, and thus the adhesive resin can be temporarily cured by light irradiation to temporarily fix the piezoelectric element without using a jig or the like, thereby increasing manufacturing efficiency.
Unlike an acrylic resin, an epoxy resin as a main component of the adhesive resin is cured by cationic polymerization, and thus does not produce reaction deactivation inhibition due to oxygen, thereby increasing the reliability of the magnetic head device.
Furthermore, since th
Sato Hidezi
Watanabe Mitsuru
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Davis David
LandOfFree
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