Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
2002-10-02
2004-04-06
Cuneo, Kamand (Department: 2827)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C174S262000, C174S267000, C361S792000, C360S323000
Reexamination Certificate
active
06717068
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circuit board, and a magnetic head incorporating the circuit board. More particularly, the present invention relates to a circuit board capable of protecting an MR magnetic head device, which incorporates the circuit board, against electrostatic breakdown.
2. Description of the Related Art
An example of a conventional magnetic head
201
for use in a computer hard disk is shown in FIG.
17
. The magnetic head
201
generally comprises a slider
203
, a load beam
202
, and a circuit board
204
. The slider
203
is attached to a fore end
202
a
of the load beam
202
through a flexure, and a base plate
209
is attached to an opposite end
202
b
of the load beam
202
. The circuit board
204
is attached to the base plate
209
.
The slider
203
includes an MR magnetic head device
208
for reproducing magnetically recorded data, and an inductive head device (not shown) for recording data to be magnetically recorded. From each of these head devices, two lead lines are extended to transmit and receive a reproduced signal and a recording signal to and from the outside of the magnetic head. These four lead lines
205
a
,
205
b
,
206
a
,
206
b
are connected to the circuit board
204
at the side of the base plate
209
where it is attached to the opposite end
202
b
of the load beam
202
.
The circuit board
204
is formed of a flexible printed board, and includes four leads
215
a
,
215
b
,
216
a
,
216
b
connected respectively to the lead lines extended from the head devices (i.e.,
205
a
,
205
b
,
206
a
,
206
b
). Mounting terminals
215
c
,
215
d
,
216
c
,
216
d
are provided respectively midway on the leads
215
a
,
215
b
,
216
a
,
216
b
. Inspection terminals
215
e
,
215
f
,
216
e
,
216
f
are provided respectively at ends of the leads
215
a
,
215
b
,
216
a
,
216
b.
The leads
215
a
,
215
b
, that are connected to the lead lines
205
a
,
205
b
of the MR magnetic head device
208
, include lands
223
,
224
provided between the mounting terminals
215
c
,
215
d
and the inspection terminals
215
e
,
215
f
, respectively.
In a conventional magnetic head of this type, the circuit including the MR magnetic head device
208
is typically constructed as a closed circuit by attaching a shunt clip or forming a bonding wire between the lands
223
,
224
so as to short the lands
223
,
224
together. This is done to prevent electrostatic breakdown of the MR magnetic head device
208
during a period from manufacture of the magnetic head to assembly thereof into a hard disk drive.
This may result in a number of problems. For example, when the lands
223
,
224
are shorted together by using a clip, there is a risk that the clip may slip off as result of vibration during transport of the magnetic head. As a result, the MR magnetic head device
208
may suffer electrostatic breakdown.
Also, shorting the lands
223
,
224
together by wire bonding requires that a wire-bonding step be included in the manufacturing process of the magnetic head, thereby resulting in an increased production cost of the magnetic head.
In view of the state of the art set forth above, an object of the present invention is to provide a magnetic head capable of positively preventing electrostatic breakdown of an MR magnetic head device, and a method of manufacturing the magnetic head, that overcomes the above-identified problems.
SUMMARY OF THE INVENTION
The present invention is directed to a circuit board comprising at least a pair of leads for constructing a circuit, lands connected respectively to the pair of leads, and solder bumps formed respectively on the lands, wherein the solder bumps are arranged in an adjacent relationship. The solder bumps are subsequently crushed, causing peripheral portions of the solder bumps to spread and overlap with each other.
The present invention is also directed to a circuit board comprising at least a pair of leads for constructing a circuit, lands formed for connection respectively to the pair of leads, and a solder bridge for electrically interconnecting the lands, wherein the solder bridge is formed by peripheral portions of the solder bumps formed on the lands so that portions of the solder bumps overlap with each other. Preferably, the solder bridge is formed by crushing the solder bumps formed on the lands to an extent that crushed peripheral portions of the solder bumps are overlapped with each other.
Consequently, the leads constructing the circuit on the circuit board can be easily shorted together by crushing the solder bumps, and the circuit can be formed into a closed circuit.
Moreover, since the solder bridge is formed by the peripheral portions of the solder bumps which are integrally overlapped with each other, the contact area between the solder bumps is increased and the leads can be positively shorted between them.
Further, the present invention is directed to a circuit shorting method for a circuit board comprising at least a pair of leads for constructing a circuit, lands connected respectively to the pair of leads, and solder bumps formed on the lands and positioned adjacent to each other. The method comprises the steps of crushing one of the solder bumps such that a peripheral portion of the one solder bump is pressed to spread outward in a radial direction to approach the other solder bump; and then crushing the other solder bump such that a peripheral portion of the other solder bump is pressed to spread outward in a radial direction to contact with the peripheral portion of the one solder bump, whereby the pair of leads are shorted.
With this circuit shorting method, two solder bumps are contacted with each other by crushing the solder bumps one by one. Therefore, the solder bumps can be each positively crushed to make the leads shorted between them, and the circuit can be positively formed into a closed circuit.
In the above circuit shorting method, the step of crushing the other solder bump is preferably performed until a part of the peripheral portion of the other solder bump overlaps the peripheral portion of the one solder bump.
One feature of this circuit shorting method is that the pair of solder bumps are contacted with each other in an overlapping relation. Thus, the solder bumps are unlikely to be separated, even when the circuit board is bent or flexed. Further, a contact area between the solder bumps is increased and the pair of leads can be positively shorted between them.
In the above circuit shorting method, the solder bumps are preferably each crushed under heating. Heating of the solder bumps causes them to soften, thereby reducing the load required for crushing the solder bumps, and the solder bumps can be positively crushed without damaging the circuit board itself.
In the above circuit shorting method, the pair of solder bumps may be crushed simultaneously underheating. Crushing the solder bumps simultaneously, while being softened under heating, reduces the load required for crushing the solder bumps, and the pair of solder bumps can be positively contacted with each other even when they are crushed simultaneously. Additionally, damage of the circuit board itself can be avoided.
In the above circuit shorting method, the solder bumps are preferably each crushed under heating and rubbing. By heating and rubbing the solder bumps, each solder bump is caused to spread in the planar direction of the circuit board while being crushed. This causes the solder bumps to be more positively contacted with each other.
The present invention is directed to a magnetic head in which a slider including an MR magnetic head device is attached to a fore end of a load beam, a circuit board is attached to an opposite end of the load beam, and a pair of lead lines extended from the MR magnetic head device are connected to the circuit board. The circuit board comprises at least a pair of leads connected respectively to the lead lines and constructing a circuit including the MR magnetic head device in cooperation with the lead lines
Moroe Michiaki
Motonishi Michiharu
Alps Electric Co. ,Ltd.
Cuneo Kamand
Patel I B
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