JPS60143419A - Magneto-resistance effective type multichannel magnetic head device - Google Patents

Abstract

PURPOSE:To operate the titled magnetic head device stably, by assembling a capacitor for stabilizing power supply and another capacitor for introducing signals in the head device under a condition where they are united in one body and practically using the capacitor for stabilizing power supply effectively. CONSTITUTION:Resistors for supplying a constant current to an MR element are collectively put in a resistor block 40 and separated form an MR head H. When such arrangement is made, a heat source is dispersed and temperature rise of the MR head H can be suppressed to, for example, about 20 deg.C. Moreover, by assembling capacitors for stabilizing power supply Cb and Cbb in the capacitor array 27' of an MR head device, power supplying impedance including conductors is lowered and invasions of high frequency noise from the outside can be checked at the leading head section of a signal system.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a multichannel magnetoresistive magnetic head device using a thin film magnetoresistive element (hereinafter referred to as Ml).

Background technology and its problems Magnetic head using MR element (hereinafter referred to as MR head)
In order for the MFL element associated with each channel to obtain an output from an external magnetic field, that is, a signal magnetic field obtained by recording on a magnetic recording medium, a constant current is passed through the MR element to generate an output from the external magnetic field in the MR element. It is necessary to extract the output by changing the voltage based on the change in resistance.

In a multi-channel magnetic head using this type of MR element, in order to simplify the structure, it is desirable to connect each MR element in parallel and supply a constant current from an external constant voltage power supply. Therefore, it is necessary to connect a high resistance in series to the MR element of each channel to obtain a constant current.

First, the electrical configuration of a conventional MR head device will be explained with reference to FIG.
,..., MRn, MR82 is an MR element provided corresponding to each channel, and MR elements MR81 and MR82 at both ends are for detecting the position in the width direction of the magnetic recording medium. "'2...MRn is for reading recording signals on each recording track.

The resistance value of these MR elements changes according to the external signal magnetic field, that is, the recording signal magnetic field of the magnetic recording medium, and each MR element
A high-resistance resistor element R for constant current is connected in series to one end of the element, and from the connection midpoint, an output terminal corresponding to each channel '81 + tl r t2...tn *
t82 is derived. The other end of each MR element is grounded, and the other end of each resistance element R is connected to a constant voltage DC power supply S via a power supply terminal tb so that a constant voltage is applied thereto. The resistance element R is set to a resistance value that is approximately two to three times the resistance value of each MR element. The fixed resistance value of the MR element is about 100Ω, and this resistance value changes by about 1 inch depending on the external magnetic field. Furthermore, an i4 capacitor Cb is connected in parallel to the power supply S in order to reduce the impedance to the signal frequency and stabilize the operation.

Each of the output terminals "81 r t1 to 'n # 182 is connected to each input side of a corresponding high gain preamplifier A via a signal deriving capacitor C. These amplifiers are connected in parallel (not shown). /A monolithic semiconductor integrated circuit (hereinafter referred to as IC) along with a serial converter, etc.
As will be described later, it is housed in a synthetic resin casing together with a capacitor array CA, which is a collection of signal deriving capacitors C, and is also integrated with the MR head H, making the MR head as a whole. The device is configured.

Note that the IC is supplied with the necessary power from an external power source B prepared separately from the power source S for the MR head, and a stabilizing capacitor Cbb is connected in parallel to this power source B as well.

Here, with reference to FIGS. 2 and 3, conventional MR
An example of the mechanical configuration of the head device will be described.

In both figures, the MR head H includes a magnetic substrate (1) on which the above-mentioned MR element and resistance element are mounted, and an MR head H.
It is composed of a wear-resistant protection substrate (IP) that is bonded to protect elements and the like. (A) is a casing made of synthetic resin, and the MR head H is attached to the head mount part (211) protruding from one end of this casing (A).The other end of the casing (2) A plurality of leads (221) are buried in the IC. be done.

One surface (24a) of a metal heat sink with high thermal conductivity is fixed to the back side of the IC mounting portion (22A). The other surface (24b) of the heat sink is exposed to the outside of the casing (A), and a screw hole (2) is provided in the center for mounting the MR head device and for heat radiation from the IC. A stool is planned.

Helad mount circle of casing CO) and heat sink (2)
A recess (to) is provided between the capacitor play (5
) is accommodated.

(G) is a printed wiring board, which is made of, for example, a glass epoxy laminate as a base material, and has upper and lower screens (30a) and (30b).
) the required printed wiring is formed.

For example, each capacitor in the capacitor array (27) has 2
The positive and negative electrode terminals C11 and Q91 are also arranged in two rows. Therefore, on the lower surface (30b) of the printed wiring board (G), the above-mentioned electrode terminals (1-te-Nero#hot runt middle 1norc^even6) are arranged opposite to 28+ and c2gl, and the corresponding electrodes The terminal and the land are connected by solder paste flow applied to each in advance. Also, the upper surface (30a) of the printed wiring board (to)
), bonding pads (c) and (2) are provided at both ends of the capacitor play (c) and (2) in order to connect each capacitor of 2η to ICt;!3 and the MR head H by a bonding wire W. In addition, land Gυ, (
33 and corresponding bonding/l'tudo (331# (
An appropriate through hole (not shown) is provided for connection to 341. Further, 0!5i is a power supply pad to which a conductive wire from a constant voltage power supply S is connected. ci6) is the ground arm.

By the way, in the conventional MR head device as described above, stabilizing capacitors Cb and Cbb are connected to the power supply S for the MR element and the power supply B for the IC, respectively, on the wiring diagram. However, in reality both capacitors Cb and C
bb are located on the sides of both power supplies S and B, respectively, and a long conductive wire is interposed between the power supply terminal tb of the MR head H and the power supply terminal tbb of the IC. Therefore, especially high frequency @
In fact, the power supply impedance seen from both tM terminals tb and tbb does not decrease, and the effect of the stabilizing capacitor is diminished. Furthermore, the operation of the MR head device (including the high gain amplifier A) may become unstable due to external high frequency noise entering the long conductor wire.

OBJECTS OF THE INVENTION In view of the above, an object of the present invention is to provide an MR head device that operates stably by effectively utilizing a power supply stabilizing capacitor.

Summary of the Invention The present invention provides a plurality of magnetoresistive elements, a constant current resistor connected in series with each of the plurality of magnetoresistive elements, and each constant current resistor and each magnetoresistive element. In a multi-channel magnetoresistive magnetic head device including a plurality of signal derivation capacitors connected to respective connection midpoints of This is a multi-channel magnetoresistive magnetic head device that is integrated with a power supply stabilizing capacitor.

According to the present invention, since the power supply stabilizing capacitor is integrated with the signal deriving capacitor and incorporated into the head device, the stabilizing capacitor is effectively utilized and the head device operates stably.

Embodiment Hereinafter, one embodiment of the magnetoresistive magnetic head device according to the present invention will be described with reference to FIGS. 4 and 5.

FIG. 4 shows an embodiment of the MR head device according to the present invention. In FIG. 4, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and redundant explanation will be omitted.

In FIG. 4, the number of capacitor elements accommodated in the capacitor array (27') is increased by at least two compared to the conventional example, and the stabilizing capacitors Cb and 2 of the above-mentioned constant current power supply S and IC power supply B are respectively Used as Cbb. At this time, the wiring and wiring of the printed wiring board (30') are changed as required, such as by providing terminals for IC power supply. (40
2 shows the resistor block as a whole, and on one side of this resistor block (40 is a ceramic substrate (4υ), a required number of constant current resistance elements R' similar to those described above are arranged, and a power terminal (421 and constant current supply terminal (43 is the board (
411 on the IC side and head side. Therefore, in this embodiment, the above-mentioned constant current resistance element R is not provided on the magnetic substrate (1') of the MR head H'.

The detailed configuration of the resistor block (40) is shown in FIG.

In FIG. 5, the edge (41a) on the IC side and the edge (41b) on the head side of the ceramic substrate (411) are connected to power supply terminals (4 wires and a current supply of the same number as the number of channels m=n+2 of the head H'). Terminal (431C (43・1), (4
32)...<43m) ) is, for example, Ag-P
d is provided by printing and firing.

Next, power supply wiring (441
and current supply terminal (431), (43z)...
・Conductors (451) each connected to (43m),
(452)...(45m) is Ag-P
d is provided by printing and firing. Then, the power supply wiring (44) and each conductor (451), (452)...
...(45m) and printed and fired ruthenium oxide RuO to make thick film resistors (461).
, (462)... (46m) are formed, and the resistance value of each thick film resistor is adjusted by laser trimming as necessary. The adjusted resistor block (4G) has terminals (4) exposed and covered with an appropriate protective layer, and then solder is applied to each terminal (c) and (43). By bringing the terminal surface of the resistor block (41) into contact with the top surface (30a) of the printed wiring board (to) at a predetermined position and reflowing the solder applied to each terminal, the desired connection state can be obtained. .

In this embodiment, the resistors for supplying constant current to the MR element are grouped into a resistor block and separated from the MR head H, so that the temperature rise of the MR head can be suppressed to, for example, about 20C by dispersing the heat source. I can do it. In addition, by incorporating the power supply stabilizing capacitors Cb and Cbb into the capacitor array (27') of the MR head device, the power supply impedance including the conductor is reduced, and high frequency noise from the outside is prevented from entering at the beginning of the signal system. It can be suppressed. Furthermore, the number of parts is reduced, and the number of man-hours for manufacturing the device is reduced.

Effects of the Invention As detailed above, according to the present invention, the power supply stabilizing capacitor is integrated with the signal deriving capacitor and incorporated into the MI'L head device, so the stabilizing capacitor can be effectively utilized. The MR head device operates stably.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram showing the electrical configuration of a conventional MR head device, Figs. 2 and 3 are a schematic plan view and a sectional view of the conventional MR head device, and Figs. 4 and 5 are the invention of the present invention. by M
FIG. 2 is a sectional view and a perspective view of essential parts of an embodiment of the R head device. H and H' are MR heads, MRs1+ MRs2,
MRl...M~ is an MR element, R and (46) are constant current resistors, (20) is a casing, (Jun and (2)
7') is a capacitor array, (to) and (30') are printed wiring boards, (40 is a resistor block. 4 Figure 0 Figure 5

Claims (1)

[Claims] A plurality of magnetoresistive elements, a constant current resistor connected to each of the plurality of magnetoresistive elements in i rows, and a connection midpoint between the six constant current resistors and each of the magnetoresistive elements. In a multi-channel magnetoresistive magnetic head device comprising a plurality of signal deriving capacitors connected to respective ones of A multi-channel magnetoresistive magnetic head device, characterized in that it is integrated with a magnetic capacitor.