GB2256740A

GB2256740A - Magnetic head support carrying electronic circuits

Info

Publication number: GB2256740A
Application number: GB9112809A
Authority: GB
Inventors: David Anthony Williams
Original assignee: Marconi Electronic Devices Ltd; Plessey Semiconductors Ltd
Current assignee: Marconi Electronic Devices Ltd; Plessey Semiconductors Ltd
Priority date: 1991-06-14
Filing date: 1991-06-14
Publication date: 1992-12-16
Also published as: FR2678417A1; GB9112809D0

Abstract

A magnetic disc reader head assembly in which the support member 13 of the electromagnetic pick-up carries read/ write amplifiers 15 connected by short leads to the pick-up to minimise induced noise. The support member may be formed in part from ceramic sheet material, on which the read/write amplifiers may be mounted directly. <IMAGE>

Description

Mounting Assembly The present invention relates to mounting assemblies, more particularly, to mounting assemblies for a magnetic disc reader head.

Magnetic discs are used to store data e.g. digital data.

Data is retrieved from the disc using a reader head including an electromagnetic pick-up which, in response to the variations in magnetic field it experiences as it passes along a track on the disc, generates electrical signals representative of the data stored on the disc. The electrical signals are then fed to further equipment, such as a computer, via a read amplifier. The reader head may additionally be used to magnetise the disc in accordance with signals to be stored on the disc, the signals being passed to the head via a write amplifier.

In conventional magnetic disc data storage arrangements, the pick-up of the reader head is required to track over the surface of the disc at a distance of about 127firm from the surface. To this end, the reader head is mounted at one end of a supporting arm which at its other end is secured to a carriage which is movable so as to allow the reader head to be moved radially across the disc.

Thus the support arm has a length comparable to the radius of the disc.

Signals to and from the reader head are fed to the read and write amplifiers via connecting wires, typically 3cm long for a 10cm diameter disc, which extend along the length of the arm.

One disadvantage of such an arrangement is that the connecting wires, between the reader head and amplifiers, more especially the read amplifier, pick up electrical noise by induction. It is an object of the present invention to provide a mounting assembly for a magnetic disc reader head which alleviates the above disadvantage.

According to the invention there is provided a mounting assembly for a magnetic disc reader head comprising an elongate supporting member adapted to support said reader head at one end characterised in that said elongate supporting member further carries at least one electric circuit for processing signals fed to or from the reader head.

The elongate supporting member is preferably formed from an insulating material e.g. a ceramic material. This enables the processing circuits to be formed in a substrate secured to the supporting member semiconductor.

By way of example, one embodiment of magnetic disc reader head assembly mounting assembly in accordance with the present invention will now be described with reference to the drawings in which: Figure 1 is a perspective view of a prior art mounting assembly and; Figure 2 is a perspective view of a reader head mounting assembly in accordance with the invention.

Referring to Figure 1, in the prior art assembly an electromagnetic reader head 1 comprises an electromagnetic pick-up (not visible) mounted on a carrier in the form of a rectangular block of a hard ceramic material. The ceramic carrier is bonded to one end of a strip of light gauge spring steel 3 using adhesive and the strip 3 is welded at its other end to one end of a triangular planar elongate supporting arm 5 formed from heavier gauge spring steel. The arm 5 is strengthened by being bent up along its edges 7 between the end of the arm 5 connected to the carrier to near the other end of the arm 5. This other end of the arm is fastened to a relatively rigid mounting plate 9. The reader head 1 is required in use to slide over the surface of the magnetic disc (not shown) to maintain the pick-up at a fixed distance from the disc surface.To this end, strip 3 and the flexible part of the arm 5 not having bent up edges 7 are arranged to hold the carrier of the reader head in sliding contact with the surface of the magnetic disc. Insulated connecting wires 11, extending from the pick-up of the reader head 1 along the length of the arm 5, serve to transfer signals to and from read and write amplifying circuits (not shown) located remote from the mounting assembly.

Referring to Figure 2 the mounting assembly according to the invention is identical to the assembly of Figure 1 except in respect of the elongate arm by which the reader head 1 is mounted on plate 9. Other components of the assemblies of Figures 1 and 2 are denoted by the same reference numerals in the two Figures.

In the assembly of Figure 2, the arm 5 of Figure 1 is replaced by a generally triangular elongate thin plate of stiff ceramic material 13. At its narrower end the arm 13 is bonded to the strip 3 of light gauge strip steel and a further strip 17 of light gauge strip steel connects the wider end of the arm 13 to the mounting plate 9, these flexible strips 3, 17 serving to hold the reader head 1 in contact with the magnetic disc in use.

On one of its main faces the arm 13 carries integrated circuits 15 which serve as read and write amplifiers for the pick-up of the reader head 1. Connecting wires 11 feed signals between the reader head 1 and the integrated circuits 15. Connection between the circuits 15 and other parts of the disc storage arrangement is made by way of further connecting wires 19.

The integrated circuits 15 are suitably formed in semiconductor e.g. silicon substrates mounted on the arm 13 prior to fabrication of the circuits per se. In this case interconnections between the circuits 15 and to the ends of connecting wires 11 and 19 are suitably made by way of metallised strips (not shown) formed on the surface of the arm 13 during circuit fabrication.

Alternatively or additionally interconnections between the circuits 15 may be made by flying leads such as 21 in Figure 2.

Alternatively the integrated circuits 15 may comprise pre-formed circuits bonded to the arm 13 after fabrication.

It will be appreciated that due to the relatively short length of connecting wires 11 in the assembly of Figure 2, the possibility of electrical noise being picked up by the wires 11 is much less in the assembly of Figure 2 than in the assembly of Figure 1. In addition the location of circuits 15 on the arm 13 in the assembly of Figure 2 enables the overall size of a disc storage arrangement incorporating the assembly of Figure 2 to be smaller than a corresponding disc storage arrangement incorporating the assembly of Figure 1.

Connection between the circuits 15 and other parts of the disc storage arrangement is made by way of further connecting wires 19.

Claims

1. A mounting assembly for a magnetic disc reader head comprising an elongate supporting member adapted to support said reader head at one end characterised in that said elongate supporting member further carries at least one electric circuit for processing signals fed to or from said reader head.

2. A mounting assembly as claimed in Claim 1 wherein said elongate supporting member is in the form of a thin plate.

3. A mounting assembly as claimed in Claim 1 or 2 wherein said supporting member is secured at one end to a flexible member, adapted to carry said reader head and at the other end is connected by way of a further flexible member to a mounting plate, said flexible members serving to hold the reader head in contact with the magnetic disc in use.

4. A mounting assembly as claimed in any preceding claim wherein said supporting member is formed from insulating material.

5. A mounting assembly as claimed in Claim 4 wherein said insulating material is a ceramic material.

6. A mounting assembly as claimed in Claims 4 or 5 wherein said supporting member further carries interconnections in the form of metallised strips on the surface of the supporting member.

7. A mounting assembly as claimed in any preceding claim wherein at least one said circuit is a read or write amplifying circuit.

8. A mounting assembly as claimed in any preceding claim wherein said at least one circuit is formed in a substrate secured to said supporting member before fabrication of said at least one circuit.

9. A mounting assembly as hereinbefore described and illustrated in Figure 2 of the accompanying drawings.