Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
2000-04-06
2003-02-18
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
Reexamination Certificate
active
06522502
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a magnetic head device including a slider having a magnetic head mounted thereon, a resilient suspension structure carrying the slider and a head IC chip. The present invention further pertains to a magnetic disc device provided with such magnetic head device.
PRIOR ART
In conventional magnetic head devices having a magnetic head for writing and/or reading information on a magnetic recording medium such as a magnetic disc, it has been common to mount the magnetic head on a slider which is maintained in a floating relationship with respect to the magnetic recording medium. The slider is generally formed from a resilient metallic material sheet which is arranged to extend from a movable arm structure and supported by a suspension member.
The movable arm is provided for supporting one end of the suspension member and it has been common to mount a head IC chip on the movable arm. The head IC is provided for including electronic circuits for amplifying writing current which is to be suppled to the magnetic head and reading voltage from the magnetic head, and for controlling the writing and/or reading operation. In an arrangement wherein the head IC chip is mounted on the movable arm, an increased length of connecting lead is required between the head IC chip and the magnetic head and this increased length of the connecting lead may be a cause of noise generation. Such increased length of the connecting lead may produce a parasitic capacitance and an inductance which have an effect of undesirably increasing rising time and falling time of pulse signals. Thus, high speed data transmission will be disturbed.
In order to solve the problems, there has been proposed by the Japanese Laid-Open Patent Publication No. Sho 53-69623 to mount the head IC chip on the slider. Further, the Japanese Laid-Open Patent Publication No. Hei 3-108120 proposes to divide the head IC into an IC main body and an IC sub-body, and mount the IC main body on the movable arm supporting the suspension member and the IC sub-body on the slider or the suspension member.
In these known structures, it is possible to decrease to a certain extent the distance between the head IC chip and the magnetic head so that it may be possible to suppress noise which may otherwise be produced because of the length of the connecting lead. However, the structure has another unsolved problem in that the temperature of the IC chin is increased due to the writing current which flows through the head IC chip during recording operation. It should further be noted that in the structure the IC chip is located close to the magnetic head so that the magnetic head may receive an adverse thermal effect from the head IC chip which generally generates heat in operation.
More specifically, in a structure where the head IC chip is mounted on the movable arm which has a sufficient thermal capacity as well as a substantial area for heat radiation, the temperature of the IC chip can be maintained sufficiently low. Further, since the head IC chip is located far from the magnetic head, there is least possibility that the magnetic head is adversely affected by the heat generated in the head IC chip. To the contrary, where the head IC chip is located on the slider, it is difficult to ensure sufficient surface area for heat dissipation so that it cannot be expected to have the temperature of the IC chip decreased through dissipation of heat. It should further be noted that the slider usually has a limited thermal capacity so that it cannot be an effective tool for providing a temperature deacrease through thermal conduction. As the result, there will be a possibility in the aforementioned structures that the temperature of the head IC chip is undesirably increased to an extent that the reliability of the IC chip will be lowered. It should further be noted that since the magnetic head is located close to the head IC chip the magnetic head is thermally affected by the heat generated in the head IC chip. Thus, the temperature of the magnetic head itself may increase to an unacceptable level. Similar problem will also be encountered in a structure where the head IC chip is located on the suspension member if the location of the head IC chip is close to a tip end of the suspension member.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a magnetic head device of the type as described above wherein the temperature increase in the head IC chip can be suppressed to a satisfactory level and the heat generated in the head IC chip is effectively prevented from being transmitted to the magnetic head.
It is another object of the present invention to provide a magnetic head device wherein noise caused by the connecting lead between the head IC chip and the magnetic head can be suppressed so that a high speed data transmission is made practical.
It is another object of the present invention to provide a magnetic disc device which includes the aforementioned magnetic head device.
According to one aspect of the present invention, there is provided a magnetic head device including a slider having a magnetic head thereon, a suspension structure having one end supporting the slider, and a head IC chip which is mounted on said suspension structure at a side adapted to face a recording medium.
According to another aspect of the present invention, there is provided a magnetic head device including a slider having a magnetic head thereon, a suspension structure formed from a resilient metallic sheet and having one end supporting the slider, and a head IC chip, the suspension structure being attached at the other end to another member such as a movable arm, the head IC chip being mounted on the suspension structure at a location defined by 0.2≦Lb/La≦1, where La is a distance between the slider and the point of connection of the slider to the aforementioned other member, and Lb is a distance between the slider and the head IC chip.
In the aforementioned aspect of the present invention wherein the head IC chip is mounted on the suspension structure at the side facing the magnetic recording medium, the magnetic recording medium is moved relative to the slider and the head IC chip and there is produced flow of air between the magnetic recording medium and the slider and also between the magnetic recording medium and the head IC chip. Usually, the slider and the head IC chip are held stationary and the magnetic recording medium is in the form of a rotatably driven disc. Then, flow of air is produced as the magnetic recording disc rotates in the vicinity of the surface of the disc and serves to cool off the head IC chip. As the result, the temperature of the head IC chip can be suppressed to a substantially low value.
In this aspect of the present invention, it is preferable that the height of the head IC chip as measured in the mounted state from the suspension structure is smaller than the height of the slider. In this instance, the head IC chip is preferably in the form of a bare chip which is preferably mounted or attached to the suspension structure by means of flip-chip-bonding. By adopting the flip-chip-bonding for mounting such bare chip, it is possible to decrease the height of the head IC chip in the mounted state. Therefore, with this arrangement, the IC chip can be mounted on the recording medium side of the suspension structure without having any risk of the head IC chip interfering with the magnetic recording medium in use.
In an arrangement wherein the suspension structure is attached at the other end to the other member such as a movable arm, it is preferable that the location of the head IC chip on the suspension structure be, in terms of La which is a distance between the slider and the point of connection of the slider to the aforementioned other member, and Lb which is a distance between the slider and the head IC chip, within a range 0.2≦Lb/La≦1, more preferably within a range 0.3≦Lb/La≦0.7, and most preferably within a range 0.4≦Lb/La≦0.6.
In a stru
Aoyama Tsutomu
Morita Haruyuki
Nomura Izumi
Sakai Masanori
Sato Isamu
Cohen & Pontani, Lieberman & Pavane
TDK Corporation
Tupper Robert S.
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