Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
2000-12-27
2004-02-10
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
Reexamination Certificate
active
06690546
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a head suspension for supporting a head of a disk device, to a disk device which uses it, and to a testing method for a head IC.
2. Description of the Related Art
Disk devices for reading a disk storage medium using a head are widely used. For example, magnetic disk drives that are used as storage devices for computers comprise a magnetic disk, a spindle motor that rotates the magnetic disk, a magnetic head for reading from or writing to the magnetic disk, and a VCM actuator that positions the magnetic head at a track on the magnetic disk.
The storage density of these kinds of disk drives is greatly increasing, as well as is the density of tracks on the magnetic disk. It is especially possible to increase the density by using a MR (GMR, TMR) head as the magnetic head. Therefore, a high precision device is also desired for processing of the head signal.
In a magnetic disk device, the magnetic head is supported by a suspension. The suspension is attached to the carriage arm of a VCM actuator. The suspension has springiness and functions such that the magnetic head follows the surface of the magnetic disk. The magnetic head performs input/output of an analog signal, so it is equipped with a head IC for processing the analog signal. The head IC comprises a preamp for amplifying the read signal of the magnetic head, and a writing amp for supplying writing current to the magnetic head.
Normally, this head IC is attached to the carriage arm located at the rear of the suspension. Moreover, the head IC is connected to the magnetic head by lead wires on the suspension. However, in the case of a weak magnetic head output, as in the case of the recent MR heads, it is not possible to ignore the effect of noise that mixes into the long lead wire.
In addition, when the lead wire is long, the rising time and falling time of the pulse signal (writing pulse) both become long, so there is a problem in that it becomes difficult to transfer data at high speed. Therefore, it is proposed to place the head IC chip on the suspension in order to shorten the distance between the magnetic head and the head IC.
With that kind of construction, it is necessary to test each suspension. Conventionally, a slider on which the head IC and magnetic head are located is attached to the suspension to form a HGA (head gimbal assembly), then this HGA is made to float above the disk medium and by the head magnetically reading/writing, the operation of the head IC and the connection status are checked.
However, with the prior method, the head and head IC of the HGA unit are checked together so when one is determined to be faulty that entire HGA is considered faulty. Therefore, there is a problem that yield decreases and it is difficult to keep costs down.
SUMMARY OF THE INVENTION
The objective of the invention is to provide a head suspension, a disk device and a testing method for testing the head IC installed in the suspension.
Another objective of the invention is to provide a head suspension, a disk device and a testing method for simply testing the head IC installed in the suspension.
A further objective of the invention is to provide a head suspension, a disk device and a testing method for testing the head IC that improves the yield of the head assembly.
In order to accomplish these objectives, the head suspension of this invention comprises: a first connection terminal that electrically connects to a head; a second connection terminal that connects to external circuits; third and fourth connection terminals that electrically connect to a head IC for processing an electrical signal from the head; a first conductive path that connects the first connection terminal with the third connection terminal; a second conductive path that connects the second connection terminal with the fourth connection terminal; and a measurement terminal that is located between the second connection terminal and fourth connection terminal of the second conductive path, and which is for measuring the head IC.
Moreover, the disk device of this invention comprises: a head for at least reading a disk medium, a head IC that processes the electrical signal from the head, a head suspension which contains the head IC and which supports the head, and an actuator that supports the head suspension and moves the head with respect to the disk medium; and where the head suspension comprises: a first connection terminal for electrically connecting to the head, a second connection terminal for connecting to external circuits, third and fourth connection terminals for electrically connecting to the head IC, a first conductive path that connects the first and third connection terminals, a second conductive path that connects the second and fourth connection terminals, and a measurement terminal that is located between the second connection terminal and fourth connection terminal of the second conductive path, and which is for measuring the head IC.
Furthermore, the testing method for head IC of this invention comprises: a step of installing a head IC for processing the electric signal from the head, and a step of placing a probe on the head suspension terminal to test the electric characteristics of the head IC.
In this invention, first a head IC is installing on the head suspension and the head IC is checked before installing the head. By doing this, it is possible to check the operation and connection of the head IC itself, and to divide the head assembly into good or faulty parts before installing the head. Therefore, it is possible to increase the yield and to keep down costs of the head assembly.
Second, in order to check the head IC that is installed on the suspension, it is necessary to place a measurement probe on the terminal. Theoretically, by placing the probe on the first and second terminals instead of the third and fourth terminals installed on the head IC, it is possible to check the head IC. However, the second terminal for external connection is located in a position that is easy for external connection and it is not easy to place a probe on it. Therefore, in this invention, a measurement terminal is located between the second and fourth connection terminals. This makes contact with the probe easy and makes it possible to quickly check the head IC.
Moreover, in the head suspension of this invention, the measurement terminal and the first connection terminal are located such that they are on the same plane as the suspension, and this makes it even easier for contact with a pair of probes, which makes it possible to check the head IC even more quickly.
In addition, in the head suspension of this invention, the first, second, third and fourth connection terminals, the first and second conductive paths, and the measurement terminal are formed using a thin-film pattern on the base of the suspension, so the measurement terminal can be formed with the same process as the other terminals and conductive paths, making construction more simple.
Furthermore, in the head suspension of this invention, flexible cable is used around the base of the head suspension, which is provided the first, second, third and fourth connection terminal, the first and second conductive paths and the measurement terminal so it is possible to separate the base and the cable.
REFERENCES:
patent: 5422764 (1995-06-01), McIlvanie
patent: 5864446 (1999-01-01), Endo et al.
patent: 6173485 (2001-01-01), Shiraishi et al.
patent: 11-213364 (1999-08-01), None
Greer Burns & Crain Ltd.
Tupper Robert S.
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