Electricity: measuring and testing – Magnetic – Magnetic information storage element testing
Reexamination Certificate
1998-11-12
2003-06-03
Patidar, Jay (Department: 2862)
Electricity: measuring and testing
Magnetic
Magnetic information storage element testing
C360S245900
Reexamination Certificate
active
06573711
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to testing equipment for rigid discs, and more particularly to a terminal connector for use with a magnetic recording head.
The demand for reliable, accurate and cost effective testing of rigid discs exists throughout the disc manufacturing industry. The rapid growth and technological innovation in the disc manufacturing industry over the last several years has created a demand for testers capable of accurately testing and evaluating the mechanical and read/write performance of the disc. The demand is particularly high in Lot Acceptance Testing (LAT), where a numerous amount of discs are tested in one batch prior to shipment to the disc supplier.
Several tests are known which verify the performance of a rigid disc, for example, a magnetic disc. One such test is glide height testing. This test verifies the mechanical performance at the surface of the disc. For example, defects such as blistering on the disc substrate may be found. Another known test is the certification test. In this test, the integrity of the magnetic layer is determined. For example, it is determined whether the magnetic layer can read or write data precisely and accurately to the desired threshold. In the glide height and certification tests, pre-designed testing heads are used. In particular, when these heads are manufactured, they are equipped with a pre-specified mechanical and wire configuration such that they are easily adapted to the disc testing equipment.
Another well-known test is parametric testing. Parametric testing determines the performance of the disc, for example, the signal-to-noise ratio of the recorded signals on the disc.
Generally in parametric testing, a signal is supplied as an input to the disc being tested in order to measure or determine an output signal. The output signal may be amplified in order to determine or monitor a characteristic of the tested item. In parametric testing, there is an AC (alternating current) and a DC (direct current) test.
In DC testing, the signal input and output vary over a broad dynamic signal range, but at relatively slow speeds. In this test, the transmission of signals is typically subject to problems such as line losses, extraneous signal pick-up, and ground and temperature differentials. In AC testing, the output and input signals operate over a narrow dynamic range, and at high speeds. Typically the output signal is affected by factors such as line loading and impedance effects.
Parametric testing heads are typically the same heads that are used in a head-disc assembly of a disc drive. These heads are manufactured in high volume with a given mechanical configuration and wire length. Thus, in many cases, the wire length is too short to connect with the testing assembly used in the parametric testing procedure. As a result, the wires are extended by splicing or adding additional wire. This splicing process can be expensive and may cause wire damage, breakage, or poor performance in the product head. In addition, such wires cause the input/output signals to suffer from the above-mentioned problems such as line loading and impedance effects.
During testing, the parametric heads are used to statistically test each loader disc prior to shipment, and also on receipt by the drive manufacturer. If the statistical sample passes a set of predetermined criteria, the entire lot is accepted or rejected. If a poor performing head is used, the lot may be rejected inadvertently. This results in the waste of magnetic discs, and adds to the manufacturer's cost.
One method of extending the wire length of product heads is to solder an additional wire to the head. Another known method is to wirebond the wires to a flex circuit. One disadvantage to these methods is that the wire is easily broken (i.e., the wire is commonly 0.002 in diameter) causing the head to malfunction. In addition, protective tubing normally traverses the length of the wire. In the above methods, this tube must be removed which exposes the wire, thereby increasing the chance of the wire being damaged.
SUMMARY OF THE INVENTION
In general, the present invention is directed towards a paddle board having a flexible leads for connection to a plurality of wires of a testing head. The paddle board includes a chassis and a flexible lead portion. A plurality of wire traces are formed onto the paddle board to receive the plurality of wires from the testing head.
Accordingly, in one aspect, the paddle board includes a first portion and a second portion. A plurality of pads are formed on the first portion. The plurality of wire traces are formed onto the first and second portion to receive the plurality of wires from the testing head.
Implementations of the invention include one or more of the following. The first and second portion may be fabricated from the same material, for example, Kapton™ or polyimide. The pads may be formed from gold, silver or copper. A second material may be added to the paddle board to increase its stiffness. A plurality of holes may be formed in the first portion. The plurality of wires from the test head may be attached to the wire traces by ultrasonic bonding, soldering, or thermo-compression. The test head may be an inductive head, a magneto-resistive head or a giant magneto-resistive head. The first portion may be connected to a testing system. One of the plurality of wire traces may transmit a read signal or a write signal between the test head and the testing assembly.
In another aspect, the invention is directed to a testing system which includes a testing assembly having a socket and a test head. A first portion of the paddle board is connected to the socket and a second portion of the paddle board is connected to the wires of the test head.
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Palmer, D., Integrated Lead Suspension Assemblies Take the Hard Disk Drive Industry by Storm, Datatech, 1996, ICG Publishing Ltd., London, England, pp. 65-69.
Schadewald Frank William
Schaenzer Mark James
Moser, Patterson and Sheridan, LLP
Patidar Jay
Seagate Technology LLC
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