Electrical connectors – Including or for use with tape cable – With mating connection region formed by bared cable
Utility Patent
1999-04-30
2001-01-02
Abrams, Neil (Department: 2839)
Electrical connectors
Including or for use with tape cable
With mating connection region formed by bared cable
C360S097010, C439S559000, C439S926000
Utility Patent
active
06168459
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of disc drive data storage devices, and more particularly but not by way of limitation, to a flex support and seal apparatus, the apparatus for connecting read/write head wires of a disc drive to a printed circuit board.
BACKGROUND OF THE INVENTION
Modern disc drives are commonly used in computer environments ranging from super computers through notebook computers, to store large amounts of data in a form that can be made readily available to a user. Typically, a disc drive has one or more magnetic discs that are rotated at a constant speed by a spindle motor. Each disc surface has a data recording surface divided into a series of generally concentric data tracks radially spaced across a band having an inner diameter and an outer diameter.
The data is stored within the data tracks on the disc in the form of magnetic flux transitions. The flux transitions are induced by an array of read/write heads. Each disc surface has a data recording surface divided into a series of generally concentric data tracks radially spaced across a band having an inner diameter and an outer diameter.
The data stored within the data tracks on the disc is in the form of magnetic flux transitions. The flux transitions are induced by an array of read/write heads. Typically, each data track is divided into a number of data sectors that store fixed sized data blocks.
The read/write head includes an interactive element such as a magnetic transducer that senses the magnetic transitions on a selected data track to read the data stored on the track. Alternatively, to write data to the disc surface, the read/write head transmits an electrically induced, short duration magnetic field that induces magnetic transitions on the selected data track.
In addition to the read/write heads the actuator assembly generally includes head wires, which conduct electrical signals from the read/write heads to a flex circuit that, in turn, conducts the electrical signals to a read/write channel located on the printed circuit board (PCB) of the disc drive. Normally the electrical signal paths are routed through one or more connectors en route to the read/write channel. The connectors facilitate the electrical connection between the flex circuit of the disc drive and the PCB of the disc drive. However in so doing, the contacts of the connectors typically induce added inductance and capacitance into the circuit, thereby causing a change in inductance per unit length along the signal path. This change in inductance per unit length along the signal path frequently results in a parasitic electrical degradation of the signal. Several approaches have been used to accommodate the data signal interconnect needs of a disc drive, but in general, these approaches have been silent regarding, resolution of parasitic electrical signal degradation problems caused by changes in inductance per unit length along, the signal path.
In the process of connecting the flex circuit and the PCB, one previous approach makes use of an apparatus with a three connector combination configuration. First is a flex circuit connector (the connector body housing, female connector pins) is soldered directly to the flex circuit. The second is a pass-through connector (the connector body housing male pins, the male pins having a top portion protruding from a top side of the connector body and a bottom portion protruding from a bottom side of the connector body) mounts to the basedeck with the bottom portions of the male pins extending from a slot in the basedeck. The third is a printed circuit board connector (a connector body housing female connector pins) is soldered directly to the PCB. The advantage of this configuration is that the flex circuit remains internal to the HDA.
Under this three-connector combination approach the flex circuit connector is mounted to a flex circuit mounting bracket. Then the flex circuit connector connects to the pass-through connector internal to the HDA. Contact between the flex circuit connector and the pass-through connector is maintained by physically securing the flex circuit mounting bracket and the pass-through connector to the basedeck of the disc drive. External to the basedeck the pass-through connector connects to the printed circuit board connector. The printed circuit board connector is mounted to the PCB of the disc drive, and the PCB is then fastened to the basedeck of the disc drive. Attaching the disc drive PCB to the basedeck provides the means of maintaining physical contact between the pass-through connector and the printed circuit board connector.
Another approach of forming the connection is to feed the flex circuit external to the HDA. Typically the flex circuit passes between the basedeck and a gasket mounted on the cover of the disc drive. Once the flex circuit is external to the HDA, the flex circuit commonly mates with an edge connector that is soldered to the PCB of the disc drive. The disadvantages of this external feed approach are exposure of the flex circuit to handling damage during the assembly process; in field applications; and difficulties encountered in automated production processes. The production difficulties tend to arise when trying to locate, secure and connect the non-rigid flex circuit via automated means.
Normally, under this external feed approach, the flex circuit is secured to an alignment member which lends support to the flex circuit and provides a means to maintain registration of the contact pads of the flex circuit in relation to female connector pins of a connector soldered to the PCB. The PCB of the disc drive is then fastened to the disc drive's basedeck to maintain stability of the connection. An example of an adaptation of this approach is disclosed by U.S. Pat. No. 5,403,202 issued to Donald P. Roehling (Roehling '202).
As is known in the art, quality, space constraints, mass production requirements, component costs and component performance (for both mechanical and electrical characteristics) are key factors that influence the choice of an interconnection solution to facilitate connection between the flex circuit and the disc drive PCB.
It is evident from the Roehling '202 disclosure the prominent key factor driving the signal interconnection selection was the space constraint challenges presented by disc drives of the 1.3 form factor.
In contrast to the Roehling '202 approach, the three-connector combination approach was driven by the desire to minimize the exposure of the flex circuit to handling and use damage while maximizing the interconnect configuration for automation. Under the three-connector combination approach the flex circuit is confined internal to the HDA of the disc drive, resolving the problem of exposing the flex circuit to handling and environmental damage, while use of the pass-through male pinned connector promotes ease of production.
Advancements in bit transfer rate technologies, with transfer rates in the range of one gigabit per second and the resultant pico-second range rise and fall signal time, has driven the interconnection electrical performance characteristics of the connection as the key factor of read/write signal management. Parasitic electrical signal degradation, due to changes in inductance and capacitance per unit length along the signal path, begin to dominate as the key electrical performance factor to be addressed by read/write signal interconnection technology as bit transfer rates approach the gigabit per second range.
The signal management burdens within read/write signal interconnection technology, brought about by the emergence of transfer rates in the gigabit per second range, coupled with the remaining key factors of quality, mechanical performance, space constraints, automation considerations and component costs, have collectively converged to generate an unmet need in the industry for an improved flex-to-PCB connector that minimizes the parasitic electrical signal degradation effects created by changes in inductance per unit length
Cox Alvin E.
Dakroub Housan
Eckerd Steven S.
Abrams Neil
Crowe & Dunlevy
Seagate Technology LLC
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